/*
 * Use the code below to control the brightness of the LEDs using
 * Linux LED framework instead of manipulating gpio pins or i2c registers
 * directly in the mts-io module.
 *
 * Usage:
 *
 * # associate a mts-io sysfs entry with the specific LEDs
 * echo led-sig1 > /sys/class/leds/pca955x:0/trigger
 * echo led-sig2 > /sys/class/leds/pca955x:1/trigger
 * echo led-sig3 > /sys/class/leds/pca955x:2/trigger
 *
 * # change the brightness
 * echo 1 > /sys/device/platform/mts-io/led-sig1
 * echo 1 > /sys/device/platform/mts-io/led-sig2
 *
 */

struct mts_led {
	const char label[32];          /* led name exposed by the mts-io kernel module */
	struct led_trigger *trigger;   /* linux led trigger */
};

static struct mts_led *mts_leds = NULL;

/*
 * Find a LED descriptor in mts_leds array by label name
 */
static
struct mts_led *mts_led_by_label(const char *label)
{
	struct mts_led *led = mts_leds;

	while (led && *led->label) {
		if (strcmp(led->label, label) == 0) {
			return led;
		}
		led++;
	}

	log_error("led with %s label is not found", label);

	return NULL;
}

/*
 * Change brightness for Linux LEDs devices
 */
static
void mts_led_set(const struct mts_led *led, int value)
{
	enum led_brightness brightness = LED_OFF;

	if (value != 0) brightness = LED_FULL;

	if (led->trigger) {
		led_trigger_event(led->trigger, brightness);
	}

	/*
	 * Note: there are also led_trigger_blink and led_trigger_blink_oneshot
	 *       functions which can potentially be used
	 */
}

/*
 * Blink one shot
 */
static
void mts_led_blink(const struct mts_led *led,
                   unsigned long *delay_on, unsigned long *delay_off,  int invert)
{
	if (led->trigger) {
		 led_trigger_blink_oneshot(led->trigger, delay_on, delay_off, invert);
	}
}


/*
 * Use the function to get current LED brightness for sysfs entry
 */
static
ssize_t mts_attr_show_led(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "%d\n", 0);
}

/*
 * Use the function to set LED brightness from sysfs entry
 */
static
ssize_t mts_attr_store_led(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	int value;

	const struct mts_led *led = mts_led_by_label(attr->attr.name);

	if (!led) {
		return -ENODEV;
	}

	if (sscanf(buf, "%i", &value) != 1) {
		return -EINVAL;
	}

	mts_led_set(led, value);

	return count;
}

/*
 * Register a LED trigger for each LED declared in the mts_leds array
 * Use in mts-io startup code.
 */
static
void mts_leds_register(void)
{
	struct mts_led *led = mts_leds;

	while (led && *led->label) {
		log_info("Registering %s led trigger", led->label);
		led_trigger_register_simple(led->label, &led->trigger);
		led++;
	}
}

/*
 * Unregister all registered LED triggers.
 * Use in mts-io cleanup code.
 */
static
void mts_leds_unregister(void)
{
	struct mts_led *led = mts_leds;

	while (led && *led->label) {
		log_info("Unregistering %s led trigger", led->label);
		if (led->trigger) {
			led_trigger_unregister_simple(led->trigger);
			led->trigger = NULL;
		}
		led++;
	}
}