Messages in this thread Patch in this message | | | From | Jamie Iles <> | Subject | [RFC PATCH 7/7] basic_mmio_gpio: support direction registers | Date | Wed, 6 Apr 2011 12:11:03 +0100 |
| |
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> Cc: Anton Vorontsov <cbouatmailru@gmail.com> Cc: Grant Likely <grant.likely@secretlab.ca> --- drivers/gpio/basic_mmio_gpio.c | 107 +++++++++++++++++++++++++++++++++++++++- 1 files changed, 105 insertions(+), 2 deletions(-)
diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c index d18a866..9dad485 100644 --- a/drivers/gpio/basic_mmio_gpio.c +++ b/drivers/gpio/basic_mmio_gpio.c @@ -71,6 +71,8 @@ struct bgpio_chip { void __iomem *reg_set; void __iomem *reg_clr; void __iomem *reg_in; + void __iomem *reg_dirout; + void __iomem *reg_dirin; /* Number of bits (GPIOs): <register width> * 8. */ int bits; @@ -90,6 +92,9 @@ struct bgpio_chip { /* Shadowed data register to clear/set bits safely. */ unsigned long data; + + /* Shadowed direction registers to clear/set direction safely. */ + unsigned long outputs, inputs; }; static struct bgpio_chip *to_bgpio_chip(struct gpio_chip *gc) @@ -194,15 +199,72 @@ static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio, bgc->write_reg(bgc->reg_clr, mask); } +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->outputs &= ~bgc->pin2mask(bgc, gpio); + bgc->write_reg(bgc->reg_dirout, bgc->outputs); + 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->outputs |= bgc->pin2mask(bgc, gpio); + bgc->write_reg(bgc->reg_dirout, bgc->outputs); + 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->inputs |= bgc->pin2mask(bgc, gpio); + bgc->write_reg(bgc->reg_dirin, bgc->inputs); + 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->inputs &= ~bgc->pin2mask(bgc, gpio); + bgc->write_reg(bgc->reg_dirin, bgc->inputs); + spin_unlock_irqrestore(&bgc->lock, flags); + return 0; } @@ -268,6 +330,14 @@ static int bgpio_setup_accessors(struct platform_device *pdev, * * - single output/input register resource (named "dat"). * - separate output/input register resources (named "dat" and "in"). + * + * 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) @@ -308,6 +378,37 @@ 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_dirout = bgpio_request_and_map(&pdev->dev, res_dirout); + if (!bgc->reg_dirout) + return -ENOMEM; + bgc->gc.direction_output = bgpio_dir_out; + bgc->gc.direction_input = bgpio_dir_in; + } else if (res_dirin) { + bgc->reg_dirin = bgpio_request_and_map(&pdev->dev, res_dirin); + if (!bgc->reg_dirin) + 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; @@ -358,12 +459,14 @@ static int __devinit bgpio_probe(struct platform_device *pdev) if (ret) return ret; + ret = bgpio_setup_direction(pdev, bgc); + if (ret) + return ret; + spin_lock_init(&bgc->lock); 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
| |