gpio: add TB10x GPIO driver

The GPIO driver for the Abilis Systems TB10x series of SOCs based on ARC700
CPUs. It supports GPIO control and GPIO interrupt generation. This driver
works in conjunction with the TB10x pinctrl driver.
Signed-off-by: Sascha Leuenberger <sascha.leuenberger@abilis.com>
Signed-off-by: Christian Ruppert <christian.ruppert@abilis.com>
Acked-by: Kumar Gala <galak@codeaurora.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/gpio/abilis,tb10x-gpio.txt

+* Abilis TB10x GPIO controller
+
+Required Properties:
+- compatible: Should be "abilis,tb10x-gpio"
+- reg: Address and length of the register set for the device
+- gpio-controller: Marks the device node as a gpio controller.
+- #gpio-cells: Should be <2>. The first cell is the pin number and the
+  second cell is used to specify optional parameters:
+   - bit 0 specifies polarity (0 for normal, 1 for inverted).
+- abilis,ngpio: the number of GPIO pins this driver controls.
+
+Optional Properties:
+- interrupt-controller: Marks the device node as an interrupt controller.
+- #interrupt-cells: Should be <1>. Interrupts are triggered on both edges.
+- interrupts: Defines the interrupt line connecting this GPIO controller to
+  its parent interrupt controller.
+- interrupt-parent: Defines the parent interrupt controller.
+
+GPIO ranges are specified as described in
+Documentation/devicetree/bindings/gpio/gpio.txt
+
+Example:
+
+	gpioa: gpio@FF140000 {
+		compatible = "abilis,tb10x-gpio";
+		interrupt-controller;
+		#interrupt-cells = <1>;
+		interrupt-parent = <&tb10x_ictl>;
+		interrupts = <27 2>;
+		reg = <0xFF140000 0x1000>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		abilis,ngpio = <3>;
+		gpio-ranges = <&iomux 0 0 0>;
+		gpio-ranges-group-names = "gpioa_pins";
+	};

drivers/gpio/Kconfig

@@ -360,6 +360,10 @@ config GPIO_GRGPIO
 	  Select this to support Aeroflex Gaisler GRGPIO cores from the GRLIB
 	  VHDL IP core library.
 
+config GPIO_TB10X
+	bool
+	select OF_GPIO
+
 comment "I2C GPIO expanders:"
 
 config GPIO_ARIZONA

drivers/gpio/Makefile

@@ -71,6 +71,7 @@ obj-$(CONFIG_GPIO_STA2X11)	+= gpio-sta2x11.o
 obj-$(CONFIG_GPIO_STMPE)	+= gpio-stmpe.o
 obj-$(CONFIG_GPIO_STP_XWAY)	+= gpio-stp-xway.o
 obj-$(CONFIG_GPIO_SX150X)	+= gpio-sx150x.o
+obj-$(CONFIG_GPIO_TB10X)	+= gpio-tb10x.o
 obj-$(CONFIG_GPIO_TC3589X)	+= gpio-tc3589x.o
 obj-$(CONFIG_ARCH_TEGRA)	+= gpio-tegra.o
 obj-$(CONFIG_GPIO_TIMBERDALE)	+= gpio-timberdale.o

