drivers/gpio/gpio-rcar.c - kernel/quantenna - Git at Google

 /*
  * Renesas R-Car GPIO Support
  *
  *  Copyright (C) 2014 Renesas Electronics Corporation
  *  Copyright (C) 2013 Magnus Damm
  *
  * 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; either version 2 of the License
  *
  * 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.
  */

 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/gpio.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
 #include <linux/irq.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>

 struct gpio_rcar_priv {
 	void __iomem *base;
 	spinlock_t lock;
 	struct platform_device *pdev;
 	struct gpio_chip gpio_chip;
 	struct irq_chip irq_chip;
 	struct clk *clk;
 	unsigned int irq_parent;
 	bool has_both_edge_trigger;
 	bool needs_clk;
 };

 #define IOINTSEL 0x00	/* General IO/Interrupt Switching Register */
 #define INOUTSEL 0x04	/* General Input/Output Switching Register */
 #define OUTDT 0x08	/* General Output Register */
 #define INDT 0x0c	/* General Input Register */
 #define INTDT 0x10	/* Interrupt Display Register */
 #define INTCLR 0x14	/* Interrupt Clear Register */
 #define INTMSK 0x18	/* Interrupt Mask Register */
 #define MSKCLR 0x1c	/* Interrupt Mask Clear Register */
 #define POSNEG 0x20	/* Positive/Negative Logic Select Register */
 #define EDGLEVEL 0x24	/* Edge/level Select Register */
 #define FILONOFF 0x28	/* Chattering Prevention On/Off Register */
 #define BOTHEDGE 0x4c	/* One Edge/Both Edge Select Register */

 #define RCAR_MAX_GPIO_PER_BANK		32

 static inline u32 gpio_rcar_read(struct gpio_rcar_priv *p, int offs)
 {
 	return ioread32(p->base + offs);
 }

 static inline void gpio_rcar_write(struct gpio_rcar_priv *p, int offs,
 				   u32 value)
 {
 	iowrite32(value, p->base + offs);
 }

 static void gpio_rcar_modify_bit(struct gpio_rcar_priv *p, int offs,
 				 int bit, bool value)
 {
 	u32 tmp = gpio_rcar_read(p, offs);

 	if (value)
 		tmp |= BIT(bit);
 	else
 		tmp &= ~BIT(bit);

 	gpio_rcar_write(p, offs, tmp);
 }

 static void gpio_rcar_irq_disable(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct gpio_rcar_priv *p = gpiochip_get_data(gc);

 	gpio_rcar_write(p, INTMSK, ~BIT(irqd_to_hwirq(d)));
 }

 static void gpio_rcar_irq_enable(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct gpio_rcar_priv *p = gpiochip_get_data(gc);

 	gpio_rcar_write(p, MSKCLR, BIT(irqd_to_hwirq(d)));
 }

 static void gpio_rcar_config_interrupt_input_mode(struct gpio_rcar_priv *p,
 						  unsigned int hwirq,
 						  bool active_high_rising_edge,
 						  bool level_trigger,
 						  bool both)
 {
 	unsigned long flags;

 	/* follow steps in the GPIO documentation for
 	 * "Setting Edge-Sensitive Interrupt Input Mode" and
 	 * "Setting Level-Sensitive Interrupt Input Mode"
 	 */

 	spin_lock_irqsave(&p->lock, flags);

 	/* Configure postive or negative logic in POSNEG */
 	gpio_rcar_modify_bit(p, POSNEG, hwirq, !active_high_rising_edge);

 	/* Configure edge or level trigger in EDGLEVEL */
 	gpio_rcar_modify_bit(p, EDGLEVEL, hwirq, !level_trigger);

 	/* Select one edge or both edges in BOTHEDGE */
 	if (p->has_both_edge_trigger)
 		gpio_rcar_modify_bit(p, BOTHEDGE, hwirq, both);

 	/* Select "Interrupt Input Mode" in IOINTSEL */
 	gpio_rcar_modify_bit(p, IOINTSEL, hwirq, true);

 	/* Write INTCLR in case of edge trigger */
 	if (!level_trigger)
 		gpio_rcar_write(p, INTCLR, BIT(hwirq));

 	spin_unlock_irqrestore(&p->lock, flags);
 }

 static int gpio_rcar_irq_set_type(struct irq_data *d, unsigned int type)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct gpio_rcar_priv *p = gpiochip_get_data(gc);
 	unsigned int hwirq = irqd_to_hwirq(d);

 	dev_dbg(&p->pdev->dev, "sense irq = %d, type = %d\n", hwirq, type);

