Microchip CSI2DC (CSI2 Demultiplexer Controller) is a misc bridge device
that converts a byte stream in IDI Synopsys format (coming from a CSI2HOST)
to a pixel stream that can be captured by a sensor controller.

Signed-off-by: Eugen Hristev <eugen.hris...@microchip.com>
---
Changes in v2:
- moved driver to platform/atmel
- fixed minor things as per Sakari's review
- still some things from v2 review are not yet addressed, to be followed up

 drivers/media/platform/atmel/Kconfig          |  13 +
 drivers/media/platform/atmel/Makefile         |   1 +
 .../media/platform/atmel/microchip-csi2dc.c   | 700 ++++++++++++++++++
 3 files changed, 714 insertions(+)
 create mode 100644 drivers/media/platform/atmel/microchip-csi2dc.c

diff --git a/drivers/media/platform/atmel/Kconfig 
b/drivers/media/platform/atmel/Kconfig
index 1850fe7f9360..80bbddcc2504 100644
--- a/drivers/media/platform/atmel/Kconfig
+++ b/drivers/media/platform/atmel/Kconfig
@@ -21,3 +21,16 @@ config VIDEO_ATMEL_ISI
        help
          This module makes the ATMEL Image Sensor Interface available
          as a v4l2 device.
+
+config VIDEO_MICROCHIP_CSI2DC
+       tristate "Microchip CSI2 Demux Controller"
+       depends on VIDEO_V4L2 && COMMON_CLK && OF
+       depends on ARCH_AT91 || COMPILE_TEST
+       select MEDIA_CONTROLLER
+       select VIDEO_V4L2_SUBDEV_API
+       select V4L2_FWNODE
+       help
+         CSI2 Demux Controller driver. CSI2DC is a helper chip
+         that converts IDI interface byte stream to a parallel pixel stream.
+         It supports various RAW formats as input.
+         Performs clock domain crossing between hardware blocks.
diff --git a/drivers/media/platform/atmel/Makefile 
b/drivers/media/platform/atmel/Makefile
index 2dba38994a70..8af7c5b534c3 100644
--- a/drivers/media/platform/atmel/Makefile
+++ b/drivers/media/platform/atmel/Makefile
@@ -3,3 +3,4 @@ atmel-isc-objs = atmel-sama5d2-isc.o atmel-isc-base.o
 
 obj-$(CONFIG_VIDEO_ATMEL_ISI) += atmel-isi.o
 obj-$(CONFIG_VIDEO_ATMEL_ISC) += atmel-isc.o
+obj-$(CONFIG_VIDEO_MICROCHIP_CSI2DC) += microchip-csi2dc.o
diff --git a/drivers/media/platform/atmel/microchip-csi2dc.c 
b/drivers/media/platform/atmel/microchip-csi2dc.c
new file mode 100644
index 000000000000..97d07a80bbf7
--- /dev/null
+++ b/drivers/media/platform/atmel/microchip-csi2dc.c
@@ -0,0 +1,700 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Microchip CSI2 Demux Controller (CSI2DC) driver
+ *
+ * Copyright (C) 2018-2020 Microchip Technology, Inc.
