Re: [PATCHv3 7/7] basic_mmio_gpio: support direction registers

[Grant Likely <grant.likely@secretlab.ca>]

On Mon, Apr 11, 2011 at 12:21:54PM +0100, Jamie Iles wrote:
> Most controllers require the direction of a GPIO to be set by writing to
> a direction register.  Add support for either an input direction
> register or an output direction register.
> 
> Signed-off-by: Jamie Iles <jamie@jamieiles.com>
> Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
> Cc: Grant Likely <grant.likely@secretlab.ca>

Merged, thanks.

g.

> ---
>  drivers/gpio/basic_mmio_gpio.c |  114 +++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 112 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c
> index 6b99489..f4afd96 100644
> --- a/drivers/gpio/basic_mmio_gpio.c
> +++ b/drivers/gpio/basic_mmio_gpio.c
> @@ -70,6 +70,7 @@ struct bgpio_chip {
>  	void __iomem *reg_dat;
>  	void __iomem *reg_set;
>  	void __iomem *reg_clr;
> +	void __iomem *reg_dir;
>  
>  	/* Number of bits (GPIOs): <register width> * 8. */
>  	int bits;
> @@ -88,6 +89,9 @@ struct bgpio_chip {
>  
>  	/* Shadowed data register to clear/set bits safely. */
>  	unsigned long data;
> +
> +	/* Shadowed direction registers to clear/set direction safely. */
> +	unsigned long dir;
>  };
>  
>  static struct bgpio_chip *to_bgpio_chip(struct gpio_chip *gc)
> @@ -203,15 +207,80 @@ static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
>  	spin_unlock_irqrestore(&bgc->lock, flags);
>  }
>  
> +static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
> +{
> +	return 0;
> +}
> +
> +static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
> +				int val)
> +{
> +	gc->set(gc, gpio, val);
> +
> +	return 0;
> +}
> +
>  static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
>  {
> +	struct bgpio_chip *bgc = to_bgpio_chip(gc);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&bgc->lock, flags);
> +
> +	bgc->dir &= ~bgc->pin2mask(bgc, gpio);
> +	bgc->write_reg(bgc->reg_dir, bgc->dir);
> +
> +	spin_unlock_irqrestore(&bgc->lock, flags);
> +
>  	return 0;
>  }
>  
>  static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
>  {
> +	struct bgpio_chip *bgc = to_bgpio_chip(gc);
> +	unsigned long flags;
> +
> +	gc->set(gc, gpio, val);
> +
> +	spin_lock_irqsave(&bgc->lock, flags);
> +
> +	bgc->dir |= bgc->pin2mask(bgc, gpio);
> +	bgc->write_reg(bgc->reg_dir, bgc->dir);
> +
> +	spin_unlock_irqrestore(&bgc->lock, flags);
> +
> +	return 0;
> +}
> +
> +static int bgpio_dir_in_inv(struct gpio_chip *gc, unsigned int gpio)
> +{
> +	struct bgpio_chip *bgc = to_bgpio_chip(gc);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&bgc->lock, flags);
> +
> +	bgc->dir |= bgc->pin2mask(bgc, gpio);
> +	bgc->write_reg(bgc->reg_dir, bgc->dir);
> +
> +	spin_unlock_irqrestore(&bgc->lock, flags);
> +
> +	return 0;
> +}
> +
> +static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
> +{
> +	struct bgpio_chip *bgc = to_bgpio_chip(gc);
> +	unsigned long flags;
> +
>  	gc->set(gc, gpio, val);
>  
> +	spin_lock_irqsave(&bgc->lock, flags);
> +
> +	bgc->dir &= ~bgc->pin2mask(bgc, gpio);
> +	bgc->write_reg(bgc->reg_dir, bgc->dir);
> +
> +	spin_unlock_irqrestore(&bgc->lock, flags);
> +
>  	return 0;
>  }
>  
> @@ -274,6 +343,14 @@ static int bgpio_setup_accessors(struct platform_device *pdev,
>   * by clearing a bit.  For the set clr pair, this drives a 1 by setting a bit
>   * in the set register and clears it by setting a bit in the clear register.
>   * The configuration is detected by which resources are present.
> + *
> + * For setting the GPIO direction, there are three supported configurations:
> + *
> + *	- simple bidirection GPIO that requires no configuration.
> + *	- an output direction register (named "dirout") where a 1 bit
> + *	indicates the GPIO is an output.
> + *	- an input direction register (named "dirin") where a 1 bit indicates
> + *	the GPIO is an input.
>   */
>  static int bgpio_setup_io(struct platform_device *pdev,
>  			  struct bgpio_chip *bgc)
> @@ -330,6 +407,37 @@ static int bgpio_setup_io(struct platform_device *pdev,
>  	return 0;
>  }
>  
> +static int bgpio_setup_direction(struct platform_device *pdev,
> +				 struct bgpio_chip *bgc)
> +{
> +	struct resource *res_dirout;
> +	struct resource *res_dirin;
> +
> +	res_dirout = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +						  "dirout");
> +	res_dirin = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dirin");
> +	if (res_dirout && res_dirin) {
> +		return -EINVAL;
> +	} else if (res_dirout) {
> +		bgc->reg_dir = bgpio_request_and_map(&pdev->dev, res_dirout);
> +		if (!bgc->reg_dir)
> +			return -ENOMEM;
> +		bgc->gc.direction_output = bgpio_dir_out;
> +		bgc->gc.direction_input = bgpio_dir_in;
> +	} else if (res_dirin) {
> +		bgc->reg_dir = bgpio_request_and_map(&pdev->dev, res_dirin);
> +		if (!bgc->reg_dir)
> +			return -ENOMEM;
> +		bgc->gc.direction_output = bgpio_dir_out_inv;
> +		bgc->gc.direction_input = bgpio_dir_in_inv;
> +	} else {
> +		bgc->gc.direction_output = bgpio_simple_dir_out;
> +		bgc->gc.direction_input = bgpio_simple_dir_in;
> +	}
> +
> +	return 0;
> +}
> +
>  static int __devinit bgpio_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -360,11 +468,13 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
>  		return ret;
>  
>  	spin_lock_init(&bgc->lock);
> +	ret = bgpio_setup_direction(pdev, bgc);
> +	if (ret)
> +		return ret;
> +
>  	bgc->data = bgc->read_reg(bgc->reg_dat);
>  
>  	bgc->gc.ngpio = ngpio;
> -	bgc->gc.direction_input = bgpio_dir_in;
> -	bgc->gc.direction_output = bgpio_dir_out;
>  	bgc->gc.dev = dev;
>  	bgc->gc.label = dev_name(dev);
>  
> -- 
> 1.7.4.2
>