Recall that on Turris Omnia, the LED controller has a global brightness
property, which allows the user to make the front LED panel dimmer.
There is also a button on the front panel, which by default is
configured so that pressing it changes the global brightness to a lower
value (unless it is at 0%, in which case pressing the button changes the
global brightness to 100%).
Newer versions of the MCU firmware support informing the SOC that the
brightness was changed by button press event via an interrupt.
Now that we have the turris-omnia-mcu driver, which adds support for MCU
interrupts, add the ability to inform the userspace (via a sysfs
notification) that the global brightness was changed.
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
---
drivers/leds/Kconfig | 1 +
drivers/leds/leds-turris-omnia.c | 62 ++++++++++++++++++++++++++++++++
2 files changed, 63 insertions(+)
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index fcbe93b61e49..9ab6b56898c6 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -218,6 +218,7 @@ config LEDS_TURRIS_OMNIA
depends on MACH_ARMADA_38X || COMPILE_TEST
depends on OF
depends on TURRIS_OMNIA_MCU
+ depends on TURRIS_OMNIA_MCU_GPIO
select LEDS_TRIGGERS
help
This option enables basic support for the LEDs found on the front
diff --git a/drivers/leds/leds-turris-omnia.c b/drivers/leds/leds-turris-omnia.c
index b60c34f57d0e..61186c3a6c2f 100644
--- a/drivers/leds/leds-turris-omnia.c
+++ b/drivers/leds/leds-turris-omnia.c
@@ -43,12 +43,15 @@ struct omnia_led {
* @client: I2C client device
* @lock: mutex to protect cached state
* @has_gamma_correction: whether the MCU firmware supports gamma correction
+ * @brightness_knode: kernel node of the "brightness" device sysfs attribute (this is the
+ * driver specific global brightness, not the LED classdev brightness)
* @leds: flexible array of per-LED data
*/
struct omnia_leds {
struct i2c_client *client;
struct mutex lock;
bool has_gamma_correction;
+ struct kernfs_node *brightness_knode;
struct omnia_led leds[];
};
@@ -373,6 +376,59 @@ static struct attribute *omnia_led_controller_attrs[] = {
};
ATTRIBUTE_GROUPS(omnia_led_controller);
+static irqreturn_t omnia_brightness_changed_threaded_fn(int irq, void *data)
+{
+ struct omnia_leds *leds = data;
+
+ if (unlikely(!leds->brightness_knode)) {
+ /*
+ * Note that sysfs_get_dirent() may sleep. This is okay, because we are in threaded
+ * context.
+ */
+ leds->brightness_knode = sysfs_get_dirent(leds->client->dev.kobj.sd, "brightness");
+ if (!leds->brightness_knode)
+ return IRQ_NONE;
+ }
+
+ sysfs_notify_dirent(leds->brightness_knode);
+
+ return IRQ_HANDLED;
+}
+
+static void omnia_brightness_knode_put(void *data)
+{
+ struct omnia_leds *leds = data;
+
+ if (leds->brightness_knode)
+ sysfs_put(leds->brightness_knode);
+}
+
+static int omnia_request_brightness_irq(struct omnia_leds *leds)
+{
+ struct device *dev = &leds->client->dev;
+ int ret;
+
+ if (!leds->client->irq) {
+ dev_info(dev,
+ "Brightness change interrupt supported by MCU firmware but not described in device-tree\n");
+
+ return 0;
+ }
+
+ /*
+ * Registering the brightness_knode destructor before requesting the IRQ ensures that on
+ * removal the brightness_knode sysfs node is put only after the IRQ is freed.
+ * This is needed because the interrupt handler uses the knode.
+ */
+ ret = devm_add_action(dev, omnia_brightness_knode_put, leds);
+ if (ret < 0)
+ return ret;
+
+ return devm_request_threaded_irq(dev, leds->client->irq, NULL,
+ omnia_brightness_changed_threaded_fn, IRQF_ONESHOT,
+ "leds-turris-omnia", leds);
+}
+
static int omnia_mcu_get_features(const struct i2c_client *mcu_client)
{
u16 reply;
@@ -459,6 +515,12 @@ static int omnia_leds_probe(struct i2c_client *client)
"Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
}
+ if (ret & OMNIA_FEAT_BRIGHTNESS_INT) {
+ ret = omnia_request_brightness_irq(leds);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Cannot request brightness IRQ\n");
+ }
+
mutex_init(&leds->lock);
ret = devm_led_trigger_register(dev, &omnia_hw_trigger);
--
2.45.2
