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Commit 31029116 authored by Jamie Iles's avatar Jamie Iles Committed by Grant Likely
Browse files

basic_mmio_gpio: support direction registers 



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: default avatarJamie Iles <jamie@jamieiles.com>
Acked-by: default avatarAnton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent dd86a0cc

drivers/gpio/basic_mmio_gpio.c

+112 −2
Original line number Diff line number Diff line
@@ -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);