This series aims to add a led-backlight driver, similar to pwm-backlight, but using a LED class device underneath.
A few years ago (2015), Tomi Valkeinen posted a series implementing a backlight driver on top of a LED device: https://patchwork.kernel.org/patch/7293991/ https://patchwork.kernel.org/patch/7294001/ https://patchwork.kernel.org/patch/7293981/
The discussion stopped because Tomi lacked the time to work on it.
changes in v9: - let to_of_node() check if the fwnode is actually a of_node - add some checks in of_led_get() - let dev_of_node() do the check about OF availabilty - refactor led_bl_probe() to register a cleanup function with devm_add_action_or_reset(). This simplifies the error handling (which was not 100% done in v7) and allows to get rid of led_bl_remove()
changes in v8: - use class_find_device_by_of_node() instead of class_find_device() - renamed devm_led_get() as devm_of_led_get()
changes in v7: - rebased on top of linux-leds/for-next - populate the of_node member of the LED device if fwnode is a of_node (this is a new patch and the first of the series). - devm_led_get() works only when the device tree is used. Add a few checks for that.
changes in v6: - trim the list of included headers - remove useless definition of BKL_FULL_BRIGHTNESS
changes in v5: - removed LED brightness scaling - disable sysfs the interface of the LEDs when used by the backlight device
changes in v4: - fix dev_err() messages and commit logs following the advices of Pavel - cosmetic changes (indents, getting rid of "? 1 : 0" in led_match_led_node())
changes in v3: - dt binding: don't limit the brightness range to 0-255. Use the range of the underlying LEDs. as a side-effect, all LEDs must now have the same range - driver: Adapt to dt binding update. - driver: rework probe() for clarity and remove the remaining goto.
changes in v2: - handle more than one LED. - don't make the backlight device a child of the LED controller. - make brightness-levels and default-brightness-level optional - removed the option to use a GPIO enable. - removed the option to use a regulator. It should be handled by the LED core - don't make any change to the LED core (not needed anymore)
Jean-Jacques Hiblot (3): leds: populate the device's of_node leds: Add managed API to get a LED from a device driver dt-bindings: backlight: Add led-backlight binding
Tomi Valkeinen (2): leds: Add of_led_get() and led_put() backlight: add led-backlight driver
.../bindings/leds/backlight/led-backlight.txt | 28 ++ drivers/leds/led-class.c | 103 ++++++- drivers/video/backlight/Kconfig | 7 + drivers/video/backlight/Makefile | 1 + drivers/video/backlight/led_bl.c | 258 ++++++++++++++++++ include/linux/leds.h | 6 + 6 files changed, 402 insertions(+), 1 deletion(-) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt create mode 100644 drivers/video/backlight/led_bl.c
If initialization data is available and its fwnode is actually a of_node, store this information in the led device's structure. This will allow the device to use or provide OF-based API such (devm_xxx).
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com --- drivers/leds/led-class.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 647b1263c579..bfa1b1033274 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -276,8 +276,10 @@ int led_classdev_register_ext(struct device *parent, mutex_unlock(&led_cdev->led_access); return PTR_ERR(led_cdev->dev); } - if (init_data && init_data->fwnode) + if (init_data && init_data->fwnode) { led_cdev->dev->fwnode = init_data->fwnode; + led_cdev->dev->of_node = to_of_node(init_data->fwnode); + }
if (ret) dev_warn(parent, "Led %s renamed to %s due to name collision",
From: Tomi Valkeinen tomi.valkeinen@ti.com
This patch adds basic support for a kernel driver to get a LED device. This will be used by the led-backlight driver.
Only OF version is implemented for now, and the behavior is similar to PWM's of_pwm_get() and pwm_put().
