1 files changed, 357 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-ftgpio010.c b/drivers/gpio/gpio-ftgpio010.c
new file mode 100644
index 0000000000..5ce59dcf02
--- /dev/null
+++ b/drivers/gpio/gpio-ftgpio010.c
@@ -0,0 +1,357 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Faraday Technolog FTGPIO010 gpiochip and interrupt routines
+ * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Based on arch/arm/mach-gemini/gpio.c:
+ * Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
+ *
+ * Based on plat-mxc/gpio.c:
+ * MXC GPIO support. (c) 2008 Daniel Mack <daniel@caiaq.de>
+ * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
+ */
+#include <linux/gpio/driver.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+
+/* GPIO registers definition */
+#define GPIO_DATA_OUT		0x00
+#define GPIO_DATA_IN		0x04
+#define GPIO_DIR		0x08
+#define GPIO_BYPASS_IN		0x0C
+#define GPIO_DATA_SET		0x10
+#define GPIO_DATA_CLR		0x14
+#define GPIO_PULL_EN		0x18
+#define GPIO_PULL_TYPE		0x1C
+#define GPIO_INT_EN		0x20
+#define GPIO_INT_STAT_RAW	0x24
+#define GPIO_INT_STAT_MASKED	0x28
+#define GPIO_INT_MASK		0x2C
+#define GPIO_INT_CLR		0x30
+#define GPIO_INT_TYPE		0x34
+#define GPIO_INT_BOTH_EDGE	0x38
+#define GPIO_INT_LEVEL		0x3C
+#define GPIO_DEBOUNCE_EN	0x40
+#define GPIO_DEBOUNCE_PRESCALE	0x44
+
+/**
+ * struct ftgpio_gpio - Gemini GPIO state container
+ * @dev: containing device for this instance
+ * @gc: gpiochip for this instance
+ * @base: remapped I/O-memory base
+ * @clk: silicon clock
+ */
+struct ftgpio_gpio {
+	struct device *dev;
+	struct gpio_chip gc;
+	void __iomem *base;
+	struct clk *clk;
+};
+
+static void ftgpio_gpio_ack_irq(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct ftgpio_gpio *g = gpiochip_get_data(gc);
+
+	writel(BIT(irqd_to_hwirq(d)), g->base + GPIO_INT_CLR);
+}
+
+static void ftgpio_gpio_mask_irq(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct ftgpio_gpio *g = gpiochip_get_data(gc);
+	u32 val;
+
+	val = readl(g->base + GPIO_INT_EN);
+	val &= ~BIT(irqd_to_hwirq(d));
+	writel(val, g->base + GPIO_INT_EN);
+	gpiochip_disable_irq(gc, irqd_to_hwirq(d));
+}
+
+static void ftgpio_gpio_unmask_irq(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct ftgpio_gpio *g = gpiochip_get_data(gc);
+	u32 val;
+
+	gpiochip_enable_irq(gc, irqd_to_hwirq(d));
+	val = readl(g->base + GPIO_INT_EN);
+	val |= BIT(irqd_to_hwirq(d));
+	writel(val, g->base + GPIO_INT_EN);
+}
+
+static int ftgpio_gpio_set_irq_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct ftgpio_gpio *g = gpiochip_get_data(gc);
+	u32 mask = BIT(irqd_to_hwirq(d));
+	u32 reg_both, reg_level, reg_type;
+
+	reg_type = readl(g->base + GPIO_INT_TYPE);
+	reg_level = readl(g->base + GPIO_INT_LEVEL);
+	reg_both = readl(g->base + GPIO_INT_BOTH_EDGE);
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_BOTH:
+		irq_set_handler_locked(d, handle_edge_irq);
+		reg_type &= ~mask;
+		reg_both |= mask;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		irq_set_handler_locked(d, handle_edge_irq);
+		reg_type &= ~mask;
+		reg_both &= ~mask;
