leds: max77693: add support for V4L2 Flash sub-device

Add support for V4L2 Flash sub-device to the max77693 LED Flash class
driver. The support allows for V4L2 Flash sub-device to take the control
of the LED Flash class device.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Bryan Wu <cooloney@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

1 files changed, 123 insertions, 6 deletions

diff --git a/drivers/leds/leds-max77693.c b/drivers/leds/leds-max77693.c
index eecaa9292b2f..b8b0eec7b540 100644
--- a/drivers/leds/leds-max77693.c
+++ b/drivers/leds/leds-max77693.c
@@ -20,6 +20,7 @@
 #include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
+#include <media/v4l2-flash-led-class.h>
 
 #define MODE_OFF                0
 #define MODE_FLASH(a)           (1 << (a))
@@ -62,6 +63,8 @@ struct max77693_sub_led {
         struct led_classdev_flash fled_cdev;
         /* assures led-triggers compatibility */
         struct work_struct work_brightness_set;
+        /* V4L2 Flash device */
+        struct v4l2_flash *v4l2_flash;
 
         /* brightness cache */
         unsigned int torch_brightness;
@@ -627,7 +630,8 @@ static int max77693_led_flash_timeout_set(
 }
 
 static int max77693_led_parse_dt(struct max77693_led_device *led,
-                                struct max77693_led_config_data *cfg)
+                                struct max77693_led_config_data *cfg,
+                                struct device_node **sub_nodes)
 {
         struct device *dev = &led->pdev->dev;
         struct max77693_sub_led *sub_leds = led->sub_leds;
@@ -674,6 +678,13 @@ static int max77693_led_parse_dt(struct max77693_led_device *led,
                         return -EINVAL;
                 }
 
+                if (sub_nodes[fled_id]) {
+                        dev_err(dev,
+                                "Conflicting \"led-sources\" DT properties\n");
+                        return -EINVAL;
+                }
+
+                sub_nodes[fled_id] = child_node;
                 sub_leds[fled_id].fled_id = fled_id;
 
                 cfg->label[fled_id] =
@@ -786,11 +797,12 @@ static void max77693_led_validate_configuration(struct max77693_led_device *led,
 }
 
 static int max77693_led_get_configuration(struct max77693_led_device *led,
-                                struct max77693_led_config_data *cfg)
+                                struct max77693_led_config_data *cfg,
+                                struct device_node **sub_nodes)
 {
         int ret;
 
-        ret = max77693_led_parse_dt(led, cfg);
+        ret = max77693_led_parse_dt(led, cfg, sub_nodes);
         if (ret < 0)
                 return ret;
 
@@ -838,6 +850,71 @@ static void max77693_init_flash_settings(struct max77693_sub_led *sub_led,
         setting->val = setting->max;
 }
 
+#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
+
+static int max77693_led_external_strobe_set(
+                                struct v4l2_flash *v4l2_flash,
+                                bool enable)
+{
+        struct max77693_sub_led *sub_led =
+                                flcdev_to_sub_led(v4l2_flash->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 (enable)
+                ret = max77693_add_mode(led, MODE_FLASH_EXTERNAL(fled_id));
+        else
+                ret = max77693_clear_mode(led, MODE_FLASH_EXTERNAL(fled_id));
+
+        mutex_unlock(&led->lock);
+
+        return ret;
+}
+
+static void max77693_init_v4l2_flash_config(struct max77693_sub_led *sub_led,
+                                struct max77693_led_config_data *led_cfg,
+                                struct v4l2_flash_config *v4l2_sd_cfg)
+{
+        struct max77693_led_device *led = sub_led_to_led(sub_led);
+        struct device *dev = &led->pdev->dev;
+        struct max77693_dev *iodev = dev_get_drvdata(dev->parent);
+        struct i2c_client *i2c = iodev->i2c;
+        struct led_flash_setting *s;
+
+        snprintf(v4l2_sd_cfg->dev_name, sizeof(v4l2_sd_cfg->dev_name),
+                 "%s %d-%04x", sub_led->fled_cdev.led_cdev.name,
+                 i2c_adapter_id(i2c->adapter), i2c->addr);
+
+        s = &v4l2_sd_cfg->torch_intensity;
+        s->min = TORCH_IOUT_MIN;
+        s->max = sub_led->fled_cdev.led_cdev.max_brightness * TORCH_IOUT_STEP;
+        s->step = TORCH_IOUT_STEP;
+        s->val = s->max;
+
+        /* Init flash faults config */
+        v4l2_sd_cfg->flash_faults = LED_FAULT_OVER_VOLTAGE |
+                                LED_FAULT_SHORT_CIRCUIT |
+                                LED_FAULT_OVER_CURRENT;
+
+        v4l2_sd_cfg->has_external_strobe = true;
+}
+
+static const struct v4l2_flash_ops v4l2_flash_ops = {
+        .external_strobe_set = max77693_led_external_strobe_set,
+};
+#else
+static inline void max77693_init_v4l2_flash_config(
+                                struct max77693_sub_led *sub_led,
+                                struct max77693_led_config_data *led_cfg,
+                                struct v4l2_flash_config *v4l2_sd_cfg)
+{
+}
+static const struct v4l2_flash_ops v4l2_flash_ops;
+#endif
+
 static void max77693_init_fled_cdev(struct max77693_sub_led *sub_led,
                                 struct max77693_led_config_data *led_cfg)
 {
@@ -870,12 +947,45 @@ static void max77693_init_fled_cdev(struct max77693_sub_led *sub_led,
         sub_led->flash_timeout = fled_cdev->timeout.val;
 }
 
