Add configure_offload helper to configure how the LED should work in
offload mode. The function require to support the particular trigger and
will use the passed offload_flags to elaborate the data and apply the
correct configuration. This function will then be used by the offload
trigger to request and update offload configuration.
Signed-off-by: Ansuel Smith <ansuelsmth@xxxxxxxxx>
---
Documentation/leds/leds-class.rst | 24 ++++++++++++++++++++++++
include/linux/leds.h | 28 ++++++++++++++++++++++++++++
2 files changed, 52 insertions(+)
diff --git a/Documentation/leds/leds-class.rst b/Documentation/leds/leds-class.rst
index 5bf6e5d471ce..0a3bbe71dac7 100644
--- a/Documentation/leds/leds-class.rst
+++ b/Documentation/leds/leds-class.rst
@@ -190,6 +190,30 @@ If the second argument (enable) to the trigger_offload() method is false, any
active HW offloading must be deactivated. In this case errors are not permitted
in the trigger_offload() method and the driver will be set to the new trigger.
+The offload trigger will use the function configure_offload() provided by the driver
+that will configure the offloaded mode for the LED.
+This function passes as the first argument (offload_flags) a u32 flag.
+The second argument (cmd) of the configure_offload() method can be used to do various
+operations for the specific trigger. We currently support ENABLE, DISABLE, READ and
+SUPPORTED to enable, disable, read the state of the offload trigger and ask the LED
+driver supports the specific offload trigger.
+
+In ENABLE/DISABLE configure_offload() should configure the LED to enable/disable the
+requested trigger (flags).
+In READ configure_offload() should return 0 or 1 based on the status of the requested
+trigger (flags).
+In SUPPORTED configure_offload() should return 0 or 1 if the LED driver supports the
+requested trigger (flags) or not.
+
+The u32 flag is specific to the trigger and change across them. It's in the LED
+driver interest know how to elaborate this flag and to declare support for a
+particular offload trigger. For this exact reason explicit support for the specific
+trigger is mandatory or the driver returns -EOPNOTSUPP if asked to enter offload mode
+with a not supported trigger.
+If the driver returns -EOPNOTSUPP on configure_offload(), the trigger activation will
+fail as the driver doesn't support that specific offload trigger or doesn't know
+how to handle the provided flags.
+
Known Issues
============
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 949ab461287f..2a1e60e4d73e 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -67,6 +67,15 @@ struct led_hw_trigger_type {
int dummy;
};
+#ifdef CONFIG_LEDS_OFFLOAD_TRIGGERS
+enum offload_trigger_cmd {
+ TRIGGER_ENABLE, /* Enable the offload trigger */
+ TRIGGER_DISABLE, /* Disable the offload trigger */
+ TRIGGER_READ, /* Read the status of the offload trigger */
+ TRIGGER_SUPPORTED, /* Ask the driver if the trigger is supported */
+};
+#endif
+
struct led_classdev {
const char *name;
unsigned int brightness;
@@ -160,6 +169,14 @@ struct led_classdev {
/* some LEDs cne be driven by HW */
int (*trigger_offload)(struct led_classdev *led_cdev,
bool enable);
+ /* Function to configure how the LEDs should work in offload mode.
+ * The function require to support the trigger and will use the
+ * passed flags to elaborate the trigger requested and apply the
+ * correct configuration.
+ */
+ int (*configure_offload)(struct led_classdev *led_cdev,
+ u32 offload_flags,
+ enum offload_trigger_cmd cmd);
#endif
#endif
@@ -417,6 +434,17 @@ static inline void *led_get_trigger_data(struct led_classdev *led_cdev)
}
#ifdef CONFIG_LEDS_OFFLOAD_TRIGGERS
+bool led_trigger_offload_is_supported(struct led_classdev *led_cdev, u32 flags)
+{
+ int ret;
+
+ ret = led_cdev->configure_offload(led_cdev, flags, TRIGGER_SUPPORTED);
+ if (ret > 0)
+ return true;
+
+ return false;
+}
+
static inline int led_trigger_offload(struct led_classdev *led_cdev)
{
int ret;
--
2.32.0