Signed-off-by: Tomi Valkeinen tomi.valkeinen@ti.com Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Acked-by: Pavel Machek pavel@ucw.cz --- drivers/leds/led-class.c | 50 ++++++++++++++++++++++++++++++++++++++++ include/linux/leds.h | 4 ++++ 2 files changed, 54 insertions(+)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index bfa1b1033274..1d1f1d546dc7 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -19,6 +19,7 @@ #include <linux/spinlock.h> #include <linux/timer.h> #include <uapi/linux/uleds.h> +#include <linux/of.h> #include "leds.h"
static struct class *leds_class; @@ -214,6 +215,55 @@ static int led_resume(struct device *dev)
static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
+/** + * of_led_get() - request a LED device via the LED framework + * @np: device node to get the LED device from + * @index: the index of the LED + * + * Returns the LED device parsed from the phandle specified in the "leds" + * property of a device tree node or a negative error-code on failure. + */ +struct led_classdev *of_led_get(struct device_node *np, int index) +{ + struct device *led_dev; + struct led_classdev *led_cdev; + struct device_node *led_node; + + /* Not using device tree? */ + if (!IS_ENABLED(CONFIG_OF)) + return ERR_PTR(-ENOTSUPP); + if (!np) + return ERR_PTR(-EINVAL); + + led_node = of_parse_phandle(np, "leds", index); + if (!led_node) + return ERR_PTR(-ENOENT); + + led_dev = class_find_device_by_of_node(leds_class, led_node); + of_node_put(led_node); + + if (!led_dev) + return ERR_PTR(-EPROBE_DEFER); + + led_cdev = dev_get_drvdata(led_dev); + + if (!try_module_get(led_cdev->dev->parent->driver->owner)) + return ERR_PTR(-ENODEV); + + return led_cdev; +} +EXPORT_SYMBOL_GPL(of_led_get); + +/** + * led_put() - release a LED device + * @led_cdev: LED device + */ +void led_put(struct led_classdev *led_cdev) +{ + module_put(led_cdev->dev->parent->driver->owner); +} +EXPORT_SYMBOL_GPL(led_put); + static int led_classdev_next_name(const char *init_name, char *name, size_t len) { diff --git a/include/linux/leds.h b/include/linux/leds.h index b8df71193329..6f7371bc7757 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -20,6 +20,7 @@
struct device; struct led_pattern; +struct device_node; /* * LED Core */ @@ -196,6 +197,9 @@ extern void devm_led_classdev_unregister(struct device *parent, extern void led_classdev_suspend(struct led_classdev *led_cdev); extern void led_classdev_resume(struct led_classdev *led_cdev);
+extern struct led_classdev *of_led_get(struct device_node *np, int index); +extern void led_put(struct led_classdev *led_cdev); + /** * led_blink_set - set blinking with software fallback * @led_cdev: the LED to start blinking
If the LED is acquired by a consumer device with devm_led_get(), it is automatically released when the device is detached.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Acked-by: Pavel Machek pavel@ucw.cz --- drivers/leds/led-class.c | 49 ++++++++++++++++++++++++++++++++++++++++ include/linux/leds.h | 2 ++ 2 files changed, 51 insertions(+)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 1d1f1d546dc7..639224392ffa 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -264,6 +264,55 @@ void led_put(struct led_classdev *led_cdev) } EXPORT_SYMBOL_GPL(led_put);
+static void devm_led_release(struct device *dev, void *res) +{ + struct led_classdev **p = res; + + led_put(*p); +} + +/** + * devm_of_led_get - Resource-managed request of a LED device + * @dev: LED consumer + * @index: index of the LED to obtain in the consumer + * + * The device node of the device is parse to find the request LED device. + * The LED device returned from this function is automatically released + * on driver detach. + * + * @return a pointer to a LED device or ERR_PTR(errno) on failure. + */ +struct led_classdev *__must_check devm_of_led_get(struct device *dev, + int index) +{ + struct led_classdev *led; + struct led_classdev **dr; + + if (!dev) + return ERR_PTR(-EINVAL); + + /* Consummer not using device tree? */ + if (!dev_of_node(dev)) + return ERR_PTR(-ENOTSUPP); + + led = of_led_get(dev_of_node(dev), index); + if (IS_ERR(led)) + return led; + + dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), + GFP_KERNEL); + if (!dr) { + led_put(led); + return ERR_PTR(-ENOMEM); + } + + *dr = led; + devres_add(dev, dr); + + return led; +} +EXPORT_SYMBOL_GPL(devm_of_led_get); + static int led_classdev_next_name(const char *init_name, char *name, size_t len) { diff --git a/include/linux/leds.h b/include/linux/leds.h index 6f7371bc7757..9b94cf752012 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -199,6 +199,8 @@ extern void led_classdev_resume(struct led_classdev *led_cdev);
extern struct led_classdev *of_led_get(struct device_node *np, int index); extern void led_put(struct led_classdev *led_cdev); +struct led_classdev *__must_check devm_of_led_get(struct device *dev, + int index);
/** * led_blink_set - set blinking with software fallback
Hi!
