gpio: mt7621: Add a driver for MT7621

Add driver support for gpio of MT7621 SoC.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: NeilBrown <neil@brown.name>
[Switched wording WIDTH to STRIDE]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -359,6 +359,14 @@ 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 MT7621 GPIO Support"
+	depends on SOC_MT7620 || SOC_MT7621 || COMPILE_TEST
+	select GPIO_GENERIC
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support the Mediatek MT7621 SoC GPIO device
+
 config GPIO_MVEBU
 	def_bool y
 	depends on PLAT_ORION || ARCH_MVEBU

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

drivers/gpio/gpio-mt7621.c

@@ -0,0 +1,335 @@
+// 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/driver.h>
+#include <linux/interrupt.h>
+#include <linux/io.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 GPIO_BANK_STRIDE	0x04
+#define GPIO_REG_CTRL		0x00
+#define GPIO_REG_POL		0x10
+#define GPIO_REG_DATA		0x20
+#define GPIO_REG_DSET		0x30
+#define GPIO_REG_DCLR		0x40
+#define GPIO_REG_REDGE		0x50
+#define GPIO_REG_FEDGE		0x60
+#define GPIO_REG_HLVL		0x70
+#define GPIO_REG_LLVL		0x80
+#define GPIO_REG_STAT		0x90
+#define GPIO_REG_EDGE		0xA0
+
+struct mtk_gc {
+	struct gpio_chip chip;
+	spinlock_t lock;
+	int bank;
+	u32 rising;
+	u32 falling;
+	u32 hlevel;
+	u32 llevel;
+};
+
+/**
+ * struct mtk_data - state container for
+ * data of the platform driver. It is 3
+ * separate gpio-chip each one with its
+ * own irq_chip.
+ * @dev: device instance
+ * @gpio_membase: memory base address
+ * @gpio_irq: irq number from the device tree
+ * @gc_map: array of the gpio chips
+ */
+struct mtk_data {
+	struct device *dev;
+	void __iomem *gpio_membase;
+	int gpio_irq;
+	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, u32 offset, u32 val)
+{
+	struct gpio_chip *gc = &rg->chip;
+	struct mtk_data *gpio_data = gpiochip_get_data(gc);
+
+	offset = (rg->bank * GPIO_BANK_STRIDE) + offset;
+	gc->write_reg(gpio_data->gpio_membase + offset, val);
+}
+
+static inline u32
+mtk_gpio_r32(struct mtk_gc *rg, u32 offset)
+{
+	struct gpio_chip *gc = &rg->chip;
+	struct mtk_data *gpio_data = gpiochip_get_data(gc);
+
+	offset = (rg->bank * GPIO_BANK_STRIDE) + offset;
+	return gc->read_reg(gpio_data->gpio_membase + offset);
+}
+
+static irqreturn_t
+mediatek_gpio_irq_handler(int irq, void *data)
+{
+	struct gpio_chip *gc = data;
+	struct mtk_gc *rg = to_mediatek_gpio(gc);
+	irqreturn_t ret = IRQ_NONE;
+	unsigned long pending;
+	int bit;
+
+	pending = mtk_gpio_r32(rg, GPIO_REG_STAT);
+
+	for_each_set_bit(bit, &pending, MTK_BANK_WIDTH) {
+		u32 map = irq_find_mapping(gc->irq.domain, bit);
+
+		generic_handle_irq(map);
+		mtk_gpio_w32(rg, GPIO_REG_STAT, BIT(bit));
+		ret |= IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static void
+mediatek_gpio_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct mtk_gc *rg = to_mediatek_gpio(gc);
+	int pin = d->hwirq;
+	unsigned long flags;
+	u32 rise, fall, high, low;
+
+	spin_lock_irqsave(&rg->lock, flags);
+	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
+	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
+	high = mtk_gpio_r32(rg, GPIO_REG_HLVL);
+	low = mtk_gpio_r32(rg, GPIO_REG_LLVL);
+	mtk_gpio_w32(rg, GPIO_REG_REDGE, rise | (BIT(pin) & rg->rising));
+	mtk_gpio_w32(rg, GPIO_REG_FEDGE, fall | (BIT(pin) & rg->falling));
+	mtk_gpio_w32(rg, GPIO_REG_HLVL, high | (BIT(pin) & rg->hlevel));
+	mtk_gpio_w32(rg, GPIO_REG_LLVL, low | (BIT(pin) & rg->llevel));
+	spin_unlock_irqrestore(&rg->lock, flags);
+}
+
+static void
+mediatek_gpio_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct mtk_gc *rg = to_mediatek_gpio(gc);
+	int pin = d->hwirq;
+	unsigned long flags;
+	u32 rise, fall, high, low;
+
+	spin_lock_irqsave(&rg->lock, flags);
+	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
+	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
+	high = mtk_gpio_r32(rg, GPIO_REG_HLVL);
+	low = mtk_gpio_r32(rg, GPIO_REG_LLVL);
+	mtk_gpio_w32(rg, GPIO_REG_FEDGE, fall & ~BIT(pin));
+	mtk_gpio_w32(rg, GPIO_REG_REDGE, rise & ~BIT(pin));
