Subject: Re: [PATCH v2] of_gpio: Return GPIO flags from of_get_gpio()

From: Anton Vorontsov <[email-masked]>
Date: Wed, 26 Nov 2008 19:20:33 +0300

On Thu, Oct 30, 2008 at 07:03:09PM -0700, Trent Piepho wrote:
> The device binding spec for OF GPIOs defines a flags field, but there is
> currently no way to get it.  This patch adds a parameter to of_get_gpio()
> where the flags will be returned if non-NULL.  of_get_gpio() in turn passes
> the parameter to the of_gpio_chip's xlate method, which can extract any
> flags present from the gpio_spec.
> 
> The default (and currently only) of_gpio_chip xlate method,
> of_gpio_simple_xlate(), is modified to do this.
> 
> Signed-off-by: Trent Piepho <[email-masked]>
> Acked-by: Grant Likely <[email-masked]>
> Acked-by: Anton Vorontsov <[email-masked]>
> ---
> Since this patch changes an API, it would be nice to get it into powerpc-next
> soon so that people who have new patches that use this API, like Anton, can
> base off it.

Can we apply it? Paul, Benjamin?

The patchwork url for this patch is:
http://patchwork.ozlabs.org/patch/6650/

Thanks!

>  drivers/mtd/nand/fsl_upm.c              |    2 +-
>  drivers/net/fs_enet/fs_enet-main.c      |    2 +-
>  drivers/net/phy/mdio-ofgpio.c           |    4 ++--
>  drivers/of/gpio.c                       |   13 ++++++++++---
>  drivers/serial/cpm_uart/cpm_uart_core.c |    2 +-
>  include/linux/of_gpio.h                 |   21 +++++++++++++++++----
>  6 files changed, 32 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/mtd/nand/fsl_upm.c b/drivers/mtd/nand/fsl_upm.c
> index 024e3ff..a25d962 100644
> --- a/drivers/mtd/nand/fsl_upm.c
> +++ b/drivers/mtd/nand/fsl_upm.c
> @@ -218,7 +218,7 @@ static int __devinit fun_probe(struct of_device *ofdev,
>  	}
>  	fun->upm_cmd_offset = *prop;
>  
> -	fun->rnb_gpio = of_get_gpio(ofdev->node, 0);
> +	fun->rnb_gpio = of_get_gpio(ofdev->node, 0, NULL);
>  	if (fun->rnb_gpio >= 0) {
>  		ret = gpio_request(fun->rnb_gpio, ofdev->dev.bus_id);
>  		if (ret) {
> diff --git a/drivers/net/fs_enet/fs_enet-main.c b/drivers/net/fs_enet/fs_enet-main.c
> index cb51c1f..5a3c7ee 100644
> --- a/drivers/net/fs_enet/fs_enet-main.c
> +++ b/drivers/net/fs_enet/fs_enet-main.c
> @@ -994,7 +994,7 @@ static int __devinit find_phy(struct device_node *np,
>  		goto out_put_phy;
>  	}
>  
> -	bus_id = of_get_gpio(mdionode, 0);
> +	bus_id = of_get_gpio(mdionode, 0, NULL);
>  	if (bus_id < 0) {
>  		struct resource res;
>  		ret = of_address_to_resource(mdionode, 0, &res);
> diff --git a/drivers/net/phy/mdio-ofgpio.c b/drivers/net/phy/mdio-ofgpio.c
> index 2ff9775..e3757c6 100644
> --- a/drivers/net/phy/mdio-ofgpio.c
> +++ b/drivers/net/phy/mdio-ofgpio.c
> @@ -78,8 +78,8 @@ static int __devinit mdio_ofgpio_bitbang_init(struct mii_bus *bus,
>  {
>  	struct mdio_gpio_info *bitbang = bus->priv;
>  
> -	bitbang->mdc = of_get_gpio(np, 0);
> -	bitbang->mdio = of_get_gpio(np, 1);
> +	bitbang->mdc = of_get_gpio(np, 0, NULL);
> +	bitbang->mdio = of_get_gpio(np, 1, NULL);
>  
>  	if (bitbang->mdc < 0 || bitbang->mdio < 0)
>  		return -ENODEV;
> diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
> index 7cd7301..ae14215 100644
> --- a/drivers/of/gpio.c
> +++ b/drivers/of/gpio.c
> @@ -22,11 +22,12 @@
>   * of_get_gpio - Get a GPIO number from the device tree to use with GPIO API
>   * @np:		device node to get GPIO from
>   * @index:	index of the GPIO
> + * @flags:	GPIO's flags are returned here if non-NULL
>   *
>   * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
>   * value on the error condition.
>   */