+ *
+ * Author: Eugen Hristev <eugen.hris...@microchip.com>
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/videodev2.h>
+
+#include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
+#include <media/v4l2-subdev.h>
+#include <media/videobuf2-dma-contig.h>
+
+/* Global configuration register */
+#define CSI2DC_GCFG                    0x0
+
+/* MIPI sensor pixel clock is free running */
+#define CSI2DC_GCFG_MIPIFRN            BIT(0)
+/* Output waveform inter-line minimum delay */
+#define CSI2DC_GCFG_HLC(v)             ((v) << 4)
+#define CSI2DC_GCFG_HLC_MASK           GENMASK(7, 4)
+
+/* Global control register */
+#define CSI2DC_GCTLR                   0x04
+#define CSI2DC_GCTLR_SWRST             BIT(0)
+
+/* Global status register */
+#define CSI2DC_GS                      0x08
+
+/* SSP interrupt status register */
+#define CSI2DC_SSPIS                   0x28
+/* Pipe update register */
+#define CSI2DC_PU                      0xC0
+/* Video pipe attributes update */
+#define CSI2DC_PU_VP                   BIT(0)
+
+/* Pipe update status register */
+#define CSI2DC_PUS                     0xC4
+
+/* Video pipeline enable register */
+#define CSI2DC_VPE                     0xF8
+#define CSI2DC_VPE_ENABLE              BIT(0)
+
+/* Video pipeline configuration register */
+#define CSI2DC_VPCFG                   0xFC
+/* Data type */
+#define CSI2DC_VPCFG_DT(v)             ((v) << 0)
+#define CSI2DC_VPCFG_DT_MASK           GENMASK(5, 0)
+/* Virtual channel identifier */
+#define CSI2DC_VPCFG_VC(v)             ((v) << 6)
+#define CSI2DC_VPCFG_VC_MASK           GENMASK(7, 6)
+/* Decompression enable */
+#define CSI2DC_VPCFG_DE                        BIT(8)
+/* Decoder mode */
+#define CSI2DC_VPCFG_DM(v)             ((v) << 9)
+#define CSI2DC_VPCFG_DM_DECODER8TO12   0
+/* Decoder predictor 2 selection */
+#define CSI2DC_VPCFG_DP2               BIT(12)
+/* Recommended memory storage */
+#define CSI2DC_VPCFG_RMS               BIT(13)
+/* Post adjustment */
+#define CSI2DC_VPCFG_PA                        BIT(14)
+
+/* Video pipeline column register */
+#define CSI2DC_VPCOL                   0x100
+/* Column number */
+#define CSI2DC_VPCOL_COL(v)            ((v) << 0)
+#define CSI2DC_VPCOL_COL_MASK          GENMASK(15, 0)
+
+/* Video pipeline row register */
+#define CSI2DC_VPROW                   0x104
+/* Row number */
+#define CSI2DC_VPROW_ROW(v)            ((v) << 0)
+#define CSI2DC_VPROW_ROW_MASK          GENMASK(15, 0)
+
+/* Version register */
+#define CSI2DC_VERSION                 0x1FC
+
+/* register read/write helpers */
+#define csi2dc_readl(st, reg)          readl_relaxed((st)->base + (reg))
+#define csi2dc_writel(st, reg, val)    writel_relaxed((val), (st)->base + 
(reg))
+
+/* supported RAW data types */
+#define CSI2DC_DT_RAW6                 0x28
+#define CSI2DC_DT_RAW7                 0x29
+#define CSI2DC_DT_RAW8                 0x2A
+#define CSI2DC_DT_RAW10                        0x2B
+#define CSI2DC_DT_RAW12                        0x2C
+#define CSI2DC_DT_RAW14                        0x2D
+
+struct csi2dc_format {
+       u32                             mbus_code;
+       u32                             dt;
+};
+
+static struct csi2dc_format csi2dc_formats_list[] = {
+       {
+               .mbus_code =            MEDIA_BUS_FMT_SRGGB10_1X10,
+               .dt =                   CSI2DC_DT_RAW10,
+       },
+};
+
+enum mipi_csi_pads {
+       CSI2DC_PAD_SINK                 = 0,
+       CSI2DC_PAD_SOURCE               = 1,
+       CSI2DC_PADS_NUM                 = 2,
+};
+
+struct csi2dc_device {
+       void __iomem                    *base;
+       struct v4l2_subdev              csi2dc_sd;
+       struct device                   *dev;
+       struct v4l2_device              v4l2_dev;
+       struct clk                      *pclk;