+	mtk_gpio_w32(rg, GPIO_REG_HLVL, high & ~BIT(pin));
+	mtk_gpio_w32(rg, GPIO_REG_LLVL, low & ~BIT(pin));
+	spin_unlock_irqrestore(&rg->lock, flags);
+}
+
+static int
+mediatek_gpio_irq_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct mtk_gc *rg = to_mediatek_gpio(gc);
+	int pin = d->hwirq;
+	u32 mask = BIT(pin);
+
+	if (type == IRQ_TYPE_PROBE) {
+		if ((rg->rising | rg->falling |
+		     rg->hlevel | rg->llevel) & mask)
+			return 0;
+
+		type = IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING;
+	}
+
+	rg->rising &= ~mask;
+	rg->falling &= ~mask;
+	rg->hlevel &= ~mask;
+	rg->llevel &= ~mask;
+
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_BOTH:
+		rg->rising |= mask;
+		rg->falling |= mask;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		rg->rising |= mask;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		rg->falling |= mask;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		rg->hlevel |= mask;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		rg->llevel |= mask;
+		break;
+	}
+
+	return 0;
+}
+
+static struct irq_chip mediatek_gpio_irq_chip = {
+	.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_xlate(struct gpio_chip *chip,
+		    const struct of_phandle_args *spec, u32 *flags)
+{
+	int gpio = spec->args[0];
+	struct mtk_gc *rg = to_mediatek_gpio(chip);
+
+	if (rg->bank != gpio / MTK_BANK_WIDTH)
+		return -EINVAL;
+
+	if (flags)
+		*flags = spec->args[1];
+
+	return gpio % MTK_BANK_WIDTH;
+}
+
+static int
+mediatek_gpio_bank_probe(struct platform_device *pdev,
+			 struct device_node *node, int bank)
+{
+	struct mtk_data *gpio = dev_get_drvdata(&pdev->dev);
+	struct mtk_gc *rg;
+	void __iomem *dat, *set, *ctrl, *diro;
+	int ret;
+
+	rg = &gpio->gc_map[bank];
+	memset(rg, 0, sizeof(*rg));
+
+	spin_lock_init(&rg->lock);
+	rg->chip.of_node = node;
+	rg->bank = bank;
+
+	dat = gpio->gpio_membase + GPIO_REG_DATA +
+		(rg->bank * GPIO_BANK_STRIDE);
+	set = gpio->gpio_membase + GPIO_REG_DSET +
+		(rg->bank * GPIO_BANK_STRIDE);
+	ctrl = gpio->gpio_membase + GPIO_REG_DCLR +
+		(rg->bank * GPIO_BANK_STRIDE);
+	diro = gpio->gpio_membase + GPIO_REG_CTRL +
+		(rg->bank * GPIO_BANK_STRIDE);
+
+	ret = bgpio_init(&rg->chip, &pdev->dev, 4,
+			 dat, set, ctrl, diro, NULL, 0);
+	if (ret) {
+		dev_err(&pdev->dev, "bgpio_init() failed\n");
+		return ret;
+	}
+
+	rg->chip.of_gpio_n_cells = 2;
+	rg->chip.of_xlate = mediatek_gpio_xlate;
+	rg->chip.label = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s-bank%d",
+					dev_name(&pdev->dev), bank);
+
+	ret = devm_gpiochip_add_data(&pdev->dev, &rg->chip, gpio);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Could not register gpio %d, ret=%d\n",
+			rg->chip.ngpio, ret);
+		return ret;
+	}
+
+	if (gpio->gpio_irq) {
+		/*
+		 * Manually request the irq here instead of passing
+		 * a flow-handler to gpiochip_set_chained_irqchip,
+		 * because the irq is shared.
+		 */
+		ret = devm_request_irq(&pdev->dev, gpio->gpio_irq,
+				       mediatek_gpio_irq_handler, IRQF_SHARED,
+				       rg->chip.label, &rg->chip);
+
+		if (ret) {
+			dev_err(&pdev->dev, "Error requesting IRQ %d: %d\n",
+				gpio->gpio_irq, ret);
+			return ret;
+		}
+
+		ret = gpiochip_irqchip_add(&rg->chip, &mediatek_gpio_irq_chip,
+					   0, handle_simple_irq, IRQ_TYPE_NONE);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to add gpiochip_irqchip\n");
+			return ret;
+		}
+
+		gpiochip_set_chained_irqchip(&rg->chip, &mediatek_gpio_irq_chip,
+					     gpio->gpio_irq, NULL);
+	}
+
+	/* 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 int
+mediatek_gpio_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	struct mtk_data *gpio_data;
+	int i;
+
+	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);
+	gpio_data->dev = &pdev->dev;
+	platform_set_drvdata(pdev, gpio_data);
+	mediatek_gpio_irq_chip.name = dev_name(&pdev->dev);
+
+	for (i = 0; i < MTK_BANK_CNT; i++)
+		mediatek_gpio_bank_probe(pdev, np, i);
+
+	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,
+	},
+};
+
+builtin_platform_driver(mediatek_gpio_driver);