 	switch (type & IRQ_TYPE_SENSE_MASK) {
 	case IRQ_TYPE_LEVEL_HIGH:
 		gpio_rcar_config_interrupt_input_mode(p, hwirq, true, true,
 						      false);
 		break;
 	case IRQ_TYPE_LEVEL_LOW:
 		gpio_rcar_config_interrupt_input_mode(p, hwirq, false, true,
 						      false);
 		break;
 	case IRQ_TYPE_EDGE_RISING:
 		gpio_rcar_config_interrupt_input_mode(p, hwirq, true, false,
 						      false);
 		break;
 	case IRQ_TYPE_EDGE_FALLING:
 		gpio_rcar_config_interrupt_input_mode(p, hwirq, false, false,
 						      false);
 		break;
 	case IRQ_TYPE_EDGE_BOTH:
 		if (!p->has_both_edge_trigger)
 			return -EINVAL;
 		gpio_rcar_config_interrupt_input_mode(p, hwirq, true, false,
 						      true);
 		break;
 	default:
 		return -EINVAL;
 	}
 	return 0;
 }

 static int gpio_rcar_irq_set_wake(struct irq_data *d, unsigned int on)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct gpio_rcar_priv *p = gpiochip_get_data(gc);
 	int error;

 	if (p->irq_parent) {
 		error = irq_set_irq_wake(p->irq_parent, on);
 		if (error) {
 			dev_dbg(&p->pdev->dev,
 				"irq %u doesn't support irq_set_wake\n",
 				p->irq_parent);
 			p->irq_parent = 0;
 		}
 	}

 	if (!p->clk)
 		return 0;

 	if (on)
 		clk_enable(p->clk);
 	else
 		clk_disable(p->clk);

 	return 0;
 }

 static irqreturn_t gpio_rcar_irq_handler(int irq, void *dev_id)
 {
 	struct gpio_rcar_priv *p = dev_id;
 	u32 pending;
 	unsigned int offset, irqs_handled = 0;

 	while ((pending = gpio_rcar_read(p, INTDT) &
 			  gpio_rcar_read(p, INTMSK))) {
 		offset = __ffs(pending);
 		gpio_rcar_write(p, INTCLR, BIT(offset));
 		generic_handle_irq(irq_find_mapping(p->gpio_chip.irqdomain,
 						    offset));
 		irqs_handled++;
 	}

 	return irqs_handled ? IRQ_HANDLED : IRQ_NONE;
 }

 static void gpio_rcar_config_general_input_output_mode(struct gpio_chip *chip,
 						       unsigned int gpio,
 						       bool output)
 {
 	struct gpio_rcar_priv *p = gpiochip_get_data(chip);
 	unsigned long flags;

 	/* follow steps in the GPIO documentation for
 	 * "Setting General Output Mode" and
 	 * "Setting General Input Mode"
 	 */

 	spin_lock_irqsave(&p->lock, flags);

 	/* Configure postive logic in POSNEG */
 	gpio_rcar_modify_bit(p, POSNEG, gpio, false);

 	/* Select "General Input/Output Mode" in IOINTSEL */
 	gpio_rcar_modify_bit(p, IOINTSEL, gpio, false);

 	/* Select Input Mode or Output Mode in INOUTSEL */
 	gpio_rcar_modify_bit(p, INOUTSEL, gpio, output);

 	spin_unlock_irqrestore(&p->lock, flags);
 }

 static int gpio_rcar_request(struct gpio_chip *chip, unsigned offset)
 {
 	return pinctrl_request_gpio(chip->base + offset);
 }

 static void gpio_rcar_free(struct gpio_chip *chip, unsigned offset)
 {
 	pinctrl_free_gpio(chip->base + offset);

 	/*
 	 * Set the GPIO as an input to ensure that the next GPIO request won't
 	 * drive the GPIO pin as an output.
 	 */
 	gpio_rcar_config_general_input_output_mode(chip, offset, false);
 }

 static int gpio_rcar_direction_input(struct gpio_chip *chip, unsigned offset)
 {
 	gpio_rcar_config_general_input_output_mode(chip, offset, false);
 	return 0;
 }

 static int gpio_rcar_get(struct gpio_chip *chip, unsigned offset)
 {
 	u32 bit = BIT(offset);

