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

1 files changed, 24 insertions, 9 deletions

diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
index c8618d3282cf..09f05a178668 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)
 {