* [PATCH v3 0/4] Add a generic driver for LED-based backlight
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: dmurphy, linux-leds, linux-kernel, dri-devel, tomi.valkeinen,
Jean-Jacques Hiblot
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 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 optionnal
- 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 (2):
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 | 92 ++++++
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/led_bl.c | 268 ++++++++++++++++++
include/linux/leds.h | 6 +
6 files changed, 402 insertions(+)
create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
create mode 100644 drivers/video/backlight/led_bl.c
--
2.17.1
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v3 0/4] Add a generic driver for LED-based backlight
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: dmurphy, linux-leds, linux-kernel, dri-devel, tomi.valkeinen,
Jean-Jacques Hiblot
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 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 optionnal
- 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 (2):
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 | 92 ++++++
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/led_bl.c | 268 ++++++++++++++++++
include/linux/leds.h | 6 +
6 files changed, 402 insertions(+)
create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
create mode 100644 drivers/video/backlight/led_bl.c
--
2.17.1
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v3 1/4] leds: Add of_led_get() and led_put()
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: linux-kernel, dri-devel, tomi.valkeinen, dmurphy,
Jean-Jacques Hiblot, linux-leds
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>
---
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 e01b2d982564..0f67b13b0f1f 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -19,6 +19,7 @@
#include <linux/timer.h>
#include <linux/regulator/consumer.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);
+static int led_match_led_node(struct device *led_dev, const void *data)
+{
+ return led_dev->of_node == data ? 1 : 0;
+}
+
+/**
+ * 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;
+
+ led_node = of_parse_phandle(np, "leds", index);
+ if (!led_node)
+ return ERR_PTR(-ENOENT);
+
+ led_dev = class_find_device(leds_class, NULL, led_node,
+ led_match_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 match_name(struct device *dev, const void *data)
{
if (!dev_name(dev))
diff --git a/include/linux/leds.h b/include/linux/leds.h
index bee8e3f8dddd..0a71c7cdd191 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -19,6 +19,7 @@
struct device;
struct led_pattern;
+struct device_node;
/*
* LED Core
*/
@@ -145,6 +146,9 @@ 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
--
2.17.1
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH v3 1/4] leds: Add of_led_get() and led_put()
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: dmurphy, linux-leds, linux-kernel, dri-devel, tomi.valkeinen,
Jean-Jacques Hiblot
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>
---
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 e01b2d982564..0f67b13b0f1f 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -19,6 +19,7 @@
#include <linux/timer.h>
#include <linux/regulator/consumer.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);
+static int led_match_led_node(struct device *led_dev, const void *data)
+{
+ return led_dev->of_node == data ? 1 : 0;
+}
+
+/**
+ * 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;
+
+ led_node = of_parse_phandle(np, "leds", index);
+ if (!led_node)
+ return ERR_PTR(-ENOENT);
+
+ led_dev = class_find_device(leds_class, NULL, led_node,
+ led_match_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 match_name(struct device *dev, const void *data)
{
if (!dev_name(dev))
diff --git a/include/linux/leds.h b/include/linux/leds.h
index bee8e3f8dddd..0a71c7cdd191 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -19,6 +19,7 @@
struct device;
struct led_pattern;
+struct device_node;
/*
* LED Core
*/
@@ -145,6 +146,9 @@ 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
--
2.17.1
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH v3 2/4] leds: Add managed API to get a LED from a device driver
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: linux-kernel, dri-devel, tomi.valkeinen, dmurphy,
Jean-Jacques Hiblot, linux-leds
If the LED is acquired by a consumer device with devm_led_get(), it is
automatically release when the device is detach.