 	/* testing on r8a7790 shows that INDT does not show correct pin state
 	 * when configured as output, so use OUTDT in case of output pins */
 	if (gpio_rcar_read(gpiochip_get_data(chip), INOUTSEL) & bit)
 		return !!(gpio_rcar_read(gpiochip_get_data(chip), OUTDT) & bit);
 	else
 		return !!(gpio_rcar_read(gpiochip_get_data(chip), INDT) & bit);
 }

 static void gpio_rcar_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct gpio_rcar_priv *p = gpiochip_get_data(chip);
 	unsigned long flags;

 	spin_lock_irqsave(&p->lock, flags);
 	gpio_rcar_modify_bit(p, OUTDT, offset, value);
 	spin_unlock_irqrestore(&p->lock, flags);
 }

 static int gpio_rcar_direction_output(struct gpio_chip *chip, unsigned offset,
 				      int value)
 {
 	/* write GPIO value to output before selecting output mode of pin */
 	gpio_rcar_set(chip, offset, value);
 	gpio_rcar_config_general_input_output_mode(chip, offset, true);
 	return 0;
 }

 struct gpio_rcar_info {
 	bool has_both_edge_trigger;
 	bool needs_clk;
 };

 static const struct gpio_rcar_info gpio_rcar_info_gen1 = {
 	.has_both_edge_trigger = false,
 	.needs_clk = false,
 };

 static const struct gpio_rcar_info gpio_rcar_info_gen2 = {
 	.has_both_edge_trigger = true,
 	.needs_clk = true,
 };

 static const struct of_device_id gpio_rcar_of_table[] = {
 	{
 		.compatible = "renesas,gpio-r8a7790",
 		.data = &gpio_rcar_info_gen2,
 	}, {
 		.compatible = "renesas,gpio-r8a7791",
 		.data = &gpio_rcar_info_gen2,
 	}, {
 		.compatible = "renesas,gpio-r8a7793",
 		.data = &gpio_rcar_info_gen2,
 	}, {
 		.compatible = "renesas,gpio-r8a7794",
 		.data = &gpio_rcar_info_gen2,
 	}, {
 		.compatible = "renesas,gpio-r8a7795",
 		/* Gen3 GPIO is identical to Gen2. */
 		.data = &gpio_rcar_info_gen2,
 	}, {
 		.compatible = "renesas,gpio-rcar",
 		.data = &gpio_rcar_info_gen1,
 	}, {
 		/* Terminator */
 	},
 };

 MODULE_DEVICE_TABLE(of, gpio_rcar_of_table);

 static int gpio_rcar_parse_dt(struct gpio_rcar_priv *p, unsigned int *npins)
 {
 	struct device_node *np = p->pdev->dev.of_node;
 	const struct of_device_id *match;
 	const struct gpio_rcar_info *info;
 	struct of_phandle_args args;
 	int ret;

 	match = of_match_node(gpio_rcar_of_table, np);
 	if (!match)
 		return -EINVAL;

 	info = match->data;

 	ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 0, &args);
 	*npins = ret == 0 ? args.args[2] : RCAR_MAX_GPIO_PER_BANK;
 	p->has_both_edge_trigger = info->has_both_edge_trigger;
 	p->needs_clk = info->needs_clk;

 	if (*npins == 0 || *npins > RCAR_MAX_GPIO_PER_BANK) {
 		dev_warn(&p->pdev->dev,
 			 "Invalid number of gpio lines %u, using %u\n", *npins,
 			 RCAR_MAX_GPIO_PER_BANK);
 		*npins = RCAR_MAX_GPIO_PER_BANK;
 	}

 	return 0;
 }

 static int gpio_rcar_probe(struct platform_device *pdev)
 {
 	struct gpio_rcar_priv *p;
 	struct resource *io, *irq;
 	struct gpio_chip *gpio_chip;
 	struct irq_chip *irq_chip;
 	struct device *dev = &pdev->dev;
 	const char *name = dev_name(dev);
 	unsigned int npins;
 	int ret;

 	p = devm_kzalloc(dev, sizeof(*p), GFP_KERNEL);
 	if (!p)
 		return -ENOMEM;

 	p->pdev = pdev;
 	spin_lock_init(&p->lock);

 	/* Get device configuration from DT node */
 	ret = gpio_rcar_parse_dt(p, &npins);
 	if (ret < 0)
 		return ret;

 	platform_set_drvdata(pdev, p);

 	p->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(p->clk)) {
 		if (p->needs_clk) {
 			dev_err(dev, "unable to get clock\n");
 			ret = PTR_ERR(p->clk);
 			goto err0;
 		}
 		p->clk = NULL;
 	}

 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);

 	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

 	if (!io || !irq) {
 		dev_err(dev, "missing IRQ or IOMEM\n");
 		ret = -EINVAL;
 		goto err0;
 	}

 	p->base = devm_ioremap_nocache(dev, io->start, resource_size(io));
 	if (!p->base) {
 		dev_err(dev, "failed to remap I/O memory\n");
 		ret = -ENXIO;
 		goto err0;
 	}

 	gpio_chip = &p->gpio_chip;
 	gpio_chip->request = gpio_rcar_request;
 	gpio_chip->free = gpio_rcar_free;
 	gpio_chip->direction_input = gpio_rcar_direction_input;
 	gpio_chip->get = gpio_rcar_get;
 	gpio_chip->direction_output = gpio_rcar_direction_output;
 	gpio_chip->set = gpio_rcar_set;
 	gpio_chip->label = name;
 	gpio_chip->parent = dev;
 	gpio_chip->owner = THIS_MODULE;
 	gpio_chip->base = -1;
 	gpio_chip->ngpio = npins;

