On 07/21/2016 10:14 AM, Songjun Wu wrote:
> Add driver for the Image Sensor Controller. It manages
> incoming data from a parallel based CMOS/CCD sensor.
> It has an internal image processor, also integrates a
> triple channel direct memory access controller master
> interface.
> 
> Signed-off-by: Songjun Wu <songjun...@microchip.com>
> ---
> 
> Changes in v6: None
> Changes in v5:
> - Modify the macro definition and the related code.
> 
> Changes in v4:
> - Modify the isc clock code since the dt is changed.
> 
> Changes in v3:
> - Add pm runtime feature.
> - Modify the isc clock code since the dt is changed.
> 
> Changes in v2:
> - Add "depends on COMMON_CLK" and "VIDEO_V4L2_SUBDEV_API"
>   in Kconfig file.
> - Correct typos and coding style according to Laurent's remarks
> - Delete the loop while in 'isc_clk_enable' function.
> - Replace 'hsync_active', 'vsync_active' and 'pclk_sample'
>   with 'pfe_cfg0' in struct isc_subdev_entity.
> - Add the code to support VIDIOC_CREATE_BUFS in
>   'isc_queue_setup' function.
> - Invoke isc_config to configure register in
>   'isc_start_streaming' function.
> - Add the struct completion 'comp' to synchronize with
>   the frame end interrupt in 'isc_stop_streaming' function.
> - Check the return value of the clk_prepare_enable
>   in 'isc_open' function.
> - Set the default format in 'isc_open' function.
> - Add an exit condition in the loop while in 'isc_config'.
> - Delete the hardware setup operation in 'isc_set_format'.
> - Refuse format modification during streaming
>   in 'isc_s_fmt_vid_cap' function.
> - Invoke v4l2_subdev_alloc_pad_config to allocate and
>   initialize the pad config in 'isc_async_complete' function.
> - Remove the '.owner  = THIS_MODULE,' in atmel_isc_driver.
> - Replace the module_platform_driver_probe() with
>   module_platform_driver().
> 
>  drivers/media/platform/Kconfig                |    1 +
>  drivers/media/platform/Makefile               |    2 +
>  drivers/media/platform/atmel/Kconfig          |    9 +
>  drivers/media/platform/atmel/Makefile         |    1 +
>  drivers/media/platform/atmel/atmel-isc-regs.h |  165 +++
>  drivers/media/platform/atmel/atmel-isc.c      | 1554 
> +++++++++++++++++++++++++
>  6 files changed, 1732 insertions(+)
>  create mode 100644 drivers/media/platform/atmel/Kconfig
>  create mode 100644 drivers/media/platform/atmel/Makefile
>  create mode 100644 drivers/media/platform/atmel/atmel-isc-regs.h
>  create mode 100644 drivers/media/platform/atmel/atmel-isc.c
> 
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index f25344b..b23db17 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -111,6 +111,7 @@ source "drivers/media/platform/s5p-tv/Kconfig"
>  source "drivers/media/platform/am437x/Kconfig"
>  source "drivers/media/platform/xilinx/Kconfig"
>  source "drivers/media/platform/rcar-vin/Kconfig"
> +source "drivers/media/platform/atmel/Kconfig"
>  
>  config VIDEO_TI_CAL
>       tristate "TI CAL (Camera Adaptation Layer) driver"
> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
> index 21771c1..37b6c75 100644
> --- a/drivers/media/platform/Makefile
> +++ b/drivers/media/platform/Makefile
> @@ -58,6 +58,8 @@ obj-$(CONFIG_VIDEO_XILINX)          += xilinx/
>  
>  obj-$(CONFIG_VIDEO_RCAR_VIN)         += rcar-vin/
>  
> +obj-$(CONFIG_VIDEO_ATMEL_ISC)                += atmel/
> +
>  ccflags-y += -I$(srctree)/drivers/media/i2c
>  
>  obj-$(CONFIG_VIDEO_MEDIATEK_VPU)     += mtk-vpu/
> diff --git a/drivers/media/platform/atmel/Kconfig 
> b/drivers/media/platform/atmel/Kconfig
> new file mode 100644
> index 0000000..867dca2
> --- /dev/null
> +++ b/drivers/media/platform/atmel/Kconfig
> @@ -0,0 +1,9 @@
> +config VIDEO_ATMEL_ISC
> +     tristate "ATMEL Image Sensor Controller (ISC) support"
> +     depends on VIDEO_V4L2 && COMMON_CLK && VIDEO_V4L2_SUBDEV_API && HAS_DMA
> +     depends on ARCH_AT91 || COMPILE_TEST
> +     select VIDEOBUF2_DMA_CONTIG
> +     select REGMAP_MMIO
> +     help
> +        This module makes the ATMEL Image Sensor Controller available
> +        as a v4l2 device.
> \ No newline at end of file
> diff --git a/drivers/media/platform/atmel/Makefile 
> b/drivers/media/platform/atmel/Makefile
> new file mode 100644
> index 0000000..9d7c999
> --- /dev/null
> +++ b/drivers/media/platform/atmel/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_VIDEO_ATMEL_ISC) += atmel-isc.o
> diff --git a/drivers/media/platform/atmel/atmel-isc-regs.h 
> b/drivers/media/platform/atmel/atmel-isc-regs.h
> new file mode 100644
> index 0000000..00c4497
> --- /dev/null
> +++ b/drivers/media/platform/atmel/atmel-isc-regs.h
> @@ -0,0 +1,165 @@
> +#ifndef __ATMEL_ISC_REGS_H
> +#define __ATMEL_ISC_REGS_H
> +
> +#include <linux/bitops.h>
> +
> +/* ISC Control Enable Register 0 */
> +#define ISC_CTRLEN      0x00000000
> +
> +/* ISC Control Disable Register 0 */
> +#define ISC_CTRLDIS     0x00000004
> +
> +/* ISC Control Status Register 0 */
> +#define ISC_CTRLSR      0x00000008
> +
> +#define ISC_CTRL_CAPTURE     BIT(0)
> +#define ISC_CTRL_UPPRO               BIT(1)
> +#define ISC_CTRL_HISREQ              BIT(2)
> +#define ISC_CTRL_HISCLR              BIT(3)
> +
> +/* ISC Parallel Front End Configuration 0 Register */
> +#define ISC_PFE_CFG0    0x0000000c
> +
> +#define ISC_PFE_CFG0_HPOL_LOW   BIT(0)
> +#define ISC_PFE_CFG0_VPOL_LOW   BIT(1)
> +#define ISC_PFE_CFG0_PPOL_LOW   BIT(2)
> +
> +#define ISC_PFE_CFG0_MODE_PROGRESSIVE   (0x0 << 4)
> +#define ISC_PFE_CFG0_MODE_MASK          GENMASK(6, 4)
> +
> +#define ISC_PFE_CFG0_BPS_EIGHT  (0x4 << 28)
> +#define ISC_PFG_CFG0_BPS_NINE   (0x3 << 28)
> +#define ISC_PFG_CFG0_BPS_TEN    (0x2 << 28)
> +#define ISC_PFG_CFG0_BPS_ELEVEN (0x1 << 28)
> +#define ISC_PFG_CFG0_BPS_TWELVE (0x0 << 28)
> +#define ISC_PFE_CFG0_BPS_MASK   GENMASK(30, 28)
> +
> +/* ISC Clock Enable Register */
> +#define ISC_CLKEN               0x00000018
> +
> +/* ISC Clock Disable Register */
> +#define ISC_CLKDIS              0x0000001c
> +
> +/* ISC Clock Status Register */
> +#define ISC_CLKSR               0x00000020
> +
> +#define ISC_CLK(n)           BIT(n)
> +
> +/* ISC Clock Configuration Register */
> +#define ISC_CLKCFG              0x00000024
> +#define ISC_CLKCFG_DIV_SHIFT(n) ((n)*16)
> +#define ISC_CLKCFG_DIV_MASK(n)  GENMASK(((n)*16 + 7), (n)*16)
> +#define ISC_CLKCFG_SEL_SHIFT(n) ((n)*16 + 8)
> +#define ISC_CLKCFG_SEL_MASK(n)  GENMASK(((n)*17 + 8), ((n)*16 + 8))
> +
> +/* ISC Interrupt Enable Register */
> +#define ISC_INTEN       0x00000028
> +
> +/* ISC Interrupt Disable Register */
> +#define ISC_INTDIS      0x0000002c
> +
> +/* ISC Interrupt Mask Register */
> +#define ISC_INTMASK     0x00000030
> +
> +/* ISC Interrupt Status Register */
> +#define ISC_INTSR       0x00000034
> +
> +#define ISC_INT_DDONE                BIT(8)
> +
> +/* ISC White Balance Control Register */
> +#define ISC_WB_CTRL     0x00000058
> +
> +/* ISC White Balance Configuration Register */
> +#define ISC_WB_CFG      0x0000005c
> +
> +/* ISC Color Filter Array Control Register */
> +#define ISC_CFA_CTRL    0x00000070
> +
> +/* ISC Color Filter Array Configuration Register */
> +#define ISC_CFA_CFG     0x00000074
> +
> +#define ISC_BAY_CFG_GRGR     0x0
> +#define ISC_BAY_CFG_RGRG     0x1
> +#define ISC_BAY_CFG_GBGB     0x2
> +#define ISC_BAY_CFG_BGBG     0x3
> +#define ISC_BAY_CFG_MASK     GENMASK(1, 0)
> +
> +/* ISC Color Correction Control Register */
> +#define ISC_CC_CTRL     0x00000078
> +
> +/* ISC Gamma Correction Control Register */
> +#define ISC_GAM_CTRL    0x00000094
> +
> +/* Color Space Conversion Control Register */
> +#define ISC_CSC_CTRL    0x00000398
> +
> +/* Contrast And Brightness Control Register */
> +#define ISC_CBC_CTRL    0x000003b4
> +
> +/* Subsampling 4:4:4 to 4:2:2 Control Register */
> +#define ISC_SUB422_CTRL 0x000003c4
> +
> +/* Subsampling 4:2:2 to 4:2:0 Control Register */
> +#define ISC_SUB420_CTRL 0x000003cc
