greybus: lights: add lights implementation

This patch adds lights implementation for Greybus Lights class, it
allows multiplexing of lights devices using the same connection. Also
adds two sysfs entries to led class (color, fade) which are commonly
used in several existing LED devices.

It support 2 major class of devices (normal LED and flash type), for
the first it registers to led_classdev, for the latest it registers in
the led_classdev_flash and v4l2_flash, depending on the support of the
kernel version.

Each Module can have N light devices attach and each light can have
multiple channel associated:
glights
   |->light0
   |     |->channel0
   |     |->channel1
   |     | ....
   |     |->channeln
   |->...
   |->lightn
         |->channel0
         |->channel1
         | ....
         |->channeln

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

1 files changed, 1201 insertions, 0 deletions

diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c
new file mode 100644
index 000000000000..e8ef7f5c37a0
--- /dev/null
+++ b/drivers/staging/greybus/light.c
@@ -0,0 +1,1201 @@
+/*
+ * Greybus Lights protocol driver.
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/version.h>
+
+#include "greybus.h"
+#include "greybus_protocols.h"
+
+#define NAMES_MAX	32
+
+struct gb_channel {
+	u8				id;
+	u32				flags;
+	u32				color;
+	char				*color_name;
+	u8				fade_in;
+	u8				fade_out;
+	u32				mode;
+	char				*mode_name;
+	struct attribute		**attrs;
+	struct attribute_group		*attr_group;
+	const struct attribute_group	**attr_groups;
+	struct work_struct		work_brightness_set;
+	struct led_classdev		*led;
+#ifdef LED_HAVE_FLASH
+	struct led_classdev_flash	fled;
+	struct led_flash_setting	intensity_uA;
+	struct led_flash_setting	timeout_us;
+#else
+	struct led_classdev		cled;
+#endif
+	struct gb_light			*light;
+	bool				is_registered;
+	bool				releasing;
+	bool				strobe_state;
+};
+
+struct gb_light {
+	u8			id;
+	char			*name;
+	struct gb_lights	*glights;
+	u32			flags;
+	u8			channels_count;
+	struct gb_channel	*channels;
+	bool			has_flash;
+#ifdef V4L2_HAVE_FLASH
+	struct v4l2_flash	*v4l2_flash;
+#endif
+};
+
+struct gb_lights {
+	struct gb_connection	*connection;
+	u8			lights_count;
+	struct gb_light		*lights;
+	struct mutex		lights_lock;
+};
+
+static void gb_lights_channel_free(struct gb_channel *channel);
+
+static struct gb_connection *get_conn_from_channel(struct gb_channel *channel)
+{
+	return channel->light->glights->connection;
+}
+
+static struct gb_connection *get_conn_from_light(struct gb_light *light)
+{
+	return light->glights->connection;
+}
+
+static bool is_channel_flash(struct gb_channel *channel)
+{
+	return !!(channel->mode & (GB_CHANNEL_MODE_FLASH | GB_CHANNEL_MODE_TORCH
+				   | GB_CHANNEL_MODE_INDICATOR));
+}
+
+#ifdef LED_HAVE_FLASH
+static struct gb_channel *get_channel_from_cdev(struct led_classdev *cdev)
+{
+	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(cdev);
+
+	return container_of(fled_cdev, struct gb_channel, fled);
+}
+
+static struct led_classdev *get_channel_cdev(struct gb_channel *channel)
+{
+	return &channel->fled.led_cdev;
+}
+
+static struct gb_channel *get_channel_from_mode(struct gb_light *light,
+						u32 mode)
+{
+	struct gb_channel *channel = NULL;
+	int i;
+
+	for (i = 0; i < light->channels_count; i++) {
+		channel = &light->channels[i];
+		if (channel && channel->mode == mode)
+			break;
+	}
+	return channel;
+}
+
+static int __gb_lights_flash_intensity_set(struct gb_channel *channel,
+					   u32 intensity)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_lights_set_flash_intensity_request req;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.intensity_uA = cpu_to_le32(intensity);
+
+	return gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_FLASH_INTENSITY,
+				 &req, sizeof(req), NULL, 0);
+}
+
+static int __gb_lights_flash_brightness_set(struct gb_channel *channel)
+{
+	u32 intensity;
+
+	/* If the channel is flash we need to get the attached torch channel */
