basic-mmio-gpio: add DT support

["Álvaro Fernández Rojas" <noltari@gmail.com>]

Add DT support while keeping legacy support.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
diff --git a/drivers/gpio/gpio-generic.c b/drivers/gpio/gpio-generic.c
index 16f6115..9792783 100644
--- a/drivers/gpio/gpio-generic.c
+++ b/drivers/gpio/gpio-generic.c
@@ -61,6 +61,9 @@ 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>
+#include <linux/of_gpio.h>
 
 static void bgpio_write8(void __iomem *reg, unsigned long data)
 {
@@ -488,8 +491,58 @@ static void __iomem *bgpio_map(struct platform_device *pdev,
 	return ret;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id bgpio_dt_ids[] = {
+	{ .compatible = "basic-mmio-gpio" },
+};
+MODULE_DEVICE_TABLE(of, bgpio_dt_ids);
+
+static int bgpio_probe_dt(struct platform_device *pdev)
+{
+	u32 tmp;
+	struct bgpio_pdata *pdata;
+	struct device_node *np;
+
+	np = pdev->dev.of_node;
+	if (!np)
+		return 0;
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	pdata->label = dev_name(&pdev->dev);
+	pdata->base = -1;
+	if (of_find_property(np, "byte-be", NULL)) {
+		pdata->flags |= BGPIOF_BIG_ENDIAN_BYTE_ORDER;
+	}
+	if (of_find_property(np, "bit-be", NULL)) {
+		pdata->flags |= BGPIOF_BIG_ENDIAN;
+	}
+	if (of_find_property(np, "regset-nr", NULL)) {
+		pdata->flags |= BGPIOF_UNREADABLE_REG_SET;
+	}
+	if (of_find_property(np, "regdir-nr", NULL)) {
+		pdata->flags |= BGPIOF_UNREADABLE_REG_DIR;
+	}
+	if (!of_property_read_u32(np, "num-gpios", &tmp)) {
+		pdata->ngpio = tmp;
+	}
+
+	pdev->dev.platform_data = pdata;
+
+	return 1;
+}
+#else
+static inline int bgpio_probe_dt(struct platform_device *pdev)
+{
+	return 0;
+}
+#endif
+
 static int bgpio_pdev_probe(struct platform_device *pdev)
 {
+	int status;
 	struct device *dev = &pdev->dev;
 	struct resource *r;
 	void __iomem *dat;
@@ -498,10 +551,24 @@ 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;
+	bool use_of = 0;
+
+	status = bgpio_probe_dt(pdev);
+	if (status < 0)
+		return status;
+	if (status > 0)
+		use_of = 1;
+
+	pdata = dev_get_platdata(dev);
+
+	if (!use_of)
+		flags = pdev->id_entry->driver_data;
+	else if (pdata)
+		flags = pdata->flags;
 
 	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
 	if (!r)
@@ -547,6 +614,9 @@ static int bgpio_pdev_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, bgc);
 
+	if (use_of)
+		of_gpiochip_add(&bgc->gc);
+
 	return gpiochip_add(&bgc->gc);
 }
 
@@ -572,6 +642,7 @@ MODULE_DEVICE_TABLE(platform, bgpio_id_table);
 static struct platform_driver bgpio_driver = {
 	.driver = {
 		.name = "basic-mmio-gpio",
+		.of_match_table = bgpio_dt_ids,
 	},
 	.id_table = bgpio_id_table,
 	.probe = bgpio_pdev_probe,
diff --git a/include/linux/basic_mmio_gpio.h b/include/linux/basic_mmio_gpio.h
index 0e97856..a35dffd 100644
--- a/include/linux/basic_mmio_gpio.h
+++ b/include/linux/basic_mmio_gpio.h
@@ -22,6 +22,7 @@ struct bgpio_pdata {
 	const char *label;
 	int base;
 	int ngpio;
+	unsigned long flags;
 };
 
 struct device;
--
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