+		reg_level &= ~mask;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		irq_set_handler_locked(d, handle_edge_irq);
+		reg_type &= ~mask;
+		reg_both &= ~mask;
+		reg_level |= mask;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		irq_set_handler_locked(d, handle_level_irq);
+		reg_type |= mask;
+		reg_level &= ~mask;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		irq_set_handler_locked(d, handle_level_irq);
+		reg_type |= mask;
+		reg_level |= mask;
+		break;
+	default:
+		irq_set_handler_locked(d, handle_bad_irq);
+		return -EINVAL;
+	}
+
+	writel(reg_type, g->base + GPIO_INT_TYPE);
+	writel(reg_level, g->base + GPIO_INT_LEVEL);
+	writel(reg_both, g->base + GPIO_INT_BOTH_EDGE);
+
+	ftgpio_gpio_ack_irq(d);
+
+	return 0;
+}
+
+static void ftgpio_gpio_irq_handler(struct irq_desc *desc)
+{
+	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
+	struct ftgpio_gpio *g = gpiochip_get_data(gc);
+	struct irq_chip *irqchip = irq_desc_get_chip(desc);
+	int offset;
+	unsigned long stat;
+
+	chained_irq_enter(irqchip, desc);
+
+	stat = readl(g->base + GPIO_INT_STAT_RAW);
+	if (stat)
+		for_each_set_bit(offset, &stat, gc->ngpio)
+			generic_handle_domain_irq(gc->irq.domain, offset);
+
+	chained_irq_exit(irqchip, desc);
+}
+
+static int ftgpio_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
+				  unsigned long config)
+{
+	enum pin_config_param param = pinconf_to_config_param(config);
+	u32 arg = pinconf_to_config_argument(config);
+	struct ftgpio_gpio *g = gpiochip_get_data(gc);
+	unsigned long pclk_freq;
+	u32 deb_div;
+	u32 val;
+
+	if (param != PIN_CONFIG_INPUT_DEBOUNCE)
+		return -ENOTSUPP;
+
+	/*
+	 * Debounce only works if interrupts are enabled. The manual
+	 * states that if PCLK is 66 MHz, and this is set to 0x7D0, then
+	 * PCLK is divided down to 33 kHz for the debounce timer. 0x7D0 is
+	 * 2000 decimal, so what they mean is simply that the PCLK is
+	 * divided by this value.
+	 *
+	 * As we get a debounce setting in microseconds, we calculate the
+	 * desired period time and see if we can get a suitable debounce
+	 * time.
+	 */
+	pclk_freq = clk_get_rate(g->clk);
+	deb_div = DIV_ROUND_CLOSEST(pclk_freq, arg);
+
+	/* This register is only 24 bits wide */
+	if (deb_div > (1 << 24))
+		return -ENOTSUPP;
+
+	dev_dbg(g->dev, "prescale divisor: %08x, resulting frequency %lu Hz\n",
+		deb_div, (pclk_freq/deb_div));
+
+	val = readl(g->base + GPIO_DEBOUNCE_PRESCALE);
+	if (val == deb_div) {
+		/*
+		 * The debounce timer happens to already be set to the
+		 * desirable value, what a coincidence! We can just enable
+		 * debounce on this GPIO line and return. This happens more
+		 * often than you think, for example when all GPIO keys
+		 * on a system are requesting the same debounce interval.
+		 */
+		val = readl(g->base + GPIO_DEBOUNCE_EN);
+		val |= BIT(offset);
+		writel(val, g->base + GPIO_DEBOUNCE_EN);
+		return 0;
+	}
+
+	val = readl(g->base + GPIO_DEBOUNCE_EN);
+	if (val) {
+		/*
+		 * Oh no! Someone is already using the debounce with
+		 * another setting than what we need. Bummer.