If the LED is acquired by a consumer device with devm_led_get(), it is automatically released when the device is detached.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Acked-by: Pavel Machek pavel@ucw.cz
drivers/leds/led-class.c | 49 ++++++++++++++++++++++++++++++++++++++++ include/linux/leds.h | 2 ++ 2 files changed, 51 insertions(+)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 1d1f1d546dc7..639224392ffa 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -264,6 +264,55 @@ void led_put(struct led_classdev *led_cdev) } EXPORT_SYMBOL_GPL(led_put);
+static void devm_led_release(struct device *dev, void *res) +{
- struct led_classdev **p = res;
- led_put(*p);
+}
+/**
- devm_of_led_get - Resource-managed request of a LED device
- @dev: LED consumer
- @index: index of the LED to obtain in the consumer
- The device node of the device is parse to find the request LED device.
- The LED device returned from this function is automatically released
- on driver detach.
- @return a pointer to a LED device or ERR_PTR(errno) on failure.
- */
+struct led_classdev *__must_check devm_of_led_get(struct device *dev,
int index)+{
- struct led_classdev *led;
- struct led_classdev **dr;
- if (!dev)
return ERR_PTR(-EINVAL);- /* Consummer not using device tree? */
Typo "consumer". I may fix it before applying the patch.
Best regards, Pavel
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com --- .../bindings/leds/backlight/led-backlight.txt | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt new file mode 100644 index 000000000000..4c7dfbe7f67a --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt @@ -0,0 +1,28 @@ +led-backlight bindings + +This binding is used to describe a basic backlight device made of LEDs. +It can also be used to describe a backlight device controlled by the output of +a LED driver. + +Required properties: + - compatible: "led-backlight" + - leds: a list of LEDs + +Optional properties: + - brightness-levels: Array of distinct brightness levels. The levels must be + in the range accepted by the underlying LED devices. + This is used to translate a backlight brightness level + into a LED brightness level. If it is not provided, the + identity mapping is used. + + - default-brightness-level: The default brightness level. + +Example: + + backlight { + compatible = "led-backlight"; + + leds = <&led1>, <&led2>; + brightness-levels = <0 4 8 16 32 64 128 255>; + default-brightness-level = <6>; + };
Please send DT bindings to DT list or it's never in my queue. IOW, send patches to the lists that get_maintainers.pl tells you to.
On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com
.../bindings/leds/backlight/led-backlight.txt | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
Please make this a DT schema.
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt new file mode 100644 index 000000000000..4c7dfbe7f67a --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt @@ -0,0 +1,28 @@ +led-backlight bindings
+This binding is used to describe a basic backlight device made of LEDs. +It can also be used to describe a backlight device controlled by the output of +a LED driver.
+Required properties:
- compatible: "led-backlight"
- leds: a list of LEDs
'leds' is already used as a node name and mixing is not ideal.
We already have 'flash-leds' in use and with the same definition, so lets continue that and use 'backlight-leds'.
+Optional properties:
- brightness-levels: Array of distinct brightness levels. The levels must be
in the range accepted by the underlying LED devices.This is used to translate a backlight brightness levelinto a LED brightness level. If it is not provided, theidentity mapping is used.
- default-brightness-level: The default brightness level.
You can just assume these 2 get a common schema at some point. So just need to define any additional constraints if possible.
Rob
Hi Rob,
On 07/10/2019 18:15, Rob Herring wrote:
Please send DT bindings to DT list or it's never in my queue. IOW, send patches to the lists that get_maintainers.pl tells you to.
On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com
.../bindings/leds/backlight/led-backlight.txt | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
Please make this a DT schema.
OK.
BTW I used "make dt_binding_check" but had to fix a couple of YAMLs file to get it to work. Do you have a kernel tree with already all the YAML files in good shape ? Or do you want me to post the changes to devicetree@vger.kernel.org ?
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt new file mode 100644 index 000000000000..4c7dfbe7f67a --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt @@ -0,0 +1,28 @@ +led-backlight bindings
+This binding is used to describe a basic backlight device made of LEDs. +It can also be used to describe a backlight device controlled by the output of +a LED driver.
+Required properties:
- compatible: "led-backlight"
- leds: a list of LEDs
'leds' is already used as a node name and mixing is not ideal.
We already have 'flash-leds' in use and with the same definition, so lets continue that and use 'backlight-leds'.