> +
> +/* Rounding, Limiting and Packing Configuration Register */
> +#define ISC_RLP_CFG     0x000003d0
> +
> +#define ISC_RLP_CFG_MODE_DAT8           0x0
> +#define ISC_RLP_CFG_MODE_DAT9           0x1
> +#define ISC_RLP_CFG_MODE_DAT10          0x2
> +#define ISC_RLP_CFG_MODE_DAT11          0x3
> +#define ISC_RLP_CFG_MODE_DAT12          0x4
> +#define ISC_RLP_CFG_MODE_DATY8          0x5
> +#define ISC_RLP_CFG_MODE_DATY10         0x6
> +#define ISC_RLP_CFG_MODE_ARGB444        0x7
> +#define ISC_RLP_CFG_MODE_ARGB555        0x8
> +#define ISC_RLP_CFG_MODE_RGB565         0x9
> +#define ISC_RLP_CFG_MODE_ARGB32         0xa
> +#define ISC_RLP_CFG_MODE_YYCC           0xb
> +#define ISC_RLP_CFG_MODE_YYCC_LIMITED   0xc
> +#define ISC_RLP_CFG_MODE_MASK           GENMASK(3, 0)
> +
> +/* DMA Configuration Register */
> +#define ISC_DCFG        0x000003e0
> +#define ISC_DCFG_IMODE_PACKED8          0x0
> +#define ISC_DCFG_IMODE_PACKED16         0x1
> +#define ISC_DCFG_IMODE_PACKED32         0x2
> +#define ISC_DCFG_IMODE_YC422SP          0x3
> +#define ISC_DCFG_IMODE_YC422P           0x4
> +#define ISC_DCFG_IMODE_YC420SP          0x5
> +#define ISC_DCFG_IMODE_YC420P           0x6
> +#define ISC_DCFG_IMODE_MASK             GENMASK(2, 0)
> +
> +#define ISC_DCFG_YMBSIZE_SINGLE         (0x0 << 4)
> +#define ISC_DCFG_YMBSIZE_BEATS4         (0x1 << 4)
> +#define ISC_DCFG_YMBSIZE_BEATS8         (0x2 << 4)
> +#define ISC_DCFG_YMBSIZE_BEATS16        (0x3 << 4)
> +#define ISC_DCFG_YMBSIZE_MASK           GENMASK(5, 4)
> +
> +#define ISC_DCFG_CMBSIZE_SINGLE         (0x0 << 8)
> +#define ISC_DCFG_CMBSIZE_BEATS4         (0x1 << 8)
> +#define ISC_DCFG_CMBSIZE_BEATS8         (0x2 << 8)
> +#define ISC_DCFG_CMBSIZE_BEATS16        (0x3 << 8)
> +#define ISC_DCFG_CMBSIZE_MASK           GENMASK(9, 8)
> +
> +/* DMA Control Register */
> +#define ISC_DCTRL       0x000003e4
> +
> +#define ISC_DCTRL_DVIEW_PACKED          (0x0 << 1)
> +#define ISC_DCTRL_DVIEW_SEMIPLANAR      (0x1 << 1)
> +#define ISC_DCTRL_DVIEW_PLANAR          (0x2 << 1)
> +#define ISC_DCTRL_DVIEW_MASK            GENMASK(2, 1)
> +
> +#define ISC_DCTRL_IE_IS                      (0x0 << 4)
> +
> +/* DMA Descriptor Address Register */
> +#define ISC_DNDA        0x000003e8
> +
> +/* DMA Address 0 Register */
> +#define ISC_DAD0        0x000003ec
> +
> +/* DMA Stride 0 Register */
> +#define ISC_DST0        0x000003f0
> +
> +#endif
> diff --git a/drivers/media/platform/atmel/atmel-isc.c 
> b/drivers/media/platform/atmel/atmel-isc.c
> new file mode 100644
> index 0000000..03bebfd
> --- /dev/null
> +++ b/drivers/media/platform/atmel/atmel-isc.c
> @@ -0,0 +1,1554 @@
> +/*
> + * Atmel Image Sensor Controller (ISC) driver
> + *
> + * Copyright (C) 2016 Atmel
> + *
> + * Author: Songjun Wu <songjun...@microchip.com>
> + *
> + * This program is free software; you may redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; version 2 of the License.
> + *
> + * Sensor-->PFE-->WB-->CFA-->CC-->GAM-->CSC-->CBC-->SUB-->RLP-->DMA
> + *
> + * ISC video pipeline integrates the following submodules:
> + * PFE: Parallel Front End to sample the camera sensor input stream
> + *  WB: Programmable white balance in the Bayer domain
> + * CFA: Color filter array interpolation module
> + *  CC: Programmable color correction
> + * GAM: Gamma correction
> + * CSC: Programmable color space conversion
> + * CBC: Contrast and Brightness control
> + * SUB: This module performs YCbCr444 to YCbCr420 chrominance subsampling
> + * RLP: This module performs rounding, range limiting
> + *      and packing of the incoming data
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk-provider.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/videodev2.h>
> +
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-image-sizes.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/v4l2-of.h>
> +#include <media/v4l2-subdev.h>
> +#include <media/videobuf2-dma-contig.h>
> +
> +#include "atmel-isc-regs.h"
> +
> +#define ATMEL_ISC_NAME               "atmel_isc"
> +
> +#define ISC_MAX_SUPPORT_WIDTH   2592
> +#define ISC_MAX_SUPPORT_HEIGHT  1944
> +
> +#define ISC_CLK_MAX_DIV              255
> +
> +enum isc_clk_id {
> +     ISC_ISPCK = 0,
> +     ISC_MCK = 1,
> +};
> +
> +struct isc_clk {
> +     struct clk_hw   hw;
> +     struct clk      *clk;
> +     struct regmap   *regmap;
> +     u8              id;
> +     u8              parent_id;
> +     u32             div;
> +     struct device   *dev;
> +};
> +
> +#define to_isc_clk(hw) container_of(hw, struct isc_clk, hw)
> +
> +struct isc_buffer {
> +     struct vb2_v4l2_buffer  vb;
> +     struct list_head        list;
> +};
> +
> +struct isc_subdev_entity {
> +     struct v4l2_subdev              *sd;
> +     struct v4l2_async_subdev        *asd;
> +     struct v4l2_async_notifier      notifier;
> +     struct v4l2_subdev_pad_config   *config;
> +
> +     u32 pfe_cfg0;
> +
> +     struct list_head list;
> +};
> +
> +/*
> + * struct isc_format - ISC media bus format information
> + * @fourcc:          Fourcc code for this format
> + * @isc_mbus_code:      V4L2 media bus format code if ISC is preferred
> + * @sd_mbus_code:       V4L2 media bus format code if subdev is preferred
> + * @bpp:             Bytes per pixel (when stored in memory)
> + * @reg_sd_bps:              reg value for bits per sample if subdev is 
> preferred
> + *                   (when transferred over a bus)
> + * @reg_isc_bps:     reg value for bits per sample if ISC is preferred
> + *                   (when transferred over a bus)
> + * @pipeline:                pipeline switch if ISC is preferred
> + * @isc_support:     ISC can convert raw format to this format
> + * @sd_support:              Subdev supports this format
> + */
> +struct isc_format {
> +     u32     fourcc;
> +     u32     isc_mbus_code;
> +     u32     sd_mbus_code;
> +
> +     u8      bpp;
> +
> +     u32     reg_sd_bps;
> +     u32     reg_isc_bps;
> +
> +     u32     reg_bay_cfg;
> +     u32     reg_rlp_mode;
> +     u32     reg_dcfg_imode;
> +     u32     reg_dctrl_dview;
> +
> +     u32     pipeline;
> +
> +     bool    isc_support;
> +     bool    sd_support;
> +};
> +
> +#define ISC_PIPE_LINE_NODE_NUM       11
> +
> +struct isc_device {
> +     struct regmap           *regmap;
> +     struct clk              *hclock;
> +     struct clk              *ispck;
> +     struct isc_clk          isc_clks[2];
> +
> +     struct device           *dev;
> +     struct v4l2_device      v4l2_dev;
> +     struct video_device     video_dev;
> +
> +     struct vb2_queue        vb2_vidq;
> +     spinlock_t              dma_queue_lock;
> +     struct list_head        dma_queue;
> +     struct isc_buffer       *cur_frm;
> +     unsigned int            sequence;
> +     bool                    stop;
> +     struct completion       comp;
> +
> +     struct v4l2_format      fmt;
> +     struct isc_format       **user_formats;
> +     unsigned int            num_user_formats;
> +     const struct isc_format *current_fmt;
> +
> +     struct mutex            lock;
> +
> +     struct regmap_field     *pipeline[ISC_PIPE_LINE_NODE_NUM];
> +
> +     struct isc_subdev_entity        *current_subdev;
> +     struct list_head                subdev_entities;
> +};
> +
> +static unsigned int sensor_preferred = 1;
> +module_param(sensor_preferred, uint, S_IRUGO|S_IWUSR);
> +MODULE_PARM_DESC(sensor_preferred,
> +              "Sensor is preferred to output the specified format (1-on 
> 0-off) default 1");
> +
> +#define RAW_FMT_INDEX_START  0
> +#define RAW_FMT_INDEX_END    11
> +#define ISC_FMT_INDEX_START  12
> +#define ISC_FMT_INDEX_END    12
> +
> +/*
> + * index(0~11):  raw formats.
> + * index(12~12): the formats which can be converted from raw format by ISC.
> + * index():      the formats which can only be provided by subdev.
> + */
> +static struct isc_format isc_formats[] = {

