[PATCH 1/2] gpio: mediatek: add driver for MT7621

[Sergio Paracuellos <sergio.paracuellos@gmail.com>]

Add driver support for gpio of MT7621 SoC.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: NeilBrown <neil@brown.name>
---
 drivers/gpio/Kconfig       |   7 +
 drivers/gpio/Makefile      |   1 +
 drivers/gpio/gpio-mt7621.c | 370 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 378 insertions(+)
 create mode 100644 drivers/gpio/gpio-mt7621.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 71c0ab4..2646949 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -359,6 +359,13 @@ config GPIO_MPC8XXX
 	  Say Y here if you're going to use hardware that connects to the
 	  MPC512x/831x/834x/837x/8572/8610/QorIQ GPIOs.
 
+config GPIO_MT7621
+	bool "Mediatek GPIO Support"
+	depends on SOC_MT7620 || SOC_MT7621
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support the Mediatek SoC GPIO device
+
 config GPIO_MVEBU
 	def_bool y
 	depends on PLAT_ORION || ARCH_MVEBU
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 1324c8f..03647ae 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_GPIO_MOCKUP)      += gpio-mockup.o
 obj-$(CONFIG_GPIO_MPC5200)	+= gpio-mpc5200.o
 obj-$(CONFIG_GPIO_MPC8XXX)	+= gpio-mpc8xxx.o
 obj-$(CONFIG_GPIO_MSIC)		+= gpio-msic.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..0c4fb4a
--- /dev/null
+++ b/drivers/gpio/gpio-mt7621.c
@@ -0,0 +1,370 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#define MTK_BANK_CNT		3
+#define MTK_BANK_WIDTH		32
+#define PIN_MASK(nr)		(1UL << ((nr % MTK_BANK_WIDTH)))
+
+enum mediatek_gpio_reg {
+	GPIO_REG_CTRL = 0,
+	GPIO_REG_POL,
+	GPIO_REG_DATA,
+	GPIO_REG_DSET,
+	GPIO_REG_DCLR,
+	GPIO_REG_REDGE,
+	GPIO_REG_FEDGE,
+	GPIO_REG_HLVL,
+	GPIO_REG_LLVL,
+	GPIO_REG_STAT,
+	GPIO_REG_EDGE,
+};
+
+struct mtk_gc {
+	struct gpio_chip chip;
+	spinlock_t lock;
+	int bank;
+	u32 rising;
+	u32 falling;
+};
+
+struct mtk_data {
+	void __iomem *gpio_membase;
+	int gpio_irq;
+	struct irq_domain *gpio_irq_domain;
+	struct mtk_gc gc_map[MTK_BANK_CNT];
+};
+
+static inline struct mtk_gc *
+to_mediatek_gpio(struct gpio_chip *chip)
+{
+	return container_of(chip, struct mtk_gc, chip);
+}
+
+static inline void
+mtk_gpio_w32(struct mtk_gc *rg, u8 reg, u32 val)
+{
+	struct mtk_data *gpio_data = gpiochip_get_data(&rg->chip);
+	u32 offset = (reg * 0x10) + (rg->bank * 0x4);
+
+	iowrite32(val, gpio_data->gpio_membase + offset);
+}
+
+static inline u32
+mtk_gpio_r32(struct mtk_gc *rg, u8 reg)
+{
+	struct mtk_data *gpio_data = gpiochip_get_data(&rg->chip);
+	u32 offset = (reg * 0x10) + (rg->bank * 0x4);
+
+	return ioread32(gpio_data->gpio_membase + offset);
+}
+
+static void
+mediatek_gpio_set(struct gpio_chip *chip, unsigned int 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 int 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 int 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 int 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_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+	struct mtk_gc *rg = to_mediatek_gpio(chip);
