* [PATCH v6 1/4] leds: Add of_led_get() and led_put()
2019-09-10 13:27 [PATCH v6 0/4] Add a generic driver for LED-based backlight Jean-Jacques Hiblot
@ 2019-09-10 13:27 ` Jean-Jacques Hiblot
2019-09-10 18:49 ` Jacek Anaszewski
2019-09-10 13:27 ` [PATCH v6 2/4] leds: Add managed API to get a LED from a device driver Jean-Jacques Hiblot
` (2 subsequent siblings)
3 siblings, 1 reply; 7+ messages in thread
From: Jean-Jacques Hiblot @ 2019-09-10 13:27 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson
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>
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 159c6caa374b..d4d22f4b5052 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -18,6 +18,7 @@
#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;
@@ -213,6 +214,55 @@ 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;
+}
+
+/**
+ * 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] 7+ messages in thread
* Re: [PATCH v6 1/4] leds: Add of_led_get() and led_put()
2019-09-10 13:27 ` [PATCH v6 1/4] leds: Add of_led_get() and led_put() Jean-Jacques Hiblot
@ 2019-09-10 18:49 ` Jacek Anaszewski
0 siblings, 0 replies; 7+ messages in thread
From: Jacek Anaszewski @ 2019-09-10 18:49 UTC (permalink / raw)
To: Jean-Jacques Hiblot, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson
Cc: dmurphy, linux-leds, linux-kernel, dri-devel, tomi.valkeinen
Hi Jean,
Please rebase your patch set onto linux-leds.git [0] -
we've had some updates in the meantime and now your
set doesn't apply.
Best regards,
Jacek Anaszewski
On 9/10/19 3:27 PM, 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>
> 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 159c6caa374b..d4d22f4b5052 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -18,6 +18,7 @@
> #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;
> @@ -213,6 +214,55 @@ 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;
> +}
> +
> +/**
> + * 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
>
[0]
https://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds.git/log/?h=for-next
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v6 2/4] leds: Add managed API to get a LED from a device driver
2019-09-10 13:27 [PATCH v6 0/4] Add a generic driver for LED-based backlight Jean-Jacques Hiblot
2019-09-10 13:27 ` [PATCH v6 1/4] leds: Add of_led_get() and led_put() Jean-Jacques Hiblot
@ 2019-09-10 13:27 ` Jean-Jacques Hiblot
2019-09-10 13:27 ` [PATCH v6 3/4] dt-bindings: backlight: Add led-backlight binding Jean-Jacques Hiblot
2019-09-10 13:27 ` [PATCH v6 4/4] backlight: add led-backlight driver Jean-Jacques Hiblot
3 siblings, 0 replies; 7+ messages in thread
From: Jean-Jacques Hiblot @ 2019-09-10 13:27 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson
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 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 | 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 d4d22f4b5052..664c81e2513c 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -263,6 +263,48 @@ 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] 7+ messages in thread
* [PATCH v6 3/4] dt-bindings: backlight: Add led-backlight binding
2019-09-10 13:27 [PATCH v6 0/4] Add a generic driver for LED-based backlight Jean-Jacques Hiblot
2019-09-10 13:27 ` [PATCH v6 1/4] leds: Add of_led_get() and led_put() Jean-Jacques Hiblot
2019-09-10 13:27 ` [PATCH v6 2/4] leds: Add managed API to get a LED from a device driver Jean-Jacques Hiblot
@ 2019-09-10 13:27 ` Jean-Jacques Hiblot
2019-09-10 13:27 ` [PATCH v6 4/4] backlight: add led-backlight driver Jean-Jacques Hiblot
3 siblings, 0 replies; 7+ messages in thread
From: Jean-Jacques Hiblot @ 2019-09-10 13:27 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson
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>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
---
.../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>;
+ };
--
2.17.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v6 4/4] backlight: add led-backlight driver
2019-09-10 13:27 [PATCH v6 0/4] Add a generic driver for LED-based backlight Jean-Jacques Hiblot
` (2 preceding siblings ...)
2019-09-10 13:27 ` [PATCH v6 3/4] dt-bindings: backlight: Add led-backlight binding Jean-Jacques Hiblot
@ 2019-09-10 13:27 ` Jean-Jacques Hiblot
2019-09-10 13:32 ` Daniel Thompson
3 siblings, 1 reply; 7+ messages in thread
From: Jean-Jacques Hiblot @ 2019-09-10 13:27 UTC (permalink / raw)
To: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
daniel.thompson
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>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/led_bl.c | 260 +++++++++++++++++++++++++++++++
3 files changed, 268 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..6044390d8b88
--- /dev/null
+++ b/drivers/video/backlight/led_bl.c
@@ -0,0 +1,260 @@
+// 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/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_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 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;
+ }
+
+ 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);
+ }
+
+ for (i = 0; i < priv->nb_leds; i++)
+ led_sysfs_disable(priv->leds[i]);
+
+ 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;
+ int i;
+
+ backlight_device_unregister(bl);
+
+ led_bl_power_off(priv);
+ for (i = 0; i < priv->nb_leds; i++)
+ led_sysfs_enable(priv->leds[i]);
+
+ 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] 7+ messages in thread
* Re: [PATCH v6 4/4] backlight: add led-backlight driver
2019-09-10 13:27 ` [PATCH v6 4/4] backlight: add led-backlight driver Jean-Jacques Hiblot
@ 2019-09-10 13:32 ` Daniel Thompson
0 siblings, 0 replies; 7+ messages in thread
From: Daniel Thompson @ 2019-09-10 13:32 UTC (permalink / raw)
To: Jean-Jacques Hiblot
Cc: jacek.anaszewski, pavel, robh+dt, mark.rutland, lee.jones,
dmurphy, linux-leds, linux-kernel, dri-devel, tomi.valkeinen
On Tue, Sep 10, 2019 at 03:27:34PM +0200, 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>
> Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---
> drivers/video/backlight/Kconfig | 7 +
> drivers/video/backlight/Makefile | 1 +
> drivers/video/backlight/led_bl.c | 260 +++++++++++++++++++++++++++++++
> 3 files changed, 268 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..6044390d8b88
> --- /dev/null
> +++ b/drivers/video/backlight/led_bl.c
> @@ -0,0 +1,260 @@
> +// 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/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_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 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;
> + }
> +
> + 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);
> + }
> +
> + for (i = 0; i < priv->nb_leds; i++)
> + led_sysfs_disable(priv->leds[i]);
> +
> + 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;
> + int i;
> +
> + backlight_device_unregister(bl);
> +
> + led_bl_power_off(priv);
> + for (i = 0; i < priv->nb_leds; i++)
> + led_sysfs_enable(priv->leds[i]);
> +
> + 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 [flat|nested] 7+ messages in thread