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
---
drivers/leds/led-class.c | 42 ++++++++++++++++++++++++++++++++++++++++
include/linux/leds.h | 2 ++
2 files changed, 44 insertions(+)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 0f67b13b0f1f..521cb76fbaf7 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -264,6 +264,48 @@ 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_led_get - Resource-managed request of a LED device
+ * @dev: LED consumer
+ * @idx: 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_led_get(struct device *dev,
+ int index)
+{
+ struct led_classdev *led;
+ struct led_classdev **dr;
+
+ led = of_led_get(dev->of_node, 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_led_get);
+
static int match_name(struct device *dev, const void *data)
{
if (!dev_name(dev))
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 0a71c7cdd191..7fcec566d774 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -148,6 +148,8 @@ 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_led_get(struct device *dev,
+ int index);
/**
* led_blink_set - set blinking with software fallback
--
2.17.1
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH v3 2/4] leds: Add managed API to get a LED from a device driver
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: dmurphy, linux-leds, linux-kernel, dri-devel, tomi.valkeinen,
Jean-Jacques Hiblot
If the LED is acquired by a consumer device with devm_led_get(), it is
automatically release when the device is detach.
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
---
drivers/leds/led-class.c | 42 ++++++++++++++++++++++++++++++++++++++++
include/linux/leds.h | 2 ++
2 files changed, 44 insertions(+)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 0f67b13b0f1f..521cb76fbaf7 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -264,6 +264,48 @@ 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_led_get - Resource-managed request of a LED device
+ * @dev: LED consumer
+ * @idx: 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_led_get(struct device *dev,
+ int index)
+{
+ struct led_classdev *led;
+ struct led_classdev **dr;
+
+ led = of_led_get(dev->of_node, 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_led_get);
+
static int match_name(struct device *dev, const void *data)
{
if (!dev_name(dev))
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 0a71c7cdd191..7fcec566d774 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -148,6 +148,8 @@ 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_led_get(struct device *dev,
+ int index);
/**
* led_blink_set - set blinking with software fallback
--
2.17.1
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH v3 3/4] dt-bindings: backlight: Add led-backlight binding
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: linux-kernel, dri-devel, tomi.valkeinen, dmurphy,
Jean-Jacques Hiblot, linux-leds
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.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..0444eec8efe1
--- /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 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>;
+ };
--
2.17.1
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH v3 3/4] dt-bindings: backlight: Add led-backlight binding
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: dmurphy, linux-leds, linux-kernel, dri-devel, tomi.valkeinen,
Jean-Jacques Hiblot
Add DT binding for led-backlight.
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.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..0444eec8efe1
--- /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 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>;
+ };
--
2.17.1
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH v3 4/4] backlight: add led-backlight driver
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: dmurphy, linux-leds, linux-kernel, dri-devel, tomi.valkeinen,
Jean-Jacques Hiblot
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>
---
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/led_bl.c | 268 +++++++++++++++++++++++++++++++
3 files changed, 276 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..58153150a618
--- /dev/null
+++ b/drivers/video/backlight/led_bl.c
@@ -0,0 +1,268 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/
+ * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
+ *
+ * Based on pwm_bl.c
+ */
+
+#include <linux/backlight.h>
+#include <linux/gpio/consumer.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define BKL_FULL_BRIGHTNESS 255
+
+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 int to_led_brightness(struct led_classdev *led, int value)
+{
+ return (value * led->max_brightness) / BKL_FULL_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++) {
+ int led_brightness;
+ struct led_classdev *led = priv->leds[i];
+
+ led_brightness = to_led_brightness(led, bkl_brightness);
+ led_set_brightness(led, led_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_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 enought 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 int led_bl_probe(struct platform_device *pdev)
+{
+ struct backlight_properties props;
+ struct led_bl_data *priv;
+ int ret;
+