+	u32 t = mtk_gpio_r32(rg, GPIO_REG_CTRL);
+
+	return (t & BIT(offset)) ? GPIOF_DIR_OUT : GPIOF_DIR_IN;
+}
+
+static int
+mediatek_gpio_to_irq(struct gpio_chip *chip, unsigned int pin)
+{
+	struct mtk_data *gpio_data = gpiochip_get_data(chip);
+	struct mtk_gc *rg = to_mediatek_gpio(chip);
+
+	return irq_create_mapping(gpio_data->gpio_irq_domain,
+				  pin + (rg->bank * MTK_BANK_WIDTH));
+}
+
+static int
+mediatek_gpio_bank_probe(struct platform_device *pdev, struct device_node *bank)
+{
+	struct mtk_data *gpio_data = dev_get_drvdata(&pdev->dev);
+	const __be32 *id = of_get_property(bank, "reg", NULL);
+	struct mtk_gc *rg;
+	int ret;
+
+	if (!id || be32_to_cpu(*id) >= MTK_BANK_CNT)
+		return -EINVAL;
+
+	rg = &gpio_data->gc_map[be32_to_cpu(*id)];
+	memset(rg, 0, sizeof(*rg));
+
+	spin_lock_init(&rg->lock);
+
+	rg->chip.parent = &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_direction = mediatek_gpio_get_direction;
+	rg->chip.get = mediatek_gpio_get;
+	rg->chip.set = mediatek_gpio_set;
+	if (gpio_data->gpio_irq_domain)
+		rg->chip.to_irq = mediatek_gpio_to_irq;
+	rg->bank = be32_to_cpu(*id);
+
+	ret = devm_gpiochip_add_data(&pdev->dev, &rg->chip, gpio_data);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Could not register gpio %d, ret=%d\n",
+			rg->chip.ngpio, ret);
+		return ret;
+	}
+
+	/* 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 0;
+}
+
+static void
+mediatek_gpio_irq_handler(struct irq_desc *desc)
+{
+	struct mtk_data *gpio_data = irq_desc_get_handler_data(desc);
+	int i;
+
+	for (i = 0; i < MTK_BANK_CNT; i++) {
+		struct mtk_gc *rg = &gpio_data->gc_map[i];
+		unsigned long pending;
+		int bit;
+
+		if (!rg)
+			continue;
+
+		pending = mtk_gpio_r32(rg, GPIO_REG_STAT);
+
+		for_each_set_bit(bit, &pending, MTK_BANK_WIDTH) {
+			u32 map = irq_find_mapping(gpio_data->gpio_irq_domain,
+						   (MTK_BANK_WIDTH * i) + bit);
+
+			generic_handle_irq(map);
+			mtk_gpio_w32(rg, GPIO_REG_STAT, BIT(bit));
+		}
+	}
+}
+
+static void
+mediatek_gpio_irq_unmask(struct irq_data *d)
+{
+	struct mtk_data *gpio_data = irq_data_get_irq_chip_data(d);
+	int pin = d->hwirq;
+	int bank = pin / MTK_BANK_WIDTH;
+	struct mtk_gc *rg = &gpio_data->gc_map[bank];
+	unsigned long flags;
+	u32 rise, fall;
+
+	if (!rg)
+		return;
+
+	spin_lock_irqsave(&rg->lock, flags);
+	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
+	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
+	mtk_gpio_w32(rg, GPIO_REG_REDGE, rise | (PIN_MASK(pin) & rg->rising));
+	mtk_gpio_w32(rg, GPIO_REG_FEDGE, fall | (PIN_MASK(pin) & rg->falling));
+	spin_unlock_irqrestore(&rg->lock, flags);
+}
+
+static void
+mediatek_gpio_irq_mask(struct irq_data *d)
+{
+	struct mtk_data *gpio_data = irq_data_get_irq_chip_data(d);
+	int pin = d->hwirq;
+	int bank = pin / MTK_BANK_WIDTH;
+	struct mtk_gc *rg = &gpio_data->gc_map[bank];