+	if (channel->mode & GB_CHANNEL_MODE_FLASH)
+		channel = get_channel_from_mode(channel->light,
+						GB_CHANNEL_MODE_TORCH);
+
+	/* For not flash we need to convert brightness to intensity */
+	intensity = channel->intensity_uA.min +
+			(channel->intensity_uA.step * channel->led->brightness);
+
+	return __gb_lights_flash_intensity_set(channel, intensity);
+}
+#else /* LED_HAVE_FLASH */
+static struct gb_channel *get_channel_from_cdev(struct led_classdev *cdev)
+{
+	return container_of(cdev, struct gb_channel, cled);
+}
+
+static struct led_classdev *get_channel_cdev(struct gb_channel *channel)
+{
+	return &channel->cled;
+}
+
+static int __gb_lights_flash_brightness_set(struct gb_channel *channel)
+{
+	return 0;
+}
+#endif /* !LED_HAVE_FLASH */
+
+#ifdef LED_HAVE_GROUPS
+static int gb_lights_color_set(struct gb_channel *channel, u32 color);
+static int gb_lights_fade_set(struct gb_channel *channel);
+
+#ifdef LED_HAVE_LOCK
+static void led_lock(struct led_classdev *cdev)
+{
+	mutex_lock(&cdev->led_access);
+}
+
+static void led_unlock(struct led_classdev *cdev)
+{
+	mutex_unlock(&cdev->led_access);
+}
+#else
+static void led_lock(struct led_classdev *cdev)
+{
+}
+
+static void led_unlock(struct led_classdev *cdev)
+{
+}
+#endif /* !LED_HAVE_LOCK */
+
+#define gb_lights_fade_attr(__dir)					\
+static ssize_t fade_##__dir##_show(struct device *dev,			\
+				   struct device_attribute *attr,	\
+				   char *buf)				\
+{									\
+	struct led_classdev *cdev = dev_get_drvdata(dev);		\
+	struct gb_channel *channel = get_channel_from_cdev(cdev);	\
+									\
+	return sprintf(buf, "%u\n", channel->fade_##__dir);		\
+}									\
+									\
+static ssize_t fade_##__dir##_store(struct device *dev,			\
+				    struct device_attribute *attr,	\
+				    const char *buf, size_t size)	\
+{									\
+	struct led_classdev *cdev = dev_get_drvdata(dev);		\
+	struct gb_channel *channel = get_channel_from_cdev(cdev);	\
+	u8 fade;							\
+	int ret;							\
+									\
+	led_lock(cdev);							\
+	if (led_sysfs_is_disabled(cdev)) {				\
+		ret = -EBUSY;						\
+		goto unlock;						\
+	}								\
+									\
+	ret = kstrtou8(buf, 0, &fade);					\
+	if (ret < 0) {							\
+		dev_err(dev, "could not parse fade value %d\n", ret);	\
+		goto unlock;						\
+	}								\
+	if (channel->fade_##__dir == fade)				\
+		goto unlock;						\
+	channel->fade_##__dir = fade;					\
+									\
+	ret = gb_lights_fade_set(channel);				\
+	if (ret < 0)							\
+		goto unlock;						\
+									\
+	ret = size;							\
+unlock:									\
+	led_unlock(cdev);						\
+	return ret;							\
+}									\
+static DEVICE_ATTR_RW(fade_##__dir)
+
+gb_lights_fade_attr(in);
+gb_lights_fade_attr(out);
+
+static ssize_t color_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct led_classdev *cdev = dev_get_drvdata(dev);
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+
+	return sprintf(buf, "0x%08x\n", channel->color);
+}
+
+static ssize_t color_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t size)
+{
+	struct led_classdev *cdev = dev_get_drvdata(dev);
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+	u32 color;
+	int ret;
+
+	led_lock(cdev);
+	if (led_sysfs_is_disabled(cdev)) {
+		ret = -EBUSY;
+		goto unlock;
+	}
+	ret = kstrtou32(buf, 0, &color);
+	if (ret < 0) {
+		dev_err(dev, "could not parse color value %d\n", ret);
+		goto unlock;
+	}
+
+	ret = gb_lights_color_set(channel, color);
+	if (ret < 0)
+		goto unlock;
+
+	channel->color = color;
+	ret = size;
+unlock:
+	led_unlock(cdev);
+	return ret;
+}
+static DEVICE_ATTR_RW(color);
+
+static int channel_attr_groups_set(struct gb_channel *channel,
+				   struct led_classdev *cdev)
+{
+	int attr = 0;
+	int size = 0;
+
+	if (channel->flags & GB_LIGHT_CHANNEL_MULTICOLOR)
+		size++;
+	if (channel->flags & GB_LIGHT_CHANNEL_FADER)
+		size++;
+
+	if (!size)
+		return 0;
+
+	/* Set attributes based in the channel flags */
+	channel->attrs = kcalloc(size, sizeof(**channel->attrs), GFP_KERNEL);
+	if (!channel->attrs)
