pinctrl: cygnus: add gpio/pinconf driver

This adds the initial support of the Broadcom Cygnus GPIO/PINCONF driver
that supports all 3 GPIO controllers on Cygnus including the ASIU GPIO
controller, the chipCommonG GPIO controller, and the always-on GPIO
controller. Basic PINCONF configurations such as bias pull up/down, and
drive strength are also supported in this driver.

Pins from the ASIU GPIO controller can be individually muxed to GPIO
function, through interaction with the Cygnus IOMUX controller

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Tested-by: Dmitry Torokhov <dtor@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 930 insertions, 0 deletions

diff --git a/drivers/pinctrl/bcm/Kconfig b/drivers/pinctrl/bcm/Kconfig
index eb1320152a87..cd11d4d9ad58 100644
--- a/drivers/pinctrl/bcm/Kconfig
+++ b/drivers/pinctrl/bcm/Kconfig
@@ -20,6 +20,28 @@ config PINCTRL_BCM2835
 	select PINMUX
 	select PINCONF
 
+config PINCTRL_CYGNUS_GPIO
+	bool "Broadcom Cygnus GPIO (with PINCONF) driver"
+	depends on OF_GPIO && ARCH_BCM_CYGNUS
+	select GPIOLIB_IRQCHIP
+	select PINCONF
+	select GENERIC_PINCONF
+	default ARCH_BCM_CYGNUS
+	help
+	  Say yes here to enable the Broadcom Cygnus GPIO driver.
+
+	  The Broadcom Cygnus SoC has 3 GPIO controllers including the ASIU
+	  GPIO controller (ASIU), the chipCommonG GPIO controller (CCM), and
+	  the always-ON GPIO controller (CRMU/AON). All 3 GPIO controllers are
+	  supported by this driver.
+
+	  All 3 Cygnus GPIO controllers support basic PINCONF functions such
+	  as bias pull up, pull down, and drive strength configurations, when
+	  these pins are muxed to GPIO.
+
+	  Pins from the ASIU GPIO can be individually muxed to GPIO function,
+	  through interaction with the Cygnus IOMUX controller.
+
 config PINCTRL_CYGNUS_MUX
 	bool "Broadcom Cygnus IOMUX driver"
 	depends on (ARCH_BCM_CYGNUS || COMPILE_TEST)
diff --git a/drivers/pinctrl/bcm/Makefile b/drivers/pinctrl/bcm/Makefile
index bb6beb66d962..2b2f70ee804c 100644
--- a/drivers/pinctrl/bcm/Makefile
+++ b/drivers/pinctrl/bcm/Makefile
@@ -2,4 +2,5 @@
 
 obj-$(CONFIG_PINCTRL_BCM281XX)		+= pinctrl-bcm281xx.o
 obj-$(CONFIG_PINCTRL_BCM2835)		+= pinctrl-bcm2835.o
+obj-$(CONFIG_PINCTRL_CYGNUS_GPIO)	+= pinctrl-cygnus-gpio.o
 obj-$(CONFIG_PINCTRL_CYGNUS_MUX)	+= pinctrl-cygnus-mux.o
diff --git a/drivers/pinctrl/bcm/pinctrl-cygnus-gpio.c b/drivers/pinctrl/bcm/pinctrl-cygnus-gpio.c
new file mode 100644
index 000000000000..4ad5c1a996e3
--- /dev/null
+++ b/drivers/pinctrl/bcm/pinctrl-cygnus-gpio.c
@@ -0,0 +1,907 @@
+/*
+ * Copyright (C) 2014-2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * This file contains the Broadcom Cygnus GPIO driver that supports 3
+ * GPIO controllers on Cygnus including the ASIU GPIO controller, the
+ * chipCommonG GPIO controller, and the always-on GPIO controller. Basic
+ * PINCONF such as bias pull up/down, and drive strength are also supported
+ * in this driver.
