From 8265b2e4e62632b01f998095d1bbda4d281629fe Mon Sep 17 00:00:00 2001
From: Thierry Reding <treding@nvidia.com>
Date: Fri, 30 Aug 2013 12:32:18 +0200
Subject: [PATCH] pwm-backlight: Use new enable_gpio field
Make use of the new enable_gpio field and allow it to be set from DT as
well. Now that all legacy users of platform data have been converted to
initialize this field to an invalid value, it is safe to use the field
from the driver.
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
.../video/backlight/pwm-backlight.txt | 5 ++
drivers/video/backlight/pwm_bl.c | 57 ++++++++++++++++---
2 files changed, 55 insertions(+), 7 deletions(-)
diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
index 1e4fc727f3b180..72810cc2dbc19e 100644
--- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
+++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
@@ -14,8 +14,11 @@ Required properties:
Optional properties:
- pwm-names: a list of names for the PWM devices specified in the
"pwms" property (see PWM binding[0])
+ - enable-gpios: contains a single GPIO specifier for the GPIO which enables
+ and disables the backlight (see GPIO binding[1])
[0]: Documentation/devicetree/bindings/pwm/pwm.txt
+[1]: Documentation/devicetree/bindings/gpio/gpio.txt
Example:
@@ -25,4 +28,6 @@ Example:
brightness-levels = <0 4 8 16 32 64 128 255>;
default-brightness-level = <6>;
+
+ enable-gpios = <&gpio 58 0>;
};
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 4053efbe5edbd8..cdef4a346555e9 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -10,6 +10,8 @@
* published by the Free Software Foundation.
*/
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
@@ -28,6 +30,8 @@ struct pwm_bl_data {
unsigned int lth_brightness;
unsigned int *levels;
bool enabled;
+ int enable_gpio;
+ unsigned long enable_gpio_flags;
int (*notify)(struct device *,
int brightness);
void (*notify_after)(struct device *,
@@ -55,6 +59,14 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness,
pb->lth_brightness;
pwm_config(pb->pwm, duty_cycle, pb->period);
+
+ if (gpio_is_valid(pb->enable_gpio)) {
+ if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
+ gpio_set_value(pb->enable_gpio, 0);
+ else
+ gpio_set_value(pb->enable_gpio, 1);
+ }
+
pwm_enable(pb->pwm);
pb->enabled = true;
}
@@ -67,6 +79,13 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
pwm_config(pb->pwm, 0, pb->period);
pwm_disable(pb->pwm);
+ if (gpio_is_valid(pb->enable_gpio)) {
+ if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
+ gpio_set_value(pb->enable_gpio, 1);
+ else
+ gpio_set_value(pb->enable_gpio, 0);
+ }
+
pb->enabled = false;
}
@@ -119,6 +138,7 @@ static int pwm_backlight_parse_dt(struct device *dev,
struct platform_pwm_backlight_data *data)
{
struct device_node *node = dev->of_node;
+ enum of_gpio_flags flags;
struct property *prop;
int length;
u32 value;
@@ -159,11 +179,13 @@ static int pwm_backlight_parse_dt(struct device *dev,
data->max_brightness--;
}
- /*
- * TODO: Most users of this driver use a number of GPIOs to control
- * backlight power. Support for specifying these needs to be
- * added.
- */
+ data->enable_gpio = of_get_named_gpio_flags(node, "enable-gpios", 0,
+ &flags);
+ if (data->enable_gpio == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+
+ if (gpio_is_valid(data->enable_gpio) && (flags & OF_GPIO_ACTIVE_LOW))
+ data->enable_gpio_flags |= PWM_BACKLIGHT_GPIO_ACTIVE_LOW;
return 0;
}
@@ -221,6 +243,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
} else
max = data->max_brightness;
+ pb->enable_gpio = data->enable_gpio;
+ pb->enable_gpio_flags = data->enable_gpio_flags;
pb->notify = data->notify;
pb->notify_after = data->notify_after;
pb->check_fb = data->check_fb;
@@ -228,6 +252,22 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->dev = &pdev->dev;
pb->enabled = false;
+ if (gpio_is_valid(pb->enable_gpio)) {
+ unsigned long flags;
+
+ if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
+ flags = GPIOF_OUT_INIT_HIGH;
+ else
+ flags = GPIOF_OUT_INIT_LOW;
+
+ ret = gpio_request_one(pb->enable_gpio, flags, "enable");
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n",
+ pb->enable_gpio, ret);
+ goto err_alloc;
+ }
+ }
+
pb->pwm = devm_pwm_get(&pdev->dev, NULL);
if (IS_ERR(pb->pwm)) {
dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
@@ -236,7 +276,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
if (IS_ERR(pb->pwm)) {
dev_err(&pdev->dev, "unable to request legacy PWM\n");
ret = PTR_ERR(pb->pwm);
- goto err_alloc;
+ goto err_gpio;
}
}
@@ -261,7 +301,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
if (IS_ERR(bl)) {
dev_err(&pdev->dev, "failed to register backlight\n");
ret = PTR_ERR(bl);
- goto err_alloc;
+ goto err_gpio;
}
if (data->dft_brightness > data->max_brightness) {
@@ -277,6 +317,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, bl);
return 0;
+err_gpio:
+ if (gpio_is_valid(pb->enable_gpio))
+ gpio_free(pb->enable_gpio);
err_alloc:
if (data->exit)
data->exit(&pdev->dev);
--
GitLab