static const

> +     { V4L2_PIX_FMT_SBGGR8, MEDIA_BUS_FMT_SBGGR8_1X8,
> +       MEDIA_BUS_FMT_SBGGR8_1X8, 1, ISC_PFE_CFG0_BPS_EIGHT,
> +       ISC_PFE_CFG0_BPS_EIGHT, ISC_BAY_CFG_BGBG,
> +       ISC_RLP_CFG_MODE_DAT8, ISC_DCFG_IMODE_PACKED8,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +     { V4L2_PIX_FMT_SGBRG8, MEDIA_BUS_FMT_SGBRG8_1X8,
> +       MEDIA_BUS_FMT_SGBRG8_1X8, 1, ISC_PFE_CFG0_BPS_EIGHT,
> +       ISC_PFE_CFG0_BPS_EIGHT, ISC_BAY_CFG_GBGB,
> +       ISC_RLP_CFG_MODE_DAT8, ISC_DCFG_IMODE_PACKED8,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +     { V4L2_PIX_FMT_SGRBG8, MEDIA_BUS_FMT_SGRBG8_1X8,
> +       MEDIA_BUS_FMT_SGRBG8_1X8, 1, ISC_PFE_CFG0_BPS_EIGHT,
> +       ISC_PFE_CFG0_BPS_EIGHT, ISC_BAY_CFG_GRGR,
> +       ISC_RLP_CFG_MODE_DAT8, ISC_DCFG_IMODE_PACKED8,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +     { V4L2_PIX_FMT_SRGGB8, MEDIA_BUS_FMT_SRGGB8_1X8,
> +       MEDIA_BUS_FMT_SRGGB8_1X8, 1, ISC_PFE_CFG0_BPS_EIGHT,
> +       ISC_PFE_CFG0_BPS_EIGHT, ISC_BAY_CFG_RGRG,
> +       ISC_RLP_CFG_MODE_DAT8, ISC_DCFG_IMODE_PACKED8,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +
> +     { V4L2_PIX_FMT_SBGGR10, MEDIA_BUS_FMT_SBGGR10_1X10,
> +       MEDIA_BUS_FMT_SBGGR10_1X10, 2, ISC_PFG_CFG0_BPS_TEN,
> +       ISC_PFG_CFG0_BPS_TEN, ISC_BAY_CFG_BGBG,
> +       ISC_RLP_CFG_MODE_DAT10, ISC_DCFG_IMODE_PACKED16,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +     { V4L2_PIX_FMT_SGBRG10, MEDIA_BUS_FMT_SGBRG10_1X10,
> +       MEDIA_BUS_FMT_SGBRG10_1X10, 2, ISC_PFG_CFG0_BPS_TEN,
> +       ISC_PFG_CFG0_BPS_TEN, ISC_BAY_CFG_GBGB,
> +       ISC_RLP_CFG_MODE_DAT10, ISC_DCFG_IMODE_PACKED16,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +     { V4L2_PIX_FMT_SGRBG10, MEDIA_BUS_FMT_SGRBG10_1X10,
> +       MEDIA_BUS_FMT_SGRBG10_1X10, 2, ISC_PFG_CFG0_BPS_TEN,
> +       ISC_PFG_CFG0_BPS_TEN, ISC_BAY_CFG_GRGR,
> +       ISC_RLP_CFG_MODE_DAT10, ISC_DCFG_IMODE_PACKED16,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +     { V4L2_PIX_FMT_SRGGB10, MEDIA_BUS_FMT_SRGGB10_1X10,
> +       MEDIA_BUS_FMT_SRGGB10_1X10, 2, ISC_PFG_CFG0_BPS_TEN,
> +       ISC_PFG_CFG0_BPS_TEN, ISC_BAY_CFG_RGRG,
> +       ISC_RLP_CFG_MODE_DAT10, ISC_DCFG_IMODE_PACKED16,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +
> +     { V4L2_PIX_FMT_SBGGR12, MEDIA_BUS_FMT_SBGGR12_1X12,
> +       MEDIA_BUS_FMT_SBGGR12_1X12, 2, ISC_PFG_CFG0_BPS_TWELVE,
> +       ISC_PFG_CFG0_BPS_TWELVE, ISC_BAY_CFG_BGBG,
> +       ISC_RLP_CFG_MODE_DAT12, ISC_DCFG_IMODE_PACKED16,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +     { V4L2_PIX_FMT_SGBRG12, MEDIA_BUS_FMT_SGBRG12_1X12,
> +       MEDIA_BUS_FMT_SGBRG12_1X12, 2, ISC_PFG_CFG0_BPS_TWELVE,
> +       ISC_PFG_CFG0_BPS_TWELVE, ISC_BAY_CFG_GBGB,
> +       ISC_RLP_CFG_MODE_DAT12, ISC_DCFG_IMODE_PACKED16,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +     { V4L2_PIX_FMT_SGRBG12, MEDIA_BUS_FMT_SGRBG12_1X12,
> +       MEDIA_BUS_FMT_SGRBG12_1X12, 2, ISC_PFG_CFG0_BPS_TWELVE,
> +       ISC_PFG_CFG0_BPS_TWELVE, ISC_BAY_CFG_GRGR,
> +       ISC_RLP_CFG_MODE_DAT12, ISC_DCFG_IMODE_PACKED16,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +     { V4L2_PIX_FMT_SRGGB12, MEDIA_BUS_FMT_SRGGB12_1X12,
> +       MEDIA_BUS_FMT_SRGGB12_1X12, 2, ISC_PFG_CFG0_BPS_TWELVE,
> +       ISC_PFG_CFG0_BPS_TWELVE, ISC_BAY_CFG_RGRG,
> +       ISC_RLP_CFG_MODE_DAT12, ISC_DCFG_IMODE_PACKED16,
> +       ISC_DCTRL_DVIEW_PACKED, 0x0, false, false },
> +
> +     { V4L2_PIX_FMT_YUYV, MEDIA_BUS_FMT_YUYV8_2X8,
> +       MEDIA_BUS_FMT_YUYV8_2X8, 2, ISC_PFE_CFG0_BPS_EIGHT,
> +       ISC_PFE_CFG0_BPS_EIGHT, ISC_BAY_CFG_BGBG,
> +       ISC_RLP_CFG_MODE_DAT8, ISC_DCFG_IMODE_PACKED8,
> +       ISC_DCTRL_DVIEW_PACKED, 0x3ff, false, false },
> +};
> +
> +static int isc_clk_enable(struct clk_hw *hw)
> +{
> +     struct isc_clk *isc_clk = to_isc_clk(hw);
> +     u32 id = isc_clk->id;
> +     struct regmap *regmap = isc_clk->regmap;
> +
> +     dev_dbg(isc_clk->dev, "ISC CLK: %s, div = %d, parent id = %d\n",
> +             __func__, isc_clk->div, isc_clk->parent_id);
> +
> +     regmap_update_bits(regmap, ISC_CLKCFG,
> +                        ISC_CLKCFG_DIV_MASK(id) | ISC_CLKCFG_SEL_MASK(id),
> +                        (isc_clk->div << ISC_CLKCFG_DIV_SHIFT(id)) |
> +                        (isc_clk->parent_id << ISC_CLKCFG_SEL_SHIFT(id)));
> +
> +     regmap_write(regmap, ISC_CLKEN, ISC_CLK(id));
> +
> +     return 0;
> +}
> +
> +static void isc_clk_disable(struct clk_hw *hw)
> +{
> +     struct isc_clk *isc_clk = to_isc_clk(hw);
> +     u32 id = isc_clk->id;
> +
> +     regmap_write(isc_clk->regmap, ISC_CLKDIS, ISC_CLK(id));
> +}
> +
> +static int isc_clk_is_enabled(struct clk_hw *hw)
> +{
> +     struct isc_clk *isc_clk = to_isc_clk(hw);
> +     u32 status;
> +
> +     regmap_read(isc_clk->regmap, ISC_CLKSR, &status);
> +
> +     return status & ISC_CLK(isc_clk->id) ? 1 : 0;
> +}
> +
> +static unsigned long
> +isc_clk_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
> +{
> +     struct isc_clk *isc_clk = to_isc_clk(hw);
> +
> +     return DIV_ROUND_CLOSEST(parent_rate, isc_clk->div + 1);
> +}
> +
> +static int isc_clk_determine_rate(struct clk_hw *hw,
> +                                struct clk_rate_request *req)
> +{
> +     struct isc_clk *isc_clk = to_isc_clk(hw);
> +     long best_rate = -EINVAL;
> +     int best_diff = -1;
> +     unsigned int i, div;
> +
> +     for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
> +             struct clk_hw *parent;
> +             unsigned long parent_rate;
> +
> +             parent = clk_hw_get_parent_by_index(hw, i);
> +             if (!parent)
> +                     continue;
> +
> +             parent_rate = clk_hw_get_rate(parent);
> +             if (!parent_rate)
> +                     continue;
> +
> +             for (div = 1; div < ISC_CLK_MAX_DIV + 2; div++) {
> +                     unsigned long rate;
> +                     int diff;
> +
> +                     rate = DIV_ROUND_CLOSEST(parent_rate, div);
> +                     diff = abs(req->rate - rate);
> +
> +                     if (best_diff < 0 || best_diff > diff) {
> +                             best_rate = rate;
> +                             best_diff = diff;
> +                             req->best_parent_rate = parent_rate;
> +                             req->best_parent_hw = parent;
> +                     }
> +
> +                     if (!best_diff || rate < req->rate)
> +                             break;
> +             }
> +
> +             if (!best_diff)
> +                     break;
> +     }
> +
> +     dev_dbg(isc_clk->dev,
> +             "ISC CLK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
> +             __func__, best_rate,
> +             __clk_get_name((req->best_parent_hw)->clk),
> +             req->best_parent_rate);
> +
> +     if (best_rate < 0)
> +             return best_rate;
> +
> +     req->rate = best_rate;
> +
> +     return 0;
> +}
> +
> +static int isc_clk_set_parent(struct clk_hw *hw, u8 index)
> +{
> +     struct isc_clk *isc_clk = to_isc_clk(hw);
> +
> +     if (index >= clk_hw_get_num_parents(hw))
> +             return -EINVAL;
> +
> +     isc_clk->parent_id = index;
> +
> +     return 0;
> +}
> +
> +static u8 isc_clk_get_parent(struct clk_hw *hw)
> +{
> +     struct isc_clk *isc_clk = to_isc_clk(hw);
> +
> +     return isc_clk->parent_id;
> +}
> +
> +static int isc_clk_set_rate(struct clk_hw *hw,
> +                          unsigned long rate,
> +                          unsigned long parent_rate)
> +{
> +     struct isc_clk *isc_clk = to_isc_clk(hw);
> +     u32 div;
> +
> +     if (!rate)
> +             return -EINVAL;
> +
> +     div = DIV_ROUND_CLOSEST(parent_rate, rate);
> +     if (div > (ISC_CLK_MAX_DIV + 1) || !div)
