This patch requires a DT Ack.

> This patch adds led-flash support to Maxim max77693 chipset.
> A device can be exposed to user space through LED subsystem
> sysfs interface. Device supports up to two leds which can
> work in flash and torch mode. The leds can be triggered
> externally or by software.
> 
> Signed-off-by: Jacek Anaszewski <j.anaszew...@samsung.com>
> Signed-off-by: Andrzej Hajda <a.ha...@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.p...@samsung.com>
> Cc: Bryan Wu <coolo...@gmail.com>
> Cc: Richard Purdie <rpur...@rpsys.net>
> Cc: Lee Jones <lee.jo...@linaro.org>
> Cc: Chanwoo Choi <cw00.c...@samsung.com>
> ---
>  drivers/leds/Kconfig         |   10 +
>  drivers/leds/Makefile        |    1 +
>  drivers/leds/leds-max77693.c |  993 
> ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1004 insertions(+)
>  create mode 100644 drivers/leds/leds-max77693.c
> 
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 25b320d..ccef436 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -467,6 +467,16 @@ config LEDS_TCA6507
>         LED driver chips accessed via the I2C bus.
>         Driver support brightness control and hardware-assisted blinking.
>  
> +config LEDS_MAX77693
> +     tristate "LED support for MAX77693 Flash"
> +     depends on LEDS_CLASS_FLASH
> +     depends on MFD_MAX77693
> +     depends on OF
> +     help
> +       This option enables support for the flash part of the MAX77693
> +       multifunction device. It has build in control for two leds in flash
> +       and torch mode.
> +
>  config LEDS_MAX8997
>       tristate "LED support for MAX8997 PMIC"
>       depends on LEDS_CLASS && MFD_MAX8997
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index cbba921..57ca62b 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -52,6 +52,7 @@ obj-$(CONFIG_LEDS_MC13783)          += leds-mc13783.o
>  obj-$(CONFIG_LEDS_NS2)                       += leds-ns2.o
>  obj-$(CONFIG_LEDS_NETXBIG)           += leds-netxbig.o
>  obj-$(CONFIG_LEDS_ASIC3)             += leds-asic3.o
> +obj-$(CONFIG_LEDS_MAX77693)          += leds-max77693.o
>  obj-$(CONFIG_LEDS_MAX8997)           += leds-max8997.o
>  obj-$(CONFIG_LEDS_LM355x)            += leds-lm355x.o
>  obj-$(CONFIG_LEDS_BLINKM)            += leds-blinkm.o
> diff --git a/drivers/leds/leds-max77693.c b/drivers/leds/leds-max77693.c
> new file mode 100644
> index 0000000..6873611
> --- /dev/null
> +++ b/drivers/leds/leds-max77693.c
> @@ -0,0 +1,993 @@
> +/*
> + * LED Flash class driver for the flash cell of max77693 mfd.
> + *
> + *   Copyright (C) 2015, Samsung Electronics Co., Ltd.
> + *
> + *   Authors: Jacek Anaszewski <j.anaszew...@samsung.com>
> + *            Andrzej Hajda <a.ha...@samsung.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * version 2 as published by the Free Software Foundation.
> + */
> +
> +#include <asm/div64.h>
> +#include <linux/led-class-flash.h>
> +#include <linux/mfd/max77693.h>
> +#include <linux/mfd/max77693-private.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/workqueue.h>
> +
> +#define MODE_OFF             0
> +#define MODE_FLASH(a)                (1 << (a))
> +#define MODE_TORCH(a)                (1 << (2 + (a)))
> +#define MODE_FLASH_EXTERNAL(a)       (1 << (4 + (a)))
> +
> +#define MODE_FLASH_MASK              (MODE_FLASH(FLED1) | MODE_FLASH(FLED2) 
> | \
> +                              MODE_FLASH_EXTERNAL(FLED1) | \
> +                              MODE_FLASH_EXTERNAL(FLED2))
> +#define MODE_TORCH_MASK              (MODE_TORCH(FLED1) | MODE_TORCH(FLED2))
> +
> +#define FLED1_IOUT           (1 << 0)
> +#define FLED2_IOUT           (1 << 1)
> +
> +#define MAX77693_LED1_NAME   "max77693-led.1"
> +#define MAX77693_LED2_NAME   "max77693-led.2"
> +
> +enum max77693_fled {
> +     FLED1,
> +     FLED2,
> +};
> +
> +enum max77693_led_mode {
> +     FLASH,
> +     TORCH,
> +};
> +
> +struct max77693_led_config_data {
> +     const char *label[2];
> +     u32 iout_torch_max[2];
> +     u32 iout_flash_max[2];
> +     u32 flash_timeout[2];
> +     u32 num_leds;
> +     u32 boost_mode;
> +     u32 boost_vout;
> +     u32 low_vsys;
> +     u32 trigger_type;
> +};
> +
> +struct max77693_sub_led {
> +     /* related FLED output identifier */
> +     int fled_id;
> +     /* related LED Flash class device */
> +     struct led_classdev_flash fled_cdev;
> +     /* assures led-triggers compatibility */
> +     struct work_struct work_brightness_set;
> +
> +     /* brightness cache */