OK
+Optional properties:
- brightness-levels: Array of distinct brightness levels. The levels must be
in the range accepted by the underlying LED devices.This is used to translate a backlight brightness levelinto a LED brightness level. If it is not provided, theidentity mapping is used.
- default-brightness-level: The default brightness level.
You can just assume these 2 get a common schema at some point. So just need to define any additional constraints if possible.
Maybe we should keep them until such a common schema is written ?
JJ
Rob
Rob,
On 08/10/2019 14:51, Jean-Jacques Hiblot wrote:
Hi Rob,
On 07/10/2019 18:15, Rob Herring wrote:
Please send DT bindings to DT list or it's never in my queue. IOW, send patches to the lists that get_maintainers.pl tells you to.
On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com
.../bindings/leds/backlight/led-backlight.txt | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
Please make this a DT schema.
OK.
BTW I used "make dt_binding_check" but had to fix a couple of YAMLs file to get it to work. Do you have a kernel tree with already all the YAML files in good shape ? Or do you want me to post the changes to devicetree@vger.kernel.org ?
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt new file mode 100644 index 000000000000..4c7dfbe7f67a --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt @@ -0,0 +1,28 @@ +led-backlight bindings
+This binding is used to describe a basic backlight device made of LEDs. +It can also be used to describe a backlight device controlled by the output of +a LED driver.
+Required properties: + - compatible: "led-backlight" + - leds: a list of LEDs
'leds' is already used as a node name and mixing is not ideal.
We already have 'flash-leds' in use and with the same definition, so lets continue that and use 'backlight-leds'.
OK
I am taking that back. I have added of_get_led() and devm_of_get_led() to the LED core to make it easier to get a LED from the DT. I modeled the interface like it is done for PWM, PHYs or clocks. The property containing list/array of phandle is always named the same. To get one particular PWM/PHY/clock, a identifier (name or integer) must be provided.
So unless there is a strong incentive to do otherwise I's rather keep this name here.
JJ
+Optional properties: + - brightness-levels: Array of distinct brightness levels. The levels must be + in the range accepted by the underlying LED devices. + This is used to translate a backlight brightness level + into a LED brightness level. If it is not provided, the + identity mapping is used.
+ - default-brightness-level: The default brightness level.
You can just assume these 2 get a common schema at some point. So just need to define any additional constraints if possible.
Maybe we should keep them until such a common schema is written ?
JJ
Rob
On Tue, Oct 8, 2019 at 8:30 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Rob,
On 08/10/2019 14:51, Jean-Jacques Hiblot wrote:
Hi Rob,
On 07/10/2019 18:15, Rob Herring wrote:
Please send DT bindings to DT list or it's never in my queue. IOW, send patches to the lists that get_maintainers.pl tells you to.
On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com
.../bindings/leds/backlight/led-backlight.txt | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
Please make this a DT schema.
OK.
BTW I used "make dt_binding_check" but had to fix a couple of YAMLs file to get it to work. Do you have a kernel tree with already all the YAML files in good shape ? Or do you want me to post the changes to devicetree@vger.kernel.org ?
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt new file mode 100644 index 000000000000..4c7dfbe7f67a --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt @@ -0,0 +1,28 @@ +led-backlight bindings
+This binding is used to describe a basic backlight device made of LEDs. +It can also be used to describe a backlight device controlled by the output of +a LED driver.
+Required properties:
- compatible: "led-backlight"
- leds: a list of LEDs
'leds' is already used as a node name and mixing is not ideal.
We already have 'flash-leds' in use and with the same definition, so lets continue that and use 'backlight-leds'.
OK
I am taking that back. I have added of_get_led() and devm_of_get_led() to the LED core to make it easier to get a LED from the DT. I modeled the interface like it is done for PWM, PHYs or clocks. The property containing list/array of phandle is always named the same. To get one particular PWM/PHY/clock, a identifier (name or integer) must be provided.
It can be done as we do support that with '-gpios', but yes, it is a bit more painful to deal with.
So unless there is a strong incentive to do otherwise I's rather keep this name here.
In that case, this needs to be documented as a common LED binding, not something hidden away in this binding.
Rob
On 10/8/19 5:00 PM, Rob Herring wrote:
On Tue, Oct 8, 2019 at 8:30 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Rob,
On 08/10/2019 14:51, Jean-Jacques Hiblot wrote:
Hi Rob,
On 07/10/2019 18:15, Rob Herring wrote:
Please send DT bindings to DT list or it's never in my queue. IOW, send patches to the lists that get_maintainers.pl tells you to.
