[PATCH] gpio: davinci: fix gpio selection for OF

[Alexander Holler]

The driver missed an of_xlate function to translate gpio numbers
as found in the DT to the correct chip and number.

While there I've set #gpio_cells to a fixed value of 2.

I've used gpio-pxa.c as template for those changes and tested my changes
successfully on a da850 board using entries for gpio-leds in a DT. So I didn't
reinvent the wheel but just copied and tested stuff.

Thanks to Grygorii Strashko for the hint of the existing code in gpio-pxa.

Signed-off-by: Alexander Holler <holler at ahsoftware.de>
---
 drivers/gpio/gpio-davinci.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/gpio/gpio-davinci.c b/drivers/gpio/gpio-davinci.c
index 7629b4f..79f45c4 100644
--- a/drivers/gpio/gpio-davinci.c
+++ b/drivers/gpio/gpio-davinci.c
@@ -44,6 +44,9 @@ struct davinci_gpio_regs {
 
 static void __iomem *gpio_base;
 
+static struct davinci_gpio_controller *davinci_gpio_chips;
+static int davinci_last_gpio;
+
 static struct davinci_gpio_regs __iomem *gpio2regs(unsigned gpio)
 {
 	void __iomem *ptr;
@@ -172,6 +175,24 @@ of_err:
 	return NULL;
 }
 
+#ifdef CONFIG_OF_GPIO
+static int davinci_gpio_of_xlate(struct gpio_chip *gc,
+			     const struct of_phandle_args *gpiospec,
+			     u32 *flags)
+{
+	if (gpiospec->args[0] > davinci_last_gpio)
+		return -EINVAL;
+
+	if (gc != &davinci_gpio_chips[gpiospec->args[0] / 32].chip)
+		return -EINVAL;
+
+	if (flags)
+		*flags = gpiospec->args[1];
+
+	return gpiospec->args[0] % 32;
+}
+#endif
+
 static int davinci_gpio_probe(struct platform_device *pdev)
 {
 	int i, base;
@@ -236,6 +257,8 @@ static int davinci_gpio_probe(struct platform_device *pdev)
 			chips[i].chip.ngpio = 32;
 
 #ifdef CONFIG_OF_GPIO
+		chips[i].chip.of_gpio_n_cells = 2;
+		chips[i].chip.of_xlate = davinci_gpio_of_xlate;
 		chips[i].chip.of_node = dev->of_node;
 #endif
 		spin_lock_init(&chips[i].lock);
@@ -251,6 +274,10 @@ static int davinci_gpio_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, chips);
 	davinci_gpio_irq_setup(pdev);
+
+	davinci_gpio_chips = chips;
+	davinci_last_gpio = ngpio;
+
 	return 0;
 }
 
-- 
1.8.3.1