> +     unsigned int torch_brightness;
> +     /* flash timeout cache */
> +     unsigned int flash_timeout;
> +     /* flash faults that may have occurred */
> +     u32 flash_faults;
> +};
> +
> +struct max77693_led_device {
> +     /* parent mfd regmap */
> +     struct regmap *regmap;
> +     /* platform device data */
> +     struct platform_device *pdev;
> +     /* secures access to the device */
> +     struct mutex lock;
> +
> +     /* sub led data */
> +     struct max77693_sub_led sub_leds[2];
> +
> +     /* maximum torch current values for FLED outputs */
> +     u32 iout_torch_max[2];
> +     /* maximum flash current values for FLED outputs */
> +     u32 iout_flash_max[2];
> +     /* flash trigger type */
> +     u32 trigger_type;
> +
> +     /* current flash timeout cache */
> +     unsigned int current_flash_timeout;
> +     /* ITORCH register cache */
> +     u8 torch_iout_reg;
> +     /* mode of fled outputs */
> +     unsigned int mode_flags;
> +     /* recently strobed fled */
> +     int strobing_sub_led_id;
> +     /* bitmask of fled outputs use state (bit 0. - FLED1, bit 1. - FLED2) */
> +     u8 fled_mask;
> +     /* FLED modes that can be set */
> +     u8 allowed_modes;
> +
> +     /* arrangement of current outputs */
> +     bool iout_joint;
> +};
> +
> +struct max77693_led_settings {
> +     struct led_flash_setting torch_brightness;
> +     struct led_flash_setting flash_brightness;
> +     struct led_flash_setting flash_timeout;
> +};
> +
> +static u8 max77693_led_iout_to_reg(u32 ua)
> +{
> +     if (ua < FLASH_IOUT_MIN)
> +             ua = FLASH_IOUT_MIN;
> +     return (ua - FLASH_IOUT_MIN) / FLASH_IOUT_STEP;
> +}
> +
> +static u8 max77693_flash_timeout_to_reg(u32 us)
> +{
> +     return (us - FLASH_TIMEOUT_MIN) / FLASH_TIMEOUT_STEP;
> +}
> +
> +static inline struct max77693_sub_led *flcdev_to_sub_led(
> +                                     struct led_classdev_flash *fled_cdev)
> +{
> +     return container_of(fled_cdev, struct max77693_sub_led, fled_cdev);
> +}
> +
> +static inline struct max77693_led_device *sub_led_to_led(
> +                                     struct max77693_sub_led *sub_led)
> +{
> +     return container_of(sub_led, struct max77693_led_device,
> +                             sub_leds[sub_led->fled_id]);
> +}
> +
> +static inline u8 max77693_led_vsys_to_reg(u32 mv)
> +{
> +     return ((mv - MAX_FLASH1_VSYS_MIN) / MAX_FLASH1_VSYS_STEP) << 2;
> +}
> +
> +static inline u8 max77693_led_vout_to_reg(u32 mv)
> +{
> +     return (mv - FLASH_VOUT_MIN) / FLASH_VOUT_STEP + FLASH_VOUT_RMIN;
> +}
> +
> +static inline bool max77693_fled_used(struct max77693_led_device *led,
> +                                      int fled_id)
> +{
> +     u8 fled_bit = (fled_id == FLED1) ? FLED1_IOUT : FLED2_IOUT;
> +
> +     return led->fled_mask & fled_bit;
> +}
> +
> +static int max77693_set_mode_reg(struct max77693_led_device *led, u8 mode)
> +{
> +     struct regmap *rmap = led->regmap;
> +     int ret, v = 0, i;
> +
> +     for (i = FLED1; i <= FLED2; ++i) {
> +             if (mode & MODE_TORCH(i))
> +                     v |= FLASH_EN_ON << TORCH_EN_SHIFT(i);
> +
> +             if (mode & MODE_FLASH(i)) {
> +                     v |= FLASH_EN_ON << FLASH_EN_SHIFT(i);
> +             } else if (mode & MODE_FLASH_EXTERNAL(i)) {
> +                     v |= FLASH_EN_FLASH << FLASH_EN_SHIFT(i);
> +                     /*
> +                      * Enable hw triggering also for torch mode, as some
> +                      * camera sensors use torch led to fathom ambient light
> +                      * conditions before strobing the flash.
> +                      */
> +                     v |= FLASH_EN_TORCH << TORCH_EN_SHIFT(i);
> +             }
> +     }
> +
> +     /* Reset the register only prior setting flash modes */
> +     if (mode & ~(MODE_TORCH(FLED1) | MODE_TORCH(FLED2))) {
> +             ret = regmap_write(rmap, MAX77693_LED_REG_FLASH_EN, 0);
> +             if (ret < 0)
> +                     return ret;
> +     }
> +
> +     return regmap_write(rmap, MAX77693_LED_REG_FLASH_EN, v);
> +}
> +
> +static int max77693_add_mode(struct max77693_led_device *led, u8 mode)
> +{
> +     int i, ret;
> +
> +     mode &= led->allowed_modes;
> +
> +     /*
> +      * Torch mode once enabled remains active until turned off. If the FLED2
> +      * output isn't to be disabled check if the torch mode to be set isn't
> +      * already activated and avoid re-setting it.
