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/*
* 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++;
}
}
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