[PATCH] added device tree support to gpio-generic driver

[Romain Baeriswyl <romain.baeriswyl@xxxxxxxxxxx>]

---
 .../devicetree/bindings/gpio/gpio-generic.txt      |   19 +++++
 drivers/gpio/gpio-generic.c                        |   81 ++++++++++++++-----
 2 files changed, 78 insertions(+), 22 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-generic.txt

diff --git a/Documentation/devicetree/bindings/gpio/gpio-generic.txt b/Documentation/devicetree/bindings/gpio/gpio-generic.txt
new file mode 100644
index 0000000..c2c4b98
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-generic.txt
@@ -0,0 +1,19 @@
+Bindings for gpio-generic
+
+Required properties:
+- compatible : "basic-mmio-gpio" for little endian register access or
+               "basic-mmio-gpio-be" for big endian register access
+- ngpios: Specifies the number of gpio mapped in the register. The value is
+          limited to the number of bits of the LONG type.
+
+Optional properties:
+- base: Allows to forces the gpio number base offset used to index the gpio in
+        the device. If it is not see then the driver search autonoumously for
+        valid index range.
+
+Examples:
+
+	gpio_a {
+		compatible = "basic-mmio-gpio";
+		ngpios = <32>;
+	};
diff --git a/drivers/gpio/gpio-generic.c b/drivers/gpio/gpio-generic.c
index b92a690..9a4354c 100644
--- a/drivers/gpio/gpio-generic.c
+++ b/drivers/gpio/gpio-generic.c
@@ -15,11 +15,11 @@
  *  `.just a single "data" register, where GPIO state can be read and/or `
  *    `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````
  *        `````````
-                                    ___
-_/~~|___/~|   . ```~~~~~~       ___/___\___     ,~.`.`.`.`````.~~...,,,,...
-__________|~$@~~~        %~    /o*o*o*o*o*o\   .. Implementing such a GPIO .
-o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`
-                                                 `....trivial..'~`.```.```
+ *                                   ___
+ * _/~~|___/~|   . ```~~~~~~       ___/___\___     ,~.`.`.`.`````.~~...,,,,...
+ * __________|~$@~~~        %~    /o*o*o*o*o*o\   .. Implementing such a GPIO .
+ * o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`
+ *                                                `....trivial..'~`.```.```
  *                                                    ```````
  *  .```````~~~~`..`.``.``.
  * .  The driver supports  `...       ,..```.`~~~```````````````....````.``,,
@@ -61,6 +61,8 @@ o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`
 #include <linux/platform_device.h>
 #include <linux/mod_devicetable.h>
 #include <linux/basic_mmio_gpio.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 
 static void bgpio_write8(void __iomem *reg, unsigned long data)
 {
@@ -375,10 +377,9 @@ static int bgpio_setup_accessors(struct device *dev,
 			dev_err(dev,
 				"64 bit big endian byte order unsupported\n");
 			return -EINVAL;
-		} else {
-			bgc->read_reg	= bgpio_read64;
-			bgc->write_reg	= bgpio_write64;
 		}
+		bgc->read_reg	= bgpio_read64;
+		bgc->write_reg	= bgpio_write64;
 		break;
 #endif /* BITS_PER_LONG >= 64 */
 	default:
@@ -564,6 +565,27 @@ static void __iomem *bgpio_map(struct platform_device *pdev,
 	return ret;
 }
 
+static const struct platform_device_id bgpio_id_table[] = {
+	{ "basic-mmio-gpio",
+	  .driver_data	= 0,
+	}, { "basic-mmio-gpio-be",
+	  .driver_data	= BGPIOF_BIG_ENDIAN
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(platform, bgpio_id_table);
+
+static const struct of_device_id  bgpio_dt_ids[] = {
+	{ .compatible = "basic-mmio-gpio",
+	  .data = bgpio_id_table + 0
+	},
+	{ .compatible = "basic-mmio-gpio-be",
+	  .data = bgpio_id_table + 1
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, bgpio_dt_ids);
+
 static int bgpio_pdev_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -574,10 +596,37 @@ static int bgpio_pdev_probe(struct platform_device *pdev)
 	void __iomem *dirout;
 	void __iomem *dirin;
 	unsigned long sz;
-	unsigned long flags = pdev->id_entry->driver_data;
+	unsigned long flags;
 	int err;
 	struct bgpio_chip *bgc;
-	struct bgpio_pdata *pdata = dev_get_platdata(dev);
+	struct bgpio_pdata *pdata;
+
+	if (of_have_populated_dt()) {
+		const struct of_device_id *of_id =
+			of_match_device(bgpio_dt_ids, dev);
+
+		pdata = devm_kzalloc(dev, sizeof(struct bgpio_pdata),
+				     GFP_KERNEL);
+		if (!pdata)
+			return -ENOMEM;
+
+		if (of_property_read_u32(dev->of_node, "ngpio",
+					 &pdata->ngpio)) {
+			dev_err(dev, "Failed to get field ngpio");
+			return -EINVAL;
+		}
+		if (of_property_read_u32(dev->of_node, "base", &pdata->base))
+			pdata->base = -1;
+
+		dev->platform_data = pdata;
+
+		if (of_id)
+			pdev->id_entry = of_id->data;
+	}
+
+	pdata = dev_get_platdata(dev);
+
+	flags = pdev->id_entry->driver_data;
 
 	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
 	if (!r)
@@ -633,18 +682,6 @@ static int bgpio_pdev_remove(struct platform_device *pdev)
 	return bgpio_remove(bgc);
 }
 
-static const struct platform_device_id bgpio_id_table[] = {
-	{
-		.name		= "basic-mmio-gpio",
-		.driver_data	= 0,
-	}, {
-		.name		= "basic-mmio-gpio-be",
-		.driver_data	= BGPIOF_BIG_ENDIAN,
-	},
-	{ }
-};
-MODULE_DEVICE_TABLE(platform, bgpio_id_table);
-
 static struct platform_driver bgpio_driver = {
 	.driver = {
 		.name = "basic-mmio-gpio",
-- 
1.7.1

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