On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com
.../bindings/leds/backlight/led-backlight.txt | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
Please make this a DT schema.
OK.
BTW I used "make dt_binding_check" but had to fix a couple of YAMLs file to get it to work. Do you have a kernel tree with already all the YAML files in good shape ? Or do you want me to post the changes to devicetree@vger.kernel.org ?
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt new file mode 100644 index 000000000000..4c7dfbe7f67a --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt @@ -0,0 +1,28 @@ +led-backlight bindings
+This binding is used to describe a basic backlight device made of LEDs. +It can also be used to describe a backlight device controlled by the output of +a LED driver.
+Required properties:
- compatible: "led-backlight"
- leds: a list of LEDs
'leds' is already used as a node name and mixing is not ideal.
for the record: child node names (if that was what you had on mind) have singular form 'led'.
We already have 'flash-leds' in use and with the same definition, so lets continue that and use 'backlight-leds'.
OK
I am taking that back. I have added of_get_led() and devm_of_get_led() to the LED core to make it easier to get a LED from the DT. I modeled the interface like it is done for PWM, PHYs or clocks. The property containing list/array of phandle is always named the same. To get one particular PWM/PHY/clock, a identifier (name or integer) must be provided.
It can be done as we do support that with '-gpios', but yes, it is a bit more painful to deal with.
So unless there is a strong incentive to do otherwise I's rather keep this name here.
In that case, this needs to be documented as a common LED binding, not something hidden away in this binding.
Rob
On Tue, Oct 8, 2019 at 12:17 PM Jacek Anaszewski jacek.anaszewski@gmail.com wrote:
On 10/8/19 5:00 PM, Rob Herring wrote:
On Tue, Oct 8, 2019 at 8:30 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Rob,
On 08/10/2019 14:51, Jean-Jacques Hiblot wrote:
Hi Rob,
On 07/10/2019 18:15, Rob Herring wrote:
Please send DT bindings to DT list or it's never in my queue. IOW, send patches to the lists that get_maintainers.pl tells you to.
On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com
.../bindings/leds/backlight/led-backlight.txt | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
Please make this a DT schema.
OK.
BTW I used "make dt_binding_check" but had to fix a couple of YAMLs file to get it to work. Do you have a kernel tree with already all the YAML files in good shape ? Or do you want me to post the changes to devicetree@vger.kernel.org ?
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt new file mode 100644 index 000000000000..4c7dfbe7f67a --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt @@ -0,0 +1,28 @@ +led-backlight bindings
+This binding is used to describe a basic backlight device made of LEDs. +It can also be used to describe a backlight device controlled by the output of +a LED driver.
+Required properties:
- compatible: "led-backlight"
- leds: a list of LEDs
'leds' is already used as a node name and mixing is not ideal.
for the record: child node names (if that was what you had on mind) have singular form 'led'.
I did actually grep this and not rely on my somewhat faulty memory:
$ git grep '\sleds {' | wc -l 463
These are mostly gpio-leds I think.
Rob
On 10/8/19 10:00 PM, Rob Herring wrote:
On Tue, Oct 8, 2019 at 12:17 PM Jacek Anaszewski jacek.anaszewski@gmail.com wrote:
On 10/8/19 5:00 PM, Rob Herring wrote:
On Tue, Oct 8, 2019 at 8:30 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Rob,
On 08/10/2019 14:51, Jean-Jacques Hiblot wrote:
Hi Rob,
On 07/10/2019 18:15, Rob Herring wrote:
Please send DT bindings to DT list or it's never in my queue. IOW, send patches to the lists that get_maintainers.pl tells you to.
On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote: > Add DT binding for led-backlight. > > Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com > Reviewed-by: Daniel Thompson daniel.thompson@linaro.org > Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com > --- > .../bindings/leds/backlight/led-backlight.txt | 28 > +++++++++++++++++++ > 1 file changed, 28 insertions(+) > create mode 100644 > Documentation/devicetree/bindings/leds/backlight/led-backlight.txt Please make this a DT schema.
OK.
BTW I used "make dt_binding_check" but had to fix a couple of YAMLs file to get it to work. Do you have a kernel tree with already all the YAML files in good shape ? Or do you want me to post the changes to devicetree@vger.kernel.org ?