> +             return -EINVAL;
> +
> +     isc_clk->div = div - 1;
> +
> +     return 0;
> +}
> +
> +static const struct clk_ops isc_clk_ops = {
> +     .enable         = isc_clk_enable,
> +     .disable        = isc_clk_disable,
> +     .is_enabled     = isc_clk_is_enabled,
> +     .recalc_rate    = isc_clk_recalc_rate,
> +     .determine_rate = isc_clk_determine_rate,
> +     .set_parent     = isc_clk_set_parent,
> +     .get_parent     = isc_clk_get_parent,
> +     .set_rate       = isc_clk_set_rate,
> +};
> +
> +static int isc_clk_register(struct isc_device *isc, unsigned int id)
> +{
> +     struct regmap *regmap = isc->regmap;
> +     struct device_node *np = isc->dev->of_node;
> +     struct isc_clk *isc_clk;
> +     struct clk_init_data init;
> +     const char *clk_name = np->name;
> +     const char *parent_names[3];
> +     int num_parents;
> +
> +     num_parents = of_clk_get_parent_count(np);
> +     if (num_parents < 1 || num_parents > 3)
> +             return -EINVAL;
> +
> +     if (num_parents > 2 && id == ISC_ISPCK)
> +             num_parents = 2;
> +
> +     of_clk_parent_fill(np, parent_names, num_parents);
> +
> +     if (id == ISC_MCK)
> +             of_property_read_string(np, "clock-output-names", &clk_name);
> +     else
> +             clk_name = "isc-ispck";
> +
> +     init.parent_names       = parent_names;
> +     init.num_parents        = num_parents;
> +     init.name               = clk_name;
> +     init.ops                = &isc_clk_ops;
> +     init.flags              = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
> +
> +     isc_clk = &isc->isc_clks[id];
> +     isc_clk->hw.init        = &init;
> +     isc_clk->regmap         = regmap;
> +     isc_clk->id             = id;
> +     isc_clk->dev            = isc->dev;
> +
> +     isc_clk->clk = clk_register(isc->dev, &isc_clk->hw);
> +     if (IS_ERR(isc_clk->clk)) {
> +             dev_err(isc->dev, "%s: clock register fail\n", clk_name);
> +             return PTR_ERR(isc_clk->clk);
> +     } else if (id == ISC_MCK)
> +             of_clk_add_provider(np, of_clk_src_simple_get, isc_clk->clk);
> +
> +     return 0;
> +}
> +
> +static int isc_clk_init(struct isc_device *isc)
> +{
> +     unsigned int i;
> +     int ret;
> +
> +     for (i = 0; i < ARRAY_SIZE(isc->isc_clks); i++)
> +             isc->isc_clks[i].clk = ERR_PTR(-EINVAL);
> +
> +     for (i = 0; i < ARRAY_SIZE(isc->isc_clks); i++) {
> +             ret = isc_clk_register(isc, i);
> +             if (ret)
> +                     return ret;
> +     }
> +
> +     return 0;
> +}
> +
> +static void isc_clk_cleanup(struct isc_device *isc)
> +{
> +     unsigned int i;
> +
> +     of_clk_del_provider(isc->dev->of_node);
> +
> +     for (i = 0; i < ARRAY_SIZE(isc->isc_clks); i++) {
> +             struct isc_clk *isc_clk = &isc->isc_clks[i];
> +
> +             if (!IS_ERR(isc_clk->clk))
> +                     clk_unregister(isc_clk->clk);
> +     }
> +}
> +
> +static int isc_queue_setup(struct vb2_queue *vq,
> +                         unsigned int *nbuffers, unsigned int *nplanes,
> +                         unsigned int sizes[], struct device *alloc_devs[])
> +{
> +     struct isc_device *isc = vb2_get_drv_priv(vq);
> +     unsigned int size = isc->fmt.fmt.pix.sizeimage;
> +
> +     if (*nplanes)
> +             return sizes[0] < size ? -EINVAL : 0;
> +
> +     *nplanes = 1;
> +     sizes[0] = size;
> +
> +     return 0;
> +}
> +
> +static int isc_buffer_prepare(struct vb2_buffer *vb)
> +{
> +     struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +     struct isc_device *isc = vb2_get_drv_priv(vb->vb2_queue);
> +     unsigned long size = isc->fmt.fmt.pix.sizeimage;
> +
> +     if (vb2_plane_size(vb, 0) < size) {
> +             v4l2_err(&isc->v4l2_dev, "buffer too small (%lu < %lu)\n",
> +                      vb2_plane_size(vb, 0), size);
> +             return -EINVAL;
> +     }
> +
> +     vb2_set_plane_payload(vb, 0, size);
> +
> +     vbuf->field = isc->fmt.fmt.pix.field;
> +
> +     return 0;
> +}
> +
> +static inline void isc_start_dma(struct regmap *regmap,
> +                               struct isc_buffer *frm, u32 dview)
> +{
> +     dma_addr_t addr;
> +
> +     addr = vb2_dma_contig_plane_dma_addr(&frm->vb.vb2_buf, 0);
> +
> +     regmap_write(regmap, ISC_DCTRL, dview | ISC_DCTRL_IE_IS);
> +     regmap_write(regmap, ISC_DAD0, addr);
> +     regmap_write(regmap, ISC_CTRLEN, ISC_CTRL_CAPTURE);
> +}
> +
> +static inline bool sensor_is_preferred(const struct isc_format *isc_fmt)
> +{
> +     if ((sensor_preferred && isc_fmt->sd_support) ||
> +         !isc_fmt->isc_support)
> +             return true;
> +     else
> +             return false;
> +}
> +
> +static void isc_set_pipeline(struct isc_device *isc, u32 pipeline)
> +{
> +     u32 val;
> +     unsigned int i;
> +
> +     for (i = 0; i < ISC_PIPE_LINE_NODE_NUM; i++) {
> +             val = pipeline & BIT(i) ? 1 : 0;
> +             regmap_field_write(isc->pipeline[i], val);
> +     }
> +}
> +
> +static int isc_configure(struct isc_device *isc)
> +{
> +     struct regmap *regmap = isc->regmap;
> +     const struct isc_format *current_fmt = isc->current_fmt;
> +     struct isc_subdev_entity *subdev = isc->current_subdev;
> +     u32 pipeline, val, mask;
> +     int counter = 10;
> +
> +     if (sensor_is_preferred(current_fmt)) {
> +             val = current_fmt->reg_sd_bps;
> +             pipeline = 0x0;
> +     } else {
> +             val = current_fmt->reg_isc_bps;
> +             pipeline = current_fmt->pipeline;
> +
> +             regmap_update_bits(regmap, ISC_WB_CFG, ISC_BAY_CFG_MASK,
> +                                current_fmt->reg_bay_cfg);
> +             regmap_update_bits(regmap, ISC_CFA_CFG, ISC_BAY_CFG_MASK,
> +                                current_fmt->reg_bay_cfg);
> +     }
> +
> +     val |= subdev->pfe_cfg0 | ISC_PFE_CFG0_MODE_PROGRESSIVE;
> +     mask = ISC_PFE_CFG0_BPS_MASK | ISC_PFE_CFG0_HPOL_LOW |
> +            ISC_PFE_CFG0_VPOL_LOW | ISC_PFE_CFG0_PPOL_LOW |
> +            ISC_PFE_CFG0_MODE_MASK;
> +
> +     regmap_update_bits(regmap, ISC_PFE_CFG0, mask, val);
> +
> +     regmap_update_bits(regmap, ISC_RLP_CFG, ISC_RLP_CFG_MODE_MASK,
> +                        current_fmt->reg_rlp_mode);
> +
> +     regmap_update_bits(regmap, ISC_DCFG, ISC_DCFG_IMODE_MASK,
> +                        current_fmt->reg_dcfg_imode);
> +
> +     isc_set_pipeline(isc, pipeline);
> +
> +     /* Update profile */
> +     regmap_write(regmap, ISC_CTRLEN, ISC_CTRL_UPPRO);
> +
> +     regmap_read(regmap, ISC_CTRLSR, &val);
> +     while ((val & ISC_CTRL_UPPRO) && counter--) {
> +             usleep_range(1000, 2000);
> +             regmap_read(regmap, ISC_CTRLSR, &val);
> +     }
> +
> +     if (counter < 0)
> +             return -ETIMEDOUT;
> +
> +     return 0;
> +}
> +
> +static int isc_start_streaming(struct vb2_queue *vq, unsigned int count)
> +{
> +     struct isc_device *isc = vb2_get_drv_priv(vq);
> +     struct regmap *regmap = isc->regmap;
> +     struct isc_buffer *buf;
> +     unsigned long flags;
> +     int ret;
> +     u32 val;
> +
> +     /* Enable stream on the sub device */
> +     ret = v4l2_subdev_call(isc->current_subdev->sd, video, s_stream, 1);
> +     if (ret && ret != -ENOIOCTLCMD) {
> +             v4l2_err(&isc->v4l2_dev, "stream on failed in subdev\n");
> +             goto err;
> +     }
> +
> +     pm_runtime_get_sync(isc->dev);
> +
> +     /* Disable all the interrupts */
> +     regmap_write(isc->regmap, ISC_INTDIS, (u32)~0UL);
> +
> +     /* Clean the interrupt status register */
> +     regmap_read(regmap, ISC_INTSR, &val);
> +
> +     ret = isc_configure(isc);
> +     if (unlikely(ret))
> +             goto err;