> +      */
> +     if ((!(mode ^ led->mode_flags)) & MODE_TORCH(FLED2)) {
> +             for (i = FLED1; i <= FLED2; ++i)
> +                     if ((mode & led->mode_flags & MODE_TORCH(i)))
> +                             return 0;
> +     }
> +
> +     if (led->iout_joint)
> +             /* Span the mode on FLED2 for joint iouts case */
> +             mode |= (mode << 1);
> +
> +     /*
> +      * FLASH_EXTERNAL mode activates FLASHEN and TORCHEN pins in the device.
> +      * The related register bits fields interfere with SW triggerred modes,
> +      * thus clear them to ensure proper device configuration.
> +      */
> +     for (i = FLED1; i <= FLED2; ++i)
> +             if (mode & MODE_FLASH_EXTERNAL(i))
> +                     led->mode_flags &= (~MODE_TORCH(i) & ~MODE_FLASH(i));
> +
> +     led->mode_flags |= mode;
> +     led->mode_flags &= led->allowed_modes;
> +
> +     ret = max77693_set_mode_reg(led, led->mode_flags);
> +     if (ret < 0)
> +             return ret;
> +
> +     /*
> +      * Clear flash mode flag after setting the mode to avoid spurious flash
> +      * strobing on each subsequent torch mode setting.
> +      */
> +     if (mode & MODE_FLASH_MASK)
> +             led->mode_flags &= ~mode;
> +
> +     return ret;
> +}
> +
> +static int max77693_clear_mode(struct max77693_led_device *led,
> +                             u8 mode)
> +{
> +     if (led->iout_joint)
> +             /* Clear mode also on FLED2 for joint iouts case */
> +             mode |= (mode << 1);
> +
> +     led->mode_flags &= ~mode;
> +
> +     return max77693_set_mode_reg(led, led->mode_flags);
> +}
> +
> +static void max77693_add_allowed_modes(struct max77693_led_device *led,
> +                             int fled_id, enum max77693_led_mode mode)
> +{
> +     if (mode == FLASH)
> +             led->allowed_modes |= (MODE_FLASH(fled_id) |
> +                                    MODE_FLASH_EXTERNAL(fled_id));
> +     else
> +             led->allowed_modes |= MODE_TORCH(fled_id);
> +}
> +
> +static void max77693_distribute_currents(struct max77693_led_device *led,
> +                             int fled_id, enum max77693_led_mode mode,
> +                             u32 micro_amp, u32 iout_max[2], u32 iout[2])
> +{
> +     if (!led->iout_joint) {
> +             iout[fled_id] = micro_amp;
> +             max77693_add_allowed_modes(led, fled_id, mode);
> +             return;
> +     }
> +
> +     iout[FLED1] = min(micro_amp, iout_max[FLED1]);
> +     iout[FLED2] = micro_amp - iout[FLED1];
> +
> +     if (mode == FLASH)
> +             led->allowed_modes &= ~MODE_FLASH_MASK;
> +     else
> +             led->allowed_modes &= ~MODE_TORCH_MASK;
> +
> +     max77693_add_allowed_modes(led, FLED1, mode);
> +
> +     if (iout[FLED2])
> +             max77693_add_allowed_modes(led, FLED2, mode);
> +}
> +
> +static int max77693_set_torch_current(struct max77693_led_device *led,
> +                             int fled_id, u32 micro_amp)
> +{
> +     struct regmap *rmap = led->regmap;
> +     u8 iout1_reg = 0, iout2_reg = 0;
> +     u32 iout[2];
> +
> +     max77693_distribute_currents(led, fled_id, TORCH, micro_amp,
> +                                     led->iout_torch_max, iout);
> +
> +     if (fled_id == FLED1 || led->iout_joint) {
> +             iout1_reg = max77693_led_iout_to_reg(iout[FLED1]);
> +             led->torch_iout_reg &= TORCH_IOUT_MASK(TORCH_IOUT2_SHIFT);
> +     }
> +     if (fled_id == FLED2 || led->iout_joint) {
> +             iout2_reg = max77693_led_iout_to_reg(iout[FLED2]);
> +             led->torch_iout_reg &= TORCH_IOUT_MASK(TORCH_IOUT1_SHIFT);
> +     }
> +
> +     led->torch_iout_reg |= ((iout1_reg << TORCH_IOUT1_SHIFT) |
> +                             (iout2_reg << TORCH_IOUT2_SHIFT));
> +
> +     return regmap_write(rmap, MAX77693_LED_REG_ITORCH,
> +                                             led->torch_iout_reg);
> +}
> +
> +static int max77693_set_flash_current(struct max77693_led_device *led,
> +                                     int fled_id,
> +                                     u32 micro_amp)
> +{
> +     struct regmap *rmap = led->regmap;
> +     u8 iout1_reg, iout2_reg;
> +     u32 iout[2];
> +     int ret = -EINVAL;
> +
> +     max77693_distribute_currents(led, fled_id, FLASH, micro_amp,
> +                                     led->iout_flash_max, iout);
> +
> +     if (fled_id == FLED1 || led->iout_joint) {
> +             iout1_reg = max77693_led_iout_to_reg(iout[FLED1]);
> +             ret = regmap_write(rmap, MAX77693_LED_REG_IFLASH1,
> +                                                     iout1_reg);
