1 files changed, 358 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-ixp4xx.c b/drivers/gpio/gpio-ixp4xx.c
new file mode 100644
index 000000000000..f34d87869c8b
--- /dev/null
+++ b/drivers/gpio/gpio-ixp4xx.c
@@ -0,0 +1,358 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// IXP4 GPIO driver
+// Copyright (C) 2019 Linus Walleij <linus.walleij@linaro.org>
+//
+// based on previous work and know-how from:
+// Deepak Saxena <dsaxena@plexity.net>
+
+#include <linux/bitops.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/generic.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define IXP4XX_REG_GPOUT	0x00
+#define IXP4XX_REG_GPOE		0x04
+#define IXP4XX_REG_GPIN		0x08
+#define IXP4XX_REG_GPIS		0x0C
+#define IXP4XX_REG_GPIT1	0x10
+#define IXP4XX_REG_GPIT2	0x14
+#define IXP4XX_REG_GPCLK	0x18
+#define IXP4XX_REG_GPDBSEL	0x1C
+
+/*
+ * The hardware uses 3 bits to indicate interrupt "style".
+ * we clear and set these three bits accordingly. The lower 24
+ * bits in two registers (GPIT1 and GPIT2) are used to set up
+ * the style for 8 lines each for a total of 16 GPIO lines.
+ */
+#define IXP4XX_GPIO_STYLE_ACTIVE_HIGH	0x0
+#define IXP4XX_GPIO_STYLE_ACTIVE_LOW	0x1
+#define IXP4XX_GPIO_STYLE_RISING_EDGE	0x2
+#define IXP4XX_GPIO_STYLE_FALLING_EDGE	0x3
+#define IXP4XX_GPIO_STYLE_TRANSITIONAL	0x4
+#define IXP4XX_GPIO_STYLE_MASK		GENMASK(2, 0)
+#define IXP4XX_GPIO_STYLE_SIZE		3
+
+/*
+ * Clock output control register defines.
+ */
+#define IXP4XX_GPCLK_CLK0DC_SHIFT	0
+#define IXP4XX_GPCLK_CLK0TC_SHIFT	4
+#define IXP4XX_GPCLK_CLK0_MASK		GENMASK(7, 0)
+#define IXP4XX_GPCLK_MUX14		BIT(8)
+#define IXP4XX_GPCLK_CLK1DC_SHIFT	16
+#define IXP4XX_GPCLK_CLK1TC_SHIFT	20
+#define IXP4XX_GPCLK_CLK1_MASK		GENMASK(23, 16)
+#define IXP4XX_GPCLK_MUX15		BIT(24)
+
+/**
+ * struct ixp4xx_gpio - IXP4 GPIO state container
+ * @chip: generic GPIO chip for this instance
+ * @dev: containing device for this instance
+ * @base: remapped I/O-memory base
+ * @irq_edge: Each bit represents an IRQ: 1: edge-triggered,
+ * 0: level triggered
+ */
+struct ixp4xx_gpio {
+	struct gpio_generic_chip chip;
+	struct device *dev;
+	void __iomem *base;
+	unsigned long long irq_edge;
+};
+
+static void ixp4xx_gpio_irq_ack(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct ixp4xx_gpio *g = gpiochip_get_data(gc);
+
+	__raw_writel(BIT(d->hwirq), g->base + IXP4XX_REG_GPIS);
+}
+
+static void ixp4xx_gpio_mask_irq(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+
+	irq_chip_mask_parent(d);
+	gpiochip_disable_irq(gc, d->hwirq);
+}
+
+static void ixp4xx_gpio_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct ixp4xx_gpio *g = gpiochip_get_data(gc);
+
+	/* ACK when unmasking if not edge-triggered */
+	if (!(g->irq_edge & BIT(d->hwirq)))
+		ixp4xx_gpio_irq_ack(d);
+
+	gpiochip_enable_irq(gc, d->hwirq);
+	irq_chip_unmask_parent(d);
+}
+
+static int ixp4xx_gpio_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct ixp4xx_gpio *g = gpiochip_get_data(gc);
+	int line = d->hwirq;
+	u32 int_style;
+	u32 int_reg;
+	u32 val;
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_BOTH:
+		irq_set_handler_locked(d, handle_edge_irq);
+		int_style = IXP4XX_GPIO_STYLE_TRANSITIONAL;
+		g->irq_edge |= BIT(d->hwirq);
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		irq_set_handler_locked(d, handle_edge_irq);
+		int_style = IXP4XX_GPIO_STYLE_RISING_EDGE;
+		g->irq_edge |= BIT(d->hwirq);
