[PATCH v5 07/11] media: v4l2-core: Make the v4l2-core code enable/disable the privacy LED if present

[Hans de Goede <hdegoede@redhat.com>]

Make v4l2_async_register_subdev_sensor() try to get a privacy LED
associated with the sensor and extend the call_s_stream() wrapper to
enable/disable the privacy LED if found.

This makes the core handle privacy LED control, rather then having to
duplicate this code in all the sensor drivers.

Suggested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v4 (requested by Laurent Pinchart):
- Move the led_get() call to v4l2_async_register_subdev_sensor() and
  make errors other then -ENOENT fail the register() call.
- Move the led_disable_sysfs() call to be done at led_get() time, instead
  of only disabling the sysfs interface when the sensor is streaming.
---
 drivers/media/v4l2-core/v4l2-fwnode.c | 15 +++++++++++++++
 drivers/media/v4l2-core/v4l2-subdev.c | 18 ++++++++++++++++++
 include/media/v4l2-subdev.h           |  3 +++
 3 files changed, 36 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index c8a2264262bc..cfac1e2ae501 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -16,6 +16,7 @@
  */
 #include <linux/acpi.h>
 #include <linux/kernel.h>
+#include <linux/leds.h>
 #include <linux/mm.h>
 #include <linux/of.h>
 #include <linux/property.h>
@@ -1295,6 +1296,20 @@ int v4l2_async_register_subdev_sensor(struct v4l2_subdev *sd)
 	if (WARN_ON(!sd->dev))
 		return -ENODEV;
 
+#if IS_REACHABLE(CONFIG_LEDS_CLASS)
+	sd->privacy_led = led_get(sd->dev, "privacy-led");
+	if (IS_ERR(sd->privacy_led) && PTR_ERR(sd->privacy_led) != -ENOENT)
+		return dev_err_probe(sd->dev, PTR_ERR(sd->privacy_led), "getting privacy LED\n");
+
+	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
+		mutex_lock(&sd->privacy_led->led_access);
+		led_sysfs_disable(sd->privacy_led);
+		led_trigger_remove(sd->privacy_led);
+		led_set_brightness(sd->privacy_led, 0);
+		mutex_unlock(&sd->privacy_led->led_access);
+	}
+#endif
+
 	notifier = kzalloc(sizeof(*notifier), GFP_KERNEL);
 	if (!notifier)
 		return -ENOMEM;
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 4988a25bd8f4..f33e943aab3f 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/ioctl.h>
+#include <linux/leds.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -322,6 +323,14 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
 {
 	int ret;
 
+#if IS_REACHABLE(CONFIG_LEDS_CLASS)
+	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
+		if (enable)
+			led_set_brightness(sd->privacy_led, sd->privacy_led->max_brightness);
+		else
+			led_set_brightness(sd->privacy_led, 0);
+	}
+#endif
 	ret = sd->ops->video->s_stream(sd, enable);
 
 	if (!enable && ret < 0) {
@@ -1050,6 +1059,14 @@ EXPORT_SYMBOL_GPL(__v4l2_subdev_init_finalize);
 
 void v4l2_subdev_cleanup(struct v4l2_subdev *sd)
 {
+#if IS_REACHABLE(CONFIG_LEDS_CLASS)
+	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
+		mutex_lock(&sd->privacy_led->led_access);
+		led_sysfs_enable(sd->privacy_led);
+		mutex_unlock(&sd->privacy_led->led_access);
+		led_put(sd->privacy_led);
+	}
+#endif
 	__v4l2_subdev_state_free(sd->active_state);
 	sd->active_state = NULL;
 }
@@ -1090,6 +1107,7 @@ void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
 	sd->grp_id = 0;
 	sd->dev_priv = NULL;
 	sd->host_priv = NULL;
+	sd->privacy_led = NULL;
 #if defined(CONFIG_MEDIA_CONTROLLER)
 	sd->entity.name = sd->name;
 	sd->entity.obj_type = MEDIA_ENTITY_TYPE_V4L2_SUBDEV;
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index b15fa9930f30..0547313f98cc 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -38,6 +38,7 @@ struct v4l2_subdev;
 struct v4l2_subdev_fh;
 struct tuner_setup;
 struct v4l2_mbus_frame_desc;
+struct led_classdev;
 
 /**
  * struct v4l2_decode_vbi_line - used to decode_vbi_line
@@ -982,6 +983,8 @@ struct v4l2_subdev {
 	 * appropriate functions.
 	 */
 
+	struct led_classdev *privacy_led;
+
 	/*
 	 * TODO: active_state should most likely be changed from a pointer to an
 	 * embedded field. For the time being it's kept as a pointer to more
-- 
2.39.0