You need to call s_stream(0) in this error path.

> +
> +     /* Enable DMA interrupt */
> +     regmap_write(regmap, ISC_INTEN, ISC_INT_DDONE);
> +
> +     spin_lock_irqsave(&isc->dma_queue_lock, flags);
> +
> +     isc->sequence = 0;
> +     isc->stop = false;
> +     reinit_completion(&isc->comp);
> +
> +     isc->cur_frm = list_first_entry(&isc->dma_queue,
> +                                     struct isc_buffer, list);
> +     list_del(&isc->cur_frm->list);
> +
> +     isc_start_dma(regmap, isc->cur_frm, isc->current_fmt->reg_dctrl_dview);
> +
> +     spin_unlock_irqrestore(&isc->dma_queue_lock, flags);
> +
> +     return 0;
> +
> +err:
> +     pm_runtime_put_sync(isc->dev);
> +
> +     spin_lock_irqsave(&isc->dma_queue_lock, flags);
> +     list_for_each_entry(buf, &isc->dma_queue, list)
> +             vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_QUEUED);
> +     INIT_LIST_HEAD(&isc->dma_queue);
> +     spin_unlock_irqrestore(&isc->dma_queue_lock, flags);
> +
> +     return ret;
> +}
> +
> +static void isc_stop_streaming(struct vb2_queue *vq)
> +{
> +     struct isc_device *isc = vb2_get_drv_priv(vq);
> +     unsigned long flags;
> +     struct isc_buffer *buf;
> +     int ret;
> +
> +     isc->stop = true;
> +
> +     /* Wait until the end of the current frame */
> +     if (isc->cur_frm && !wait_for_completion_timeout(&isc->comp, 5 * HZ))
> +             v4l2_err(&isc->v4l2_dev,
> +                      "Timeout waiting for end of the capture\n");
> +
> +     /* Disable DMA interrupt */
> +     regmap_write(isc->regmap, ISC_INTDIS, ISC_INT_DDONE);
> +
> +     pm_runtime_put_sync(isc->dev);
> +
> +     /* Disable stream on the sub device */
> +     ret = v4l2_subdev_call(isc->current_subdev->sd, video, s_stream, 0);
> +     if (ret && ret != -ENOIOCTLCMD)
> +             v4l2_err(&isc->v4l2_dev, "stream off failed in subdev\n");
> +
> +     /* Release all active buffers */
> +     spin_lock_irqsave(&isc->dma_queue_lock, flags);
> +     if (unlikely(isc->cur_frm)) {
> +             vb2_buffer_done(&isc->cur_frm->vb.vb2_buf,
> +                             VB2_BUF_STATE_ERROR);
> +             isc->cur_frm = NULL;
> +     }
> +     list_for_each_entry(buf, &isc->dma_queue, list)
> +             vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
> +     INIT_LIST_HEAD(&isc->dma_queue);
> +     spin_unlock_irqrestore(&isc->dma_queue_lock, flags);
> +}
> +
> +static void isc_buffer_queue(struct vb2_buffer *vb)
> +{
> +     struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +     struct isc_buffer *buf = container_of(vbuf, struct isc_buffer, vb);
> +     struct isc_device *isc = vb2_get_drv_priv(vb->vb2_queue);
> +     unsigned long flags;
> +
> +     spin_lock_irqsave(&isc->dma_queue_lock, flags);
> +     list_add_tail(&buf->list, &isc->dma_queue);
> +     spin_unlock_irqrestore(&isc->dma_queue_lock, flags);
> +}
> +
> +static struct vb2_ops isc_vb2_ops = {
> +     .queue_setup            = isc_queue_setup,
> +     .wait_prepare           = vb2_ops_wait_prepare,
> +     .wait_finish            = vb2_ops_wait_finish,
> +     .buf_prepare            = isc_buffer_prepare,
> +     .start_streaming        = isc_start_streaming,
> +     .stop_streaming         = isc_stop_streaming,
> +     .buf_queue              = isc_buffer_queue,
> +};
> +
> +static int isc_querycap(struct file *file, void *priv,
> +                      struct v4l2_capability *cap)
> +{
> +     struct isc_device *isc = video_drvdata(file);
> +
> +     strcpy(cap->driver, ATMEL_ISC_NAME);
> +     strcpy(cap->card, "Atmel Image Sensor Controller");
> +     snprintf(cap->bus_info, sizeof(cap->bus_info),
> +              "platform:%s", isc->v4l2_dev.name);
> +
> +     cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
> +     cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;

Fill in the device_caps field of struct video_device. After that you can drop
these two fields. The v4l2 core will fill them in for you.

> +
> +     return 0;
> +}
> +
> +static int isc_enum_fmt_vid_cap(struct file *file, void *priv,
> +                              struct v4l2_fmtdesc *f)
> +{
> +     struct isc_device *isc = video_drvdata(file);
> +     u32 index = f->index;
> +
> +     if (index >= isc->num_user_formats)
> +             return -EINVAL;
> +
> +     f->pixelformat = isc->user_formats[index]->fourcc;
> +
> +     return 0;
> +}
> +
> +static int isc_g_fmt_vid_cap(struct file *file, void *priv,
> +                           struct v4l2_format *fmt)
> +{
> +     struct isc_device *isc = video_drvdata(file);
> +
> +     *fmt = isc->fmt;
> +
> +     return 0;
> +}
> +
> +static struct isc_format *find_format_by_fourcc(struct isc_device *isc,
> +                                              unsigned int fourcc)
> +{
> +     unsigned int num_formats = isc->num_user_formats;
> +     struct isc_format *fmt;
> +     unsigned int i;
> +
> +     for (i = 0; i < num_formats; i++) {
> +             fmt = isc->user_formats[i];
> +             if (fmt->fourcc == fourcc)
> +                     return fmt;
> +     }
> +
> +     return NULL;
> +}
> +
> +static int isc_try_fmt(struct isc_device *isc, struct v4l2_format *f,
> +                     struct isc_format **current_fmt, u32 *code)
> +{
> +     struct isc_format *isc_fmt;
> +     struct v4l2_pix_format *pixfmt = &f->fmt.pix;
> +     struct v4l2_subdev_format format = {
> +             .which = V4L2_SUBDEV_FORMAT_TRY,
> +     };
> +     u32 mbus_code;
> +     int ret;
> +
> +     if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +             return -EINVAL;
> +
> +     isc_fmt = find_format_by_fourcc(isc, pixfmt->pixelformat);
> +     if (!isc_fmt) {
> +             v4l2_warn(&isc->v4l2_dev, "Format 0x%x not found\n",
> +                       pixfmt->pixelformat);
> +             isc_fmt = isc->user_formats[isc->num_user_formats - 1];
> +             pixfmt->pixelformat = isc_fmt->fourcc;
> +     }
> +
> +     /* Limit to Atmel ISC hardware capabilities */
> +     if (pixfmt->width > ISC_MAX_SUPPORT_WIDTH)
> +             pixfmt->width = ISC_MAX_SUPPORT_WIDTH;
> +     if (pixfmt->height > ISC_MAX_SUPPORT_HEIGHT)
> +             pixfmt->height = ISC_MAX_SUPPORT_HEIGHT;
> +
> +     if (sensor_is_preferred(isc_fmt))
> +             mbus_code = isc_fmt->sd_mbus_code;
> +     else
> +             mbus_code = isc_fmt->isc_mbus_code;
> +
> +     v4l2_fill_mbus_format(&format.format, pixfmt, mbus_code);
> +     ret = v4l2_subdev_call(isc->current_subdev->sd, pad, set_fmt,
> +                            isc->current_subdev->config, &format);
> +     if (ret < 0)
> +             return ret;
> +
> +     v4l2_fill_pix_format(pixfmt, &format.format);
> +
> +     switch (pixfmt->field) {
> +     case V4L2_FIELD_ANY:
> +     case V4L2_FIELD_NONE:
> +             break;
> +     default:
> +             v4l2_err(&isc->v4l2_dev, "Field type %d unsupported.\n",
> +                      pixfmt->field);
> +             return -EINVAL;
> +     }

Just set field to FIELD_NONE directly. try_fmt is not allowed to fail on wrong
field values, it should silently correct them. Since you only support 
FIELD_NONE,
just set it to FIELD_NONE.