+ *
+ * Pins from the ASIU GPIO can be individually muxed to GPIO function,
+ * through the interaction with the Cygnus IOMUX controller
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/gpio.h>
+#include <linux/ioport.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinconf-generic.h>
+
+#include "../pinctrl-utils.h"
+
+#define CYGNUS_GPIO_DATA_IN_OFFSET   0x00
+#define CYGNUS_GPIO_DATA_OUT_OFFSET  0x04
+#define CYGNUS_GPIO_OUT_EN_OFFSET    0x08
+#define CYGNUS_GPIO_IN_TYPE_OFFSET   0x0c
+#define CYGNUS_GPIO_INT_DE_OFFSET    0x10
+#define CYGNUS_GPIO_INT_EDGE_OFFSET  0x14
+#define CYGNUS_GPIO_INT_MSK_OFFSET   0x18
+#define CYGNUS_GPIO_INT_STAT_OFFSET  0x1c
+#define CYGNUS_GPIO_INT_MSTAT_OFFSET 0x20
+#define CYGNUS_GPIO_INT_CLR_OFFSET   0x24
+#define CYGNUS_GPIO_PAD_RES_OFFSET   0x34
+#define CYGNUS_GPIO_RES_EN_OFFSET    0x38
+
+/* drive strength control for ASIU GPIO */
+#define CYGNUS_GPIO_ASIU_DRV0_CTRL_OFFSET 0x58
+
+/* drive strength control for CCM/CRMU (AON) GPIO */
+#define CYGNUS_GPIO_DRV0_CTRL_OFFSET  0x00
+
+#define GPIO_BANK_SIZE 0x200
+#define NGPIOS_PER_BANK 32
+#define GPIO_BANK(pin) ((pin) / NGPIOS_PER_BANK)
+
+#define CYGNUS_GPIO_REG(pin, reg) (GPIO_BANK(pin) * GPIO_BANK_SIZE + (reg))
+#define CYGNUS_GPIO_SHIFT(pin) ((pin) % NGPIOS_PER_BANK)
+
+#define GPIO_DRV_STRENGTH_BIT_SHIFT  20
+#define GPIO_DRV_STRENGTH_BITS       3
+#define GPIO_DRV_STRENGTH_BIT_MASK   ((1 << GPIO_DRV_STRENGTH_BITS) - 1)
+
+/*
+ * Cygnus GPIO core
+ *
+ * @dev: pointer to device
+ * @base: I/O register base for Cygnus GPIO controller
+ * @io_ctrl: I/O register base for certain type of Cygnus GPIO controller that
+ * has the PINCONF support implemented outside of the GPIO block
+ * @lock: lock to protect access to I/O registers
+ * @gc: GPIO chip
+ * @num_banks: number of GPIO banks, each bank supports up to 32 GPIOs
+ * @pinmux_is_supported: flag to indicate this GPIO controller contains pins
+ * that can be individually muxed to GPIO
+ * @pctl: pointer to pinctrl_dev
+ * @pctldesc: pinctrl descriptor
+ */
+struct cygnus_gpio {
+	struct device *dev;
+
+	void __iomem *base;
+	void __iomem *io_ctrl;
+
+	spinlock_t lock;
+
+	struct gpio_chip gc;
+	unsigned num_banks;
+
+	bool pinmux_is_supported;
+
+	struct pinctrl_dev *pctl;
+	struct pinctrl_desc pctldesc;
+};
+
+static inline struct cygnus_gpio *to_cygnus_gpio(struct gpio_chip *gc)
+{
+	return container_of(gc, struct cygnus_gpio, gc);
+}
+
+/*
+ * Mapping from PINCONF pins to GPIO pins is 1-to-1
+ */
+static inline unsigned cygnus_pin_to_gpio(unsigned pin)
+{
+	return pin;
+}
+
+/**
+ *  cygnus_set_bit - set or clear one bit (corresponding to the GPIO pin) in a
+ *  Cygnus GPIO register
+ *
+ *  @cygnus_gpio: Cygnus GPIO device
+ *  @reg: register offset
+ *  @gpio: GPIO pin
+ *  @set: set or clear
+ */
+static inline void cygnus_set_bit(struct cygnus_gpio *chip, unsigned int reg,
+				  unsigned gpio, bool set)
+{
+	unsigned int offset = CYGNUS_GPIO_REG(gpio, reg);
+	unsigned int shift = CYGNUS_GPIO_SHIFT(gpio);
+	u32 val;
+
+	val = readl(chip->base + offset);
+	if (set)
+		val |= BIT(shift);
+	else
+		val &= ~BIT(shift);
+	writel(val, chip->base + offset);
+}
+
