gpio: davinci: add OF support

This patch adds OF parser support for davinci gpio
driver and also appropriate documentation in gpio-davinci.txt
located at Documentation/devicetree/bindings/gpio/.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: KV Sujith <sujithkv@ti.com>
Signed-off-by: Philip Avinash <avinashphilip@ti.com>
[prabhakar.csengg@gmail.com: simplified the OF code, removed
		unnecessary DT property and also simplified
		the commit message]
Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

2 files changed, 95 insertions, 3 deletions

diff --git a/Documentation/devicetree/bindings/gpio/gpio-davinci.txt b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt
new file mode 100644
index 000000000000..a2e839d6e338
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt
@@ -0,0 +1,41 @@
+Davinci GPIO controller bindings
+
+Required Properties:
+- compatible: should be "ti,dm6441-gpio"
+
+- reg: Physical base address of the controller and the size of memory mapped
+       registers.
+
+- gpio-controller : Marks the device node as a gpio controller.
+
+- interrupt-parent: phandle of the parent interrupt controller.
+
+- interrupts: Array of GPIO interrupt number. Only banked or unbanked IRQs are
+              supported at a time.
+
+- ti,ngpio: The number of GPIO pins supported.
+
+- ti,davinci-gpio-unbanked: The number of GPIOs that have an individual interrupt
+                             line to processor.
+
+The GPIO controller also acts as an interrupt controller. It uses the default
+two cells specifier as described in Documentation/devicetree/bindings/
+interrupt-controller/interrupts.txt.
+
+Example:
+
+gpio: gpio@1e26000 {
+        compatible = "ti,dm6441-gpio";
+        gpio-controller;
+        reg = <0x226000 0x1000>;
+        interrupt-parent = <&intc>;
+        interrupts = <42 IRQ_TYPE_EDGE_BOTH 43 IRQ_TYPE_EDGE_BOTH
+                44 IRQ_TYPE_EDGE_BOTH 45 IRQ_TYPE_EDGE_BOTH
+                46 IRQ_TYPE_EDGE_BOTH 47 IRQ_TYPE_EDGE_BOTH
+                48 IRQ_TYPE_EDGE_BOTH 49 IRQ_TYPE_EDGE_BOTH
+                50 IRQ_TYPE_EDGE_BOTH>;
+        ti,ngpio = <144>;
+        ti,davinci-gpio-unbanked = <0>;
+        interrupt-controller;
+        #interrupt-cells = <2>;
+};
diff --git a/drivers/gpio/gpio-davinci.c b/drivers/gpio/gpio-davinci.c
index 92d9922cfcc7..37cf95254df1 100644
--- a/drivers/gpio/gpio-davinci.c
+++ b/drivers/gpio/gpio-davinci.c
@@ -17,6 +17,9 @@
 #include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/gpio-davinci.h>
 
@@ -134,6 +137,40 @@ davinci_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
         writel_relaxed((1 << offset), value ? &g->set_data : &g->clr_data);
 }
 
+static struct davinci_gpio_platform_data *
+davinci_gpio_get_pdata(struct platform_device *pdev)
+{
+        struct device_node *dn = pdev->dev.of_node;
+        struct davinci_gpio_platform_data *pdata;
+        int ret;
+        u32 val;
+
+        if (!IS_ENABLED(CONFIG_OF) || !pdev->dev.of_node)
+                return pdev->dev.platform_data;
+
+        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+        if (!pdata)
+                return NULL;
+
+        ret = of_property_read_u32(dn, "ti,ngpio", &val);
+        if (ret)
+                goto of_err;
+
+        pdata->ngpio = val;
+
+        ret = of_property_read_u32(dn, "ti,davinci-gpio-unbanked", &val);
+        if (ret)
+                goto of_err;
+
+        pdata->gpio_unbanked = val;
+
+        return pdata;
+
+of_err:
+        dev_err(&pdev->dev, "Populating pdata from DT failed: err %d\n", ret);
+        return NULL;
+}
+
 static int davinci_gpio_probe(struct platform_device *pdev)
 {
         int i, base;
@@ -144,12 +181,14 @@ static int davinci_gpio_probe(struct platform_device *pdev)
         struct device *dev = &pdev->dev;
         struct resource *res;
 
-        pdata = dev->platform_data;
+        pdata = davinci_gpio_get_pdata(pdev);
         if (!pdata) {
                 dev_err(dev, "No platform data found\n");
                 return -EINVAL;
         }
 
+        dev->platform_data = pdata;
+
         /*
          * The gpio banks conceptually expose a segmented bitmap,
          * and "ngpio" is one more than the largest zero-based
@@ -195,6 +234,9 @@ static int davinci_gpio_probe(struct platform_device *pdev)
                 if (chips[i].chip.ngpio > 32)
                         chips[i].chip.ngpio = 32;
 
+#ifdef CONFIG_OF_GPIO
+                chips[i].chip.of_node = dev->of_node;
+#endif
                 spin_lock_init(&chips[i].lock);
 
                 regs = gpio2regs(base);
@@ -506,11 +548,20 @@ done:
         return 0;
 }
 
+#if IS_ENABLED(CONFIG_OF)
+static const struct of_device_id davinci_gpio_ids[] = {
+        { .compatible = "ti,dm6441-gpio", },
+        { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, davinci_gpio_ids);
+#endif
+
 static struct platform_driver davinci_gpio_driver = {
         .probe          = davinci_gpio_probe,
         .driver         = {
-                .name   = "davinci_gpio",
-                .owner  = THIS_MODULE,
+                .name           = "davinci_gpio",
+                .owner          = THIS_MODULE,
+                .of_match_table = of_match_ptr(davinci_gpio_ids),
         },
 };