> +             if (ret < 0)
> +                     return ret;
> +     }
> +     if (fled_id == FLED2 || led->iout_joint) {
> +             iout2_reg = max77693_led_iout_to_reg(iout[FLED2]);
> +             ret = regmap_write(rmap, MAX77693_LED_REG_IFLASH2,
> +                                                     iout2_reg);
> +     }
> +
> +     return ret;
> +}
> +
> +static int max77693_set_timeout(struct max77693_led_device *led, u32 
> microsec)
> +{
> +     struct regmap *rmap = led->regmap;
> +     u8 v;
> +     int ret;
> +
> +     v = max77693_flash_timeout_to_reg(microsec);
> +
> +     if (led->trigger_type == MAX77693_LED_TRIG_TYPE_LEVEL)
> +             v |= FLASH_TMR_LEVEL;
> +
> +     ret = regmap_write(rmap, MAX77693_LED_REG_FLASH_TIMER, v);
> +     if (ret < 0)
> +             return ret;
> +
> +     led->current_flash_timeout = microsec;
> +
> +     return 0;
> +}
> +
> +static int max77693_get_strobe_status(struct max77693_led_device *led,
> +                                     bool *state)
> +{
> +     struct regmap *rmap = led->regmap;
> +     unsigned int v;
> +     int ret;
> +
> +     ret = regmap_read(rmap, MAX77693_LED_REG_FLASH_STATUS, &v);
> +     if (ret < 0)
> +             return ret;
> +
> +     *state = v & FLASH_STATUS_FLASH_ON;
> +
> +     return ret;
> +}
> +
> +static int max77693_get_flash_faults(struct max77693_sub_led *sub_led)
> +{
> +     struct max77693_led_device *led = sub_led_to_led(sub_led);
> +     struct regmap *rmap = led->regmap;
> +     unsigned int v;
> +     u8 fault_open_mask, fault_short_mask;
> +     int ret;
> +
> +     sub_led->flash_faults = 0;
> +
> +     if (led->iout_joint) {
> +             fault_open_mask = FLASH_INT_FLED1_OPEN | FLASH_INT_FLED2_OPEN;
> +             fault_short_mask = FLASH_INT_FLED1_SHORT |
> +                                                     FLASH_INT_FLED2_SHORT;
> +     } else {
> +             fault_open_mask = (sub_led->fled_id == FLED1) ?
> +                                             FLASH_INT_FLED1_OPEN :
> +                                             FLASH_INT_FLED2_OPEN;
> +             fault_short_mask = (sub_led->fled_id == FLED1) ?
> +                                             FLASH_INT_FLED1_SHORT :
> +                                             FLASH_INT_FLED2_SHORT;
> +     }
> +
> +     ret = regmap_read(rmap, MAX77693_LED_REG_FLASH_INT, &v);
> +     if (ret < 0)
> +             return ret;
> +
> +     if (v & fault_open_mask)
> +             sub_led->flash_faults |= LED_FAULT_OVER_VOLTAGE;
> +     if (v & fault_short_mask)
> +             sub_led->flash_faults |= LED_FAULT_SHORT_CIRCUIT;
> +     if (v & FLASH_INT_OVER_CURRENT)
> +             sub_led->flash_faults |= LED_FAULT_OVER_CURRENT;
> +
> +     return 0;
> +}
> +
> +static int max77693_setup(struct max77693_led_device *led,
> +                      struct max77693_led_config_data *cfg)
> +{
> +     struct regmap *rmap = led->regmap;
> +     int i, first_led, last_led, ret;
> +     u32 max_flash_curr[2];
> +     u8 v;
> +
> +     /*
> +      * Initialize only flash current. Torch current doesn't
> +      * require initialization as ITORCH register is written with
> +      * new value each time brightness_set op is called.
> +      */
> +     if (led->iout_joint) {
> +             first_led = FLED1;
> +             last_led = FLED1;
> +             max_flash_curr[FLED1] = cfg->iout_flash_max[FLED1] +
> +                                     cfg->iout_flash_max[FLED2];
> +     } else {
> +             first_led = max77693_fled_used(led, FLED1) ? FLED1 : FLED2;
> +             last_led = max77693_fled_used(led, FLED2) ? FLED2 : FLED1;
> +             max_flash_curr[FLED1] = cfg->iout_flash_max[FLED1];
> +             max_flash_curr[FLED2] = cfg->iout_flash_max[FLED2];
> +     }
> +
> +     for (i = first_led; i <= last_led; ++i) {
> +             ret = max77693_set_flash_current(led, i,
> +                                     max_flash_curr[i]);
> +             if (ret < 0)
> +                     return ret;
> +     }
> +
> +     v = TORCH_TMR_NO_TIMER | MAX77693_LED_TRIG_TYPE_LEVEL;
> +     ret = regmap_write(rmap, MAX77693_LED_REG_ITORCHTIMER, v);
> +     if (ret < 0)
> +             return ret;
> +
> +     if (cfg->low_vsys > 0)
> +             v = max77693_led_vsys_to_reg(cfg->low_vsys) |
> +                                             MAX_FLASH1_MAX_FL_EN;
> +     else
> +             v = 0;
> +
> +     ret = regmap_write(rmap, MAX77693_LED_REG_MAX_FLASH1, v);
> +     if (ret < 0)
> +             return ret;
> +     ret = regmap_write(rmap, MAX77693_LED_REG_MAX_FLASH2, 0);
> +     if (ret < 0)
