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Subject[PATCH 2/2] pwm-backlight: switch to gpiod interface
Date
Switch to the new gpiod interface, which allows to handle GPIO
properties such as active low transparently and removes a whole bunch of
code.

There are still a couple of users of this driver that rely on passing
the enable GPIO number through platform data, so a fallback mechanism
using a GPIO number is still available to avoid breaking them. It will
be removed once current users have switched to the GPIO lookup tables
provided by the gpiod interface.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
drivers/video/backlight/pwm_bl.c | 72 +++++++++++++++++-----------------------
include/linux/pwm_backlight.h | 5 +--
2 files changed, 32 insertions(+), 45 deletions(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index b75201ff46f6..533057688d93 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -10,8 +10,8 @@
* published by the Free Software Foundation.
*/

+#include <linux/gpio/consumer.h>
#include <linux/gpio.h>
-#include <linux/of_gpio.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
@@ -32,8 +32,7 @@ struct pwm_bl_data {
unsigned int *levels;
bool enabled;
struct regulator *power_supply;
- int enable_gpio;
- unsigned long enable_gpio_flags;
+ struct gpio_desc *enable_gpio;
unsigned int scale;
int (*notify)(struct device *,
int brightness);
@@ -54,12 +53,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
if (err < 0)
dev_err(pb->dev, "failed to enable power supply\n");

- 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);
- }
+ if (pb->enable_gpio)
+ gpiod_set_value(pb->enable_gpio, 1);

pwm_enable(pb->pwm);
pb->enabled = true;
@@ -73,12 +68,8 @@ 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);
- }
+ if (pb->enable_gpio)
+ gpiod_set_value(pb->enable_gpio, 0);

regulator_disable(pb->power_supply);
pb->enabled = false;
@@ -148,7 +139,6 @@ 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;
@@ -189,14 +179,6 @@ static int pwm_backlight_parse_dt(struct device *dev,
data->max_brightness--;
}

- 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;
}

@@ -256,8 +238,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
} else
pb->scale = 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;
@@ -265,26 +245,39 @@ 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;
+ pb->enable_gpio = devm_gpiod_get(&pdev->dev, "enable");
+ if (IS_ERR(pb->enable_gpio)) {
+ ret = PTR_ERR(pb->enable_gpio);
+ if (ret == -ENOENT) {
+ pb->enable_gpio = NULL;
+ ret = 0;
+ } else {
+ goto err_alloc;
+ }
+ }

- ret = gpio_request_one(pb->enable_gpio, flags, "enable");
+ /*
+ * Compatibility fallback for drivers still using the integer GPIO
+ * platform data. Must go away soon.
+ */
+ if (pb->enable_gpio == NULL && gpio_is_valid(data->enable_gpio)) {
+ ret = devm_gpio_request_one(&pdev->dev, data->enable_gpio,
+ GPIOF_OUT_INIT_HIGH, "enable");
if (ret < 0) {
dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n",
- pb->enable_gpio, ret);
+ data->enable_gpio, ret);
goto err_alloc;
}
+ pb->enable_gpio = gpio_to_desc(data->enable_gpio);
}

+ if (pb->enable_gpio)
+ gpiod_direction_output(pb->enable_gpio, 1);
+
pb->power_supply = devm_regulator_get(&pdev->dev, "power");
if (IS_ERR(pb->power_supply)) {
ret = PTR_ERR(pb->power_supply);
- goto err_gpio;
+ goto err_alloc;
}

pb->pwm = devm_pwm_get(&pdev->dev, NULL);
@@ -295,7 +288,7 @@ 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_gpio;
+ goto err_alloc;
}
}

@@ -320,7 +313,7 @@ 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_gpio;
+ goto err_alloc;
}

if (data->dft_brightness > data->max_brightness) {
@@ -336,9 +329,6 @@ 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);
diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
index 2de2e275b2cb..efdd9227a49c 100644
--- a/include/linux/pwm_backlight.h
+++ b/include/linux/pwm_backlight.h
@@ -6,9 +6,6 @@

#include <linux/backlight.h>

-/* TODO: convert to gpiod_*() API once it has been merged */
-#define PWM_BACKLIGHT_GPIO_ACTIVE_LOW (1 << 0)
-
struct platform_pwm_backlight_data {
int pwm_id;
unsigned int max_brightness;
@@ -16,8 +13,8 @@ struct platform_pwm_backlight_data {
unsigned int lth_brightness;
unsigned int pwm_period_ns;
unsigned int *levels;
+ /* TODO remove once all users are switched to gpiod_* API */
int enable_gpio;
- unsigned long enable_gpio_flags;
int (*init)(struct device *dev);
int (*notify)(struct device *dev, int brightness);
void (*notify_after)(struct device *dev, int brightness);
--
1.9.0


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