+static inline bool cygnus_get_bit(struct cygnus_gpio *chip, unsigned int reg,
+				  unsigned gpio)
+{
+	unsigned int offset = CYGNUS_GPIO_REG(gpio, reg);
+	unsigned int shift = CYGNUS_GPIO_SHIFT(gpio);
+
+	return !!(readl(chip->base + offset) & BIT(shift));
+}
+
+static void cygnus_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
+	int i, bit;
+
+	chained_irq_enter(irq_chip, desc);
+
+	/* go through the entire GPIO banks and handle all interrupts */
+	for (i = 0; i < chip->num_banks; i++) {
+		unsigned long val = readl(chip->base + (i * GPIO_BANK_SIZE) +
+					  CYGNUS_GPIO_INT_MSTAT_OFFSET);
+
+		for_each_set_bit(bit, &val, NGPIOS_PER_BANK) {
+			unsigned pin = NGPIOS_PER_BANK * i + bit;
+			int child_irq = irq_find_mapping(gc->irqdomain, pin);
+
+			/*
+			 * Clear the interrupt before invoking the
+			 * handler, so we do not leave any window
+			 */
+			writel(BIT(bit), chip->base + (i * GPIO_BANK_SIZE) +
+			       CYGNUS_GPIO_INT_CLR_OFFSET);
+
+			generic_handle_irq(child_irq);
+		}
+	}
+
+	chained_irq_exit(irq_chip, desc);
+}
+
+
+static void cygnus_gpio_irq_ack(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned gpio = d->hwirq;
+	unsigned int offset = CYGNUS_GPIO_REG(gpio,
+			CYGNUS_GPIO_INT_CLR_OFFSET);
+	unsigned int shift = CYGNUS_GPIO_SHIFT(gpio);
+	u32 val = BIT(shift);
+
+	writel(val, chip->base + offset);
+}
+
+/**
+ *  cygnus_gpio_irq_set_mask - mask/unmask a GPIO interrupt
+ *
+ *  @d: IRQ chip data
+ *  @unmask: mask/unmask GPIO interrupt
+ */
+static void cygnus_gpio_irq_set_mask(struct irq_data *d, bool unmask)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned gpio = d->hwirq;
+
+	cygnus_set_bit(chip, CYGNUS_GPIO_INT_MSK_OFFSET, gpio, unmask);
+}
+
+static void cygnus_gpio_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+	cygnus_gpio_irq_set_mask(d, false);
+	spin_unlock_irqrestore(&chip->lock, flags);
+}
+
+static void cygnus_gpio_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+	cygnus_gpio_irq_set_mask(d, true);
+	spin_unlock_irqrestore(&chip->lock, flags);
+}
+
+static int cygnus_gpio_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned gpio = d->hwirq;
+	bool level_triggered = false;
+	bool dual_edge = false;
+	bool rising_or_high = false;
+	unsigned long flags;
+
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_RISING:
+		rising_or_high = true;
+		break;
+
+	case IRQ_TYPE_EDGE_FALLING:
+		break;
+
+	case IRQ_TYPE_EDGE_BOTH:
+		dual_edge = true;
+		break;
+
+	case IRQ_TYPE_LEVEL_HIGH:
+		level_triggered = true;
+		rising_or_high = true;
+		break;
+
+	case IRQ_TYPE_LEVEL_LOW:
+		level_triggered = true;
+		break;
+
+	default:
+		dev_err(chip->dev, "invalid GPIO IRQ type 0x%x\n",
+			type);
+		return -EINVAL;
+	}
+
+	spin_lock_irqsave(&chip->lock, flags);
+	cygnus_set_bit(chip, CYGNUS_GPIO_IN_TYPE_OFFSET, gpio,
+		       level_triggered);
+	cygnus_set_bit(chip, CYGNUS_GPIO_INT_DE_OFFSET, gpio, dual_edge);
+	cygnus_set_bit(chip, CYGNUS_GPIO_INT_EDGE_OFFSET, gpio,
+		       rising_or_high);
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	dev_dbg(chip->dev,
+		"gpio:%u level_triggered:%d dual_edge:%d rising_or_high:%d\n",
+		gpio, level_triggered, dual_edge, rising_or_high);
+
+	return 0;
+}
+