+static int max77693_register_led(struct max77693_sub_led *sub_led,
+                                 struct max77693_led_config_data *led_cfg,
+                                 struct device_node *sub_node)
+{
+        struct max77693_led_device *led = sub_led_to_led(sub_led);
+        struct led_classdev_flash *fled_cdev = &sub_led->fled_cdev;
+        struct device *dev = &led->pdev->dev;
+        struct v4l2_flash_config v4l2_sd_cfg = {};
+        int ret;
+
+        /* Register in the LED subsystem */
+        ret = led_classdev_flash_register(dev, fled_cdev);
+        if (ret < 0)
+                return ret;
+
+        max77693_init_v4l2_flash_config(sub_led, led_cfg, &v4l2_sd_cfg);
+
+        /* Register in the V4L2 subsystem. */
+        sub_led->v4l2_flash = v4l2_flash_init(dev, sub_node, fled_cdev, NULL,
+                                              &v4l2_flash_ops, &v4l2_sd_cfg);
+        if (IS_ERR(sub_led->v4l2_flash)) {
+                ret = PTR_ERR(sub_led->v4l2_flash);
+                goto err_v4l2_flash_init;
+        }
+
+        return 0;
+
+err_v4l2_flash_init:
+        led_classdev_flash_unregister(fled_cdev);
+        return ret;
+}
+
 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 device_node *sub_nodes[2] = {};
         struct max77693_led_config_data led_cfg = {};
         int init_fled_cdev[2], i, ret;
 
@@ -889,7 +999,7 @@ static int max77693_led_probe(struct platform_device *pdev)
         sub_leds = led->sub_leds;
 
         platform_set_drvdata(pdev, led);
-        ret = max77693_led_get_configuration(led, &led_cfg);
+        ret = max77693_led_get_configuration(led, &led_cfg, sub_nodes);
         if (ret < 0)
                 return ret;
 
@@ -911,8 +1021,12 @@ static int max77693_led_probe(struct platform_device *pdev)
                 /* Initialize LED Flash class device */
                 max77693_init_fled_cdev(&sub_leds[i], &led_cfg);
 
-                /* Register LED Flash class device */
-                ret = led_classdev_flash_register(dev, &sub_leds[i].fled_cdev);
+                /*
+                 * Register LED Flash class device and corresponding
+                 * V4L2 Flash device.
+                 */
+                ret = max77693_register_led(&sub_leds[i], &led_cfg,
+                                                sub_nodes[i]);
                 if (ret < 0) {
                         /*
                          * At this moment FLED1 might have been already
@@ -931,6 +1045,7 @@ err_register_led2:
         /* It is possible than only FLED2 was to be registered */
         if (!init_fled_cdev[FLED1])
                 goto err_register_led1;
+        v4l2_flash_release(sub_leds[FLED1].v4l2_flash);
         led_classdev_flash_unregister(&sub_leds[FLED1].fled_cdev);
 err_register_led1:
         mutex_destroy(&led->lock);
@@ -944,11 +1059,13 @@ static int max77693_led_remove(struct platform_device *pdev)
         struct max77693_sub_led *sub_leds = led->sub_leds;
 
         if (led->iout_joint || max77693_fled_used(led, FLED1)) {
+                v4l2_flash_release(sub_leds[FLED1].v4l2_flash);
                 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)) {
+                v4l2_flash_release(sub_leds[FLED2].v4l2_flash);
                 led_classdev_flash_unregister(&sub_leds[FLED2].fled_cdev);
                 cancel_work_sync(&sub_leds[FLED2].work_brightness_set);
         }