linux-kernel - [RFC PATCH 6/7] basic_mmio_gpio: support different input/output registers

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Date:	Wed,  6 Apr 2011 12:11:02 +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 6/7] basic_mmio_gpio: support different input/output registers

Some controllers have separate input and output registers.  For these
controllers, allow a register named "in" to be used for reading the
value of a GPIO pin.

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 |   29 +++++++++++++++++++++++++++--
 1 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c
index 500eb6ae..d18a866 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_in;
 
 	/* Number of bits (GPIOs): <register width> * 8. */
 	int bits;
@@ -149,13 +150,20 @@ static unsigned long bgpio_pin2mask_be(struct bgpio_chip *bgc,
 	return 1 << (bgc->bits - 1 - pin);
 }
 
-static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
+static int bgpio_get_dat(struct gpio_chip *gc, unsigned int gpio)
 {
 	struct bgpio_chip *bgc = to_bgpio_chip(gc);
 
 	return bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio);
 }
 
+static int bgpio_get_in(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+	return bgc->read_reg(bgc->reg_in) & bgc->pin2mask(bgc, gpio);
+}
+
 static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 {
 	struct bgpio_chip *bgc = to_bgpio_chip(gc);
@@ -255,12 +263,18 @@ 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 getting GPIO values, there are two supported configurations:
+ *
+ *	- single output/input register resource (named "dat").
+ *	- separate output/input register resources (named "dat" and "in").
  */
 static int bgpio_setup_io(struct platform_device *pdev,
 			  struct bgpio_chip *bgc)
 {
 	struct resource *res_set;
 	struct resource *res_clr;
+	struct resource *res_in;
 
 	res_set = platform_get_resource_byname(pdev, IORESOURCE_MEM, "set");
 	res_clr = platform_get_resource_byname(pdev, IORESOURCE_MEM, "clr");
@@ -281,6 +295,16 @@ static int bgpio_setup_io(struct platform_device *pdev,
 		bgc->gc.set = bgpio_set;
 	}
 
+	res_in = platform_get_resource_byname(pdev, IORESOURCE_MEM, "in");
+	if (res_in) {
+		bgc->reg_in = bgpio_request_and_map(&pdev->dev, res_in);
+		if (!bgc->reg_in)
+			return -ENOMEM;
+		bgc->gc.get = bgpio_get_in;
+	} else {
+		bgc->gc.get = bgpio_get_dat;
+	}
+
 	return 0;
 }
 
@@ -316,6 +340,8 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
 	if (!bgc->reg_dat)
 		return -ENOMEM;
 
+	spin_lock_init(&bgc->lock);
+
 	if (pdata) {
 		bgc->gc.base = pdata->base;
 		if (pdata->ngpio > 0)
@@ -338,7 +364,6 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
 	bgc->gc.ngpio = ngpio;
 	bgc->gc.direction_input = bgpio_dir_in;
 	bgc->gc.direction_output = bgpio_dir_out;
-	bgc->gc.get = bgpio_get;
 	bgc->gc.dev = dev;
 	bgc->gc.label = dev_name(dev);
 
-- 
1.7.4

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