+static struct irq_chip cygnus_gpio_irq_chip = {
+	.name = "bcm-cygnus-gpio",
+	.irq_ack = cygnus_gpio_irq_ack,
+	.irq_mask = cygnus_gpio_irq_mask,
+	.irq_unmask = cygnus_gpio_irq_unmask,
+	.irq_set_type = cygnus_gpio_irq_set_type,
+};
+
+/*
+ * Request the Cygnus IOMUX pinmux controller to mux individual pins to GPIO
+ */
+static int cygnus_gpio_request(struct gpio_chip *gc, unsigned offset)
+{
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned gpio = gc->base + offset;
+
+	/* not all Cygnus GPIO pins can be muxed individually */
+	if (!chip->pinmux_is_supported)
+		return 0;
+
+	return pinctrl_request_gpio(gpio);
+}
+
+static void cygnus_gpio_free(struct gpio_chip *gc, unsigned offset)
+{
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned gpio = gc->base + offset;
+
+	if (!chip->pinmux_is_supported)
+		return;
+
+	pinctrl_free_gpio(gpio);
+}
+
+static int cygnus_gpio_direction_input(struct gpio_chip *gc, unsigned gpio)
+{
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+	cygnus_set_bit(chip, CYGNUS_GPIO_OUT_EN_OFFSET, gpio, false);
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	dev_dbg(chip->dev, "gpio:%u set input\n", gpio);
+
+	return 0;
+}
+
+static int cygnus_gpio_direction_output(struct gpio_chip *gc, unsigned gpio,
+					int val)
+{
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+	cygnus_set_bit(chip, CYGNUS_GPIO_OUT_EN_OFFSET, gpio, true);
+	cygnus_set_bit(chip, CYGNUS_GPIO_DATA_OUT_OFFSET, gpio, !!(val));
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	dev_dbg(chip->dev, "gpio:%u set output, value:%d\n", gpio, val);
+
+	return 0;
+}
+
+static void cygnus_gpio_set(struct gpio_chip *gc, unsigned gpio, int val)
+{
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+	cygnus_set_bit(chip, CYGNUS_GPIO_DATA_OUT_OFFSET, gpio, !!(val));
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	dev_dbg(chip->dev, "gpio:%u set, value:%d\n", gpio, val);
+}
+
+static int cygnus_gpio_get(struct gpio_chip *gc, unsigned gpio)
+{
+	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
+	unsigned int offset = CYGNUS_GPIO_REG(gpio,
+					      CYGNUS_GPIO_DATA_IN_OFFSET);
+	unsigned int shift = CYGNUS_GPIO_SHIFT(gpio);
+
+	return !!(readl(chip->base + offset) & BIT(shift));
+}
+
+static int cygnus_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	return 1;
+}
+
+/*
+ * Only one group: "gpio_grp", since this local pinctrl device only performs
+ * GPIO specific PINCONF configurations
+ */
+static const char *cygnus_get_group_name(struct pinctrl_dev *pctldev,
+					 unsigned selector)
+{
+	return "gpio_grp";
+}
+
+static const struct pinctrl_ops cygnus_pctrl_ops = {
+	.get_groups_count = cygnus_get_groups_count,
+	.get_group_name = cygnus_get_group_name,
+	.dt_node_to_map = pinconf_generic_dt_node_to_map_pin,
+	.dt_free_map = pinctrl_utils_dt_free_map,
+};
+
+static int cygnus_gpio_set_pull(struct cygnus_gpio *chip, unsigned gpio,
+				bool disable, bool pull_up)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+
+	if (disable) {
+		cygnus_set_bit(chip, CYGNUS_GPIO_RES_EN_OFFSET, gpio, false);
+	} else {
+		cygnus_set_bit(chip, CYGNUS_GPIO_PAD_RES_OFFSET, gpio,
+			       pull_up);
+		cygnus_set_bit(chip, CYGNUS_GPIO_RES_EN_OFFSET, gpio, true);