+       struct clk                      *scck;
+
+       bool                            video_pipe;
+
+       u32                             num_fmts;
+       struct csi2dc_format            **formats;
+
+       struct csi2dc_format            *cur_fmt;
+       struct csi2dc_format            *try_fmt;
+
+       struct media_pad                pads[CSI2DC_PADS_NUM];
+
+       bool                            clk_gated;
+       u32                             inter_line_delay;
+       u32                             vc;
+
+       struct v4l2_async_subdev        *asd;
+       struct v4l2_async_notifier      notifier;
+
+       struct v4l2_subdev              *input_sd;
+       bool                            completed;
+};
+
+static void csi2dc_vp_update(struct csi2dc_device *csi2dc)
+{
+       u32 vp;
+
+       vp = CSI2DC_VPCFG_DT(csi2dc->cur_fmt->dt) & CSI2DC_VPCFG_DT_MASK;
+       vp |= CSI2DC_VPCFG_VC(csi2dc->vc) & CSI2DC_VPCFG_VC_MASK;
+       vp &= ~CSI2DC_VPCFG_DE;
+       vp |= CSI2DC_VPCFG_DM(CSI2DC_VPCFG_DM_DECODER8TO12);
+       vp &= ~CSI2DC_VPCFG_DP2;
+       vp &= ~CSI2DC_VPCFG_RMS;
+       vp |= CSI2DC_VPCFG_PA;
+
+       csi2dc_writel(csi2dc, CSI2DC_VPCFG, vp);
+       csi2dc_writel(csi2dc, CSI2DC_VPE, CSI2DC_VPE_ENABLE);
+       csi2dc_writel(csi2dc, CSI2DC_PU, CSI2DC_PU_VP);
+}
+
+static inline struct csi2dc_device *
+csi2dc_sd_to_csi2dc_device(struct v4l2_subdev *csi2dc_sd)
+{
+       return container_of(csi2dc_sd, struct csi2dc_device, csi2dc_sd);
+}
+
+static int csi2dc_enum_mbus_code(struct v4l2_subdev *csi2dc_sd,
+                                struct v4l2_subdev_pad_config *cfg,
+                                struct v4l2_subdev_mbus_code_enum *code)
+{
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+
+       if (code->index >= csi2dc->num_fmts)
+               return -EINVAL;
+
+       code->code = csi2dc->formats[code->index]->mbus_code;
+       return 0;
+}
+
+static int csi2dc_try_fmt(struct v4l2_subdev *csi2dc_sd,
+                         struct v4l2_subdev_pad_config *cfg,
+                         struct v4l2_subdev_format *req_fmt)
+{
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+       struct csi2dc_format *fmt;
+
+       if (!csi2dc->completed) {
+               dev_dbg((csi2dc)->dev, "subdev not registered yet\n");
+               return 0;
+       }
+
+       for (fmt = csi2dc->formats[0]; fmt; fmt++)
+               if (req_fmt->format.code == fmt->mbus_code)
+                       csi2dc->try_fmt = fmt;
+
+       /* in case we could not find the desired format, default to something */
+       if (!csi2dc->try_fmt  ||
+           req_fmt->format.code != csi2dc->try_fmt->mbus_code) {
+               csi2dc->try_fmt = csi2dc->formats[0];
+               req_fmt->format.code = csi2dc->formats[0]->mbus_code;
+       }
+
+       return v4l2_subdev_call(csi2dc->input_sd, pad, set_fmt, cfg, req_fmt);
+}
+
+static int csi2dc_set_fmt(struct v4l2_subdev *csi2dc_sd,
+                         struct v4l2_subdev_pad_config *cfg,
+                         struct v4l2_subdev_format *req_fmt)
+{
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+       int ret;
+
+       if (!csi2dc->completed) {
+               dev_dbg((csi2dc)->dev, "subdev not registered yet\n");
+               return 0;
+       }
+
+       csi2dc_try_fmt(csi2dc_sd, cfg, req_fmt);
+
+       if (csi2dc->try_fmt->mbus_code != req_fmt->format.code) {
+               dev_dbg(csi2dc->dev, "CSI2DC unsupported format 0x%x\n",
+                       req_fmt->format.code);
+               return -EINVAL;
+       }
+
+       ret = v4l2_subdev_call(csi2dc->input_sd, pad, set_fmt, cfg, req_fmt);
+       if (ret) {
+               dev_err(csi2dc->dev, "input subdev failed %d\n", ret);
+               return ret;
+       }
+
+       csi2dc->cur_fmt = csi2dc->try_fmt;
+       /* update video pipe */