> -int of_get_gpio(struct device_node *np, int index)
> +int of_get_gpio(struct device_node *np, int index, enum of_gpio_flags *flags)
>  {
>  	int ret;
>  	struct device_node *gc;
> @@ -59,7 +60,9 @@ int of_get_gpio(struct device_node *np, int index)
>  		goto err1;
>  	}
>  
> -	ret = of_gc->xlate(of_gc, np, gpio_spec);
> +	if (flags)
> +		*flags = 0;
> +	ret = of_gc->xlate(of_gc, np, gpio_spec, flags);
>  	if (ret < 0)
>  		goto err1;
>  
> @@ -77,19 +80,23 @@ EXPORT_SYMBOL(of_get_gpio);
>   * @of_gc:	pointer to the of_gpio_chip structure
>   * @np:		device node of the GPIO chip
>   * @gpio_spec:	gpio specifier as found in the device tree
> + * @flags:	if non-NULL flags are returned here
>   *
>   * This is simple translation function, suitable for the most 1:1 mapped
>   * gpio chips. This function performs only one sanity check: whether gpio
>   * is less than ngpios (that is specified in the gpio_chip).
>   */
>  int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np,
> -			 const void *gpio_spec)
> +			 const void *gpio_spec, enum of_gpio_flags *flags)
>  {
>  	const u32 *gpio = gpio_spec;
>  
>  	if (*gpio > of_gc->gc.ngpio)
>  		return -EINVAL;
>  
> +	if (flags && of_gc->gpio_cells > 1)
> +		*flags = gpio[1];
> +
>  	return *gpio;
>  }
>  EXPORT_SYMBOL(of_gpio_simple_xlate);
> diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
> index bde4b4b..7835cd4 100644
> --- a/drivers/serial/cpm_uart/cpm_uart_core.c
> +++ b/drivers/serial/cpm_uart/cpm_uart_core.c
> @@ -1094,7 +1094,7 @@ static int cpm_uart_init_port(struct device_node *np,
>  	}
>  
>  	for (i = 0; i < NUM_GPIOS; i++)
> -		pinfo->gpios[i] = of_get_gpio(np, i);
> +		pinfo->gpios[i] = of_get_gpio(np, i, NULL);
>  
>  	return cpm_uart_request_port(&pinfo->port);
>  
> diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
> index 67db101..d611746 100644
> --- a/include/linux/of_gpio.h
> +++ b/include/linux/of_gpio.h
> @@ -20,13 +20,23 @@
>  #ifdef CONFIG_OF_GPIO
>  
>  /*
> + * Flags as returned by OF GPIO chip's xlate method.
> + * The GPIO specifier in the OF device tree does not need to use this
> + * same format for its flags, but it's convenient if it does.  For
> + * example, the of_mm_gpio_chip driver works this way.
> + */
> +enum of_gpio_flags {
> +	OF_GPIO_ACTIVE_LOW = 1,
> +};
> +
> +/*
>   * Generic OF GPIO chip
>   */
>  struct of_gpio_chip {
>  	struct gpio_chip gc;
>  	int gpio_cells;
>  	int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,
> -		     const void *gpio_spec);
> +		     const void *gpio_spec, enum of_gpio_flags *flags);
>  };
>  
>  static inline struct of_gpio_chip *to_of_gpio_chip(struct gpio_chip *gc)
> @@ -50,16 +60,19 @@ static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
>  	return container_of(of_gc, struct of_mm_gpio_chip, of_gc);
>  }
>  
> -extern int of_get_gpio(struct device_node *np, int index);
> +extern int of_get_gpio(struct device_node *np, int index,
> +		       enum of_gpio_flags *flags);
>  extern int of_mm_gpiochip_add(struct device_node *np,
>  			      struct of_mm_gpio_chip *mm_gc);
>  extern int of_gpio_simple_xlate(struct of_gpio_chip *of_gc,
>  				struct device_node *np,
> -				const void *gpio_spec);
> +				const void *gpio_spec,
> +				enum of_gpio_flags *flags);
>  #else
>  
>  /* Drivers may not strictly depend on the GPIO support, so let them link. */
> -static inline int of_get_gpio(struct device_node *np, int index)
> +static inline int of_get_gpio(struct device_node *np, int index,
> +			      enum of_gpio_flags *flags)
>  {
>  	return -ENOSYS;
>  }
> -- 
> 1.5.4.3
>