+	}
+
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	dev_dbg(chip->dev, "gpio:%u set pullup:%d\n", gpio, pull_up);
+
+	return 0;
+}
+
+static void cygnus_gpio_get_pull(struct cygnus_gpio *chip, unsigned gpio,
+				 bool *disable, bool *pull_up)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+	*disable = !cygnus_get_bit(chip, CYGNUS_GPIO_RES_EN_OFFSET, gpio);
+	*pull_up = cygnus_get_bit(chip, CYGNUS_GPIO_PAD_RES_OFFSET, gpio);
+	spin_unlock_irqrestore(&chip->lock, flags);
+}
+
+static int cygnus_gpio_set_strength(struct cygnus_gpio *chip, unsigned gpio,
+				    unsigned strength)
+{
+	void __iomem *base;
+	unsigned int i, offset, shift;
+	u32 val;
+	unsigned long flags;
+
+	/* make sure drive strength is supported */
+	if (strength < 2 ||  strength > 16 || (strength % 2))
+		return -ENOTSUPP;
+
+	if (chip->io_ctrl) {
+		base = chip->io_ctrl;
+		offset = CYGNUS_GPIO_DRV0_CTRL_OFFSET;
+	} else {
+		base = chip->base;
+		offset = CYGNUS_GPIO_REG(gpio,
+					 CYGNUS_GPIO_ASIU_DRV0_CTRL_OFFSET);
+	}
+
+	shift = CYGNUS_GPIO_SHIFT(gpio);
+
+	dev_dbg(chip->dev, "gpio:%u set drive strength:%d mA\n", gpio,
+		strength);
+
+	spin_lock_irqsave(&chip->lock, flags);
+	strength = (strength / 2) - 1;
+	for (i = 0; i < GPIO_DRV_STRENGTH_BITS; i++) {
+		val = readl(base + offset);
+		val &= ~BIT(shift);
+		val |= ((strength >> i) & 0x1) << shift;
+		writel(val, base + offset);
+		offset += 4;
+	}
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	return 0;
+}
+
+static int cygnus_gpio_get_strength(struct cygnus_gpio *chip, unsigned gpio,
+				    u16 *strength)
+{
+	void __iomem *base;
+	unsigned int i, offset, shift;
+	u32 val;
+	unsigned long flags;
+
+	if (chip->io_ctrl) {
+		base = chip->io_ctrl;
+		offset = CYGNUS_GPIO_DRV0_CTRL_OFFSET;
+	} else {
+		base = chip->base;
+		offset = CYGNUS_GPIO_REG(gpio,
+					 CYGNUS_GPIO_ASIU_DRV0_CTRL_OFFSET);
+	}
+
+	shift = CYGNUS_GPIO_SHIFT(gpio);
+
+	spin_lock_irqsave(&chip->lock, flags);
+	*strength = 0;
+	for (i = 0; i < GPIO_DRV_STRENGTH_BITS; i++) {
+		val = readl(base + offset) & BIT(shift);
+		val >>= shift;
+		*strength += (val << i);
+		offset += 4;
+	}
+
+	/* convert to mA */
+	*strength = (*strength + 1) * 2;
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	return 0;
+}
+
+static int cygnus_pin_config_get(struct pinctrl_dev *pctldev, unsigned pin,
+				 unsigned long *config)
+{
+	struct cygnus_gpio *chip = pinctrl_dev_get_drvdata(pctldev);
+	enum pin_config_param param = pinconf_to_config_param(*config);
+	unsigned gpio = cygnus_pin_to_gpio(pin);
+	u16 arg;
+	bool disable, pull_up;
+	int ret;
+
+	switch (param) {
+	case PIN_CONFIG_BIAS_DISABLE:
+		cygnus_gpio_get_pull(chip, gpio, &disable, &pull_up);
+		if (disable)
+			return 0;
+		else
+			return -EINVAL;
+
+	case PIN_CONFIG_BIAS_PULL_UP:
+		cygnus_gpio_get_pull(chip, gpio, &disable, &pull_up);
+		if (!disable && pull_up)
+			return 0;
+		else
+			return -EINVAL;
+
+	case PIN_CONFIG_BIAS_PULL_DOWN:
+		cygnus_gpio_get_pull(chip, gpio, &disable, &pull_up);
+		if (!disable && !pull_up)
+			return 0;
+		else
+			return -EINVAL;
+
+	case PIN_CONFIG_DRIVE_STRENGTH:
+		ret = cygnus_gpio_get_strength(chip, gpio, &arg);
+		if (ret)