+       csi2dc_vp_update(csi2dc);
+
+       dev_dbg(csi2dc->dev, "CSI2DC new format: 0x%x\n", req_fmt->format.code);
+       return 0;
+}
+
+static int csi2dc_formats_init(struct csi2dc_device *csi2dc)
+{
+       int i, j;
+       struct csi2dc_format *fmt = &csi2dc_formats_list[0];
+
+       csi2dc->num_fmts = 1;
+
+       csi2dc->formats = devm_kcalloc(csi2dc->dev, csi2dc->num_fmts,
+                                      sizeof(*csi2dc->formats), GFP_KERNEL);
+
+       for (i = 0, j = 0; i < ARRAY_SIZE(csi2dc_formats_list); i++, fmt++)
+               if (fmt->mbus_code == MEDIA_BUS_FMT_SRGGB10_1X10)
+                       csi2dc->formats[j++] = fmt;
+       return 0;
+}
+
+static int csi2dc_s_power(struct v4l2_subdev *csi2dc_sd, int on)
+{
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+       int ret = 0;
+
+       if (!csi2dc->completed) {
+               dev_dbg((csi2dc)->dev, "subdev not registered yet\n");
+               return 0;
+       }
+
+       if (on)
+               ret = clk_prepare_enable(csi2dc->scck);
+       else
+               clk_disable_unprepare(csi2dc->scck);
+       if (ret)
+               dev_err(csi2dc->dev, "failed to enable scck: %d\n", ret);
+
+       /* if powering up, deassert reset line */
+       if (on)
+               csi2dc_writel(csi2dc, CSI2DC_GCTLR, CSI2DC_GCTLR_SWRST);
+
+       ret = v4l2_subdev_call(csi2dc->input_sd, core, s_power, on);
+
+       /* if powering down, assert reset line */
+       if (!on)
+               csi2dc_writel(csi2dc, CSI2DC_GCTLR, !CSI2DC_GCTLR_SWRST);
+
+       return ret;
+}
+
+static int csi2dc_s_stream(struct v4l2_subdev *csi2dc_sd, int enable)
+{
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+
+       if (!csi2dc->completed) {
+               dev_dbg((csi2dc)->dev, "subdev not registered yet\n");
+               return 0;
+       }
+
+       return v4l2_subdev_call(csi2dc->input_sd, video, s_stream, enable);
+}
+
+static int csi2dc_g_frame_interval(struct v4l2_subdev *csi2dc_sd,
+                                  struct v4l2_subdev_frame_interval *interval)
+{
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+
+       if (!csi2dc->completed) {
+               dev_dbg((csi2dc)->dev, "subdev not registered yet\n");
+               return 0;
+       }
+
+       return v4l2_subdev_call(csi2dc->input_sd, video, g_frame_interval,
+                               interval);
+}
+
+static int csi2dc_s_frame_interval(struct v4l2_subdev *csi2dc_sd,
+                                  struct v4l2_subdev_frame_interval *interval)
+{
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+
+       if (!csi2dc->completed) {
+               dev_dbg((csi2dc)->dev, "subdev not registered yet\n");
+               return 0;
+       }
+
+       return v4l2_subdev_call(csi2dc->input_sd, video, s_frame_interval,
+                               interval);
+}
+
+static int csi2dc_enum_frame_size(struct v4l2_subdev *csi2dc_sd,
+                                 struct v4l2_subdev_pad_config *cfg,
+                                 struct v4l2_subdev_frame_size_enum *fse)
+{
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+
+       if (!csi2dc->completed) {
+               dev_dbg((csi2dc)->dev, "subdev not registered yet\n");
+               return 0;
+       }
+
+       return v4l2_subdev_call(csi2dc->input_sd, pad, enum_frame_size, cfg,
+                               fse);
+}
+
+static int csi2dc_enum_frame_interval(struct v4l2_subdev *csi2dc_sd,
+                                     struct v4l2_subdev_pad_config *cfg,
+                                     struct v4l2_subdev_frame_interval_enum 
*fie)
+{
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+
+       if (!csi2dc->completed) {
+               dev_dbg((csi2dc)->dev, "subdev not registered yet\n");
+               return 0;
+       }
+