> diff --git > a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt > b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt > new file mode 100644 > index 000000000000..4c7dfbe7f67a > --- /dev/null > +++ > b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt > @@ -0,0 +1,28 @@ > +led-backlight bindings > + > +This binding is used to describe a basic backlight device made of > LEDs. > +It can also be used to describe a backlight device controlled by > the output of > +a LED driver. > + > +Required properties: > + - compatible: "led-backlight" > + - leds: a list of LEDs 'leds' is already used as a node name and mixing is not ideal.
for the record: child node names (if that was what you had on mind) have singular form 'led'.
I did actually grep this and not rely on my somewhat faulty memory:
$ git grep '\sleds {' | wc -l 463
These are mostly gpio-leds I think.
Indeed. So this is legacy, but common LED bindings have never stated that. If should be OK to add leds property to common bindings with proper description.
On 10/8/19 5:00 PM, Rob Herring wrote:
On Tue, Oct 8, 2019 at 8:30 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Rob,
On 08/10/2019 14:51, Jean-Jacques Hiblot wrote:
Hi Rob,
On 07/10/2019 18:15, Rob Herring wrote:
Please send DT bindings to DT list or it's never in my queue. IOW, send patches to the lists that get_maintainers.pl tells you to.
On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com
.../bindings/leds/backlight/led-backlight.txt | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
Please make this a DT schema.
OK.
BTW I used "make dt_binding_check" but had to fix a couple of YAMLs file to get it to work. Do you have a kernel tree with already all the YAML files in good shape ? Or do you want me to post the changes to devicetree@vger.kernel.org ?
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt new file mode 100644 index 000000000000..4c7dfbe7f67a --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt @@ -0,0 +1,28 @@ +led-backlight bindings
+This binding is used to describe a basic backlight device made of LEDs. +It can also be used to describe a backlight device controlled by the output of +a LED driver.
+Required properties:
- compatible: "led-backlight"
- leds: a list of LEDs
'leds' is already used as a node name and mixing is not ideal.
for the record: child node names (if that was what you had on mind) have singular form 'led'.
We already have 'flash-leds' in use and with the same definition, so lets continue that and use 'backlight-leds'.
OK
I am taking that back. I have added of_get_led() and devm_of_get_led() to the LED core to make it easier to get a LED from the DT. I modeled the interface like it is done for PWM, PHYs or clocks. The property containing list/array of phandle is always named the same. To get one particular PWM/PHY/clock, a identifier (name or integer) must be provided.
It can be done as we do support that with '-gpios', but yes, it is a bit more painful to deal with.
So unless there is a strong incentive to do otherwise I's rather keep this name here.
In that case, this needs to be documented as a common LED binding, not something hidden away in this binding.
Rob
On Tue, Oct 8, 2019 at 7:51 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Hi Rob,
On 07/10/2019 18:15, Rob Herring wrote:
Please send DT bindings to DT list or it's never in my queue. IOW, send patches to the lists that get_maintainers.pl tells you to.
On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot jjhiblot@ti.com wrote:
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com
.../bindings/leds/backlight/led-backlight.txt | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
Please make this a DT schema.
OK.
BTW I used "make dt_binding_check" but had to fix a couple of YAMLs file to get it to work. Do you have a kernel tree with already all the YAML files in good shape ? Or do you want me to post the changes to devicetree@vger.kernel.org ?
linux-next is fixed now.
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt new file mode 100644 index 000000000000..4c7dfbe7f67a --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt @@ -0,0 +1,28 @@ +led-backlight bindings
+This binding is used to describe a basic backlight device made of LEDs. +It can also be used to describe a backlight device controlled by the output of +a LED driver.
+Required properties:
- compatible: "led-backlight"
- leds: a list of LEDs
'leds' is already used as a node name and mixing is not ideal.
We already have 'flash-leds' in use and with the same definition, so lets continue that and use 'backlight-leds'.
OK
+Optional properties:
- brightness-levels: Array of distinct brightness levels. The levels must be
in the range accepted by the underlying LED devices.This is used to translate a backlight brightness levelinto a LED brightness level. If it is not provided, theidentity mapping is used.
- default-brightness-level: The default brightness level.
You can just assume these 2 get a common schema at some point. So just need to define any additional constraints if possible.
Maybe we should keep them until such a common schema is written ?
I'm not saying to remove them, but you can just have a description if there are no other constraints.
