[PATCH 4/5] GPIO: MIPS: ralink: add gpio driver for ralink MT762x SoC

[John Crispin <blogic@openwrt.org>]

Add gpio driver for Ralink SoC. This driver makes the gpio core on
MT7621 and MT7628 work.

Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: linux-gpio@vger.kernel.org
---
 drivers/gpio/Kconfig       |    6 ++
 drivers/gpio/Makefile      |    1 +
 drivers/gpio/gpio-mt7621.c |  195 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 202 insertions(+)
 create mode 100644 drivers/gpio/gpio-mt7621.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index c91b15b..1ef83a0 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -523,6 +523,12 @@ config GPIO_MC9S08DZ60
 	help
 	  Select this to enable the MC9S08DZ60 GPIO driver
 
+config GPIO_MT7621
+	bool "Mediatek GPIO Support"
+	depends on MIPS && (SOC_MT7620 || SOC_MT7621)
+	help
+	  Say yes here to support the Mediatek SoC GPIO device
+
 config GPIO_PCA953X
 	tristate "PCA95[357]x, PCA9698, TCA64xx, and MAX7310 I/O ports"
 	depends on I2C
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index d8f0f17..60a9e0e 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_GPIO_MPC8XXX)	+= gpio-mpc8xxx.o
 obj-$(CONFIG_GPIO_MSIC)		+= gpio-msic.o
 obj-$(CONFIG_GPIO_MSM_V1)	+= gpio-msm-v1.o
 obj-$(CONFIG_GPIO_MSM_V2)	+= gpio-msm-v2.o
+obj-$(CONFIG_GPIO_MT7621)	+= gpio-mt7621.o
 obj-$(CONFIG_GPIO_MVEBU)        += gpio-mvebu.o
 obj-$(CONFIG_GPIO_MXC)		+= gpio-mxc.o
 obj-$(CONFIG_GPIO_MXS)		+= gpio-mxs.o
diff --git a/drivers/gpio/gpio-mt7621.c b/drivers/gpio/gpio-mt7621.c
new file mode 100644
index 0000000..7faf2c0
--- /dev/null
+++ b/drivers/gpio/gpio-mt7621.c
@@ -0,0 +1,195 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/spinlock.h>
+#include <linux/irqdomain.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+
+#define MTK_BANK_WIDTH		32
+
+enum mediatek_gpio_reg {
+	GPIO_REG_CTRL = 0,
+	GPIO_REG_POL,
+	GPIO_REG_DATA,
+	GPIO_REG_DSET,
+	GPIO_REG_DCLR,
+};
+
+static void __iomem *mtk_gc_membase;
+
+struct mtk_gc {
+	struct gpio_chip chip;
+	spinlock_t lock;
+	int bank;
+};
+
+static inline struct mtk_gc
+*to_mediatek_gpio(struct gpio_chip *chip)
+{
+	struct mtk_gc *mgc;
+
+	mgc = container_of(chip, struct mtk_gc, chip);
+
+	return mgc;
+}
+
+static inline void
+mtk_gpio_w32(struct mtk_gc *rg, u8 reg, u32 val)
+{
+	iowrite32(val, mtk_gc_membase + (reg * 0x10) + (rg->bank * 0x4));
+}
+
+static inline u32
+mtk_gpio_r32(struct mtk_gc *rg, u8 reg)
+{
+	return ioread32(mtk_gc_membase + (reg * 0x10) + (rg->bank * 0x4));
+}
+
+static void
+mediatek_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct mtk_gc *rg = to_mediatek_gpio(chip);
+
+	mtk_gpio_w32(rg, (value) ? GPIO_REG_DSET : GPIO_REG_DCLR, BIT(offset));
+}
+
+static int
+mediatek_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct mtk_gc *rg = to_mediatek_gpio(chip);
+
+	return !!(mtk_gpio_r32(rg, GPIO_REG_DATA) & BIT(offset));
+}
+
+static int
+mediatek_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct mtk_gc *rg = to_mediatek_gpio(chip);