+		return -ENOMEM;
+	channel->attr_group = kcalloc(1, sizeof(*channel->attr_group),
+				      GFP_KERNEL);
+	if (!channel->attr_group)
+		return -ENOMEM;
+	channel->attr_groups = kcalloc(2, sizeof(*channel->attr_groups),
+				       GFP_KERNEL);
+	if (!channel->attr_groups)
+		return -ENOMEM;
+
+	if (channel->flags & GB_LIGHT_CHANNEL_MULTICOLOR)
+		channel->attrs[attr++] = &dev_attr_color.attr;
+	if (channel->flags & GB_LIGHT_CHANNEL_FADER) {
+		channel->attrs[attr++] = &dev_attr_fade_in.attr;
+		channel->attrs[attr++] = &dev_attr_fade_out.attr;
+	}
+
+	channel->attr_group->attrs = channel->attrs;
+
+	channel->attr_groups[0] = channel->attr_group;
+
+	cdev->groups = channel->attr_groups;
+
+	return 0;
+}
+
+static int gb_lights_fade_set(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_lights_set_fade_request req;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.fade_in = channel->fade_in;
+	req.fade_out = channel->fade_out;
+	return gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_FADE,
+				 &req, sizeof(req), NULL, 0);
+}
+
+static int gb_lights_color_set(struct gb_channel *channel, u32 color)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_lights_set_color_request req;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.color = cpu_to_le32(color);
+	return gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_COLOR,
+				 &req, sizeof(req), NULL, 0);
+}
+#else /* LED_HAVE_GROUPS */
+static int channel_attr_groups_set(struct gb_channel *channel,
+				   struct led_classdev *cdev)
+{
+	return 0;
+}
+#endif /* !LED_HAVE_GROUPS */
+
+static int __gb_lights_led_brightness_set(struct gb_channel *channel)
+{
+	struct gb_lights_set_brightness_request req;
+	struct gb_connection *connection = get_conn_from_channel(channel);
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.brightness = (u8)channel->led->brightness;
+
+	return gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_BRIGHTNESS,
+				 &req, sizeof(req), NULL, 0);
+}
+
+static int __gb_lights_brightness_set(struct gb_channel *channel)
+{
+	int ret;
+
+	if (channel->releasing)
+		return 0;
+
+	if (is_channel_flash(channel))
+		ret = __gb_lights_flash_brightness_set(channel);
+	else
+		ret = __gb_lights_led_brightness_set(channel);
+
+	return ret;
+}
+
+static void gb_brightness_set_work(struct work_struct *work)
+{
+	struct gb_channel *channel = container_of(work, struct gb_channel,
+						  work_brightness_set);
+
+	__gb_lights_brightness_set(channel);
+}
+
+#ifdef LED_HAVE_SET_SYNC
+static int gb_brightness_set_sync(struct led_classdev *cdev,
+				  enum led_brightness value)
+{
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+
+	channel->led->brightness = value;
+
+	return __gb_lights_brightness_set(channel);
+}
+#endif
+
+static void gb_brightness_set(struct led_classdev *cdev,
+			      enum led_brightness value)
+{
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+
+	if (channel->releasing)
+		return;
+
+	cdev->brightness = value;
+	schedule_work(&channel->work_brightness_set);
+}
+
+static enum led_brightness gb_brightness_get(struct led_classdev *cdev)
+
+{
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+
+	return channel->led->brightness;
+}
+
+static int gb_blink_set(struct led_classdev *cdev, unsigned long *delay_on,
+			unsigned long *delay_off)
+{
+	struct gb_channel *channel = get_channel_from_cdev(cdev);
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_lights_blink_request req;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.time_on_ms = cpu_to_le16(*delay_on);
+	req.time_off_ms = cpu_to_le16(*delay_off);
+
+	return gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_BLINK, &req,
+				 sizeof(req), NULL, 0);
+}
+
+static void gb_lights_led_operations_set(struct gb_channel *channel,
+					 struct led_classdev *cdev)
+{
+	cdev->brightness_set = gb_brightness_set;
+	cdev->brightness_get = gb_brightness_get;
+#ifdef LED_HAVE_SET_SYNC
+	cdev->brightness_set_sync = gb_brightness_set_sync;
+#endif
