of/gpio: add default of_xlate function if device has a node pointer

Implement generic OF gpio hooks and thus make device-enabled GPIO chips
(i.e.  the ones that have gpio_chip->dev specified) automatically attach
to the OpenFirmware subsystem.  Which means that now we can handle I2C and
SPI GPIO chips almost* transparently.

* "Almost" because some chips still require platform data, and for these
  chips OF-glue is still needed, though with this change the glue will
  be much smaller.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Bill Gatliff <bgat@billgatliff.com>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
CC: linux-kernel@vger.kernel.org
CC: devicetree-discuss@lists.ozlabs.org

3 files changed, 29 insertions, 10 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 73fd328f6fe..83cbc34e3a7 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -8,6 +8,7 @@
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 #include <linux/gpio.h>
+#include <linux/of_gpio.h>
 #include <linux/idr.h>
 #include <linux/slab.h>
 
@@ -1099,6 +1100,8 @@ int gpiochip_add(struct gpio_chip *chip)
 		}
 	}
 
+	of_gpiochip_add(chip);
+
 unlock:
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
@@ -1133,6 +1136,8 @@ int gpiochip_remove(struct gpio_chip *chip)
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
+	of_gpiochip_remove(chip);
+
 	for (id = chip->base; id < chip->base + chip->ngpio; id++) {
 		if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) {
 			status = -EBUSY;
diff --git a/drivers/gpio/xilinx_gpio.c b/drivers/gpio/xilinx_gpio.c
index 2993c40b48e..709690995d0 100644
--- a/drivers/gpio/xilinx_gpio.c
+++ b/drivers/gpio/xilinx_gpio.c
@@ -190,7 +190,6 @@ static int __devinit xgpio_of_probe(struct device_node *np)
 
 	spin_lock_init(&chip->gpio_lock);
 
-	chip->mmchip.gc.of_gpio_n_cells = 2;
 	chip->mmchip.gc.direction_input = xgpio_dir_in;
 	chip->mmchip.gc.direction_output = xgpio_dir_out;
 	chip->mmchip.gc.get = xgpio_get;
diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
index c8618d3282c..09f05a17866 100644
--- a/drivers/of/gpio.c
+++ b/drivers/of/gpio.c
@@ -125,8 +125,8 @@ EXPORT_SYMBOL(of_gpio_count);
  * gpio chips. This function performs only one sanity check: whether gpio
  * is less than ngpios (that is specified in the gpio_chip).
  */
-int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
-			 const void *gpio_spec, u32 *flags)
+static int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
+				const void *gpio_spec, u32 *flags)
 {
 	const __be32 *gpio = gpio_spec;
 	const u32 n = be32_to_cpup(gpio);
@@ -150,7 +150,6 @@ int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
 
 	return n;
 }
-EXPORT_SYMBOL(of_gpio_simple_xlate);
 
 /**
  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
@@ -187,9 +186,6 @@ int of_mm_gpiochip_add(struct device_node *np,
 
 	gc->base = -1;
 
-	if (!gc->of_xlate)
-		gc->of_xlate = of_gpio_simple_xlate;
-
 	if (mm_gc->save_regs)
 		mm_gc->save_regs(mm_gc);
 
@@ -199,9 +195,6 @@ int of_mm_gpiochip_add(struct device_node *np,
 	if (ret)
 		goto err2;
 
-	/* We don't want to lose the node and its ->data */
-	of_node_get(np);
-
 	pr_debug("%s: registered as generic GPIO chip, base is %d\n",
 		 np->full_name, gc->base);
 	return 0;
@@ -216,6 +209,28 @@ err0:
 }
 EXPORT_SYMBOL(of_mm_gpiochip_add);
 
+void of_gpiochip_add(struct gpio_chip *chip)
+{
+	if ((!chip->of_node) && (chip->dev))
+		chip->of_node = chip->dev->of_node;
+
+	if (!chip->of_node)
+		return;
+
+	if (!chip->of_xlate) {
+		chip->of_gpio_n_cells = 2;
+		chip->of_xlate = of_gpio_simple_xlate;
+	}
+
+	of_node_get(chip->of_node);
+}
+
+void of_gpiochip_remove(struct gpio_chip *chip)
+{
+	if (chip->of_node)
+		of_node_put(chip->of_node);
+}
+
 /* Private function for resolving node pointer to gpio_chip */
 static int of_gpiochip_is_match(struct gpio_chip *chip, void *data)
 {