+			return ret;
+		else
+			*config = pinconf_to_config_packed(param, arg);
+
+		return 0;
+
+	default:
+		return -ENOTSUPP;
+	}
+
+	return -ENOTSUPP;
+}
+
+static int cygnus_pin_config_set(struct pinctrl_dev *pctldev, unsigned pin,
+				 unsigned long *configs, unsigned num_configs)
+{
+	struct cygnus_gpio *chip = pinctrl_dev_get_drvdata(pctldev);
+	enum pin_config_param param;
+	u16 arg;
+	unsigned i, gpio = cygnus_pin_to_gpio(pin);
+	int ret = -ENOTSUPP;
+
+	for (i = 0; i < num_configs; i++) {
+		param = pinconf_to_config_param(configs[i]);
+		arg = pinconf_to_config_argument(configs[i]);
+
+		switch (param) {
+		case PIN_CONFIG_BIAS_DISABLE:
+			ret = cygnus_gpio_set_pull(chip, gpio, true, false);
+			if (ret < 0)
+				goto out;
+			break;
+
+		case PIN_CONFIG_BIAS_PULL_UP:
+			ret = cygnus_gpio_set_pull(chip, gpio, false, true);
+			if (ret < 0)
+				goto out;
+			break;
+
+		case PIN_CONFIG_BIAS_PULL_DOWN:
+			ret = cygnus_gpio_set_pull(chip, gpio, false, false);
+			if (ret < 0)
+				goto out;
+			break;
+
+		case PIN_CONFIG_DRIVE_STRENGTH:
+			ret = cygnus_gpio_set_strength(chip, gpio, arg);
+			if (ret < 0)
+				goto out;
+			break;
+
+		default:
+			dev_err(chip->dev, "invalid configuration\n");
+			return -ENOTSUPP;
+		}
+	} /* for each config */
+
+out:
+	return ret;
+}
+
+static const struct pinconf_ops cygnus_pconf_ops = {
+	.is_generic = true,
+	.pin_config_get = cygnus_pin_config_get,
+	.pin_config_set = cygnus_pin_config_set,
+};
+
+/*
+ * Map a GPIO in the local gpio_chip pin space to a pin in the Cygnus IOMUX
+ * pinctrl pin space
+ */
+struct cygnus_gpio_pin_range {
+	unsigned offset;
+	unsigned pin_base;
+	unsigned num_pins;
+};
+
+#define CYGNUS_PINRANGE(o, p, n) { .offset = o, .pin_base = p, .num_pins = n }
+
+/*
+ * Pin mapping table for mapping local GPIO pins to Cygnus IOMUX pinctrl pins
+ */
+static const struct cygnus_gpio_pin_range cygnus_gpio_pintable[] = {
+	CYGNUS_PINRANGE(0, 42, 1),
+	CYGNUS_PINRANGE(1, 44, 3),
+	CYGNUS_PINRANGE(4, 48, 1),
+	CYGNUS_PINRANGE(5, 50, 3),
+	CYGNUS_PINRANGE(8, 126, 1),
+	CYGNUS_PINRANGE(9, 155, 1),
+	CYGNUS_PINRANGE(10, 152, 1),
+	CYGNUS_PINRANGE(11, 154, 1),
+	CYGNUS_PINRANGE(12, 153, 1),
+	CYGNUS_PINRANGE(13, 127, 3),
+	CYGNUS_PINRANGE(16, 140, 1),
+	CYGNUS_PINRANGE(17, 145, 7),
+	CYGNUS_PINRANGE(24, 130, 10),
+	CYGNUS_PINRANGE(34, 141, 4),
+	CYGNUS_PINRANGE(38, 54, 1),
+	CYGNUS_PINRANGE(39, 56, 3),
+	CYGNUS_PINRANGE(42, 60, 3),
+	CYGNUS_PINRANGE(45, 64, 3),
+	CYGNUS_PINRANGE(48, 68, 2),
+	CYGNUS_PINRANGE(50, 84, 6),
+	CYGNUS_PINRANGE(56, 94, 6),
+	CYGNUS_PINRANGE(62, 72, 1),
+	CYGNUS_PINRANGE(63, 70, 1),
+	CYGNUS_PINRANGE(64, 80, 1),
+	CYGNUS_PINRANGE(65, 74, 3),
+	CYGNUS_PINRANGE(68, 78, 1),
+	CYGNUS_PINRANGE(69, 82, 1),
+	CYGNUS_PINRANGE(70, 156, 17),
+	CYGNUS_PINRANGE(87, 104, 12),
+	CYGNUS_PINRANGE(99, 102, 2),
+	CYGNUS_PINRANGE(101, 90, 4),
+	CYGNUS_PINRANGE(105, 116, 10),
+	CYGNUS_PINRANGE(123, 11, 1),
+	CYGNUS_PINRANGE(124, 38, 4),
+	CYGNUS_PINRANGE(128, 43, 1),
+	CYGNUS_PINRANGE(129, 47, 1),
+	CYGNUS_PINRANGE(130, 49, 1),
+	CYGNUS_PINRANGE(131, 53, 1),
+	CYGNUS_PINRANGE(132, 55, 1),
+	CYGNUS_PINRANGE(133, 59, 1),
+	CYGNUS_PINRANGE(134, 63, 1),
+	CYGNUS_PINRANGE(135, 67, 1),