+	INIT_WORK(&channel->work_brightness_set, gb_brightness_set_work);
+
+	if (channel->flags & GB_LIGHT_CHANNEL_BLINK)
+		cdev->blink_set = gb_blink_set;
+}
+
+#ifdef V4L2_HAVE_FLASH
+/* V4L2 specific helpers */
+static void __gb_lights_channel_v4l2_config(struct led_flash_setting *channel_s,
+					    struct led_flash_setting *v4l2_s)
+{
+	v4l2_s->min = channel_s->min;
+	v4l2_s->max = channel_s->max;
+	v4l2_s->step = channel_s->step;
+	/* For v4l2 val is the default value */
+	v4l2_s->val = channel_s->max;
+}
+
+static int gb_lights_light_v4l2_register(struct gb_light *light)
+{
+	struct gb_connection *connection = get_conn_from_light(light);
+	struct device *dev = &connection->dev;
+	struct v4l2_flash_config *sd_cfg;
+	struct led_classdev_flash *fled;
+	struct led_classdev_flash *iled = NULL;
+	struct gb_channel *channel_torch, *channel_ind, *channel_flash;
+	int ret = 0;
+
+	sd_cfg = kcalloc(1, sizeof(*sd_cfg), GFP_KERNEL);
+	if (!sd_cfg)
+		return -ENOMEM;
+
+	channel_torch = get_channel_from_mode(light, GB_CHANNEL_MODE_TORCH);
+	if (channel_torch)
+		__gb_lights_channel_v4l2_config(&channel_torch->intensity_uA,
+						&sd_cfg->torch_intensity);
+
+	channel_ind = get_channel_from_mode(light, GB_CHANNEL_MODE_INDICATOR);
+	if (channel_ind) {
+		__gb_lights_channel_v4l2_config(&channel_ind->intensity_uA,
+						&sd_cfg->indicator_intensity);
+		iled = &channel_ind->fled;
+	}
+
+	channel_flash = get_channel_from_mode(light, GB_CHANNEL_MODE_FLASH);
+	WARN_ON(!channel_flash);
+
+	fled = &channel_flash->fled;
+
+	snprintf(sd_cfg->dev_name, sizeof(sd_cfg->dev_name), "%s", light->name);
+
+	/* Set the possible values to faults, in our case all faults */
+	sd_cfg->flash_faults = LED_FAULT_OVER_VOLTAGE | LED_FAULT_TIMEOUT |
+		LED_FAULT_OVER_TEMPERATURE | LED_FAULT_SHORT_CIRCUIT |
+		LED_FAULT_OVER_CURRENT | LED_FAULT_INDICATOR |
+		LED_FAULT_UNDER_VOLTAGE | LED_FAULT_INPUT_VOLTAGE |
+		LED_FAULT_LED_OVER_TEMPERATURE;
+
+	light->v4l2_flash = v4l2_flash_init(dev, NULL, fled, iled,
+					    NULL, sd_cfg);
+	if (IS_ERR_OR_NULL(light->v4l2_flash)) {
+		ret = PTR_ERR(light->v4l2_flash);
+		goto out_free;
+	}
+
+	return ret;
+
+out_free:
+	kfree(sd_cfg);
+	return ret;
+}
+
+static void gb_lights_light_v4l2_unregister(struct gb_light *light)
+{
+	v4l2_flash_release(light->v4l2_flash);
+}
+#else
+static int gb_lights_light_v4l2_register(struct gb_light *light)
+{
+	struct gb_connection *connection = get_conn_from_light(light);
+
+	dev_err(&connection->dev, "no support for v4l2 subdevices\n");
+	return 0;
+}
+
+static void gb_lights_light_v4l2_unregister(struct gb_light *light)
+{
+}
+#endif
+
+#ifdef LED_HAVE_FLASH
+/* Flash specific operations */
+static int gb_lights_flash_intensity_set(struct led_classdev_flash *fcdev,
+					 u32 brightness)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+	int ret;
+
+	ret = __gb_lights_flash_intensity_set(channel, brightness);
+	if (ret < 0)
+		return ret;
+
+	fcdev->brightness.val = brightness;
+
+	return 0;
+}
+
+static int gb_lights_flash_intensity_get(struct led_classdev_flash *fcdev,
+					 u32 *brightness)
+{
+	*brightness = fcdev->brightness.val;
+
+	return 0;
+}
+
+static int gb_lights_flash_strobe_set(struct led_classdev_flash *fcdev,
+				      bool state)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_lights_set_flash_strobe_request req;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.state = state ? 1 : 0;
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_FLASH_STROBE,
+				&req, sizeof(req), NULL, 0);
+	if (ret < 0)
+		return ret;
+	channel->strobe_state = state;
+
+	return 0;
+}
+
+static int gb_lights_flash_strobe_get(struct led_classdev_flash *fcdev,
+				      bool *state)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+
+	*state = channel->strobe_state;
+	return 0;
+}
+
+static int gb_lights_flash_timeout_set(struct led_classdev_flash *fcdev,
+				       u32 timeout)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_lights_set_flash_timeout_request req;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+	req.timeout_us = cpu_to_le32(timeout);