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		irq_set_handler_locked(d, handle_edge_irq);
+		int_style = IXP4XX_GPIO_STYLE_FALLING_EDGE;
+		g->irq_edge |= BIT(d->hwirq);
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		irq_set_handler_locked(d, handle_level_irq);
+		int_style = IXP4XX_GPIO_STYLE_ACTIVE_HIGH;
+		g->irq_edge &= ~BIT(d->hwirq);
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		irq_set_handler_locked(d, handle_level_irq);
+		int_style = IXP4XX_GPIO_STYLE_ACTIVE_LOW;
+		g->irq_edge &= ~BIT(d->hwirq);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (line >= 8) {
+		/* pins 8-15 */
+		line -= 8;
+		int_reg = IXP4XX_REG_GPIT2;
+	} else {
+		/* pins 0-7 */
+		int_reg = IXP4XX_REG_GPIT1;
+	}
+
+	scoped_guard(gpio_generic_lock_irqsave, &g->chip) {
+		/* Clear the style for the appropriate pin */
+		val = __raw_readl(g->base + int_reg);
+		val &= ~(IXP4XX_GPIO_STYLE_MASK << (line * IXP4XX_GPIO_STYLE_SIZE));
+		__raw_writel(val, g->base + int_reg);
+
+		__raw_writel(BIT(line), g->base + IXP4XX_REG_GPIS);
+
+		/* Set the new style */
+		val = __raw_readl(g->base + int_reg);
+		val |= (int_style << (line * IXP4XX_GPIO_STYLE_SIZE));
+		__raw_writel(val, g->base + int_reg);
+
+		/* Force-configure this line as an input */
+		val = __raw_readl(g->base + IXP4XX_REG_GPOE);
+		val |= BIT(d->hwirq);
+		__raw_writel(val, g->base + IXP4XX_REG_GPOE);
+	}
+
+	/* This parent only accept level high (asserted) */
+	return irq_chip_set_type_parent(d, IRQ_TYPE_LEVEL_HIGH);
+}
+
+static const struct irq_chip ixp4xx_gpio_irqchip = {
+	.name = "IXP4GPIO",
+	.irq_ack = ixp4xx_gpio_irq_ack,
+	.irq_mask = ixp4xx_gpio_mask_irq,
+	.irq_unmask = ixp4xx_gpio_irq_unmask,
+	.irq_set_type = ixp4xx_gpio_irq_set_type,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static int ixp4xx_gpio_child_to_parent_hwirq(struct gpio_chip *gc,
+					     unsigned int child,
+					     unsigned int child_type,
+					     unsigned int *parent,
+					     unsigned int *parent_type)
+{
+	/* All these interrupts are level high in the CPU */
+	*parent_type = IRQ_TYPE_LEVEL_HIGH;
+
+	/* GPIO lines 0..12 have dedicated IRQs */
+	if (child == 0) {
+		*parent = 6;
+		return 0;
+	}
+	if (child == 1) {
+		*parent = 7;
+		return 0;
+	}
+	if (child >= 2 && child <= 12) {
+		*parent = child + 17;
+		return 0;
+	}
+	return -EINVAL;
+}
+
+static int ixp4xx_gpio_probe(struct platform_device *pdev)
+{
+	struct gpio_generic_chip_config config;
+	unsigned long flags;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct irq_domain *parent;
+	struct ixp4xx_gpio *g;
+	struct gpio_irq_chip *girq;
+	struct device_node *irq_parent;
+	bool clk_14, clk_15;
+	u32 val;
+	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_parent = of_irq_find_parent(np);
+	if (!irq_parent) {
+		dev_err(dev, "no IRQ parent node\n");
+		return -ENODEV;
+	}
+	parent = irq_find_host(irq_parent);
+	if (!parent) {
+		dev_err(dev, "no IRQ parent domain\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * If either clock output is enabled explicitly in the device tree
+	 * we take full control of the clock by masking off all bits for
+	 * the clock control and selectively enabling them. Otherwise
+	 * we leave the hardware default settings.
+	 *
+	 * Enable clock outputs with default timings of requested clock.
+	 * If you need control over TC and DC, add these to the device
+	 * tree bindings and use them here.