+	CYGNUS_PINRANGE(136, 71, 1),
+	CYGNUS_PINRANGE(137, 73, 1),
+	CYGNUS_PINRANGE(138, 77, 1),
+	CYGNUS_PINRANGE(139, 79, 1),
+	CYGNUS_PINRANGE(140, 81, 1),
+	CYGNUS_PINRANGE(141, 83, 1),
+	CYGNUS_PINRANGE(142, 10, 1)
+};
+
+/*
+ * The Cygnus IOMUX controller mainly supports group based mux configuration,
+ * but certain pins can be muxed to GPIO individually. Only the ASIU GPIO
+ * controller can support this, so it's an optional configuration
+ *
+ * Return -ENODEV means no support and that's fine
+ */
+static int cygnus_gpio_pinmux_add_range(struct cygnus_gpio *chip)
+{
+	struct device_node *node = chip->dev->of_node;
+	struct device_node *pinmux_node;
+	struct platform_device *pinmux_pdev;
+	struct gpio_chip *gc = &chip->gc;
+	int i, ret = 0;
+
+	/* parse DT to find the phandle to the pinmux controller */
+	pinmux_node = of_parse_phandle(node, "pinmux", 0);
+	if (!pinmux_node)
+		return -ENODEV;
+
+	pinmux_pdev = of_find_device_by_node(pinmux_node);
+	/* no longer need the pinmux node */
+	of_node_put(pinmux_node);
+	if (!pinmux_pdev) {
+		dev_err(chip->dev, "failed to get pinmux device\n");
+		return -EINVAL;
+	}
+
+	/* now need to create the mapping between local GPIO and PINMUX pins */
+	for (i = 0; i < ARRAY_SIZE(cygnus_gpio_pintable); i++) {
+		ret = gpiochip_add_pin_range(gc, dev_name(&pinmux_pdev->dev),
+					     cygnus_gpio_pintable[i].offset,
+					     cygnus_gpio_pintable[i].pin_base,
+					     cygnus_gpio_pintable[i].num_pins);
+		if (ret) {
+			dev_err(chip->dev, "unable to add GPIO pin range\n");
+			goto err_put_device;
+		}
+	}
+
+	chip->pinmux_is_supported = true;
+
+	/* no need for pinmux_pdev device reference anymore */
+	put_device(&pinmux_pdev->dev);
+	return 0;
+
+err_put_device:
+	put_device(&pinmux_pdev->dev);
+	gpiochip_remove_pin_ranges(gc);
+	return ret;
+}
+
+/*
+ * Cygnus GPIO controller supports some PINCONF related configurations such as
+ * pull up, pull down, and drive strength, when the pin is configured to GPIO
+ *
+ * Here a local pinctrl device is created with simple 1-to-1 pin mapping to the
+ * local GPIO pins
+ */
+static int cygnus_gpio_register_pinconf(struct cygnus_gpio *chip)
+{
+	struct pinctrl_desc *pctldesc = &chip->pctldesc;
+	struct pinctrl_pin_desc *pins;
+	struct gpio_chip *gc = &chip->gc;
+	int i;
+
+	pins = devm_kcalloc(chip->dev, gc->ngpio, sizeof(*pins), GFP_KERNEL);
+	if (!pins)
+		return -ENOMEM;
+
+	for (i = 0; i < gc->ngpio; i++) {
+		pins[i].number = i;
+		pins[i].name = devm_kasprintf(chip->dev, GFP_KERNEL,
+					      "gpio-%d", i);
+		if (!pins[i].name)
+			return -ENOMEM;
+	}
+
+	pctldesc->name = dev_name(chip->dev);
+	pctldesc->pctlops = &cygnus_pctrl_ops;
+	pctldesc->pins = pins;
+	pctldesc->npins = gc->ngpio;
+	pctldesc->confops = &cygnus_pconf_ops;
+
+	chip->pctl = pinctrl_register(pctldesc, chip->dev, chip);
+	if (!chip->pctl) {
+		dev_err(chip->dev, "unable to register pinctrl device\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void cygnus_gpio_unregister_pinconf(struct cygnus_gpio *chip)
+{
+	if (chip->pctl)
+		pinctrl_unregister(chip->pctl);
+}
+
+struct cygnus_gpio_data {
+	unsigned num_gpios;
+};
+
+static const struct cygnus_gpio_data cygnus_cmm_gpio_data = {