drivers/gpio/gpio-tb10x.c

+/* Abilis Systems MODULE DESCRIPTION
+ *
+ * Copyright (C) Abilis Systems 2013
+ *
+ * Authors: Sascha Leuenberger <sascha.leuenberger@abilis.com>
+ *          Christian Ruppert <christian.ruppert@abilis.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
+#include <linux/spinlock.h>
+#include <linux/bitops.h>
+#include <linux/pinctrl/consumer.h>
+
+#define TB10X_GPIO_DIR_IN	(0x00000000)
+#define TB10X_GPIO_DIR_OUT	(0x00000001)
+#define OFFSET_TO_REG_DDR	(0x00)
+#define OFFSET_TO_REG_DATA	(0x04)
+#define OFFSET_TO_REG_INT_EN	(0x08)
+#define OFFSET_TO_REG_CHANGE	(0x0C)
+#define OFFSET_TO_REG_WRMASK	(0x10)
+#define OFFSET_TO_REG_INT_TYPE	(0x14)
+
+
+/**
+ * @spinlock: used for atomic read/modify/write of registers
+ * @base: register base address
+ * @domain: IRQ domain of GPIO generated interrupts managed by this controller
+ * @irq: Interrupt line of parent interrupt controller
+ * @gc: gpio_chip structure associated to this GPIO controller
+ */
+struct tb10x_gpio {
+	spinlock_t spinlock;
+	void __iomem *base;
+	struct irq_domain *domain;
+	int irq;
+	struct gpio_chip gc;
+};
+
+static inline u32 tb10x_reg_read(struct tb10x_gpio *gpio, unsigned int offs)
+{
+	return ioread32(gpio->base + offs);
+}
+
+static inline void tb10x_reg_write(struct tb10x_gpio *gpio, unsigned int offs,
+				u32 val)
+{
+	iowrite32(val, gpio->base + offs);
+}
+
+static inline void tb10x_set_bits(struct tb10x_gpio *gpio, unsigned int offs,
+				u32 mask, u32 val)
+{
+	u32 r;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpio->spinlock, flags);
+
+	r = tb10x_reg_read(gpio, offs);
+	r = (r & ~mask) | (val & mask);
+
+	tb10x_reg_write(gpio, offs, r);
+
+	spin_unlock_irqrestore(&gpio->spinlock, flags);
+}
+
+static inline struct tb10x_gpio *to_tb10x_gpio(struct gpio_chip *chip)
+{
+	return container_of(chip, struct tb10x_gpio, gc);
+}
+
+static int tb10x_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
+{
+	struct tb10x_gpio *tb10x_gpio = to_tb10x_gpio(chip);
+	int mask = BIT(offset);
+	int val = TB10X_GPIO_DIR_IN << offset;
+
+	tb10x_set_bits(tb10x_gpio, OFFSET_TO_REG_DDR, mask, val);
+
+	return 0;
+}
+
+static int tb10x_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct tb10x_gpio *tb10x_gpio = to_tb10x_gpio(chip);
+	int val;
+
+	val = tb10x_reg_read(tb10x_gpio, OFFSET_TO_REG_DATA);
+
+	if (val & BIT(offset))
+		return 1;
+	else
+		return 0;
+}
+
+static void tb10x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct tb10x_gpio *tb10x_gpio = to_tb10x_gpio(chip);
+	int mask = BIT(offset);
+	int val = value << offset;
+
+	tb10x_set_bits(tb10x_gpio, OFFSET_TO_REG_DATA, mask, val);
+}
+
+static int tb10x_gpio_direction_out(struct gpio_chip *chip,
+					unsigned offset, int value)
+{
+	struct tb10x_gpio *tb10x_gpio = to_tb10x_gpio(chip);
+	int mask = BIT(offset);
+	int val = TB10X_GPIO_DIR_OUT << offset;
+
+	tb10x_set_bits(tb10x_gpio, OFFSET_TO_REG_DDR, mask, val);
+
+	return 0;
+}
+
+static int tb10x_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	return pinctrl_request_gpio(chip->base + offset);
+}
+
+static void tb10x_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	pinctrl_free_gpio(chip->base + offset);
+}
+
+static int tb10x_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	struct tb10x_gpio *tb10x_gpio = to_tb10x_gpio(chip);
+
+	return irq_create_mapping(tb10x_gpio->domain, offset);
+}
+
+static int tb10x_gpio_irq_set_type(struct irq_data *data, unsigned int type)
+{
+	if ((type & IRQF_TRIGGER_MASK) != IRQ_TYPE_EDGE_BOTH) {
+		pr_err("Only (both) edge triggered interrupts supported.\n");
+		return -EINVAL;
+	}
+
+	irqd_set_trigger_type(data, type);
+
+	return IRQ_SET_MASK_OK;
+}
+
+static irqreturn_t tb10x_gpio_irq_cascade(int irq, void *data)
+{
+	struct tb10x_gpio *tb10x_gpio = data;
+	u32 r = tb10x_reg_read(tb10x_gpio, OFFSET_TO_REG_CHANGE);
+	u32 m = tb10x_reg_read(tb10x_gpio, OFFSET_TO_REG_INT_EN);
+	const unsigned long bits = r & m;
+	int i;
+
+	for_each_set_bit(i, &bits, 32)
+		generic_handle_irq(irq_find_mapping(tb10x_gpio->domain, i));
+
+	return IRQ_HANDLED;
+}
+
+static int tb10x_gpio_probe(struct platform_device *pdev)
+{
+	struct tb10x_gpio *tb10x_gpio;
+	struct resource *mem;
+	struct device_node *dn = pdev->dev.of_node;