+       return v4l2_subdev_call(csi2dc->input_sd, pad, enum_frame_interval, cfg,
+                               fie);
+}
+
+static const struct v4l2_subdev_core_ops csi2dc_core_ops = {
+       .s_power = csi2dc_s_power,
+};
+
+static const struct v4l2_subdev_pad_ops csi2dc_pad_ops = {
+       .enum_mbus_code = csi2dc_enum_mbus_code,
+       .set_fmt = csi2dc_set_fmt,
+       .enum_frame_size = csi2dc_enum_frame_size,
+       .enum_frame_interval = csi2dc_enum_frame_interval,
+};
+
+static const struct v4l2_subdev_video_ops csi2dc_video_ops = {
+       .s_stream = csi2dc_s_stream,
+       .g_frame_interval = csi2dc_g_frame_interval,
+       .s_frame_interval = csi2dc_s_frame_interval,
+};
+
+static const struct v4l2_subdev_ops csi2dc_subdev_ops = {
+       .core = &csi2dc_core_ops,
+       .pad = &csi2dc_pad_ops,
+       .video = &csi2dc_video_ops,
+};
+
+static int csi2dc_async_bound(struct v4l2_async_notifier *notifier,
+                             struct v4l2_subdev *subdev,
+                             struct v4l2_async_subdev *asd)
+{
+       struct csi2dc_device *csi2dc = container_of(notifier->v4l2_dev,
+                                       struct csi2dc_device, v4l2_dev);
+       csi2dc->input_sd = subdev;
+
+       return 0;
+}
+
+static int csi2dc_async_complete(struct v4l2_async_notifier *notifier)
+{
+       struct csi2dc_device *csi2dc =
+               container_of(notifier->v4l2_dev, struct csi2dc_device, 
v4l2_dev);
+       int ret;
+
+       ret = v4l2_device_register_subdev_nodes(&csi2dc->v4l2_dev);
+       if (ret < 0) {
+               v4l2_err(&csi2dc->v4l2_dev, "failed to register subdev 
nodes\n");
+               return ret;
+       }
+
+       csi2dc_writel(csi2dc, CSI2DC_GCFG,
+                     (CSI2DC_GCFG_HLC(csi2dc->inter_line_delay) &
+                     CSI2DC_GCFG_HLC_MASK) |
+                     (csi2dc->clk_gated ? 0 : CSI2DC_GCFG_MIPIFRN));
+
+       csi2dc_writel(csi2dc, CSI2DC_VPCOL,
+                     CSI2DC_VPCOL_COL(0xFFF) & CSI2DC_VPCOL_COL_MASK);
+       csi2dc_writel(csi2dc, CSI2DC_VPROW,
+                     CSI2DC_VPROW_ROW(0xFFF) & CSI2DC_VPROW_ROW_MASK);
+
+       csi2dc->completed = true;
+
+       return ret;
+}
+
+static const struct v4l2_async_notifier_operations csi2dc_async_ops = {
+       .bound = csi2dc_async_bound,
+       .complete = csi2dc_async_complete,
+};
+
+static void csi2dc_cleanup_notifier(struct csi2dc_device *csi2dc)
+{
+       v4l2_async_notifier_unregister(&csi2dc->notifier);
+       v4l2_async_notifier_cleanup(&csi2dc->notifier);
+}
+
+static int csi2dc_prepare_notifier(struct csi2dc_device *csi2dc,
+                                  struct device_node *input_parent)
+{
+       int ret;
+
+       v4l2_async_notifier_init(&csi2dc->notifier);
+
+       csi2dc->asd = kzalloc(sizeof(*csi2dc->asd), GFP_KERNEL);
+       if (!csi2dc->asd)
+               return -ENOMEM;
+
+       csi2dc->asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
+       csi2dc->asd->match.fwnode = of_fwnode_handle(input_parent);
+
+       ret = v4l2_async_notifier_add_subdev(&csi2dc->notifier, csi2dc->asd);
+       if (ret) {
+               dev_err(csi2dc->dev, "failed to add async notifier.\n");
+               v4l2_async_notifier_cleanup(&csi2dc->notifier);
+               goto csi2dc_prepare_notifier_err;
+       }
+
+       csi2dc->notifier.ops = &csi2dc_async_ops;
+
+       ret = v4l2_async_notifier_register(&csi2dc->v4l2_dev,
+                                          &csi2dc->notifier);
+
+       if (ret) {
+               dev_err(csi2dc->dev, "fail to register async notifier.\n");
+               goto csi2dc_prepare_notifier_err;
+       }
+
+csi2dc_prepare_notifier_err:
+       of_node_put(input_parent);
+
+       return ret;
+}
+
+static int csi2dc_of_parse(struct csi2dc_device *csi2dc,
