Hi all,
I have a problem while using the pwm-backlight driver.
I want to match the panel power sequence timing but fail in the probe
function. I think it is right to set the gpio "inactive" at
initialization. For now, the probe function always pulls high
enable_gpio although I set it as GPIO_ACTIVE_HIGH in dts.
I find the change and excerpt part of it. I am not sure if it is right.
If I misunderstanding something, please let me know.
Regards,
YH Huang
From Alexandre Courbot <>
Subject [PATCH 2/2] pwm-backlight: switch to gpiod interface
Date Thu, 27 Feb 2014 14:53:34 +0900
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.
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -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);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Is here right?
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