+ 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;
+ }
+
+ 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 = backlight_device_register(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 int led_bl_remove(struct platform_device *pdev)
+{
+ struct led_bl_data *priv = platform_get_drvdata(pdev);
+ struct backlight_device *bl = priv->bl_dev;
+
+ backlight_device_unregister(bl);
+
+ led_bl_power_off(priv);
+
+ 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 = of_match_ptr(led_bl_of_match),
+ },
+ .probe = led_bl_probe,
+ .remove = led_bl_remove,
+};
+
+module_platform_driver(led_bl_driver);
+
+MODULE_DESCRIPTION("LED based Backlight Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:led-backlight");
--
2.17.1
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH v3 4/4] backlight: add led-backlight driver
@ 2019-07-10 12:39 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-10 12:39 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1
Cc: dmurphy, linux-leds, linux-kernel, dri-devel, tomi.valkeinen,
Jean-Jacques Hiblot
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>
---
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/led_bl.c | 268 +++++++++++++++++++++++++++++++
3 files changed, 276 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..58153150a618
--- /dev/null
+++ b/drivers/video/backlight/led_bl.c
@@ -0,0 +1,268 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/
+ * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
+ *
+ * Based on pwm_bl.c
+ */
+
+#include <linux/backlight.h>
+#include <linux/gpio/consumer.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define BKL_FULL_BRIGHTNESS 255
+
+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 int to_led_brightness(struct led_classdev *led, int value)
+{
+ return (value * led->max_brightness) / BKL_FULL_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++) {
+ int led_brightness;
+ struct led_classdev *led = priv->leds[i];
+
+ led_brightness = to_led_brightness(led, bkl_brightness);
+ led_set_brightness(led, led_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_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 enought 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 int led_bl_probe(struct platform_device *pdev)
+{
+ struct backlight_properties props;
+ struct led_bl_data *priv;
+ int ret;
+
+ 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;
+ }
+
+ 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 = backlight_device_register(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 int led_bl_remove(struct platform_device *pdev)
+{
+ struct led_bl_data *priv = platform_get_drvdata(pdev);
+ struct backlight_device *bl = priv->bl_dev;
+
+ backlight_device_unregister(bl);
+
+ led_bl_power_off(priv);
+
+ 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 = of_match_ptr(led_bl_of_match),
+ },
+ .probe = led_bl_probe,
+ .remove = led_bl_remove,
+};
+
+module_platform_driver(led_bl_driver);
+
+MODULE_DESCRIPTION("LED based Backlight Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:led-backlight");
--
2.17.1
^ permalink raw reply related [flat|nested] 18+ messages in thread
* Re: [PATCH v3 1/4] leds: Add of_led_get() and led_put()
2019-07-10 12:39 ` Jean-Jacques Hiblot
(?)
@ 2019-07-10 19:09 ` Pavel Machek
2019-07-12 13:52 ` Jean-Jacques Hiblot
-1 siblings, 1 reply; 18+ messages in thread
From: Pavel Machek @ 2019-07-10 19:09 UTC (permalink / raw)
To: Jean-Jacques Hiblot
Cc: jacek.anaszewski, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1, dmurphy, linux-leds, linux-kernel,
dri-devel, tomi.valkeinen
[-- Attachment #1: Type: text/plain, Size: 1281 bytes --]
On Wed 2019-07-10 14:39:29, Jean-Jacques Hiblot wrote:
> 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>
> @@ -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);
>
> +static int led_match_led_node(struct device *led_dev, const void *data)
> +{
> + return led_dev->of_node == data ? 1 : 0;
> +}
Get rid of the "? 1 : 0"?
> + led_node = of_parse_phandle(np, "leds", index);
> + if (!led_node)
> + return ERR_PTR(-ENOENT);
> + led_dev = class_find_device(leds_class, NULL, led_node,
> + led_match_led_node);
> + of_node_put(led_node);
> +
> + if (!led_dev)
> + return ERR_PTR(-EPROBE_DEFER);
Won't this defer probe "forever" when the driver is not available?
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v3 2/4] leds: Add managed API to get a LED from a device driver
2019-07-10 12:39 ` Jean-Jacques Hiblot
(?)
@ 2019-07-10 19:11 ` Pavel Machek
-1 siblings, 0 replies; 18+ messages in thread
From: Pavel Machek @ 2019-07-10 19:11 UTC (permalink / raw)
To: Jean-Jacques Hiblot
Cc: jacek.anaszewski, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1, dmurphy, linux-leds, linux-kernel,
dri-devel, tomi.valkeinen
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On Wed 2019-07-10 14:39:30, Jean-Jacques Hiblot wrote:
> If the LED is acquired by a consumer device with devm_led_get(), it is
> automatically release when the device is detach.
released, detached.
Acked-by: Pavel Machek <pavel@ucw.cz>
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v3 3/4] dt-bindings: backlight: Add led-backlight binding
2019-07-10 12:39 ` Jean-Jacques Hiblot
(?)