> +             return ret;
> +
> +     if (cfg->boost_mode == MAX77693_LED_BOOST_FIXED)
> +             v = FLASH_BOOST_FIXED;
> +     else
> +             v = cfg->boost_mode | cfg->boost_mode << 1;
> +
> +     if (max77693_fled_used(led, FLED1) && max77693_fled_used(led, FLED2))
> +             v |= FLASH_BOOST_LEDNUM_2;
> +
> +     ret = regmap_write(rmap, MAX77693_LED_REG_VOUT_CNTL, v);
> +     if (ret < 0)
> +             return ret;
> +
> +     v = max77693_led_vout_to_reg(cfg->boost_vout);
> +     ret = regmap_write(rmap, MAX77693_LED_REG_VOUT_FLASH1, v);
> +     if (ret < 0)
> +             return ret;
> +
> +     return max77693_set_mode_reg(led, MODE_OFF);
> +}
> +
> +static int __max77693_led_brightness_set(struct max77693_led_device *led,
> +                                     int fled_id, enum led_brightness value)
> +{
> +     int ret;
> +
> +     mutex_lock(&led->lock);
> +
> +     if (value == 0) {
> +             ret = max77693_clear_mode(led, MODE_TORCH(fled_id));
> +             if (ret < 0)
> +                     dev_dbg(&led->pdev->dev,
> +                             "Failed to clear torch mode (%d)\n",
> +                             ret);
> +             goto unlock;
> +     }
> +
> +     ret = max77693_set_torch_current(led, fled_id, value * TORCH_IOUT_STEP);
> +     if (ret < 0) {
> +             dev_dbg(&led->pdev->dev,
> +                     "Failed to set torch current (%d)\n",
> +                     ret);
> +             goto unlock;
> +     }
> +
> +     ret = max77693_add_mode(led, MODE_TORCH(fled_id));
> +     if (ret < 0)
> +             dev_dbg(&led->pdev->dev,
> +                     "Failed to set torch mode (%d)\n",
> +                     ret);
> +unlock:
> +     mutex_unlock(&led->lock);
> +     return ret;
> +}
> +
> +static void max77693_led_brightness_set_work(
> +                                     struct work_struct *work)
> +{
> +     struct max77693_sub_led *sub_led =
> +                     container_of(work, struct max77693_sub_led,
> +                                     work_brightness_set);
> +     struct max77693_led_device *led = sub_led_to_led(sub_led);
> +
> +     __max77693_led_brightness_set(led, sub_led->fled_id,
> +                             sub_led->torch_brightness);
> +}
> +
> +/* LED subsystem callbacks */
> +
> +static int max77693_led_brightness_set_sync(
> +                             struct led_classdev *led_cdev,
> +                             enum led_brightness value)
> +{
> +     struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
> +     struct max77693_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
> +     struct max77693_led_device *led = sub_led_to_led(sub_led);
> +
> +     return __max77693_led_brightness_set(led, sub_led->fled_id, value);
> +}
> +
> +static void max77693_led_brightness_set(
> +                             struct led_classdev *led_cdev,
> +                             enum led_brightness value)
> +{
> +     struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
> +     struct max77693_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
> +
> +     sub_led->torch_brightness = value;
> +     schedule_work(&sub_led->work_brightness_set);
> +}
> +
> +static int max77693_led_flash_brightness_set(
> +                             struct led_classdev_flash *fled_cdev,
> +                             u32 brightness)
> +{
> +     struct max77693_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
> +     struct max77693_led_device *led = sub_led_to_led(sub_led);
> +     int ret;
> +
> +     mutex_lock(&led->lock);
> +     ret = max77693_set_flash_current(led, sub_led->fled_id, brightness);
> +     mutex_unlock(&led->lock);
> +
> +     return ret;
> +}
> +
> +static int max77693_led_flash_strobe_set(
> +                             struct led_classdev_flash *fled_cdev,
> +                             bool state)
> +{
> +     struct max77693_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
> +     struct max77693_led_device *led = sub_led_to_led(sub_led);
> +     int fled_id = sub_led->fled_id;
> +     int ret;
> +
> +     mutex_lock(&led->lock);
> +
> +     if (!state) {
> +             ret = max77693_clear_mode(led, MODE_FLASH(fled_id));
> +             goto unlock;
> +     }
> +
> +     if (sub_led->flash_timeout != led->current_flash_timeout) {
> +             ret = max77693_set_timeout(led, sub_led->flash_timeout);
> +             if (ret < 0)
> +                     goto unlock;
> +     }
> +
> +     led->strobing_sub_led_id = fled_id;
> +
> +     ret = max77693_add_mode(led, MODE_FLASH(fled_id));
> +     if (ret < 0)