Rob
From: Tomi Valkeinen tomi.valkeinen@ti.com
This patch adds a led-backlight driver (led_bl), which is similar to pwm_bl except the driver uses a LED class driver to adjust the brightness in the HW. Multiple LEDs can be used for a single backlight.
Signed-off-by: Tomi Valkeinen tomi.valkeinen@ti.com Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Acked-by: Pavel Machek pavel@ucw.cz Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com --- drivers/video/backlight/Kconfig | 7 + drivers/video/backlight/Makefile | 1 + drivers/video/backlight/led_bl.c | 258 +++++++++++++++++++++++++++++++ 3 files changed, 266 insertions(+) create mode 100644 drivers/video/backlight/led_bl.c
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index 8b081d61773e..585a1787618c 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -458,6 +458,13 @@ config BACKLIGHT_RAVE_SP help Support for backlight control on RAVE SP device.
+config BACKLIGHT_LED + tristate "Generic LED based Backlight Driver" + depends on LEDS_CLASS && OF + help + If you have a LCD backlight adjustable by LED class driver, say Y + to enable this driver. + endif # BACKLIGHT_CLASS_DEVICE
endmenu diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile index 63c507c07437..2a67642966a5 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -57,3 +57,4 @@ obj-$(CONFIG_BACKLIGHT_TPS65217) += tps65217_bl.o obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o obj-$(CONFIG_BACKLIGHT_ARCXCNN) += arcxcnn_bl.o obj-$(CONFIG_BACKLIGHT_RAVE_SP) += rave-sp-backlight.o +obj-$(CONFIG_BACKLIGHT_LED) += led_bl.o diff --git a/drivers/video/backlight/led_bl.c b/drivers/video/backlight/led_bl.c new file mode 100644 index 000000000000..b89ba20c1d16 --- /dev/null +++ b/drivers/video/backlight/led_bl.c @@ -0,0 +1,258 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/ + * Authors: Tomi Valkeinen tomi.valkeinen@ti.com + * Jean-Jacques Hiblot jjhiblot@ti.com + */ + +#include <linux/backlight.h> +#include <linux/leds.h> +#include <linux/module.h> +#include <linux/platform_device.h> + +struct led_bl_data { + struct device *dev; + struct backlight_device *bl_dev; + struct led_classdev **leds; + bool enabled; + int nb_leds; + unsigned int *levels; + unsigned int default_brightness; + unsigned int max_brightness; +}; + +static void led_bl_set_brightness(struct led_bl_data *priv, int level) +{ + int i; + int bkl_brightness; + + if (priv->levels) + bkl_brightness = priv->levels[level]; + else + bkl_brightness = level; + + for (i = 0; i < priv->nb_leds; i++) + led_set_brightness(priv->leds[i], bkl_brightness); + + priv->enabled = true; +} + +static void led_bl_power_off(struct led_bl_data *priv) +{ + int i; + + if (!priv->enabled) + return; + + for (i = 0; i < priv->nb_leds; i++) + led_set_brightness(priv->leds[i], LED_OFF); + + priv->enabled = false; +} + +static int led_bl_update_status(struct backlight_device *bl) +{ + struct led_bl_data *priv = bl_get_data(bl); + int brightness = bl->props.brightness; + + if (bl->props.power != FB_BLANK_UNBLANK || + bl->props.fb_blank != FB_BLANK_UNBLANK || + bl->props.state & BL_CORE_FBBLANK) + brightness = 0; + + if (brightness > 0) + led_bl_set_brightness(priv, brightness); + else + led_bl_power_off(priv); + + return 0; +} + +static const struct backlight_ops led_bl_ops = { + .update_status = led_bl_update_status, +}; + +static int led_bl_get_leds(struct device *dev, + struct led_bl_data *priv) +{ + int i, nb_leds, ret; + struct device_node *node = dev->of_node; + struct led_classdev **leds; + unsigned int max_brightness; + unsigned int default_brightness; + + ret = of_count_phandle_with_args(node, "leds", NULL); + if (ret < 0) { + dev_err(dev, "Unable to get led count\n"); + return -EINVAL; + } + + nb_leds = ret; + if (nb_leds < 1) { + dev_err(dev, "At least one LED must be specified!