Re: [PATCH net-next + leds v2 2/7] leds: add generic API for LEDs that can be controlled by hardware

On 9/9/20 11:31 AM, Marek Behún wrote:

On Wed, 9 Sep 2020 11:20:00 -0700
Randy Dunlap [off-list ref] wrote:

quoted

Hi,

On 9/9/20 9:25 AM, Marek Behún wrote:

quoted

Many an ethernet PHY (and other chips) supports various HW control
modes for LEDs connected directly to them.

This patch adds a generic API for registering such LEDs when
described in device tree. This API also exposes generic way to
select between these hardware control modes.

This API registers a new private LED trigger called dev-hw-mode.
When this trigger is enabled for a LED, the various HW control
modes which are supported by the device for given LED can be
get/set via hw_mode sysfs file.

Signed-off-by: Marek Behún <redacted>
---
 .../sysfs-class-led-trigger-dev-hw-mode       |   8 +
 drivers/leds/Kconfig                          |  10 +
 drivers/leds/Makefile                         |   1 +
 drivers/leds/leds-hw-controlled.c             | 227
++++++++++++++++++ include/linux/leds-hw-controlled.h            |
74 ++++++ 5 files changed, 320 insertions(+)
 create mode 100644
Documentation/ABI/testing/sysfs-class-led-trigger-dev-hw-mode
create mode 100644 drivers/leds/leds-hw-controlled.c create mode
100644 include/linux/leds-hw-controlled.h 

quoted

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 1c181df24eae4..5e47ab21aafb4 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig

@@ -49,6 +49,16 @@ config LEDS_BRIGHTNESS_HW_CHANGED
 
 	  See Documentation/ABI/testing/sysfs-class-led for

details. 
+config LEDS_HW_CONTROLLED
+	bool "API for LEDs that can be controlled by hardware"
+	depends on LEDS_CLASS  

	depends on OF || COMPILE_TEST
?

I specifically did not add OF dependency so that this can be also used
on non-OF systems. A device driver may register such LED itself...
That's why hw_controlled_led_brightness_set symbol is exported.

Do you think I shouldn't do it?

I have no problem with it as it is.

quoted

quoted

+	select LEDS_TRIGGERS
+	help
+	  This option enables support for a generic API via which
other drivers
+	  can register LEDs that can be put into hardware
controlled mode, eg.  

thanks.
-- 
~Randy