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Date: Tue, 3 May 2011 13:42:29 -0600
From: Grant Likely <grant.likely@...retlab.ca>
To: Jamie Iles <jamie@...ieiles.com>
Cc: linux-kernel@...r.kernel.org, linux@....linux.org.uk,
tglx@...utronix.de, cbouatmailru@...il.com, arnd@...db.de,
nico@...xnic.net
Subject: Re: [PATCHv3 7/7] basic_mmio_gpio: support direction registers
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@...ieiles.com>
> Acked-by: Anton Vorontsov <cbouatmailru@...il.com>
> Cc: Grant Likely <grant.likely@...retlab.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
>
--
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