\n"); + return -EINVAL; + } + + leds = devm_kzalloc(dev, sizeof(struct led_classdev *) * nb_leds, + GFP_KERNEL); + if (!leds) + return -ENOMEM; + + for (i = 0; i < nb_leds; i++) { + leds[i] = devm_of_led_get(dev, i); + if (IS_ERR(leds[i])) + return PTR_ERR(leds[i]); + } + + /* check that the LEDs all have the same brightness range */ + max_brightness = leds[0]->max_brightness; + for (i = 1; i < nb_leds; i++) { + if (max_brightness != leds[i]->max_brightness) { + dev_err(dev, "LEDs must have identical ranges\n"); + return -EINVAL; + } + } + + /* get the default brightness from the first LED from the list */ + default_brightness = leds[0]->brightness; + + priv->nb_leds = nb_leds; + priv->leds = leds; + priv->max_brightness = max_brightness; + priv->default_brightness = default_brightness; + + return 0; +} + +static int led_bl_parse_levels(struct device *dev, + struct led_bl_data *priv) +{ + struct device_node *node = dev->of_node; + int num_levels; + u32 value; + int ret; + + if (!node) + return -ENODEV; + + num_levels = of_property_count_u32_elems(node, "brightness-levels"); + if (num_levels > 1) { + int i; + unsigned int db; + u32 *levels = NULL; + + levels = devm_kzalloc(dev, sizeof(u32) * num_levels, + GFP_KERNEL); + if (!levels) + return -ENOMEM; + + ret = of_property_read_u32_array(node, "brightness-levels", + levels, + num_levels); + if (ret < 0) + return ret; + + /* + * Try to map actual LED brightness to backlight brightness + * level + */ + db = priv->default_brightness; + for (i = 0 ; i < num_levels; i++) { + if ((i && db > levels[i-1]) && db <= levels[i]) + break; + } + priv->default_brightness = i; + priv->max_brightness = num_levels - 1; + priv->levels = levels; + } else if (num_levels >= 0) + dev_warn(dev, "Not enough levels defined\n"); + + ret = of_property_read_u32(node, "default-brightness-level", &value); + if (!ret && value <= priv->max_brightness) + priv->default_brightness = value; + else if (!ret && value > priv->max_brightness) + dev_warn(dev, "Invalid default brightness. Ignoring it\n"); + + return 0; +} + +static void led_bl_cleanup(void *data) +{ + struct led_bl_data *priv = data; + int i; + + led_bl_power_off(priv); + for (i = 0; i < priv->nb_leds; i++) + led_sysfs_enable(priv->leds[i]); +} + +static int led_bl_probe(struct platform_device *pdev) +{ + struct backlight_properties props; + struct led_bl_data *priv; + int ret, i; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + platform_set_drvdata(pdev, priv); + + priv->dev = &pdev->dev; + + ret = led_bl_get_leds(&pdev->dev, priv); + if (ret) + return ret; + + ret = led_bl_parse_levels(&pdev->dev, priv); + if (ret < 0) { + dev_err(&pdev->dev, "Failed to parse DT data\n"); + return ret; + } + + ret = devm_add_action_or_reset(&pdev->dev, led_bl_cleanup, priv); + if (ret) + return ret; + + for (i = 0; i < priv->nb_leds; i++) + led_sysfs_disable(priv->leds[i]); + + memset(&props, 0, sizeof(struct backlight_properties)); + props.type = BACKLIGHT_RAW; + props.max_brightness = priv->max_brightness; + props.brightness = priv->default_brightness; + props.power = (priv->default_brightness > 0) ? FB_BLANK_POWERDOWN : + FB_BLANK_UNBLANK; + priv->bl_dev = devm_backlight_device_register(&pdev->dev, + dev_name(&pdev->dev), &pdev->dev, priv, &led_bl_ops, + &props); + if (IS_ERR(priv->bl_dev)) { + dev_err(&pdev->dev, "Failed to register backlight\n"); + return PTR_ERR(priv->bl_dev); + } + + backlight_update_status(priv->bl_dev); + + return 0; +} + +static const struct of_device_id led_bl_of_match[] = { + { .compatible = "led-backlight" }, + { } +}; + +MODULE_DEVICE_TABLE(of, led_bl_of_match); + +static struct platform_driver led_bl_driver = { + .driver = { + .name = "led-backlight", + .of_match_table = led_bl_of_match, + }, + .probe = led_bl_probe, +}; + +module_platform_driver(led_bl_driver); + +MODULE_DESCRIPTION("LED based Backlight Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:led-backlight");
dri-devel@lists.freedesktop.org
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Jacek Anaszewski -
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Rob Herring