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_SET_FLASH_TIMEOUT,
+				&req, sizeof(req), NULL, 0);
+	if (ret < 0)
+		return ret;
+	fcdev->timeout.val = timeout;
+
+	return 0;
+}
+
+static int gb_lights_flash_fault_get(struct led_classdev_flash *fcdev,
+				     u32 *fault)
+{
+	struct gb_channel *channel = container_of(fcdev, struct gb_channel,
+						  fled);
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_lights_get_flash_fault_request req;
+	struct gb_lights_get_flash_fault_response resp;
+	int ret;
+
+	if (channel->releasing)
+		return -ESHUTDOWN;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_GET_FLASH_FAULT,
+				&req, sizeof(req), &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	*fault = le32_to_cpu(resp.fault);
+
+	return 0;
+}
+
+static const struct led_flash_ops gb_lights_flash_ops = {
+	.flash_brightness_set	= gb_lights_flash_intensity_set,
+	.flash_brightness_get	= gb_lights_flash_intensity_get,
+	.strobe_set		= gb_lights_flash_strobe_set,
+	.strobe_get		= gb_lights_flash_strobe_get,
+	.timeout_set		= gb_lights_flash_timeout_set,
+	.fault_get		= gb_lights_flash_fault_get,
+};
+
+static int __gb_lights_channel_torch_attach(struct gb_channel *channel,
+					    struct gb_channel *channel_torch)
+{
+	char *name;
+
+	/* we can only attach torch to a flash channel */
+	if (!(channel->mode & GB_CHANNEL_MODE_FLASH))
+		return 0;
+
+	/* Move torch brightness to the destination */
+	channel->led->max_brightness = channel_torch->led->max_brightness;
+
+	/* append mode name to flash name */
+	name = kasprintf(GFP_KERNEL, "%s_%s", channel->led->name,
+			 channel_torch->mode_name);
+	if (!name)
+		return -ENOMEM;
+	kfree(channel->led->name);
+	channel->led->name = name;
+
+	/* free original torch channel resources */
+	gb_lights_channel_free(channel_torch);
+
+	channel_torch->led = channel->led;
+
+	return 0;
+}
+
+static int __gb_lights_flash_led_register(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct led_classdev_flash *fled = &channel->fled;
+	struct led_flash_setting *fset;
+	struct gb_channel *channel_torch;
+	int ret;
+
+	fled->ops = &gb_lights_flash_ops;
+
+	fled->led_cdev.flags |= LED_DEV_CAP_FLASH;
+
+	fset = &fled->brightness;
+	fset->min = channel->intensity_uA.min;
+	fset->max = channel->intensity_uA.max;
+	fset->step = channel->intensity_uA.step;
+
+	/* Only the flash mode have the timeout constraints settings */
+	if (channel->mode & GB_CHANNEL_MODE_FLASH) {
+		fset = &fled->timeout;
+		fset->min = channel->timeout_us.min;
+		fset->max = channel->timeout_us.max;
+		fset->step = channel->timeout_us.step;
+	}
+
+	/*
+	 * If light have torch mode channel, this channel will be the led
+	 * classdev of the registered above flash classdev
+	 */
+	channel_torch = get_channel_from_mode(channel->light,
+					      GB_CHANNEL_MODE_TORCH);
+	if (channel_torch) {
+		ret = __gb_lights_channel_torch_attach(channel, channel_torch);
+		if (ret < 0)
+			goto fail;
+	}
+
+	ret = led_classdev_flash_register(&connection->bundle->intf->dev,
+					  fled);
+	if (ret < 0)
+		goto fail;
+
+	channel->is_registered = true;
+	return 0;
+fail:
+	channel->led = NULL;
+	return ret;
+}
+
+static void __gb_lights_flash_led_unregister(struct gb_channel *channel)
+{
+	if (!channel->is_registered)
+		return;
+
+	led_classdev_flash_unregister(&channel->fled);
+}
+
+static int gb_lights_channel_flash_config(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct gb_lights_get_channel_flash_config_request req;
+	struct gb_lights_get_channel_flash_config_response conf;
+	struct led_flash_setting *fset;
+	int ret;
+
+	req.light_id = channel->light->id;
+	req.channel_id = channel->id;
+
+	ret = gb_operation_sync(connection,
+				GB_LIGHTS_TYPE_GET_CHANNEL_FLASH_CONFIG,
+				&req, sizeof(req), &conf, sizeof(conf));
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Intensity constraints for flash related modes: flash, torch,
+	 * indicator.  They will be needed for v4l2 registration.