> +             goto unlock;
> +
> +     ret = max77693_get_flash_faults(sub_led);
> +
> +unlock:
> +     mutex_unlock(&led->lock);
> +     return ret;
> +}
> +
> +static int max77693_led_flash_fault_get(
> +                             struct led_classdev_flash *fled_cdev,
> +                             u32 *fault)
> +{
> +     struct max77693_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
> +
> +     *fault = sub_led->flash_faults;
> +
> +     return 0;
> +}
> +
> +static int max77693_led_flash_strobe_get(
> +                             struct led_classdev_flash *fled_cdev,
> +                             bool *state)
> +{
> +     struct max77693_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
> +     struct max77693_led_device *led = sub_led_to_led(sub_led);
> +     int ret;
> +
> +     if (!state)
> +             return -EINVAL;
> +
> +     mutex_lock(&led->lock);
> +
> +     ret = max77693_get_strobe_status(led, state);
> +
> +     *state = !!(*state && (led->strobing_sub_led_id == sub_led->fled_id));
> +
> +     mutex_unlock(&led->lock);
> +
> +     return ret;
> +}
> +
> +static int max77693_led_flash_timeout_set(
> +                             struct led_classdev_flash *fled_cdev,
> +                             u32 timeout)
> +{
> +     struct max77693_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
> +     struct max77693_led_device *led = sub_led_to_led(sub_led);
> +
> +     mutex_lock(&led->lock);
> +     sub_led->flash_timeout = timeout;
> +     mutex_unlock(&led->lock);
> +
> +     return 0;
> +}
> +
> +static int max77693_led_parse_dt(struct max77693_led_device *led,
> +                             struct max77693_led_config_data *cfg)
> +{
> +     struct device *dev = &led->pdev->dev;
> +     struct max77693_sub_led *sub_leds = led->sub_leds;
> +     struct device_node *node = dev->of_node, *child_node;
> +     struct property *prop;
> +     u32 led_sources[2];
> +     int i, fled_id;
> +
> +     of_property_read_u32(node, "maxim,trigger-type", &cfg->trigger_type);
> +     of_property_read_u32(node, "maxim,boost-mode", &cfg->boost_mode);
> +     of_property_read_u32(node, "maxim,boost-mvout", &cfg->boost_vout);
> +     of_property_read_u32(node, "maxim,mvsys-min", &cfg->low_vsys);
> +
> +     for_each_available_child_of_node(node, child_node) {
> +             prop = of_find_property(child_node, "led-sources", NULL);
> +             if (prop) {
> +                     const __be32 *srcs = NULL;
> +
> +                     for (i = 0; i < ARRAY_SIZE(led_sources); ++i) {
> +                             srcs = of_prop_next_u32(prop, srcs,
> +                                                     &led_sources[i]);
> +                             if (!srcs)
> +                                     break;
> +                     }
> +             } else {
> +                     dev_err(dev,
> +                             "\"led-sources\" DT property not found.\n");
> +                     return -EINVAL;
> +             }
> +
> +             if (i == 2) {
> +                     fled_id = FLED1;
> +                     led->fled_mask = FLED1_IOUT | FLED2_IOUT;
> +             } else if (led_sources[0] == FLED1) {
> +                     fled_id = FLED1;
> +                     led->fled_mask |= FLED1_IOUT;
> +             } else if (led_sources[0] == FLED2) {
> +                     fled_id = FLED2;
> +                     led->fled_mask |= FLED2_IOUT;
> +             } else {
> +                     dev_err(dev,
> +                             "Wrong \"led-sources\" DT property value.\n");
> +                     return -EINVAL;
> +             }
> +
> +             sub_leds[fled_id].fled_id = fled_id;
> +
> +             of_property_read_string(child_node, "label",
> +                                     (const char **) &cfg->label[fled_id]);
> +
> +             of_property_read_u32(child_node, "max-microamp",
> +                                             &cfg->iout_torch_max[fled_id]);
> +             of_property_read_u32(child_node, "flash-max-microamp",
> +                                             &cfg->iout_flash_max[fled_id]);
> +             of_property_read_u32(child_node, "flash-timeout-us",
> +                                             &cfg->flash_timeout[fled_id]);
> +
> +             if (++cfg->num_leds == 2 ||
> +                 (max77693_fled_used(led, FLED1) &&
> +                  max77693_fled_used(led, FLED2)))
> +                     break;
> +     }
> +
> +     if (cfg->num_leds == 0) {
> +             dev_err(dev, "No DT child node found for connected LED(s).\n");
> +             return -EINVAL;
> +     }