+                          struct device_node *of_node)
+{
+       struct device_node *input_node, *sink_node, *input_parent;
+       struct v4l2_fwnode_endpoint input_endpoint = { 0 }, sink_endpoint = { 0 
};
+       int ret;
+
+       input_node = of_graph_get_next_endpoint(of_node, NULL);
+
+       if (!input_node) {
+               dev_err(csi2dc->dev, "missing port node at %s, input node is 
mandatory.\n",
+                       of_node->full_name);
+               return -EINVAL;
+       }
+
+       ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(input_node),
+                                        &input_endpoint);
+
+       if (ret) {
+               dev_err(csi2dc->dev, "endpoint not defined at %s\n",
+                       of_node->full_name);
+               return ret;
+       }
+
+       input_parent = of_graph_get_remote_port_parent(input_node);
+       if (!input_parent) {
+               dev_err(csi2dc->dev, "could not get input node's parent 
node.\n");
+               return -EINVAL;
+       }
+
+       sink_node = of_graph_get_next_endpoint(of_node, input_node);
+
+       if (sink_node)
+               ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(sink_node),
+                                                &sink_endpoint);
+
+       if (!sink_node || ret) {
+               dev_info(csi2dc->dev, "missing sink node at %s, data pipe 
available only.\n",
+                        of_node->full_name);
+       } else {
+               csi2dc->video_pipe = true;
+               csi2dc->vc = sink_endpoint.base.id;
+
+               dev_dbg(csi2dc->dev, "block %s %d.%d->%d.%d video pipe VC %d\n",
+                       of_node->full_name, input_endpoint.base.port,
+                       input_endpoint.base.id, sink_endpoint.base.port,
+                       sink_endpoint.base.id, csi2dc->vc);
+       }
+
+       csi2dc->clk_gated = of_property_read_bool(of_node,
+                                                 "microchip,clk-gated");
+
+       dev_dbg(csi2dc->dev, "%s clock\n",
+               csi2dc->clk_gated ? "Gated" : "Free running");
+
+       ret = of_property_read_u32(of_node, "microchip,inter-line-delay",
+                                  &csi2dc->inter_line_delay);
+
+       if (ret || csi2dc->inter_line_delay > 16 ||
+           csi2dc->inter_line_delay == 0) {
+               dev_dbg(csi2dc->dev, "assuming inter line delay = 16 clocks");
+               csi2dc->inter_line_delay = 16;
+               ret = 0;
+       }
+       /* hardware automatically adds 1 */
+       csi2dc->inter_line_delay--;
+
+       /* prepare async notifier for subdevice completion */
+
+       of_node_put(sink_node);
+       of_node_put(input_node);
+
+       return csi2dc_prepare_notifier(csi2dc, input_parent);
+}
+
+static int csi2dc_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct csi2dc_device *csi2dc;
+       struct resource *res = NULL;
+       int ret = 0;
+
+       csi2dc = devm_kzalloc(dev, sizeof(*csi2dc), GFP_KERNEL);
+       if (!csi2dc)
+               return -ENOMEM;
+
+       csi2dc->dev = dev;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res)
+               return -EINVAL;
+
+       csi2dc->base = devm_ioremap_resource(dev, res);
+
+       if (IS_ERR(csi2dc->base)) {
+               dev_err(dev, "base address not set\n");
+               return PTR_ERR(csi2dc->base);
+       }
+
+       csi2dc->pclk = devm_clk_get(dev, "pclk");
+       if (IS_ERR(csi2dc->pclk)) {
+               ret = PTR_ERR(csi2dc->pclk);
+               dev_err(dev, "failed to get pclk: %d\n", ret);
+               return ret;
+       }
+
+       ret = clk_prepare_enable(csi2dc->pclk);
+       if (ret) {
+               dev_err(dev, "failed to enable pclk: %d\n", ret);
+               return ret;
+       }
+
+       csi2dc->scck = devm_clk_get(dev, "scck");