+	 */
+	clk_14 = of_property_read_bool(np, "intel,ixp4xx-gpio14-clkout");
+	clk_15 = of_property_read_bool(np, "intel,ixp4xx-gpio15-clkout");
+
+	/*
+	 * Make sure GPIO 14 and 15 are NOT used as clocks but GPIO on
+	 * specific machines.
+	 */
+	if (of_machine_is_compatible("dlink,dsm-g600-a") ||
+	    of_machine_is_compatible("iom,nas-100d"))
+		val = 0;
+	else {
+		val = __raw_readl(g->base + IXP4XX_REG_GPCLK);
+
+		if (clk_14 || clk_15) {
+			val &= ~(IXP4XX_GPCLK_MUX14 | IXP4XX_GPCLK_MUX15);
+			val &= ~IXP4XX_GPCLK_CLK0_MASK;
+			val &= ~IXP4XX_GPCLK_CLK1_MASK;
+			if (clk_14) {
+				/* IXP4XX_GPCLK_CLK0DC implicit low */
+				val |= (1 << IXP4XX_GPCLK_CLK0TC_SHIFT);
+				val |= IXP4XX_GPCLK_MUX14;
+			}
+
+			if (clk_15) {
+				/* IXP4XX_GPCLK_CLK1DC implicit low */
+				val |= (1 << IXP4XX_GPCLK_CLK1TC_SHIFT);
+				val |= IXP4XX_GPCLK_MUX15;
+			}
+		}
+	}
+
+	__raw_writel(val, g->base + IXP4XX_REG_GPCLK);
+
+	/*
+	 * This is a very special big-endian ARM issue: when the IXP4xx is
+	 * run in big endian mode, all registers in the machine are switched
+	 * around to the CPU-native endianness. As you see mostly in the
+	 * driver we use __raw_readl()/__raw_writel() to access the registers
+	 * in the appropriate order. With the GPIO library we need to specify
+	 * byte order explicitly, so this flag needs to be set when compiling
+	 * for big endian.
+	 */
+#if defined(CONFIG_CPU_BIG_ENDIAN)
+	flags = GPIO_GENERIC_BIG_ENDIAN_BYTE_ORDER;
+#else
+	flags = 0;
+#endif
+
+	config = (struct gpio_generic_chip_config) {
+		.dev = dev,
+		.sz = 4,
+		.dat = g->base + IXP4XX_REG_GPIN,
+		.set = g->base + IXP4XX_REG_GPOUT,
+		.dirin = g->base + IXP4XX_REG_GPOE,
+		.flags = flags,
+	};
+
+	/* Populate and register gpio chip */
+	ret = gpio_generic_chip_init(&g->chip, &config);
+	if (ret) {
+		dev_err(dev, "unable to init generic GPIO\n");
+		return ret;
+	}
+	g->chip.gc.ngpio = 16;
+	g->chip.gc.label = "IXP4XX_GPIO_CHIP";
+	/*
+	 * TODO: when we have migrated to device tree and all GPIOs
+	 * are fetched using phandles, set this to -1 to get rid of
+	 * the fixed gpiochip base.
+	 */
+	g->chip.gc.base = 0;
+	g->chip.gc.parent = &pdev->dev;
+	g->chip.gc.owner = THIS_MODULE;
+
+	girq = &g->chip.gc.irq;
+	gpio_irq_chip_set_chip(girq, &ixp4xx_gpio_irqchip);
+	girq->fwnode = dev_fwnode(dev);
+	girq->parent_domain = parent;
+	girq->child_to_parent_hwirq = ixp4xx_gpio_child_to_parent_hwirq;
+	girq->handler = handle_bad_irq;
+	girq->default_type = IRQ_TYPE_NONE;
+
+	ret = devm_gpiochip_add_data(dev, &g->chip.gc, g);
+	if (ret) {
+		dev_err(dev, "failed to add SoC gpiochip\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, g);
+	dev_info(dev, "IXP4 GPIO registered\n");
+
+	return 0;
+}
+
+static const struct of_device_id ixp4xx_gpio_of_match[] = {
+	{
+		.compatible = "intel,ixp4xx-gpio",
+	},
+	{},
+};
+
+
+static struct platform_driver ixp4xx_gpio_driver = {
+	.driver = {
+		.name		= "ixp4xx-gpio",
+		.of_match_table = ixp4xx_gpio_of_match,
+	},
+	.probe = ixp4xx_gpio_probe,
+};
+builtin_platform_driver(ixp4xx_gpio_driver);