+	unsigned long flags;
+	u32 t;
+
+	spin_lock_irqsave(&rg->lock, flags);
+	t = mtk_gpio_r32(rg, GPIO_REG_CTRL);
+	t &= ~BIT(offset);
+	mtk_gpio_w32(rg, GPIO_REG_CTRL, t);
+	spin_unlock_irqrestore(&rg->lock, flags);
+
+	return 0;
+}
+
+static int
+mediatek_gpio_direction_output(struct gpio_chip *chip,
+					unsigned offset, int value)
+{
+	struct mtk_gc *rg = to_mediatek_gpio(chip);
+	unsigned long flags;
+	u32 t;
+
+	spin_lock_irqsave(&rg->lock, flags);
+	t = mtk_gpio_r32(rg, GPIO_REG_CTRL);
+	t |= BIT(offset);
+	mtk_gpio_w32(rg, GPIO_REG_CTRL, t);
+	mediatek_gpio_set(chip, offset, value);
+	spin_unlock_irqrestore(&rg->lock, flags);
+
+	return 0;
+}
+
+static int
+mediatek_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	int gpio = chip->base + offset;
+
+	return pinctrl_request_gpio(gpio);
+}
+
+static void
+mediatek_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	int gpio = chip->base + offset;
+
+	pinctrl_free_gpio(gpio);
+}
+
+static int
+mediatek_gpio_bank_probe(struct platform_device *pdev, struct device_node *bank)
+{
+	const __be32 *id = of_get_property(bank, "reg", NULL);
+	struct mtk_gc *rg = devm_kzalloc(&pdev->dev,
+				sizeof(struct mtk_gc), GFP_KERNEL);
+	if (!rg || !id)
+		return -ENOMEM;
+
+	spin_lock_init(&rg->lock);
+
+	rg->chip.dev = &pdev->dev;
+	rg->chip.label = dev_name(&pdev->dev);
+	rg->chip.of_node = bank;
+	rg->chip.base = MTK_BANK_WIDTH * be32_to_cpu(*id);
+	rg->chip.ngpio = MTK_BANK_WIDTH;
+	rg->chip.direction_input = mediatek_gpio_direction_input;
+	rg->chip.direction_output = mediatek_gpio_direction_output;
+	rg->chip.get = mediatek_gpio_get;
+	rg->chip.set = mediatek_gpio_set;
+	rg->chip.request = mediatek_gpio_request;
+	rg->chip.free = mediatek_gpio_free;
+
+	/* set polarity to low for all gpios */
+	mtk_gpio_w32(rg, GPIO_REG_POL, 0);
+
+	dev_info(&pdev->dev, "registering %d gpios\n", rg->chip.ngpio);
+
+	return gpiochip_add(&rg->chip);
+}
+
+static int
+mediatek_gpio_probe(struct platform_device *pdev)
+{
+	struct device_node *bank, *np = pdev->dev.of_node;
+	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	mtk_gc_membase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(mtk_gc_membase))
+		return PTR_ERR(mtk_gc_membase);
+
+	for_each_child_of_node(np, bank)
+		if (of_device_is_compatible(bank, "mediatek,mt7621-gpio-bank"))
+			mediatek_gpio_bank_probe(pdev, bank);
+
+	return 0;
+}
+
+static const struct of_device_id mediatek_gpio_match[] = {
+	{ .compatible = "mediatek,mt7621-gpio" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mediatek_gpio_match);
+
+static struct platform_driver mediatek_gpio_driver = {
+	.probe = mediatek_gpio_probe,
+	.driver = {
+		.name = "mt7621_gpio",
+		.owner = THIS_MODULE,
+		.of_match_table = mediatek_gpio_match,
+	},
+};
+
+static int __init
+mediatek_gpio_init(void)
+{
+	return platform_driver_register(&mediatek_gpio_driver);
+}
+
+subsys_initcall(mediatek_gpio_init);
-- 
1.7.10.4