+       if (IS_ERR(csi2dc->scck)) {
+               ret = PTR_ERR(csi2dc->scck);
+               dev_err(dev, "failed to get scck: %d\n", ret);
+               goto csi2dc_clk_fail;
+       }
+
+       ret = v4l2_device_register(dev, &csi2dc->v4l2_dev);
+       if (ret) {
+               dev_err(dev, "unable to register v4l2 device.\n");
+               goto csi2dc_clk_fail;
+       }
+
+       v4l2_subdev_init(&csi2dc->csi2dc_sd, &csi2dc_subdev_ops);
+
+       csi2dc->csi2dc_sd.owner = THIS_MODULE;
+       csi2dc->csi2dc_sd.dev = dev;
+       snprintf(csi2dc->csi2dc_sd.name, sizeof(csi2dc->csi2dc_sd.name),
+                "CSI2DC.0");
+
+       csi2dc->csi2dc_sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+       csi2dc->csi2dc_sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
+       csi2dc->pads[CSI2DC_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
+       csi2dc->pads[CSI2DC_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
+
+       ret = media_entity_pads_init(&csi2dc->csi2dc_sd.entity, CSI2DC_PADS_NUM,
+                                    csi2dc->pads);
+       if (ret < 0) {
+               dev_err(dev, "media entity init failed\n");
+               goto csi2dc_probe_entity_err;
+       }
+
+       v4l2_set_subdevdata(&csi2dc->csi2dc_sd, pdev);
+
+       platform_set_drvdata(pdev, &csi2dc->csi2dc_sd);
+
+       ret = csi2dc_of_parse(csi2dc, dev->of_node);
+       if (ret)
+               goto csi2dc_probe_entity_err;
+
+       ret = csi2dc_formats_init(csi2dc);
+       if (ret)
+               goto csi2dc_probe_error;
+
+       ret = v4l2_async_register_subdev(&csi2dc->csi2dc_sd);
+       if (ret)
+               goto csi2dc_probe_error;
+
+       pr_info("Microchip CSI2DC version %x\n",
+               csi2dc_readl(csi2dc, CSI2DC_VERSION));
+
+       pm_runtime_set_active(dev);
+       pm_runtime_enable(dev);
+       pm_request_idle(dev);
+
+       return 0;
+
+csi2dc_probe_error:
+       v4l2_async_unregister_subdev(&csi2dc->csi2dc_sd);
+       csi2dc_cleanup_notifier(csi2dc);
+
+csi2dc_probe_entity_err:
+       media_entity_cleanup(&csi2dc->csi2dc_sd.entity);
+       v4l2_device_unregister(&csi2dc->v4l2_dev);
+csi2dc_clk_fail:
+       clk_disable_unprepare(csi2dc->pclk);
+       return ret;
+}
+
+static int csi2dc_remove(struct platform_device *pdev)
+{
+       struct v4l2_subdev *csi2dc_sd = platform_get_drvdata(pdev);
+       struct csi2dc_device *csi2dc = csi2dc_sd_to_csi2dc_device(csi2dc_sd);
+
+       pm_runtime_disable(&pdev->dev);
+       csi2dc_cleanup_notifier(csi2dc);
+       media_entity_cleanup(&csi2dc->csi2dc_sd.entity);
+       v4l2_device_unregister(&csi2dc->v4l2_dev);
+       clk_disable_unprepare(csi2dc->pclk);
+
+       return 0;
+}
+
+static int __maybe_unused csi2dc_runtime_suspend(struct device *dev)
+{
+       return 0;
+}
+
+static int __maybe_unused csi2dc_runtime_resume(struct device *dev)
+{
+       return 0;
+}
+
+static const struct dev_pm_ops csi2dc_dev_pm_ops = {
+       SET_RUNTIME_PM_OPS(csi2dc_runtime_suspend, csi2dc_runtime_resume, NULL)
+};
+
+static const struct of_device_id csi2dc_of_match[] = {
+       { .compatible = "microchip,sama7g5-csi2dc" },
+       { }
+};
+
+MODULE_DEVICE_TABLE(of, csi2dc_of_match);
+
+static struct platform_driver csi2dc_driver = {
+       .probe  = csi2dc_probe,
+       .remove = csi2dc_remove,
+       .driver = {
+               .name           = "microchip-csi2dc",
+               .pm             = &csi2dc_dev_pm_ops,
+               .of_match_table = of_match_ptr(csi2dc_of_match),
+       },
+};
+
+module_platform_driver(csi2dc_driver);
+
+MODULE_AUTHOR("Eugen Hristev <eugen.hris...@microchip.com>");
+MODULE_DESCRIPTION("Microchip CSI2 Demux Controller driver");
+MODULE_LICENSE("GPL v2");
+MODULE_SUPPORTED_DEVICE("video");
-- 
2.25.1

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