+	 */
+	fset = &channel->intensity_uA;
+	fset->min = le32_to_cpu(conf.intensity_min_uA);
+	fset->max = le32_to_cpu(conf.intensity_max_uA);
+	fset->step = le32_to_cpu(conf.intensity_step_uA);
+
+	/*
+	 * On flash type, max brightness is set as the number of intensity steps
+	 * available.
+	 */
+	channel->led->max_brightness = (fset->max - fset->min) / fset->step;
+
+	/* Only the flash mode have the timeout constraints settings */
+	if (channel->mode & GB_CHANNEL_MODE_FLASH) {
+		fset = &channel->timeout_us;
+		fset->min = le32_to_cpu(conf.timeout_min_us);
+		fset->max = le32_to_cpu(conf.timeout_max_us);
+		fset->step = le32_to_cpu(conf.timeout_step_us);
+	}
+
+	return 0;
+}
+#else
+static int gb_lights_channel_flash_config(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+
+	dev_err(&connection->dev, "no support for flash devices\n");
+	return 0;
+}
+
+static int __gb_lights_flash_led_register(struct gb_channel *channel)
+{
+	return 0;
+}
+
+static void __gb_lights_flash_led_unregister(struct gb_channel *channel)
+{
+}
+
+#endif /* LED_HAVE_FLASH */
+
+static int __gb_lights_led_register(struct gb_channel *channel)
+{
+	struct gb_connection *connection = get_conn_from_channel(channel);
+	struct led_classdev *cdev = get_channel_cdev(channel);
+	int ret;
+
+	ret = led_classdev_register(&connection->bundle->intf->dev,
+				    cdev);
+	if (ret < 0)
+		channel->led = NULL;
+	else
+		channel->is_registered = true;
+	return ret;
+}
+
+static int gb_lights_channel_register(struct gb_channel *channel)
+{
+	/* Normal LED channel, just register in led classdev and we are done */
+	if (!is_channel_flash(channel))
+		return __gb_lights_led_register(channel);
+
+	/*
+	 * Flash Type need more work, register flash classdev, indicator as
+	 * flash classdev, torch will be led classdev of the flash classdev.
+	 */
+	if (!(channel->mode & GB_CHANNEL_MODE_TORCH))
+		return __gb_lights_flash_led_register(channel);
+
+	return 0;
+}
+
+static void __gb_lights_led_unregister(struct gb_channel *channel)
+{
+	struct led_classdev *cdev = get_channel_cdev(channel);
+
+	if (!channel->is_registered)
+		return;
+
+	led_classdev_unregister(cdev);
+	channel->led = NULL;
+}
+
+static void gb_lights_channel_unregister(struct gb_channel *channel)
+{
+	/* The same as register, handle channels differently */
+	if (!is_channel_flash(channel)) {
+		__gb_lights_led_unregister(channel);
+		return;
+	}
+
+	if (channel->mode & GB_CHANNEL_MODE_TORCH)
+		__gb_lights_led_unregister(channel);
+	else
+		__gb_lights_flash_led_unregister(channel);
+}
+
+static int gb_lights_channel_config(struct gb_light *light,
+				    struct gb_channel *channel)
+{
+	struct gb_lights_get_channel_config_response conf;
+	struct gb_lights_get_channel_config_request req;
+	struct gb_connection *connection = get_conn_from_light(light);
+	struct led_classdev *cdev = get_channel_cdev(channel);
+	char *name;
+	int ret;
+
+	req.light_id = light->id;
+	req.channel_id = channel->id;
+
+	ret = gb_operation_sync(connection, GB_LIGHTS_TYPE_GET_CHANNEL_CONFIG,
+				&req, sizeof(req), &conf, sizeof(conf));
+	if (ret < 0)
+		return ret;
+
+	channel->light = light;
+	channel->mode = le32_to_cpu(conf.mode);
+	channel->flags = le32_to_cpu(conf.flags);
+	channel->color = le32_to_cpu(conf.color);
+	channel->color_name = kstrndup(conf.color_name, NAMES_MAX, GFP_KERNEL);
+	if (!channel->color_name)
+		return -ENOMEM;
+	channel->mode_name = kstrndup(conf.mode_name, NAMES_MAX, GFP_KERNEL);
+	if (!channel->mode_name)
+		return -ENOMEM;
+
+	channel->led = cdev;
+
+	name = kasprintf(GFP_KERNEL, "%s:%s:%s", light->name,
+			 channel->color_name, channel->mode_name);
+	if (!name)
+		return -ENOMEM;
+
+	cdev->name = name;
+
+	cdev->max_brightness = conf.max_brightness;
+
+	ret = channel_attr_groups_set(channel, cdev);
+	if (ret < 0)
+		return ret;
+
+	gb_lights_led_operations_set(channel, cdev);
+
+	/*
+	 * If it is not a flash related channel (flash, torch or indicator) we
+	 * are done here. If not, continue and fetch flash related
+	 * configurations.