> +
> +     pixfmt->bytesperline = pixfmt->width * isc_fmt->bpp;
> +     pixfmt->sizeimage = pixfmt->bytesperline * pixfmt->height;
> +
> +     if (current_fmt)
> +             *current_fmt = isc_fmt;
> +
> +     if (code)
> +             *code = mbus_code;
> +
> +     return 0;
> +}
> +
> +static int isc_set_fmt(struct isc_device *isc, struct v4l2_format *f)
> +{
> +     struct v4l2_subdev_format format = {
> +             .which = V4L2_SUBDEV_FORMAT_ACTIVE,
> +     };
> +     struct isc_format *current_fmt;
> +     int ret;
> +     u32 mbus_code;
> +
> +     ret = isc_try_fmt(isc, f, &current_fmt, &mbus_code);
> +     if (ret)
> +             return ret;
> +
> +     v4l2_fill_mbus_format(&format.format, &f->fmt.pix, mbus_code);
> +     ret = v4l2_subdev_call(isc->current_subdev->sd, pad,
> +                            set_fmt, NULL, &format);
> +     if (ret < 0)
> +             return ret;
> +
> +     isc->fmt = *f;
> +     isc->current_fmt = current_fmt;
> +
> +     return 0;
> +}
> +
> +static int isc_s_fmt_vid_cap(struct file *file, void *priv,
> +                           struct v4l2_format *f)
> +{
> +     struct isc_device *isc = video_drvdata(file);
> +
> +     if (vb2_is_streaming(&isc->vb2_vidq))
> +             return -EBUSY;
> +
> +     return isc_set_fmt(isc, f);
> +}
> +
> +static int isc_try_fmt_vid_cap(struct file *file, void *priv,
> +                             struct v4l2_format *f)
> +{
> +     struct isc_device *isc = video_drvdata(file);
> +
> +     return isc_try_fmt(isc, f, NULL, NULL);
> +}
> +
> +static int isc_enum_input(struct file *file, void *priv,
> +                        struct v4l2_input *inp)
> +{
> +     if (inp->index != 0)
> +             return -EINVAL;
> +
> +     inp->type = V4L2_INPUT_TYPE_CAMERA;
> +     inp->std = 0;
> +     strcpy(inp->name, "Camera");
> +
> +     return 0;
> +}
> +
> +static int isc_g_input(struct file *file, void *priv, unsigned int *i)
> +{
> +     *i = 0;
> +
> +     return 0;
> +}
> +
> +static int isc_s_input(struct file *file, void *priv, unsigned int i)
> +{
> +     if (i > 0)
> +             return -EINVAL;
> +
> +     return 0;
> +}
> +
> +static int isc_g_parm(struct file *file, void *fh, struct v4l2_streamparm *a)
> +{
> +     struct isc_device *isc = video_drvdata(file);
> +     int ret;
> +
> +     if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +             return -EINVAL;
> +
> +     ret = v4l2_subdev_call(isc->current_subdev->sd, video, g_parm, a);
> +     if (ret == -ENOIOCTLCMD)
> +             ret = 0;

If there is no g/s_parm, then this ioctl should be disabled. See my comment 
later on.

> +
> +     return ret;
> +}
> +
> +static int isc_s_parm(struct file *file, void *fh, struct v4l2_streamparm *a)
> +{
> +     struct isc_device *isc = video_drvdata(file);
> +     int ret;
> +
> +     if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +             return -EINVAL;
> +
> +     ret = v4l2_subdev_call(isc->current_subdev->sd, video, s_parm, a);
> +     if (ret == -ENOIOCTLCMD)
> +             ret = 0;
> +
> +     return ret;
> +}
> +
> +static const struct v4l2_ioctl_ops isc_ioctl_ops = {
> +     .vidioc_querycap                = isc_querycap,
> +     .vidioc_enum_fmt_vid_cap        = isc_enum_fmt_vid_cap,
> +     .vidioc_g_fmt_vid_cap           = isc_g_fmt_vid_cap,
> +     .vidioc_s_fmt_vid_cap           = isc_s_fmt_vid_cap,
> +     .vidioc_try_fmt_vid_cap         = isc_try_fmt_vid_cap,
> +
> +     .vidioc_enum_input              = isc_enum_input,
> +     .vidioc_g_input                 = isc_g_input,
> +     .vidioc_s_input                 = isc_s_input,
> +
> +     .vidioc_reqbufs                 = vb2_ioctl_reqbufs,
> +     .vidioc_querybuf                = vb2_ioctl_querybuf,
> +     .vidioc_qbuf                    = vb2_ioctl_qbuf,
> +     .vidioc_expbuf                  = vb2_ioctl_expbuf,
> +     .vidioc_dqbuf                   = vb2_ioctl_dqbuf,
> +     .vidioc_create_bufs             = vb2_ioctl_create_bufs,
> +     .vidioc_prepare_buf             = vb2_ioctl_prepare_buf,
> +     .vidioc_streamon                = vb2_ioctl_streamon,
> +     .vidioc_streamoff               = vb2_ioctl_streamoff,
> +
> +     .vidioc_g_parm                  = isc_g_parm,
> +     .vidioc_s_parm                  = isc_s_parm,
> +};
> +
> +static int isc_set_default_fmt(struct isc_device *isc)
> +{
> +     u32 index = isc->num_user_formats - 1;
> +     struct v4l2_format f = {
> +             .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
> +             .fmt.pix = {
> +                     .width          = VGA_WIDTH,
> +                     .height         = VGA_HEIGHT,
> +                     .field          = V4L2_FIELD_ANY,
> +                     .pixelformat    = isc->user_formats[index]->fourcc,
> +             },
> +     };
> +
> +     return isc_set_fmt(isc, &f);
> +}
> +
> +static int isc_open(struct file *file)
> +{
> +     struct isc_device *isc = video_drvdata(file);
> +     struct v4l2_subdev *sd = isc->current_subdev->sd;
> +     int ret;
> +
> +     if (mutex_lock_interruptible(&isc->lock))
> +             return -ERESTARTSYS;
> +
> +     ret = v4l2_fh_open(file);
> +     if (ret < 0)
> +             goto unlock;
> +
> +     ret = v4l2_subdev_call(sd, core, s_power, 1);
> +     if (ret < 0 && ret != -ENOIOCTLCMD)
> +             goto unlock;
> +
> +     ret = isc_set_default_fmt(isc);
> +     if (ret)
> +             goto unlock;
> +
> +unlock:
> +     mutex_unlock(&isc->lock);
> +     return ret;
> +}
> +
> +static int isc_release(struct file *file)
> +{
> +     struct isc_device *isc = video_drvdata(file);
> +     struct v4l2_subdev *sd = isc->current_subdev->sd;
> +     int ret;
> +
> +     mutex_lock(&isc->lock);
> +
> +     ret = _vb2_fop_release(file, NULL);
> +
> +     v4l2_subdev_call(sd, core, s_power, 0);
> +
> +     mutex_unlock(&isc->lock);
> +
> +     return ret;
> +}
> +
> +static const struct v4l2_file_operations isc_fops = {
> +     .owner          = THIS_MODULE,
> +     .open           = isc_open,
> +     .release        = isc_release,
> +     .unlocked_ioctl = video_ioctl2,
> +     .read           = vb2_fop_read,
> +     .mmap           = vb2_fop_mmap,
> +     .poll           = vb2_fop_poll,
> +};
> +
> +static irqreturn_t isc_interrupt(int irq, void *dev_id)
> +{
> +     struct isc_device *isc = (struct isc_device *)dev_id;
> +     struct regmap *regmap = isc->regmap;
> +     u32 isc_intsr, isc_intmask, pending;
> +     irqreturn_t ret = IRQ_NONE;
> +
> +     spin_lock(&isc->dma_queue_lock);
> +
> +     regmap_read(regmap, ISC_INTSR, &isc_intsr);
> +     regmap_read(regmap, ISC_INTMASK, &isc_intmask);
> +
> +     pending = isc_intsr & isc_intmask;
> +
> +     if (likely(pending & ISC_INT_DDONE)) {
> +             if (isc->cur_frm) {
> +                     struct vb2_v4l2_buffer *vbuf = &isc->cur_frm->vb;
> +                     struct vb2_buffer *vb = &vbuf->vb2_buf;
> +
> +                     vb->timestamp = ktime_get_ns();
> +                     vbuf->sequence = isc->sequence++;
> +                     vb2_buffer_done(vb, VB2_BUF_STATE_DONE);
> +                     isc->cur_frm = NULL;
> +             }
> +
> +             if (!list_empty(&isc->dma_queue) && !isc->stop) {
> +                     isc->cur_frm = list_first_entry(&isc->dma_queue,
> +                                                  struct isc_buffer, list);
> +                     list_del(&isc->cur_frm->list);
> +
> +                     isc_start_dma(regmap, isc->cur_frm,
> +                                   isc->current_fmt->reg_dctrl_dview);
> +             }
> +
> +             if (isc->stop)
> +                     complete(&isc->comp);
> +
> +             ret = IRQ_HANDLED;
> +     }
> +
> +     spin_unlock(&isc->dma_queue_lock);
> +
> +     return ret;
> +}
> +
> +static int isc_async_bound(struct v4l2_async_notifier *notifier,
> +                         struct v4l2_subdev *subdev,
> +                         struct v4l2_async_subdev *asd)
> +{
> +     struct isc_device *isc = container_of(notifier->v4l2_dev,
> +                                           struct isc_device, v4l2_dev);
> +     struct isc_subdev_entity *subdev_entity =
> +             container_of(notifier, struct isc_subdev_entity, notifier);
> +
> +     if (video_is_registered(&isc->video_dev)) {
> +             v4l2_err(&isc->v4l2_dev, "only supports one sub-device.\n");
> +             return -EBUSY;
> +     }
> +
> +     subdev_entity->sd = subdev;
> +
> +     return 0;
> +}
> +
> +static void isc_async_unbind(struct v4l2_async_notifier *notifier,
> +                           struct v4l2_subdev *subdev,
> +                           struct v4l2_async_subdev *asd)
> +{
> +     struct isc_device *isc = container_of(notifier->v4l2_dev,
> +                                           struct isc_device, v4l2_dev);
> +
> +     video_unregister_device(&isc->video_dev);
> +     if (isc->current_subdev->config)
> +             v4l2_subdev_free_pad_config(isc->current_subdev->config);
> +}
> +
> +static struct isc_format *find_format_by_code(unsigned int code, int *index)
> +{
> +     struct isc_format *fmt = &isc_formats[0];
> +     unsigned int i;
> +
> +     for (i = 0; i < ARRAY_SIZE(isc_formats); i++) {
> +             if (fmt->sd_mbus_code == code) {
> +                     *index = i;
> +                     return fmt;
> +             }
> +
> +             fmt++;
> +     }
> +
> +     return NULL;
> +}
> +
> +static int isc_formats_init(struct isc_device *isc)
> +{
> +     struct isc_format *fmt;
> +     struct v4l2_subdev *subdev = isc->current_subdev->sd;
> +     int num_fmts, i, j;
> +     struct v4l2_subdev_mbus_code_enum mbus_code = {
> +             .which = V4L2_SUBDEV_FORMAT_ACTIVE,
> +     };
> +
> +     fmt = &isc_formats[0];
> +     for (i = 0; i < ARRAY_SIZE(isc_formats); i++) {
> +             fmt->isc_support = false;
> +             fmt->sd_support = false;
> +
> +             fmt++;
> +     }
> +
> +     while (!v4l2_subdev_call(subdev, pad, enum_mbus_code,
> +            NULL, &mbus_code)) {
> +             mbus_code.index++;
> +             fmt = find_format_by_code(mbus_code.code, &i);
> +             if (!fmt)
> +                     continue;
> +
> +             fmt->sd_support = true;
> +
> +             if (i <= RAW_FMT_INDEX_END) {
> +                     for (j = ISC_FMT_INDEX_START;
> +                          j <= ISC_FMT_INDEX_END; j++) {
> +                             isc_formats[j].isc_support = true;
> +                             isc_formats[j].isc_mbus_code = mbus_code.code;
> +                             isc_formats[j].reg_isc_bps = fmt->reg_sd_bps;
> +                             isc_formats[j].reg_bay_cfg = fmt->reg_bay_cfg;
> +                     }
> +             }
> +     }
> +
> +     fmt = &isc_formats[0];
> +     for (i = 0, num_fmts = 0; i < ARRAY_SIZE(isc_formats); i++) {
> +             if (fmt->isc_support || fmt->sd_support)
> +                     num_fmts++;
> +
> +             fmt++;
> +     }
> +
> +     if (!num_fmts)
> +             return -ENXIO;
> +
> +     isc->num_user_formats = num_fmts;
> +     isc->user_formats = devm_kcalloc(isc->dev,
> +                                      num_fmts, sizeof(struct isc_format *),
> +                                      GFP_KERNEL);
> +     if (!isc->user_formats) {
> +             v4l2_err(&isc->v4l2_dev, "could not allocate memory\n");
> +             return -ENOMEM;
> +     }
> +
> +     fmt = &isc_formats[0];
> +     for (i = 0, j = 0; i < ARRAY_SIZE(isc_formats); i++) {
> +             if (fmt->isc_support || fmt->sd_support)
> +                     isc->user_formats[j++] = fmt;
> +
> +             fmt++;
> +     }
> +
> +     return 0;
> +}
> +
> +static int isc_async_complete(struct v4l2_async_notifier *notifier)
> +{
> +     struct isc_device *isc = container_of(notifier->v4l2_dev,
> +                                           struct isc_device, v4l2_dev);
> +     struct isc_subdev_entity *sd_entity;
> +     struct video_device *vdev = &isc->video_dev;
> +     struct vb2_queue *q = &isc->vb2_vidq;
> +     int ret;
> +
> +     isc->current_subdev = container_of(notifier,
> +                                        struct isc_subdev_entity, notifier);
> +
> +     mutex_init(&isc->lock);
> +     init_completion(&isc->comp);
> +
> +     /* Initialize videobuf2 queue */
> +     q->type                 = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +     q->io_modes             = VB2_MMAP;
> +     q->drv_priv             = isc;
> +     q->buf_struct_size      = sizeof(struct isc_buffer);
> +     q->ops                  = &isc_vb2_ops;
> +     q->mem_ops              = &vb2_dma_contig_memops;
> +     q->timestamp_flags      = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +     q->lock                 = &isc->lock;
> +     q->min_buffers_needed   = 1;