@ 2019-07-10 19:13 ` Pavel Machek
2019-07-12 13:57 ` Jean-Jacques Hiblot
-1 siblings, 1 reply; 18+ messages in thread
From: Pavel Machek @ 2019-07-10 19:13 UTC (permalink / raw)
To: Jean-Jacques Hiblot
Cc: jacek.anaszewski, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1, dmurphy, linux-leds, linux-kernel,
dri-devel, tomi.valkeinen
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On Wed 2019-07-10 14:39:31, Jean-Jacques Hiblot wrote:
> Add DT binding for led-backlight.
>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.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..0444eec8efe1
> --- /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.
Ok.
> +It can also be used to describe a backlight device controlled by the output of
> +a LED driver.
? The LED driver should better be driving some LEDs...
> +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 not provided, the
> + identity mapping is used.
"If it is not"
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v3 4/4] backlight: add led-backlight driver
2019-07-10 12:39 ` Jean-Jacques Hiblot
(?)
@ 2019-07-10 19:16 ` Pavel Machek
-1 siblings, 0 replies; 18+ messages in thread
From: Pavel Machek @ 2019-07-10 19:16 UTC (permalink / raw)
To: Jean-Jacques Hiblot
Cc: jacek.anaszewski, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1, dmurphy, linux-leds, linux-kernel,
dri-devel, tomi.valkeinen
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On Wed 2019-07-10 14:39:32, Jean-Jacques Hiblot wrote:
> 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>
> +
> + /*
> + *try to map actual LED brightness to backlight brightness
> + * level
> + */
"* Try"
> + 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 enought levels defined\n");
"Not enough"
> + 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");
"Invalid... Ignoring it."
Acked-by: Pavel Machek <pavel@ucw.cz>
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v3 1/4] leds: Add of_led_get() and led_put()
@ 2019-07-12 13:52 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-12 13:52 UTC (permalink / raw)
To: Pavel Machek
Cc: mark.rutland, daniel.thompson, jingoohan1, tomi.valkeinen,
linux-kernel, dri-devel, robh+dt, jacek.anaszewski, lee.jones,
linux-leds, dmurphy
hi Pavel
On 10/07/2019 21:09, Pavel Machek wrote:
> On Wed 2019-07-10 14:39:29, Jean-Jacques Hiblot wrote:
>> 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>
>>
>>
>> @@ -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);
>>
>> +static int led_match_led_node(struct device *led_dev, const void *data)
>> +{
>> + return led_dev->of_node == data ? 1 : 0;
>> +}
> Get rid of the "? 1 : 0"?
OK
>
>
>> + led_node = of_parse_phandle(np, "leds", index);
>> + if (!led_node)
>> + return ERR_PTR(-ENOENT);
>> + led_dev = class_find_device(leds_class, NULL, led_node,
>> + led_match_led_node);
>> + of_node_put(led_node);
>> +
>> + if (!led_dev)
>> + return ERR_PTR(-EPROBE_DEFER);
> Won't this defer probe "forever" when the driver is not available?
Yes it will.
However I don't see how we can fix this because we don't know for sure
that the LED driver will not become available at a later time.
JJ
>
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v3 1/4] leds: Add of_led_get() and led_put()
@ 2019-07-12 13:52 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-12 13:52 UTC (permalink / raw)
To: Pavel Machek
Cc: jacek.anaszewski, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1, dmurphy, linux-leds, linux-kernel,
dri-devel, tomi.valkeinen
hi Pavel
On 10/07/2019 21:09, Pavel Machek wrote:
> On Wed 2019-07-10 14:39:29, Jean-Jacques Hiblot wrote:
>> 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>
>>
>>
>> @@ -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);
>>
>> +static int led_match_led_node(struct device *led_dev, const void *data)
>> +{
>> + return led_dev->of_node == data ? 1 : 0;
>> +}
> Get rid of the "? 1 : 0"?
OK
>
>
>> + led_node = of_parse_phandle(np, "leds", index);
>> + if (!led_node)
>> + return ERR_PTR(-ENOENT);
>> + led_dev = class_find_device(leds_class, NULL, led_node,
>> + led_match_led_node);
>> + of_node_put(led_node);
>> +
>> + if (!led_dev)
>> + return ERR_PTR(-EPROBE_DEFER);
> Won't this defer probe "forever" when the driver is not available?
