Re: [PATCH] gpio: Pass a flag to gpiochip_request_own_desc()

[Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>]

Hi Linus,
 
 On mar., sept. 04 2018, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:

> Before things go out of hand, make it possible to pass
> flags when requesting "own" descriptors from a gpio_chip.
> This is necessary if the chip wants to reques a GPIO with
> active low semantics, for example.

For mvebu:

Reviewed-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>

Thanks,

Gregory


>
> Cc: Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx>
> Cc: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
> Cc: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
> Cc: Jason Cooper <jason@xxxxxxxxxxxxxx>
> Cc: Jiri Kosina <jkosina@xxxxxxx>
> Cc: Roger Quadros <rogerq@xxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
>  Documentation/driver-api/gpio/driver.rst |  4 +++-
>  arch/arm/mach-omap1/ams-delta-fiq.c      |  2 +-
>  arch/arm/mach-omap1/board-ams-delta.c    |  2 +-
>  drivers/gpio/gpio-mvebu.c                |  2 +-
>  drivers/gpio/gpiolib-acpi.c              | 13 +++----------
>  drivers/gpio/gpiolib.c                   | 21 +++++++++++++++++++--
>  drivers/hid/hid-cp2112.c                 |  2 +-
>  drivers/memory/omap-gpmc.c               |  3 ++-
>  include/linux/gpio/driver.h              |  4 +++-
>  9 files changed, 34 insertions(+), 19 deletions(-)
>
> diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst
> index cbe0242842d1..e9a5aae8c84c 100644
> --- a/Documentation/driver-api/gpio/driver.rst
> +++ b/Documentation/driver-api/gpio/driver.rst
> @@ -413,7 +413,9 @@ try_module_get()). A GPIO driver can use the following functions instead
>  to request and free descriptors without being pinned to the kernel forever::
>  
>  	struct gpio_desc *gpiochip_request_own_desc(struct gpio_desc *desc,
> -						    const char *label)
> +						    u16 hwnum,
> +						    const char *label,
> +						    enum gpiod_flags flags)
>  
>  	void gpiochip_free_own_desc(struct gpio_desc *desc)
>  
> diff --git a/arch/arm/mach-omap1/ams-delta-fiq.c b/arch/arm/mach-omap1/ams-delta-fiq.c
> index b0dc7ddf5877..0324d0f209ea 100644
> --- a/arch/arm/mach-omap1/ams-delta-fiq.c
> +++ b/arch/arm/mach-omap1/ams-delta-fiq.c
> @@ -103,7 +103,7 @@ void __init ams_delta_init_fiq(struct gpio_chip *chip,
>  	}
>  
>  	for (i = 0; i < ARRAY_SIZE(irq_data); i++) {
> -		gpiod = gpiochip_request_own_desc(chip, i, pin_name[i]);
> +		gpiod = gpiochip_request_own_desc(chip, i, pin_name[i], 0);
>  		if (IS_ERR(gpiod)) {
>  			pr_err("%s: failed to get GPIO pin %d (%ld)\n",
>  			       __func__, i, PTR_ERR(gpiod));
> diff --git a/arch/arm/mach-omap1/board-ams-delta.c b/arch/arm/mach-omap1/board-ams-delta.c
> index dd28d2614d7f..085438d17662 100644
> --- a/arch/arm/mach-omap1/board-ams-delta.c
> +++ b/arch/arm/mach-omap1/board-ams-delta.c
> @@ -784,7 +784,7 @@ static void __init ams_delta_led_init(struct gpio_chip *chip)
>  	int i;
>  
>  	for (i = LATCH1_PIN_LED_CAMERA; i < LATCH1_PIN_DOCKIT1; i++) {
> -		gpiod = gpiochip_request_own_desc(chip, i, NULL);
> +		gpiod = gpiochip_request_own_desc(chip, i, "camera-led", 0);
>  		if (IS_ERR(gpiod)) {
>  			pr_warn("%s: %s GPIO %d request failed (%ld)\n",
>  				__func__, LATCH1_LABEL, i, PTR_ERR(gpiod));
> diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
> index 6e02148c208b..6c675c5accba 100644
> --- a/drivers/gpio/gpio-mvebu.c
> +++ b/drivers/gpio/gpio-mvebu.c
> @@ -608,7 +608,7 @@ static int mvebu_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
>  		ret = -EBUSY;
>  	} else {
>  		desc = gpiochip_request_own_desc(&mvchip->chip,
> -						 pwm->hwpwm, "mvebu-pwm");
> +						 pwm->hwpwm, "mvebu-pwm", 0);
>  		if (IS_ERR(desc)) {
>  			ret = PTR_ERR(desc);
>  			goto out;
> diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
> index c48ed9d89ff5..2b76ccaf0350 100644
> --- a/drivers/gpio/gpiolib-acpi.c
> +++ b/drivers/gpio/gpiolib-acpi.c
> @@ -178,7 +178,7 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
>  	if (!handler)
>  		return AE_OK;
>  
> -	desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
> +	desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event", 0);
>  	if (IS_ERR(desc)) {
>  		dev_err(chip->parent, "Failed to request GPIO\n");
>  		return AE_ERROR;
> @@ -883,21 +883,14 @@ acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
>  			const char *label = "ACPI:OpRegion";
>  			int err;
>  
> -			desc = gpiochip_request_own_desc(chip, pin, label);