> +
> +     return 0;
> +}
> +
> +static void clamp_align(u32 *v, u32 min, u32 max, u32 step)
> +{
> +     *v = clamp_val(*v, min, max);
> +     if (step > 1)
> +             *v = (*v - min) / step * step + min;
> +}
> +
> +static void max77693_led_validate_configuration(struct max77693_led_device 
> *led,
> +                                     struct max77693_led_config_data *cfg)
> +{
> +     int i;
> +
> +     if (cfg->num_leds == 1 &&
> +         max77693_fled_used(led, FLED1) && max77693_fled_used(led, FLED2))
> +             led->iout_joint = true;
> +
> +     cfg->boost_mode = clamp_val(cfg->boost_mode, MAX77693_LED_BOOST_NONE,
> +                         MAX77693_LED_BOOST_FIXED);
> +
> +     /* Boost must be enabled if both current outputs are used */
> +     if ((cfg->boost_mode == MAX77693_LED_BOOST_NONE) && led->iout_joint)
> +             cfg->boost_mode = MAX77693_LED_BOOST_FIXED;
> +
> +     /* Split max current settings to both outputs in case of joint leds */
> +     if (led->iout_joint) {
> +             cfg->iout_torch_max[FLED1] /= 2;
> +             cfg->iout_torch_max[FLED2] = cfg->iout_torch_max[FLED1];
> +             cfg->iout_flash_max[FLED1] /= 2;
> +             cfg->iout_flash_max[FLED2] = cfg->iout_flash_max[FLED1];
> +     }
> +
> +     for (i = FLED1; i <= FLED2; ++i) {
> +             if (max77693_fled_used(led, i)) {
> +                     clamp_align(&cfg->iout_torch_max[i], TORCH_IOUT_MIN,
> +                                     TORCH_IOUT_MAX, TORCH_IOUT_STEP);
> +                     clamp_align(&cfg->iout_flash_max[i], FLASH_IOUT_MIN,
> +                                     cfg->boost_mode ? FLASH_IOUT_MAX_2LEDS :
> +                                                     FLASH_IOUT_MAX_1LED,
> +                                     FLASH_IOUT_STEP);
> +             } else {
> +                     cfg->iout_torch_max[i] = cfg->iout_flash_max[i] = 0;
> +             }
> +     }
> +
> +     for (i = 0; i < ARRAY_SIZE(cfg->flash_timeout); ++i)
> +             clamp_align(&cfg->flash_timeout[i], FLASH_TIMEOUT_MIN,
> +                             FLASH_TIMEOUT_MAX, FLASH_TIMEOUT_STEP);
> +
> +     cfg->trigger_type = clamp_val(cfg->trigger_type,
> +                                     MAX77693_LED_TRIG_TYPE_EDGE,
> +                                     MAX77693_LED_TRIG_TYPE_LEVEL);
> +
> +     clamp_align(&cfg->boost_vout, FLASH_VOUT_MIN, FLASH_VOUT_MAX,
> +                                                     FLASH_VOUT_STEP);
> +
> +     if (cfg->low_vsys)
> +             clamp_align(&cfg->low_vsys, MAX_FLASH1_VSYS_MIN,
> +                             MAX_FLASH1_VSYS_MAX, MAX_FLASH1_VSYS_STEP);
> +}
> +
> +static int max77693_led_get_configuration(struct max77693_led_device *led,
> +                             struct max77693_led_config_data *cfg)
> +{
> +     int ret;
> +
> +     ret = max77693_led_parse_dt(led, cfg);
> +     if (ret < 0)
> +             return ret;
> +
> +     max77693_led_validate_configuration(led, cfg);
> +
> +     memcpy(led->iout_torch_max, cfg->iout_torch_max,
> +                             sizeof(led->iout_torch_max));
> +     memcpy(led->iout_flash_max, cfg->iout_flash_max,
> +                             sizeof(led->iout_flash_max));
> +     led->trigger_type = cfg->trigger_type;
> +
> +     return 0;
> +}
> +
> +static const struct led_flash_ops flash_ops = {
> +     .flash_brightness_set   = max77693_led_flash_brightness_set,
> +     .strobe_set             = max77693_led_flash_strobe_set,
> +     .strobe_get             = max77693_led_flash_strobe_get,
> +     .timeout_set            = max77693_led_flash_timeout_set,
> +     .fault_get              = max77693_led_flash_fault_get,
> +};
> +
> +static void max77693_init_flash_settings(struct max77693_led_device *led,
> +                                      int fled_id,
> +                                      struct max77693_led_config_data *cfg,
> +                                      struct max77693_led_settings *s)
> +{
> +     struct led_flash_setting *setting;
> +
> +     /* Init torch intensity setting */
> +     setting = &s->torch_brightness;
> +     setting->min = TORCH_IOUT_MIN;
> +     setting->max = cfg->iout_torch_max[fled_id];
> +     setting->max = led->iout_joint ?
> +             cfg->iout_torch_max[FLED1] + cfg->iout_torch_max[FLED2] :
> +             cfg->iout_torch_max[fled_id];
> +     setting->step = TORCH_IOUT_STEP;
> +     setting->val = setting->max;
> +
> +     /* Init flash intensity setting */
> +     setting = &s->flash_brightness;
> +     setting->min = FLASH_IOUT_MIN;
> +     setting->max = led->iout_joint ?