+	 */
+	if (!is_channel_flash(channel))
+		return ret;
+
+	light->has_flash = true;
+
+	ret = gb_lights_channel_flash_config(channel);
+	if (ret < 0)
+		return ret;
+
+	return ret;
+}
+
+static int gb_lights_light_config(struct gb_lights *glights, u8 id)
+{
+	struct gb_light *light = &glights->lights[id];
+	struct gb_lights_get_light_config_request req;
+	struct gb_lights_get_light_config_response conf;
+	int ret;
+	int i;
+
+	light->glights = glights;
+	light->id = id;
+
+	req.id = id;
+
+	ret = gb_operation_sync(glights->connection,
+				GB_LIGHTS_TYPE_GET_LIGHT_CONFIG,
+				&req, sizeof(req), &conf, sizeof(conf));
+	if (ret < 0)
+		return ret;
+
+	if (!conf.channel_count)
+		return -EINVAL;
+	if (!strlen(conf.name))
+		return -EINVAL;
+
+	light->channels_count = conf.channel_count;
+	light->name = kstrndup(conf.name, NAMES_MAX, GFP_KERNEL);
+
+	light->channels = kzalloc(light->channels_count *
+				  sizeof(struct gb_channel), GFP_KERNEL);
+	if (!light->channels)
+		return -ENOMEM;
+
+	/* First we collect all the configurations for all channels */
+	for (i = 0; i < light->channels_count; i++) {
+		light->channels[i].id = i;
+		ret = gb_lights_channel_config(light, &light->channels[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	/*
+	 * Then, if everything went ok in getting configurations, we register
+	 * the classdev, flash classdev and v4l2 subsystem, if a flash device is
+	 * found.
+	 */
+	for (i = 0; i < light->channels_count; i++) {
+		ret = gb_lights_channel_register(&light->channels[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (light->has_flash) {
+		ret = gb_lights_light_v4l2_register(light);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void gb_lights_channel_free(struct gb_channel *channel)
+{
+	if (&channel->work_brightness_set)
+		flush_work(&channel->work_brightness_set);
+	kfree(channel->attrs);
+	kfree(channel->attr_group);
+	kfree(channel->attr_groups);
+	kfree(channel->color_name);
+	kfree(channel->mode_name);
+}
+
+static void gb_lights_channel_release(struct gb_channel *channel)
+{
+	if (!channel)
+		return;
+
+	channel->releasing = true;
+
+	gb_lights_channel_unregister(channel);
+
+	gb_lights_channel_free(channel);
+}
+
+static void gb_lights_light_release(struct gb_light *light)
+{
+	int i;
+	int count;
+
+	if (!light)
+		return;
+
+	count = light->channels_count;
+
+	if (light->has_flash)
+		gb_lights_light_v4l2_unregister(light);
+
+	for (i = 0; i < count; i++) {
+		gb_lights_channel_release(&light->channels[i]);
+		light->channels_count--;
+	}
+	kfree(light->channels);
+	kfree(light->name);
+}
+
+static void gb_lights_release(struct gb_lights *glights)
+{
+	int i;
+
+	if (!glights)
+		return;
+
+	mutex_lock(&glights->lights_lock);
+	if (!glights->lights)
+		goto free_glights;
+
+	for (i = 0; i < glights->lights_count; i++)
+		gb_lights_light_release(&glights->lights[i]);
+
+	kfree(glights->lights);
+
+free_glights:
+	mutex_unlock(&glights->lights_lock);
+	mutex_destroy(&glights->lights_lock);
+	kfree(glights);
+}
+
+static int gb_lights_get_count(struct gb_lights *glights)
+{
+	struct gb_lights_get_lights_response resp;
+	int ret;
+
+	ret = gb_operation_sync(glights->connection, GB_LIGHTS_TYPE_GET_LIGHTS,