> +			desc = gpiochip_request_own_desc(chip, pin, label,
> +							 0, flags);
>  			if (IS_ERR(desc)) {
>  				status = AE_ERROR;
>  				mutex_unlock(&achip->conn_lock);
>  				goto out;
>  			}
>  
> -			err = gpiod_configure_flags(desc, label, 0, flags);
> -			if (err < 0) {
> -				status = AE_NOT_CONFIGURED;
> -				gpiochip_free_own_desc(desc);
> -				mutex_unlock(&achip->conn_lock);
> -				goto out;
> -			}
> -
>  			conn = kzalloc(sizeof(*conn), GFP_KERNEL);
>  			if (!conn) {
>  				status = AE_NO_MEMORY;
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index e8f8a1999393..26e2ec06eb43 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -2446,6 +2446,7 @@ EXPORT_SYMBOL_GPL(gpiochip_is_requested);
>   * @chip: GPIO chip
>   * @hwnum: hardware number of the GPIO for which to request the descriptor
>   * @label: label for the GPIO
> + * @flags: flags for this GPIO or 0 if default
>   *
>   * Function allows GPIO chip drivers to request and use their own GPIO
>   * descriptors via gpiolib API. Difference to gpiod_request() is that this
> @@ -2458,7 +2459,8 @@ EXPORT_SYMBOL_GPL(gpiochip_is_requested);
>   * code on failure.
>   */
>  struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
> -					    const char *label)
> +					    const char *label,
> +					    enum gpiod_flags flags)
>  {
>  	struct gpio_desc *desc = gpiochip_get_desc(chip, hwnum);
>  	int err;
> @@ -2472,6 +2474,13 @@ struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
>  	if (err < 0)
>  		return ERR_PTR(err);
>  
> +	err = gpiod_configure_flags(desc, label, 0, flags);
> +	if (err) {
> +		chip_err(chip, "setup of own GPIO %s failed\n", label);
> +		gpiod_free_commit(desc);
> +		return ERR_PTR(err);
> +	}
> +
>  	return desc;
>  }
>  EXPORT_SYMBOL_GPL(gpiochip_request_own_desc);
> @@ -4108,7 +4117,15 @@ int gpiod_hog(struct gpio_desc *desc, const char *name,
>  	chip = gpiod_to_chip(desc);
>  	hwnum = gpio_chip_hwgpio(desc);
>  
> -	local_desc = gpiochip_request_own_desc(chip, hwnum, name);
> +	/*
> +	 * FIXME: not very elegant that we call gpiod_configure_flags()
> +	 * twice here (once inside gpiochip_request_own_desc() and
> +	 * again here), but the gpiochip_request_own_desc() is external
> +	 * and cannot really pass the lflags so this is the lesser evil
> +	 * at the moment. Pass zero as dflags on this first call so we
> +	 * don't screw anything up.
> +	 */
> +	local_desc = gpiochip_request_own_desc(chip, hwnum, name, 0);
>  	if (IS_ERR(local_desc)) {
>  		status = PTR_ERR(local_desc);
>  		pr_err("requesting hog GPIO %s (chip %s, offset %d) failed, %d\n",
> diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
> index 271f31461da4..47f65857408d 100644
> --- a/drivers/hid/hid-cp2112.c
> +++ b/drivers/hid/hid-cp2112.c
> @@ -1203,7 +1203,7 @@ static int __maybe_unused cp2112_allocate_irq(struct cp2112_device *dev,
>  		return -EINVAL;
>  
>  	dev->desc[pin] = gpiochip_request_own_desc(&dev->gc, pin,
> -						   "HID/I2C:Event");
> +						   "HID/I2C:Event", 0);
>  	if (IS_ERR(dev->desc[pin])) {
>  		dev_err(dev->gc.parent, "Failed to request GPIO\n");
>  		return PTR_ERR(dev->desc[pin]);
> diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
> index c215287e80cf..b9b4f7058b05 100644
> --- a/drivers/memory/omap-gpmc.c
> +++ b/drivers/memory/omap-gpmc.c
> @@ -2170,7 +2170,8 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
>  		unsigned int wait_pin = gpmc_s.wait_pin;
>  
>  		waitpin_desc = gpiochip_request_own_desc(&gpmc->gpio_chip,
> -							 wait_pin, "WAITPIN");
> +							 wait_pin, "WAITPIN",
> +							 0);
>  		if (IS_ERR(waitpin_desc)) {
>  			dev_err(&pdev->dev, "invalid wait-pin: %d\n", wait_pin);
>  			ret = PTR_ERR(waitpin_desc);
> diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
> index 0ea328e71ec9..86d9db466444 100644
> --- a/include/linux/gpio/driver.h
> +++ b/include/linux/gpio/driver.h
> @@ -17,6 +17,7 @@ struct device_node;
>  struct seq_file;
>  struct gpio_device;
>  struct module;
> +enum gpiod_flags;
>  
>  #ifdef CONFIG_GPIOLIB
>  
> @@ -570,7 +571,8 @@ gpiochip_remove_pin_ranges(struct gpio_chip *chip)
>  #endif /* CONFIG_PINCTRL */
>  
>  struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
> -					    const char *label);
> +					    const char *label,
> +					    enum gpiod_flags flags);
>  void gpiochip_free_own_desc(struct gpio_desc *desc);
>  
>  #else /* CONFIG_GPIOLIB */
> -- 
> 2.17.1
>

-- 
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com