+		 */
+		return -ENOTSUPP;
+	}
+
+	/* First come, first serve */
+	writel(deb_div, g->base + GPIO_DEBOUNCE_PRESCALE);
+	/* Enable debounce */
+	val |= BIT(offset);
+	writel(val, g->base + GPIO_DEBOUNCE_EN);
+
+	return 0;
+}
+
+static const struct irq_chip ftgpio_irq_chip = {
+	.name = "FTGPIO010",
+	.irq_ack = ftgpio_gpio_ack_irq,
+	.irq_mask = ftgpio_gpio_mask_irq,
+	.irq_unmask = ftgpio_gpio_unmask_irq,
+	.irq_set_type = ftgpio_gpio_set_irq_type,
+	.flags = IRQCHIP_IMMUTABLE,
+	 GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static int ftgpio_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ftgpio_gpio *g;
+	struct gpio_irq_chip *girq;
+	int irq;
+	int ret;
+
+	g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL);
+	if (!g)
+		return -ENOMEM;
+
+	g->dev = dev;
+
+	g->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(g->base))
+		return PTR_ERR(g->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	g->clk = devm_clk_get(dev, NULL);
+	if (!IS_ERR(g->clk)) {
+		ret = clk_prepare_enable(g->clk);
+		if (ret)
+			return ret;
+	} else if (PTR_ERR(g->clk) == -EPROBE_DEFER) {
+		/*
+		 * Percolate deferrals, for anything else,
+		 * just live without the clocking.
+		 */
+		return PTR_ERR(g->clk);
+	}
+
+	ret = bgpio_init(&g->gc, dev, 4,
+			 g->base + GPIO_DATA_IN,
+			 g->base + GPIO_DATA_SET,
+			 g->base + GPIO_DATA_CLR,
+			 g->base + GPIO_DIR,
+			 NULL,
+			 0);
+	if (ret) {
+		dev_err(dev, "unable to init generic GPIO\n");
+		goto dis_clk;
+	}
+	g->gc.label = dev_name(dev);
+	g->gc.base = -1;
+	g->gc.parent = dev;
+	g->gc.owner = THIS_MODULE;
+	/* ngpio is set by bgpio_init() */
+
+	/* We need a silicon clock to do debounce */
+	if (!IS_ERR(g->clk))
+		g->gc.set_config = ftgpio_gpio_set_config;
+
+	girq = &g->gc.irq;
+	gpio_irq_chip_set_chip(girq, &ftgpio_irq_chip);
+	girq->parent_handler = ftgpio_gpio_irq_handler;
+	girq->num_parents = 1;
+	girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents),
+				     GFP_KERNEL);
+	if (!girq->parents) {
+		ret = -ENOMEM;
+		goto dis_clk;
+	}
+	girq->default_type = IRQ_TYPE_NONE;
+	girq->handler = handle_bad_irq;
+	girq->parents[0] = irq;
+
+	/* Disable, unmask and clear all interrupts */
+	writel(0x0, g->base + GPIO_INT_EN);
+	writel(0x0, g->base + GPIO_INT_MASK);
+	writel(~0x0, g->base + GPIO_INT_CLR);
+
+	/* Clear any use of debounce */
+	writel(0x0, g->base + GPIO_DEBOUNCE_EN);
+
+	ret = devm_gpiochip_add_data(dev, &g->gc, g);
+	if (ret)
+		goto dis_clk;
+
+	platform_set_drvdata(pdev, g);
+	dev_info(dev, "FTGPIO010 @%p registered\n", g->base);
+
+	return 0;
+
+dis_clk:
+	clk_disable_unprepare(g->clk);
+
+	return ret;
+}
+
+static int ftgpio_gpio_remove(struct platform_device *pdev)
+{
+	struct ftgpio_gpio *g = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(g->clk);
+
+	return 0;
+}
+
+static const struct of_device_id ftgpio_gpio_of_match[] = {
+	{
+		.compatible = "cortina,gemini-gpio",
+	},
+	{
+		.compatible = "moxa,moxart-gpio",
+	},
+	{
+		.compatible = "faraday,ftgpio010",
+	},
+	{},
+};
+
+static struct platform_driver ftgpio_gpio_driver = {
+	.driver = {
+		.name		= "ftgpio010-gpio",
+		.of_match_table = ftgpio_gpio_of_match,
+	},
+	.probe = ftgpio_gpio_probe,
+	.remove = ftgpio_gpio_remove,
+};
+builtin_platform_driver(ftgpio_gpio_driver);