+				NULL, 0, &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	if (!resp.lights_count)
+		return -EINVAL;
+
+	glights->lights_count = resp.lights_count;
+
+	return 0;
+}
+
+static int gb_lights_setup(struct gb_lights *glights)
+{
+	struct gb_connection *connection = glights->connection;
+	int ret;
+	int i;
+
+	mutex_lock(&glights->lights_lock);
+	ret = gb_lights_get_count(glights);
+	if (ret < 0)
+		goto out;
+
+	glights->lights = kzalloc(glights->lights_count *
+				  sizeof(struct gb_light), GFP_KERNEL);
+	if (!glights->lights) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	for (i = 0; i < glights->lights_count; i++) {
+		ret = gb_lights_light_config(glights, i);
+		if (ret < 0) {
+			dev_err(&connection->dev,
+				"Fail to configure lights device\n");
+			goto out;
+		}
+	}
+
+out:
+	mutex_unlock(&glights->lights_lock);
+	return ret;
+}
+
+static int gb_lights_event_recv(u8 type, struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_lights *glights = connection->private;
+	struct gb_message *request;
+	struct gb_lights_event_request *payload;
+	int ret =  0;
+	u8 light_id;
+	u8 event;
+
+	if (type != GB_LIGHTS_TYPE_EVENT) {
+		dev_err(&connection->dev,
+			"Unsupported unsolicited event: %u\n", type);
+		return -EINVAL;
+	}
+
+	request = op->request;
+
+	if (request->payload_size < sizeof(*payload)) {
+		dev_err(&connection->dev,
+			"Wrong event size received (%zu < %zu)\n",
+			request->payload_size, sizeof(*payload));
+		return -EINVAL;
+	}
+
+	payload = request->payload;
+	light_id = payload->light_id;
+
+	if (light_id >= glights->lights_count || !&glights->lights[light_id]) {
+		dev_err(&connection->dev,
+			"Event received for unconfigured light id: %d\n",
+			light_id);
+		return -EINVAL;
+	}
+
+	event = payload->event;
+
+	if (event & GB_LIGHTS_LIGHT_CONFIG) {
+		mutex_lock(&glights->lights_lock);
+		gb_lights_light_release(&glights->lights[light_id]);
+		ret = gb_lights_light_config(glights, light_id);
+		if (ret < 0)
+			gb_lights_light_release(&glights->lights[light_id]);
+		mutex_unlock(&glights->lights_lock);
+	}
+
+	return ret;
+}
+
+static int gb_lights_connection_init(struct gb_connection *connection)
+{
+	struct gb_lights *glights;
+	int ret;
+
+	glights = kzalloc(sizeof(*glights), GFP_KERNEL);
+	if (!glights)
+		return -ENOMEM;
+
+	glights->connection = connection;
+	connection->private = glights;
+
+	mutex_init(&glights->lights_lock);
+
+	/*
+	 * Setup all the lights devices over this connection, if anything goes
+	 * wrong tear down all lights
+	 */
+	ret = gb_lights_setup(glights);
+	if (ret < 0)
+		goto out;
+
+	return 0;
+
+out:
+	gb_lights_release(glights);
+	return ret;
+}
+
+static void gb_lights_connection_exit(struct gb_connection *connection)
+{
+	struct gb_lights *glights = connection->private;
+
+	gb_lights_release(glights);
+}
+
+static struct gb_protocol lights_protocol = {
+	.name			= "lights",
+	.id			= GREYBUS_PROTOCOL_LIGHTS,
+	.major			= GB_LIGHTS_VERSION_MAJOR,
+	.minor			= GB_LIGHTS_VERSION_MINOR,
+	.connection_init	= gb_lights_connection_init,
+	.connection_exit	= gb_lights_connection_exit,
+	.request_recv		= gb_lights_event_recv,
+};
+
+gb_protocol_driver(&lights_protocol);
+
+MODULE_LICENSE("GPL v2");