> +             cfg->iout_flash_max[FLED1] + cfg->iout_flash_max[FLED2] :
> +             cfg->iout_flash_max[fled_id];
> +     setting->step = FLASH_IOUT_STEP;
> +     setting->val = setting->max;
> +
> +     /* Init flash timeout setting */
> +     setting = &s->flash_timeout;
> +     setting->min = FLASH_TIMEOUT_MIN;
> +     setting->max = cfg->flash_timeout[fled_id];
> +     setting->step = FLASH_TIMEOUT_STEP;
> +     setting->val = setting->max;
> +}
> +
> +static void max77693_init_fled_cdev(struct max77693_led_device *led,
> +                             int fled_id,
> +                             struct max77693_led_config_data *cfg)
> +{
> +     struct led_classdev_flash *fled_cdev;
> +     struct led_classdev *led_cdev;
> +     struct max77693_sub_led *sub_led = &led->sub_leds[fled_id];
> +     struct max77693_led_settings settings;
> +
> +     /* Initialize flash settings */
> +     max77693_init_flash_settings(led, fled_id, cfg, &settings);
> +
> +     /* Initialize LED Flash class device */
> +     fled_cdev = &sub_led->fled_cdev;
> +     fled_cdev->ops = &flash_ops;
> +     led_cdev = &fled_cdev->led_cdev;
> +
> +     if (cfg->label[fled_id])
> +             led_cdev->name = cfg->label[fled_id];
> +     else
> +             led_cdev->name = (fled_id == FLED1) ? MAX77693_LED1_NAME :
> +                                                   MAX77693_LED2_NAME;
> +
> +     led_cdev->brightness_set = max77693_led_brightness_set;
> +     led_cdev->brightness_set_sync = max77693_led_brightness_set_sync;
> +     INIT_WORK(&sub_led->work_brightness_set,
> +                     max77693_led_brightness_set_work);
> +
> +     led_cdev->max_brightness = settings.torch_brightness.val /
> +                                     TORCH_IOUT_STEP;
> +     led_cdev->flags |= LED_DEV_CAP_FLASH;
> +
> +     fled_cdev->brightness = settings.flash_brightness;
> +     fled_cdev->timeout = settings.flash_timeout;
> +     sub_led->flash_timeout = fled_cdev->timeout.val;
> +}
> +
> +static int max77693_led_probe(struct platform_device *pdev)
> +{
> +     struct device *dev = &pdev->dev;
> +     struct max77693_dev *iodev = dev_get_drvdata(dev->parent);
> +     struct max77693_led_device *led;
> +     struct max77693_sub_led *sub_leds;
> +     struct max77693_led_config_data cfg = {};
> +     int init_fled_cdev[2], i, ret;
> +
> +     led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
> +     if (!led)
> +             return -ENOMEM;
> +
> +     led->pdev = pdev;
> +     led->regmap = iodev->regmap;
> +     led->allowed_modes = MODE_FLASH_MASK;
> +     sub_leds = led->sub_leds;
> +
> +     platform_set_drvdata(pdev, led);
> +     ret = max77693_led_get_configuration(led, &cfg);
> +     if (ret < 0)
> +             return ret;
> +
> +     ret = max77693_setup(led, &cfg);
> +     if (ret < 0)
> +             return ret;
> +
> +     init_fled_cdev[FLED1] =
> +                     led->iout_joint || max77693_fled_used(led, FLED1);
> +     init_fled_cdev[FLED2] =
> +                     !led->iout_joint && max77693_fled_used(led, FLED2);
> +
> +     /* Initialize LED Flash class device(s) */
> +     for (i = FLED1; i <= FLED2; ++i)
> +             if (init_fled_cdev[i])
> +                     max77693_init_fled_cdev(led, i, &cfg);
> +     mutex_init(&led->lock);
> +
> +     /* Register LED Flash class device(s) */
> +     for (i = FLED1; i <= FLED2; ++i) {
> +             if (!init_fled_cdev[i])
> +                     continue;
> +
> +             ret = led_classdev_flash_register(dev, &sub_leds[i].fled_cdev);
> +             if (ret < 0) {
> +                     /*
> +                      * At this moment FLED1 might have been already
> +                      * registered and it needs to be released.
> +                      */
> +                     if (i == FLED2)
> +                             goto err_register_led2;
> +                     else
> +                             goto err_register_led1;
> +             }
> +     }
> +
> +     return 0;
> +
> +err_register_led2:
> +     /* It is possible than only FLED2 was to be registered */
> +     if (!init_fled_cdev[FLED1])
> +             goto err_register_led1;
> +     led_classdev_flash_unregister(&sub_leds[FLED1].fled_cdev);
> +err_register_led1:
> +     mutex_destroy(&led->lock);
> +
> +     return ret;
> +}
> +
> +static int max77693_led_remove(struct platform_device *pdev)
> +{
> +     struct max77693_led_device *led = platform_get_drvdata(pdev);
> +     struct max77693_sub_led *sub_leds = led->sub_leds;
> +
> +     if (led->iout_joint || max77693_fled_used(led, FLED1)) {
> +             led_classdev_flash_unregister(&sub_leds[FLED1].fled_cdev);
> +             cancel_work_sync(&sub_leds[FLED1].work_brightness_set);
> +     }
> +
> +     if (!led->iout_joint && max77693_fled_used(led, FLED2)) {
> +             led_classdev_flash_unregister(&sub_leds[FLED2].fled_cdev);
> +             cancel_work_sync(&sub_leds[FLED2].work_brightness_set);
> +     }
> +
> +     mutex_destroy(&led->lock);
> +
> +     return 0;
> +}
> +
> +static const struct of_device_id max77693_led_dt_match[] = {
> +     {.compatible = "maxim,max77693-led"},
> +     {},
> +};
> +
> +static struct platform_driver max77693_led_driver = {
> +     .probe          = max77693_led_probe,
> +     .remove         = max77693_led_remove,
> +     .driver         = {
> +             .name   = "max77693-led",
> +             .owner  = THIS_MODULE,
> +             .of_match_table = max77693_led_dt_match,
> +     },
> +};
> +
> +module_platform_driver(max77693_led_driver);
> +
> +MODULE_AUTHOR("Jacek Anaszewski <j.anaszew...@samsung.com>");
> +MODULE_AUTHOR("Andrzej Hajda <a.ha...@samsung.com>");
> +MODULE_DESCRIPTION("Maxim MAX77693 led flash driver");
> +MODULE_LICENSE("GPL v2");

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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