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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: Jamie Iles <jamie@jamieiles.com>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Jamie Iles 2011-05-20 00:40:17 -06:00 committed by Grant Likely
parent dd86a0cc5e
commit 31029116eb
1 changed files with 112 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

114
drivers/gpio/basic_mmio_gpio.c
View File

@ -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);