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Message-Id: <1302088263-12714-8-git-send-email-jamie@jamieiles.com>
Date: Wed, 6 Apr 2011 12:11:03 +0100
From: Jamie Iles <jamie@...ieiles.com>
To: linux-kernel@...r.kernel.org
Cc: linux@....linux.org.uk, tglx@...utronix.de, cbouatmailru@...il.com,
grant.likely@...retlab.ca, arnd@...db.de, nico@...xnic.net,
Jamie Iles <jamie@...ieiles.com>
Subject: [RFC PATCH 7/7] 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@...ieiles.com>
Cc: Anton Vorontsov <cbouatmailru@...il.com>
Cc: Grant Likely <grant.likely@...retlab.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
--
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