+	.num_gpios = 24,
+};
+
+static const struct cygnus_gpio_data cygnus_asiu_gpio_data = {
+	.num_gpios = 146,
+};
+
+static const struct cygnus_gpio_data cygnus_crmu_gpio_data = {
+	.num_gpios = 6,
+};
+
+static const struct of_device_id cygnus_gpio_of_match[] = {
+	{
+		.compatible = "brcm,cygnus-ccm-gpio",
+		.data = &cygnus_cmm_gpio_data,
+	},
+	{
+		.compatible = "brcm,cygnus-asiu-gpio",
+		.data = &cygnus_asiu_gpio_data,
+	},
+	{
+		.compatible = "brcm,cygnus-crmu-gpio",
+		.data = &cygnus_crmu_gpio_data,
+	}
+};
+
+static int cygnus_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	struct cygnus_gpio *chip;
+	struct gpio_chip *gc;
+	u32 ngpios;
+	int irq, ret;
+	const struct of_device_id *match;
+	const struct cygnus_gpio_data *gpio_data;
+
+	match = of_match_device(cygnus_gpio_of_match, dev);
+	if (!match)
+		return -ENODEV;
+	gpio_data = match->data;
+	ngpios = gpio_data->num_gpios;
+
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->dev = dev;
+	platform_set_drvdata(pdev, chip);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	chip->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(chip->base)) {
+		dev_err(dev, "unable to map I/O memory\n");
+		return PTR_ERR(chip->base);
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (res) {
+		chip->io_ctrl = devm_ioremap_resource(dev, res);
+		if (IS_ERR(chip->io_ctrl)) {
+			dev_err(dev, "unable to map I/O memory\n");
+			return PTR_ERR(chip->io_ctrl);
+		}
+	}
+
+	spin_lock_init(&chip->lock);
+
+	gc = &chip->gc;
+	gc->base = -1;
+	gc->ngpio = ngpios;
+	chip->num_banks = (ngpios + NGPIOS_PER_BANK - 1) / NGPIOS_PER_BANK;
+	gc->label = dev_name(dev);
+	gc->dev = dev;
+	gc->of_node = dev->of_node;
+	gc->request = cygnus_gpio_request;
+	gc->free = cygnus_gpio_free;
+	gc->direction_input = cygnus_gpio_direction_input;
+	gc->direction_output = cygnus_gpio_direction_output;
+	gc->set = cygnus_gpio_set;
+	gc->get = cygnus_gpio_get;
+
+	ret = gpiochip_add(gc);
+	if (ret < 0) {
+		dev_err(dev, "unable to add GPIO chip\n");
+		return ret;
+	}
+
+	ret = cygnus_gpio_pinmux_add_range(chip);
+	if (ret && ret != -ENODEV) {
+		dev_err(dev, "unable to add GPIO pin range\n");
+		goto err_rm_gpiochip;
+	}
+
+	ret = cygnus_gpio_register_pinconf(chip);
+	if (ret) {
+		dev_err(dev, "unable to register pinconf\n");
+		goto err_rm_gpiochip;
+	}
+
+	/* optional GPIO interrupt support */
+	irq = platform_get_irq(pdev, 0);
+	if (irq) {
+		ret = gpiochip_irqchip_add(gc, &cygnus_gpio_irq_chip, 0,
+					   handle_simple_irq, IRQ_TYPE_NONE);
+		if (ret) {
+			dev_err(dev, "no GPIO irqchip\n");
+			goto err_unregister_pinconf;
+		}
+
+		gpiochip_set_chained_irqchip(gc, &cygnus_gpio_irq_chip, irq,
+					     cygnus_gpio_irq_handler);
+	}
+
+	return 0;
+
+err_unregister_pinconf:
+	cygnus_gpio_unregister_pinconf(chip);
+
+err_rm_gpiochip:
+	gpiochip_remove(gc);
+
+	return ret;
+}
+
+static struct platform_driver cygnus_gpio_driver = {
+	.driver = {
+		.name = "cygnus-gpio",
+		.of_match_table = cygnus_gpio_of_match,
+	},
+	.probe = cygnus_gpio_probe,
+};
+
+static int __init cygnus_gpio_init(void)
+{
+	return platform_driver_probe(&cygnus_gpio_driver, cygnus_gpio_probe);
+}
+arch_initcall_sync(cygnus_gpio_init);