From: Tomi Valkeinen <[email protected]>
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 <[email protected]>
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
Acked-by: Pavel Machek <[email protected]>
---
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/led_bl.c | 264 +++++++++++++++++++++++++++++++
3 files changed, 272 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..a72456e11fb9
--- /dev/null
+++ b/drivers/video/backlight/led_bl.c
@@ -0,0 +1,264 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/
+ * Author: Tomi Valkeinen <[email protected]>
+ *
+ * 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 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
On Tue, Sep 10, 2019 at 12:59:46PM +0200, Jean-Jacques Hiblot wrote:
> From: Tomi Valkeinen <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Jean-Jacques Hiblot <[email protected]>
> Acked-by: Pavel Machek <[email protected]>
> ---
> drivers/video/backlight/Kconfig | 7 +
> drivers/video/backlight/Makefile | 1 +
> drivers/video/backlight/led_bl.c | 264 +++++++++++++++++++++++++++++++
> 3 files changed, 272 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..a72456e11fb9
> --- /dev/null
> +++ b/drivers/video/backlight/led_bl.c
> @@ -0,0 +1,264 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/
> + * Author: Tomi Valkeinen <[email protected]>
> + *
> + * Based on pwm_bl.c
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/gpio/consumer.h>
Maybe this is a nitpick but it is one I have now raised three times and
I don't recall any response, what symbols from this header are used in
this file?
AFAICT everything defined in this header includes the string "gpio" and
that string doesn't appear anywhere in the file (except this line).
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
Come to think of it, are you sure you need this include? devm_kzalloc()
doesn't comes from this file.
> +#define BKL_FULL_BRIGHTNESS 255
This is unused. Please remove.
Other than that, looks good!
Daniel.
On Tue, Sep 10, 2019 at 01:38:18PM +0200, Jean-Jacques Hiblot wrote:
>
> On 10/09/2019 13:26, Daniel Thompson wrote:
> >
> > > 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-$(CONFIG_BACKLIGHT_LED) += led_bl.o
> > > diff --git a/drivers/video/backlight/led_bl.c b/drivers/video/backlight/led_bl.c
> > > new file mode 100644
> > > index 000000000000..a72456e11fb9
> > > --- /dev/null
> > > +++ b/drivers/video/backlight/led_bl.c
> > > @@ -0,0 +1,264 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/
> > > + * Author: Tomi Valkeinen <[email protected]>
> > > + *
> > > + * Based on pwm_bl.c
> > > + */
> > > +
> > > +#include <linux/backlight.h>
> > > +#include <linux/gpio/consumer.h>
> > Maybe this is a nitpick but it is one I have now raised three times and
> > I don't recall any response, what symbols from this header are used in
> > this file?
> >
> > AFAICT everything defined in this header includes the string "gpio" and
> > that string doesn't appear anywhere in the file (except this line).
> >
> >
> > > +#include <linux/leds.h>
> > > +#include <linux/module.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/slab.h>
> > Come to think of it, are you sure you need this include? devm_kzalloc()
> > doesn't comes from this file.
> >
> >
> > > +#define BKL_FULL_BRIGHTNESS 255
> > This is unused. Please remove.
> >
> >
> > Other than that, looks good!
>
> Thanks for the quick review. I forgot to cleanup the headers. I'll fix that
> now
I felt I owed it to this patch series after my performance so far this
dev cycle!
Daniel.
On 10/09/2019 13:26, Daniel Thompson wrote:
>
>> endmenu
>> diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
>> index 63c507c07437..2a67642966a5 100644
>> --- a/drivers/video/backlight/Makefile
>> +++ b/drivers/video/backlight/Makefile
>> @@ -57,3 +57,4 @@ obj-$(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..a72456e11fb9
>> --- /dev/null
>> +++ b/drivers/video/backlight/led_bl.c
>> @@ -0,0 +1,264 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/
>> + * Author: Tomi Valkeinen <[email protected]>
>> + *
>> + * Based on pwm_bl.c
>> + */
>> +
>> +#include <linux/backlight.h>
>> +#include <linux/gpio/consumer.h>
> Maybe this is a nitpick but it is one I have now raised three times and
> I don't recall any response, what symbols from this header are used in
> this file?
>
> AFAICT everything defined in this header includes the string "gpio" and
> that string doesn't appear anywhere in the file (except this line).
>
>
>> +#include <linux/leds.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/slab.h>
> Come to think of it, are you sure you need this include? devm_kzalloc()
> doesn't comes from this file.
>
>
>> +#define BKL_FULL_BRIGHTNESS 255
> This is unused. Please remove.
>
>
> Other than that, looks good!
Thanks for the quick review. I forgot to cleanup the headers. I'll fix
that now
JJ
>
>
> Daniel.