[PATCHv3 5/7] basic_mmio_gpio: detect output method at probe time

[Jamie Iles <jamie@jamieiles.com>]

Rather than detecting the output method each time in the .set()
callback, do it at probe time and set the appropriate callback.

Changes since v2: moved the reg_dat initialization into
bgpio_setup_io().

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 |   90 ++++++++++++++++++++++++++--------------
 1 files changed, 59 insertions(+), 31 deletions(-)

diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c
index 90f7f89..728bc67 100644
--- a/drivers/gpio/basic_mmio_gpio.c
+++ b/drivers/gpio/basic_mmio_gpio.c
@@ -161,14 +161,6 @@ static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 	unsigned long mask = bgc->pin2mask(bgc, gpio);
 	unsigned long flags;
 
-	if (bgc->reg_set) {
-		if (val)
-			bgc->write_reg(bgc->reg_set, mask);
-		else
-			bgc->write_reg(bgc->reg_clr, mask);
-		return;
-	}
-
 	spin_lock_irqsave(&bgc->lock, flags);
 
 	if (val)
@@ -181,6 +173,18 @@ static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 	spin_unlock_irqrestore(&bgc->lock, flags);
 }
 
+static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
+				 int val)
+{
+	struct bgpio_chip *bgc = to_bgpio_chip(gc);
+	unsigned long mask = bgc->pin2mask(bgc, gpio);
+
+	if (val)
+		bgc->write_reg(bgc->reg_set, mask);
+	else
+		bgc->write_reg(bgc->reg_clr, mask);
+}
+
 static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 {
 	return 0;
@@ -188,7 +192,8 @@ static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 
 static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 {
-	bgpio_set(gc, gpio, val);
+	gc->set(gc, gpio, val);
+
 	return 0;
 }
 
@@ -238,18 +243,25 @@ static int bgpio_setup_accessors(struct platform_device *pdev,
 	return 0;
 }
 
-static int __devinit bgpio_probe(struct platform_device *pdev)
+/*
+ * Create the device and allocate the resources.  For setting GPIO's there are
+ * two supported configurations:
+ *
+ *	- single output register resource (named "dat").
+ *	- set/clear pair (named "set" and "clr").
+ *
+ * For the single output register, this drives a 1 by setting a bit and a zero
+ * 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.
+ */
+static int bgpio_setup_io(struct platform_device *pdev,
+			  struct bgpio_chip *bgc)
 {
-	struct device *dev = &pdev->dev;
-	struct bgpio_pdata *pdata = dev_get_platdata(dev);
-	struct bgpio_chip *bgc;
-	struct resource *res_dat;
 	struct resource *res_set;
 	struct resource *res_clr;
+	struct resource *res_dat;
 	resource_size_t dat_sz;
-	int bits;
-	int ret;
-	int ngpio;
 
 	res_dat = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
 	if (!res_dat)
@@ -259,16 +271,11 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
 	if (!is_power_of_2(dat_sz))
 		return -EINVAL;
 
-	bits = dat_sz * 8;
-	ngpio = bits;
-	if (bits > BITS_PER_LONG)
+	bgc->bits = dat_sz * 8;
+	if (bgc->bits > BITS_PER_LONG)
 		return -EINVAL;
 
-	bgc = devm_kzalloc(dev, sizeof(*bgc), GFP_KERNEL);
-	if (!bgc)
-		return -ENOMEM;
-
-	bgc->reg_dat = bgpio_request_and_map(dev, res_dat);
+	bgc->reg_dat = bgpio_request_and_map(&pdev->dev, res_dat);
 	if (!bgc->reg_dat)
 		return -ENOMEM;
 
@@ -276,19 +283,41 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
 	res_clr = platform_get_resource_byname(pdev, IORESOURCE_MEM, "clr");
 	if (res_set && res_clr) {
 		if (resource_size(res_set) != resource_size(res_clr) ||
-				resource_size(res_set) != dat_sz)
+		    resource_size(res_set) != resource_size(res_dat))
 			return -EINVAL;
 
-		bgc->reg_set = bgpio_request_and_map(dev, res_set);
-		bgc->reg_clr = bgpio_request_and_map(dev, res_clr);
+		bgc->reg_set = bgpio_request_and_map(&pdev->dev, res_set);
+		bgc->reg_clr = bgpio_request_and_map(&pdev->dev, res_clr);
 		if (!bgc->reg_set || !bgc->reg_clr)
 			return -ENOMEM;
+
+		bgc->gc.set = bgpio_set_with_clear;
 	} else if (res_set || res_clr) {
 		return -EINVAL;
+	} else {
+		bgc->gc.set = bgpio_set;
 	}
 
-	spin_lock_init(&bgc->lock);
+	return 0;
+}
+
+static int __devinit bgpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct bgpio_pdata *pdata = dev_get_platdata(dev);
+	struct bgpio_chip *bgc;
+	int ret;
+	int ngpio;
+
+	bgc = devm_kzalloc(dev, sizeof(*bgc), GFP_KERNEL);
+	if (!bgc)
+		return -ENOMEM;
+
+	ret = bgpio_setup_io(pdev, bgc);
+	if (ret)
+		return ret;
 
+	ngpio = bgc->bits;
 	if (pdata) {
 		bgc->gc.base = pdata->base;
 		if (pdata->ngpio > 0)
@@ -297,18 +326,17 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
 		bgc->gc.base = -1;
 	}
 
-	bgc->bits = bits;
 	ret = bgpio_setup_accessors(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.get = bgpio_get;
-	bgc->gc.set = bgpio_set;
 	bgc->gc.dev = dev;
 	bgc->gc.label = dev_name(dev);
 
-- 
1.7.4.2