+	unsigned long flags;
+	u32 rise, fall;
+
+	if (!rg)
+		return;
+
+	spin_lock_irqsave(&rg->lock, flags);
+	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
+	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
+	mtk_gpio_w32(rg, GPIO_REG_FEDGE, fall & ~PIN_MASK(pin));
+	mtk_gpio_w32(rg, GPIO_REG_REDGE, rise & ~PIN_MASK(pin));
+	spin_unlock_irqrestore(&rg->lock, flags);
+}
+
+static int
+mediatek_gpio_irq_type(struct irq_data *d, unsigned int type)
+{
+	struct mtk_data *gpio_data = irq_data_get_irq_chip_data(d);
+	int pin = d->hwirq;
+	int bank = pin / MTK_BANK_WIDTH;
+	struct mtk_gc *rg = &gpio_data->gc_map[bank];
+	u32 mask = PIN_MASK(pin);
+
+	if (!rg)
+		return -1;
+
+	if (type == IRQ_TYPE_PROBE) {
+		if ((rg->rising | rg->falling) & mask)
+			return 0;
+
+		type = IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING;
+	}
+
+	if (type & IRQ_TYPE_EDGE_RISING)
+		rg->rising |= mask;
+	else
+		rg->rising &= ~mask;
+
+	if (type & IRQ_TYPE_EDGE_FALLING)
+		rg->falling |= mask;
+	else
+		rg->falling &= ~mask;
+
+	return 0;
+}
+
+static struct irq_chip mediatek_gpio_irq_chip = {
+	.name		= "GPIO",
+	.irq_unmask	= mediatek_gpio_irq_unmask,
+	.irq_mask	= mediatek_gpio_irq_mask,
+	.irq_mask_ack	= mediatek_gpio_irq_mask,
+	.irq_set_type	= mediatek_gpio_irq_type,
+};
+
+static int
+mediatek_gpio_gpio_map(struct irq_domain *d, unsigned int irq,
+		       irq_hw_number_t hw)
+{
+	int ret;
+
+	ret = irq_set_chip_data(irq, d->host_data);
+	if (ret < 0)
+		return ret;
+	irq_set_chip_and_handler(irq, &mediatek_gpio_irq_chip,
+				 handle_level_irq);
+	irq_set_handler_data(irq, d);
+
+	return 0;
+}
+
+static const struct irq_domain_ops irq_domain_ops = {
+	.xlate = irq_domain_xlate_twocell,
+	.map = mediatek_gpio_gpio_map,
+};
+
+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);
+	struct mtk_data *gpio_data;
+
+	gpio_data = devm_kzalloc(&pdev->dev, sizeof(*gpio_data), GFP_KERNEL);
+	if (!gpio_data)
+		return -ENOMEM;
+
+	gpio_data->gpio_membase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(gpio_data->gpio_membase))
+		return PTR_ERR(gpio_data->gpio_membase);
+
+	gpio_data->gpio_irq = irq_of_parse_and_map(np, 0);
+	if (gpio_data->gpio_irq) {
+		gpio_data->gpio_irq_domain = irq_domain_add_linear(np,
+			MTK_BANK_CNT * MTK_BANK_WIDTH,
+			&irq_domain_ops, gpio_data);
+		if (!gpio_data->gpio_irq_domain)
+			dev_err(&pdev->dev, "irq_domain_add_linear failed\n");
+	}
+
+	platform_set_drvdata(pdev, gpio_data);
+
+	for_each_child_of_node(np, bank)
+		if (of_device_is_compatible(bank, "mediatek,mt7621-gpio-bank"))
+			mediatek_gpio_bank_probe(pdev, bank);
+
+	if (gpio_data->gpio_irq_domain)
+		irq_set_chained_handler_and_data(gpio_data->gpio_irq,
+						 mediatek_gpio_irq_handler,
+						 gpio_data);
+
+	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",
+		.of_match_table = mediatek_gpio_match,
+	},
+};
+
+module_platform_driver(mediatek_gpio_driver);
-- 
2.7.4