q->dev isn't initialized, which is required for dma_contig.

> +
> +     ret = vb2_queue_init(q);
> +     if (ret < 0) {
> +             v4l2_err(&isc->v4l2_dev,
> +                      "vb2_queue_init() failed: %d\n", ret);
> +             return ret;
> +     }
> +
> +     /* Init video dma queues */
> +     INIT_LIST_HEAD(&isc->dma_queue);
> +     spin_lock_init(&isc->dma_queue_lock);
> +
> +     /* Register video device */
> +     strlcpy(vdev->name, ATMEL_ISC_NAME, sizeof(vdev->name));
> +     vdev->release           = video_device_release_empty;
> +     vdev->fops              = &isc_fops;
> +     vdev->ioctl_ops         = &isc_ioctl_ops;
> +     vdev->v4l2_dev          = &isc->v4l2_dev;
> +     vdev->vfl_dir           = VFL_DIR_RX;
> +     vdev->queue             = q;
> +     vdev->lock              = &isc->lock;
> +     vdev->ctrl_handler      = isc->current_subdev->sd->ctrl_handler;
> +     video_set_drvdata(vdev, isc);

Disable g/s_parm if not supported:

        sd_entity = isc->current_subdev;

        if (!v4l2_subdev_has_op(sd_entity->sd, video, g_parm))
                v4l2_disable_ioctl(vdev, VIDIOC_G_PARM);
        if (!v4l2_subdev_has_op(sd_entity->sd, video, s_parm))
                v4l2_disable_ioctl(vdev, VIDIOC_S_PARM);