Yes it will.
However I don't see how we can fix this because we don't know for sure
that the LED driver will not become available at a later time.
JJ
>
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v3 3/4] dt-bindings: backlight: Add led-backlight binding
@ 2019-07-12 13:57 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-12 13:57 UTC (permalink / raw)
To: Pavel Machek
Cc: mark.rutland, daniel.thompson, jingoohan1, tomi.valkeinen,
linux-kernel, dri-devel, robh+dt, jacek.anaszewski, lee.jones,
linux-leds, dmurphy
Pavel,
On 10/07/2019 21:13, Pavel Machek wrote:
> On Wed 2019-07-10 14:39:31, Jean-Jacques Hiblot wrote:
>> Add DT binding for led-backlight.
>>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.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..0444eec8efe1
>> --- /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.
> Ok.
>
>> +It can also be used to describe a backlight device controlled by the output of
>> +a LED driver.
> ? The LED driver should better be driving some LEDs...
Well. we are dependent of the board design. If a board designer decided
to control a backlight with a LED-controller, then we have to deal with it.
In practice there are a lot of LED drivers that actually drive the LEDs
using PWMs and can be used for this purpose.
JJ
>
>> +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 not provided, the
>> + identity mapping is used.
> "If it is not"
> Pavel
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v3 3/4] dt-bindings: backlight: Add led-backlight binding
@ 2019-07-12 13:57 ` Jean-Jacques Hiblot
0 siblings, 0 replies; 18+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-12 13:57 UTC (permalink / raw)
To: Pavel Machek
Cc: jacek.anaszewski, robh+dt, mark.rutland, lee.jones,
daniel.thompson, jingoohan1, dmurphy, linux-leds, linux-kernel,
dri-devel, tomi.valkeinen
Pavel,
On 10/07/2019 21:13, Pavel Machek wrote:
> On Wed 2019-07-10 14:39:31, Jean-Jacques Hiblot wrote:
>> Add DT binding for led-backlight.
>>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.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..0444eec8efe1
>> --- /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.
> Ok.
>
>> +It can also be used to describe a backlight device controlled by the output of
>> +a LED driver.
> ? The LED driver should better be driving some LEDs...
Well. we are dependent of the board design. If a board designer decided
to control a backlight with a LED-controller, then we have to deal with it.
In practice there are a lot of LED drivers that actually drive the LEDs
using PWMs and can be used for this purpose.
JJ
>
>> +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 not provided, the
>> + identity mapping is used.
> "If it is not"
> Pavel
^ permalink raw reply [flat|nested] 18+ messages in thread
end of thread, other threads:[~2019-07-12 13:57 UTC | newest]
Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-07-10 12:39 [PATCH v3 0/4] Add a generic driver for LED-based backlight Jean-Jacques Hiblot
2019-07-10 12:39 ` Jean-Jacques Hiblot
2019-07-10 12:39 ` [PATCH v3 1/4] leds: Add of_led_get() and led_put() Jean-Jacques Hiblot
2019-07-10 12:39 ` Jean-Jacques Hiblot
2019-07-10 19:09 ` Pavel Machek
2019-07-12 13:52 ` Jean-Jacques Hiblot
2019-07-12 13:52 ` Jean-Jacques Hiblot
2019-07-10 12:39 ` [PATCH v3 2/4] leds: Add managed API to get a LED from a device driver Jean-Jacques Hiblot
2019-07-10 12:39 ` Jean-Jacques Hiblot
2019-07-10 19:11 ` Pavel Machek
2019-07-10 12:39 ` [PATCH v3 3/4] dt-bindings: backlight: Add led-backlight binding Jean-Jacques Hiblot
2019-07-10 12:39 ` Jean-Jacques Hiblot
2019-07-10 19:13 ` Pavel Machek
2019-07-12 13:57 ` Jean-Jacques Hiblot
2019-07-12 13:57 ` Jean-Jacques Hiblot
2019-07-10 12:39 ` [PATCH v3 4/4] backlight: add led-backlight driver Jean-Jacques Hiblot
2019-07-10 12:39 ` Jean-Jacques Hiblot
2019-07-10 19:16 ` Pavel Machek
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