+	int ret = -EBUSY;
+	u32 ngpio;
+
+	if (!dn)
+		return -EINVAL;
+
+	if (of_property_read_u32(dn, "abilis,ngpio", &ngpio))
+		return -EINVAL;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem) {
+		dev_err(&pdev->dev, "No memory resource defined.\n");
+		return -EINVAL;
+	}
+
+	tb10x_gpio = devm_kzalloc(&pdev->dev, sizeof(*tb10x_gpio), GFP_KERNEL);
+	if (tb10x_gpio == NULL)
+		return -ENOMEM;
+
+	spin_lock_init(&tb10x_gpio->spinlock);
+
+	tb10x_gpio->base = devm_ioremap_resource(&pdev->dev, mem);
+	if (!tb10x_gpio->base) {
+		dev_err(&pdev->dev, "Could not remap reg space.\n");
+		goto fail_ioremap;
+	}
+
+	tb10x_gpio->gc.label		= of_node_full_name(dn);
+	tb10x_gpio->gc.dev		= &pdev->dev;
+	tb10x_gpio->gc.owner		= THIS_MODULE;
+	tb10x_gpio->gc.direction_input	= tb10x_gpio_direction_in;
+	tb10x_gpio->gc.get		= tb10x_gpio_get;
+	tb10x_gpio->gc.direction_output	= tb10x_gpio_direction_out;
+	tb10x_gpio->gc.set		= tb10x_gpio_set;
+	tb10x_gpio->gc.request		= tb10x_gpio_request;
+	tb10x_gpio->gc.free		= tb10x_gpio_free;
+	tb10x_gpio->gc.base		= -1;
+	tb10x_gpio->gc.ngpio		= ngpio;
+	tb10x_gpio->gc.can_sleep	= 0;
+
+
+	ret = gpiochip_add(&tb10x_gpio->gc);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Could not add gpiochip.\n");
+		goto fail_gpiochip_registration;
+	}
+
+	platform_set_drvdata(pdev, tb10x_gpio);
+
+	if (of_find_property(dn, "interrupt-controller", NULL)) {
+		struct irq_chip_generic *gc;
+
+		ret = platform_get_irq(pdev, 0);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "No interrupt specified.\n");
+			goto fail_get_irq;
+		}
+
+		tb10x_gpio->gc.to_irq	= tb10x_gpio_to_irq;
+		tb10x_gpio->irq		= ret;
+
+		ret = devm_request_irq(&pdev->dev, ret, tb10x_gpio_irq_cascade,
+				IRQF_TRIGGER_NONE | IRQF_SHARED,
+				dev_name(&pdev->dev), tb10x_gpio);
+		if (ret != 0)
+			goto fail_request_irq;
+
+		tb10x_gpio->domain = irq_domain_add_linear(dn,
+						tb10x_gpio->gc.ngpio,
+						&irq_generic_chip_ops, NULL);
+		if (!tb10x_gpio->domain) {
+			ret = -ENOMEM;
+			goto fail_irq_domain;
+		}
+
+		ret = irq_alloc_domain_generic_chips(tb10x_gpio->domain,
+				tb10x_gpio->gc.ngpio, 1, tb10x_gpio->gc.label,
+				handle_edge_irq, IRQ_NOREQUEST, IRQ_NOPROBE,
+				IRQ_GC_INIT_MASK_CACHE);
+		if (ret)
+			goto fail_irq_domain;
+
+		gc = tb10x_gpio->domain->gc->gc[0];
+		gc->reg_base                         = tb10x_gpio->base;
+		gc->chip_types[0].type               = IRQ_TYPE_EDGE_BOTH;
+		gc->chip_types[0].chip.irq_ack       = irq_gc_ack_set_bit;
+		gc->chip_types[0].chip.irq_mask      = irq_gc_mask_clr_bit;
+		gc->chip_types[0].chip.irq_unmask    = irq_gc_mask_set_bit;
+		gc->chip_types[0].chip.irq_set_type  = tb10x_gpio_irq_set_type;
+		gc->chip_types[0].regs.ack           = OFFSET_TO_REG_CHANGE;
+		gc->chip_types[0].regs.mask          = OFFSET_TO_REG_INT_EN;
+	}
+
+	return 0;
+
+fail_irq_domain:
+fail_request_irq:
+fail_get_irq:
+	gpiochip_remove(&tb10x_gpio->gc);
+fail_gpiochip_registration:
+fail_ioremap:
+	return ret;
+}
+
+static int __exit tb10x_gpio_remove(struct platform_device *pdev)
+{
+	struct tb10x_gpio *tb10x_gpio = platform_get_drvdata(pdev);
+	int ret;
+
+	if (tb10x_gpio->gc.to_irq) {
+		irq_remove_generic_chip(tb10x_gpio->domain->gc->gc[0],
+					BIT(tb10x_gpio->gc.ngpio) - 1, 0, 0);
+		kfree(tb10x_gpio->domain->gc);
+		irq_domain_remove(tb10x_gpio->domain);
+		free_irq(tb10x_gpio->irq, tb10x_gpio);
+	}
+	ret = gpiochip_remove(&tb10x_gpio->gc);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct of_device_id tb10x_gpio_dt_ids[] = {
+	{ .compatible = "abilis,tb10x-gpio" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tb10x_gpio_dt_ids);
+
+static struct platform_driver tb10x_gpio_driver = {
+	.probe		= tb10x_gpio_probe,
+	.remove		= tb10x_gpio_remove,
+	.driver = {
+		.name	= "tb10x-gpio",
+		.of_match_table = of_match_ptr(tb10x_gpio_dt_ids),
+		.owner	= THIS_MODULE,
+	}
+};
+
+static int __init ab_gpio_init(void)
+{
+	return platform_driver_register(&tb10x_gpio_driver);
+}
+
+static void __exit ab_gpio_exit(void)
+{
+	platform_driver_unregister(&tb10x_gpio_driver);
+}
+
+module_init(ab_gpio_init);
+module_exit(ab_gpio_exit);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("tb10x gpio.");
+MODULE_VERSION("0.0.1");