> +
> +     ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
> +     if (ret < 0) {
> +             v4l2_err(&isc->v4l2_dev,
> +                      "video_register_device failed: %d\n", ret);
> +             return ret;
> +     }
> +
> +     sd_entity = isc->current_subdev;
> +     sd_entity->config = v4l2_subdev_alloc_pad_config(sd_entity->sd);
> +     if (sd_entity->config == NULL)
> +             return -ENOMEM;
> +
> +     ret = isc_formats_init(isc);
> +     if (ret < 0) {
> +             v4l2_err(&isc->v4l2_dev,
> +                      "Init format failed: %d\n", ret);
> +             return ret;
> +     }
> +
> +     return 0;
> +}
> +
> +static void isc_subdev_cleanup(struct isc_device *isc)
> +{
> +     struct isc_subdev_entity *subdev_entity;
> +
> +     list_for_each_entry(subdev_entity, &isc->subdev_entities, list)
> +             v4l2_async_notifier_unregister(&subdev_entity->notifier);
> +
> +     INIT_LIST_HEAD(&isc->subdev_entities);
> +}
> +
> +static int isc_pipeline_init(struct isc_device *isc)
> +{
> +     struct device *dev = isc->dev;
> +     struct regmap *regmap = isc->regmap;
> +     struct regmap_field *regs;
> +     unsigned int i;
> +
> +     /* WB-->CFA-->CC-->GAM-->CSC-->CBC-->SUB422-->SUB420 */
> +     static const struct reg_field regfields[ISC_PIPE_LINE_NODE_NUM] = {
> +             REG_FIELD(ISC_WB_CTRL, 0, 0),
> +             REG_FIELD(ISC_CFA_CTRL, 0, 0),
> +             REG_FIELD(ISC_CC_CTRL, 0, 0),
> +             REG_FIELD(ISC_GAM_CTRL, 0, 0),
> +             REG_FIELD(ISC_GAM_CTRL, 1, 1),
> +             REG_FIELD(ISC_GAM_CTRL, 2, 2),
> +             REG_FIELD(ISC_GAM_CTRL, 3, 3),
> +             REG_FIELD(ISC_CSC_CTRL, 0, 0),
> +             REG_FIELD(ISC_CBC_CTRL, 0, 0),
> +             REG_FIELD(ISC_SUB422_CTRL, 0, 0),
> +             REG_FIELD(ISC_SUB420_CTRL, 0, 0),
> +     };
> +
> +     for (i = 0; i < ISC_PIPE_LINE_NODE_NUM; i++) {
> +             regs = devm_regmap_field_alloc(dev, regmap, regfields[i]);
> +             if (IS_ERR(regs))
> +                     return PTR_ERR(regs);
> +
> +             isc->pipeline[i] =  regs;
> +     }
> +
> +     return 0;
> +}
> +
> +static int isc_parse_dt(struct device *dev, struct isc_device *isc)
> +{
> +     struct device_node *np = dev->of_node;
> +     struct device_node *epn = NULL, *rem;
> +     struct v4l2_of_endpoint v4l2_epn;
> +     struct isc_subdev_entity *subdev_entity;
> +     unsigned int flags;
> +     int ret;
> +
> +     INIT_LIST_HEAD(&isc->subdev_entities);
> +
> +     for (; ;) {
> +             epn = of_graph_get_next_endpoint(np, epn);
> +             if (!epn)
> +                     break;
> +
> +             rem = of_graph_get_remote_port_parent(epn);
> +             if (!rem) {
> +                     dev_notice(dev, "Remote device at %s not found\n",
> +                                of_node_full_name(epn));
> +                     continue;
> +             }
> +
> +             ret = v4l2_of_parse_endpoint(epn, &v4l2_epn);
> +             if (ret) {
> +                     of_node_put(rem);
> +                     ret = -EINVAL;
> +                     dev_err(dev, "Could not parse the endpoint\n");
> +                     break;
> +             }
> +
> +             subdev_entity = devm_kzalloc(dev,
> +                                       sizeof(*subdev_entity), GFP_KERNEL);
> +             if (subdev_entity == NULL) {
> +                     of_node_put(rem);
> +                     ret = -ENOMEM;
> +                     break;
> +             }
> +
> +             subdev_entity->asd = devm_kzalloc(dev,
> +                                  sizeof(*subdev_entity->asd), GFP_KERNEL);
> +             if (subdev_entity->asd == NULL) {
> +                     of_node_put(rem);
> +                     ret = -ENOMEM;
> +                     break;
> +             }
> +
> +             flags = v4l2_epn.bus.parallel.flags;
> +
> +             if (flags & V4L2_MBUS_HSYNC_ACTIVE_LOW)
> +                     subdev_entity->pfe_cfg0 = ISC_PFE_CFG0_HPOL_LOW;
> +
> +             if (flags & V4L2_MBUS_VSYNC_ACTIVE_LOW)
> +                     subdev_entity->pfe_cfg0 |= ISC_PFE_CFG0_VPOL_LOW;
> +
> +             if (flags & V4L2_MBUS_PCLK_SAMPLE_FALLING)
> +                     subdev_entity->pfe_cfg0 |= ISC_PFE_CFG0_PPOL_LOW;
> +
> +             subdev_entity->asd->match_type = V4L2_ASYNC_MATCH_OF;
> +             subdev_entity->asd->match.of.node = rem;
> +             list_add_tail(&subdev_entity->list, &isc->subdev_entities);
> +     }
> +
> +     of_node_put(epn);
> +     return ret;
> +}
> +
> +/* regmap configuration */
> +#define ATMEL_ISC_REG_MAX    0xbfc
> +static const struct regmap_config isc_regmap_config = {
> +     .reg_bits       = 32,
> +     .reg_stride     = 4,
> +     .val_bits       = 32,
> +     .max_register   = ATMEL_ISC_REG_MAX,
> +};
> +
> +static int atmel_isc_probe(struct platform_device *pdev)
> +{
> +     struct device *dev = &pdev->dev;
> +     struct isc_device *isc;
> +     struct resource *res;
> +     void __iomem *io_base;
> +     struct isc_subdev_entity *subdev_entity;
> +     int irq;
> +     int ret;
> +
> +     isc = devm_kzalloc(dev, sizeof(*isc), GFP_KERNEL);
> +     if (!isc)
> +             return -ENOMEM;
> +
> +     platform_set_drvdata(pdev, isc);
> +     isc->dev = dev;
> +
> +     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +     io_base = devm_ioremap_resource(dev, res);
> +     if (IS_ERR(io_base))
> +             return PTR_ERR(io_base);
> +
> +     isc->regmap = devm_regmap_init_mmio(dev, io_base, &isc_regmap_config);
> +     if (IS_ERR(isc->regmap)) {
> +             ret = PTR_ERR(isc->regmap);
> +             dev_err(dev, "failed to init register map: %d\n", ret);
> +             return ret;
> +     }
> +
> +     irq = platform_get_irq(pdev, 0);
> +     if (IS_ERR_VALUE(irq)) {
> +             ret = irq;
> +             dev_err(dev, "failed to get irq: %d\n", ret);
> +             return ret;
> +     }
> +
> +     ret = devm_request_irq(dev, irq, isc_interrupt, 0,
> +                            ATMEL_ISC_NAME, isc);
> +     if (ret < 0) {
> +             dev_err(dev, "can't register ISR for IRQ %u (ret=%i)\n",
> +                     irq, ret);
> +             return ret;
> +     }
> +
> +     ret = isc_pipeline_init(isc);
> +     if (ret)
> +             return ret;
> +
> +     isc->hclock = devm_clk_get(dev, "hclock");
> +     if (IS_ERR(isc->hclock)) {
> +             ret = PTR_ERR(isc->hclock);
> +             dev_err(dev, "failed to get hclock: %d\n", ret);
> +             return ret;
> +     }
> +
> +     ret = isc_clk_init(isc);
> +     if (ret) {
> +             dev_err(dev, "failed to init isc clock: %d\n", ret);
> +             goto clean_isc_clk;
> +     }
> +
> +     isc->ispck = isc->isc_clks[ISC_ISPCK].clk;
> +
> +     /* ispck should be greater or equal to hclock */
> +     ret = clk_set_rate(isc->ispck, clk_get_rate(isc->hclock));
> +     if (ret) {
> +             dev_err(dev, "failed to set ispck rate: %d\n", ret);
> +             goto clean_isc_clk;
> +     }
> +
> +     ret = v4l2_device_register(dev, &isc->v4l2_dev);
> +     if (ret) {
> +             dev_err(dev, "unable to register v4l2 device.\n");
> +             goto clean_isc_clk;
> +     }
> +
> +     ret = isc_parse_dt(dev, isc);
> +     if (ret) {
> +             dev_err(dev, "fail to parse device tree\n");
> +             goto unregister_v4l2_device;
> +     }
> +
> +     if (list_empty(&isc->subdev_entities)) {
> +             dev_err(dev, "no subdev found\n");
> +             goto unregister_v4l2_device;
> +     }
> +
> +     list_for_each_entry(subdev_entity, &isc->subdev_entities, list) {
> +             subdev_entity->notifier.subdevs = &subdev_entity->asd;
> +             subdev_entity->notifier.num_subdevs = 1;
> +             subdev_entity->notifier.bound = isc_async_bound;
> +             subdev_entity->notifier.unbind = isc_async_unbind;
> +             subdev_entity->notifier.complete = isc_async_complete;
> +
> +             ret = v4l2_async_notifier_register(&isc->v4l2_dev,
> +                                                &subdev_entity->notifier);
> +             if (ret) {
> +                     dev_err(dev, "fail to register async notifier\n");
> +                     goto cleanup_subdev;
> +             }
> +
> +             if (video_is_registered(&isc->video_dev))
> +                     break;
> +     }
> +
> +     pm_runtime_enable(dev);
> +
> +     return 0;
> +
> +cleanup_subdev:
> +     isc_subdev_cleanup(isc);
> +
> +unregister_v4l2_device:
> +     v4l2_device_unregister(&isc->v4l2_dev);
> +
> +clean_isc_clk:
> +     isc_clk_cleanup(isc);
> +
> +     return ret;
> +}
> +
> +static int atmel_isc_remove(struct platform_device *pdev)
> +{
> +     struct isc_device *isc = platform_get_drvdata(pdev);
> +
> +     pm_runtime_disable(&pdev->dev);
> +
> +     isc_subdev_cleanup(isc);
> +
> +     v4l2_device_unregister(&isc->v4l2_dev);
> +
> +     isc_clk_cleanup(isc);
> +
> +     return 0;
> +}
> +
> +static int isc_runtime_suspend(struct device *dev)
> +{
> +     struct isc_device *isc = dev_get_drvdata(dev);
> +
> +     clk_disable_unprepare(isc->ispck);
> +     clk_disable_unprepare(isc->hclock);
> +
> +     return 0;
> +}
> +
> +static int isc_runtime_resume(struct device *dev)
> +{
> +     struct isc_device *isc = dev_get_drvdata(dev);
> +     int ret;
> +
> +     ret = clk_prepare_enable(isc->hclock);
> +     if (ret)
> +             return ret;
> +
> +     return clk_prepare_enable(isc->ispck);
> +}
> +
> +static const struct dev_pm_ops atmel_isc_dev_pm_ops = {
> +     SET_RUNTIME_PM_OPS(isc_runtime_suspend, isc_runtime_resume, NULL)
> +};
> +
> +static const struct of_device_id atmel_isc_of_match[] = {
> +     { .compatible = "atmel,sama5d2-isc" },
> +     { }
> +};
> +MODULE_DEVICE_TABLE(of, atmel_isc_of_match);
> +
> +static struct platform_driver atmel_isc_driver = {
> +     .probe  = atmel_isc_probe,
> +     .remove = atmel_isc_remove,
> +     .driver = {
> +             .name           = ATMEL_ISC_NAME,
> +             .pm             = &atmel_isc_dev_pm_ops,
> +             .of_match_table = of_match_ptr(atmel_isc_of_match),
> +     },
> +};
> +
> +module_platform_driver(atmel_isc_driver);
> +
> +MODULE_AUTHOR("Songjun Wu <songjun...@atmel.com>");
> +MODULE_DESCRIPTION("The V4L2 driver for Atmel-ISC");
> +MODULE_LICENSE("GPL v2");
> +MODULE_SUPPORTED_DEVICE("video");
> 

Regards,

        Hans

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