 	irq_chip = &p->irq_chip;
 	irq_chip->name = name;
 	irq_chip->irq_mask = gpio_rcar_irq_disable;
 	irq_chip->irq_unmask = gpio_rcar_irq_enable;
 	irq_chip->irq_set_type = gpio_rcar_irq_set_type;
 	irq_chip->irq_set_wake = gpio_rcar_irq_set_wake;
 	irq_chip->flags	= IRQCHIP_SET_TYPE_MASKED | IRQCHIP_MASK_ON_SUSPEND;

 	ret = gpiochip_add_data(gpio_chip, p);
 	if (ret) {
 		dev_err(dev, "failed to add GPIO controller\n");
 		goto err0;
 	}

 	ret = gpiochip_irqchip_add(gpio_chip, irq_chip, 0, handle_level_irq,
 				   IRQ_TYPE_NONE);
 	if (ret) {
 		dev_err(dev, "cannot add irqchip\n");
 		goto err1;
 	}

 	p->irq_parent = irq->start;
 	if (devm_request_irq(dev, irq->start, gpio_rcar_irq_handler,
 			     IRQF_SHARED, name, p)) {
 		dev_err(dev, "failed to request IRQ\n");
 		ret = -ENOENT;
 		goto err1;
 	}

 	dev_info(dev, "driving %d GPIOs\n", npins);

 	return 0;

 err1:
 	gpiochip_remove(gpio_chip);
 err0:
 	pm_runtime_put(dev);
 	pm_runtime_disable(dev);
 	return ret;
 }

 static int gpio_rcar_remove(struct platform_device *pdev)
 {
 	struct gpio_rcar_priv *p = platform_get_drvdata(pdev);

 	gpiochip_remove(&p->gpio_chip);

 	pm_runtime_put(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 	return 0;
 }

 static struct platform_driver gpio_rcar_device_driver = {
 	.probe		= gpio_rcar_probe,
 	.remove		= gpio_rcar_remove,
 	.driver		= {
 		.name	= "gpio_rcar",
 		.of_match_table = of_match_ptr(gpio_rcar_of_table),
 	}
 };

 module_platform_driver(gpio_rcar_device_driver);

 MODULE_AUTHOR("Magnus Damm");
 MODULE_DESCRIPTION("Renesas R-Car GPIO Driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Renesas R-Car GPIO Support
	*
	* Copyright (C) 2014 Renesas Electronics Corporation
	* Copyright (C) 2013 Magnus Damm
	*
	* 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; either version 2 of the License
	*
	* 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.
	*/

	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/gpio.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/ioport.h>
	#include <linux/irq.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/pinctrl/consumer.h>
	#include <linux/platform_device.h>
	#include <linux/pm_runtime.h>
	#include <linux/spinlock.h>
	#include <linux/slab.h>

	struct gpio_rcar_priv {
	void __iomem *base;
	spinlock_t lock;
	struct platform_device *pdev;
	struct gpio_chip gpio_chip;
	struct irq_chip irq_chip;
	struct clk *clk;
	unsigned int irq_parent;
	bool has_both_edge_trigger;
	bool needs_clk;
	};

	#define IOINTSEL 0x00 /* General IO/Interrupt Switching Register */
	#define INOUTSEL 0x04 /* General Input/Output Switching Register */
	#define OUTDT 0x08 /* General Output Register */
	#define INDT 0x0c /* General Input Register */
	#define INTDT 0x10 /* Interrupt Display Register */
	#define INTCLR 0x14 /* Interrupt Clear Register */
	#define INTMSK 0x18 /* Interrupt Mask Register */
	#define MSKCLR 0x1c /* Interrupt Mask Clear Register */
	#define POSNEG 0x20 /* Positive/Negative Logic Select Register */
	#define EDGLEVEL 0x24 /* Edge/level Select Register */
	#define FILONOFF 0x28 /* Chattering Prevention On/Off Register */
	#define BOTHEDGE 0x4c /* One Edge/Both Edge Select Register */

	#define RCAR_MAX_GPIO_PER_BANK 32

	static inline u32 gpio_rcar_read(struct gpio_rcar_priv *p, int offs)
	{
	return ioread32(p->base + offs);
	}

	static inline void gpio_rcar_write(struct gpio_rcar_priv *p, int offs,
	u32 value)
	{
	iowrite32(value, p->base + offs);
	}

	static void gpio_rcar_modify_bit(struct gpio_rcar_priv *p, int offs,
	int bit, bool value)
	{
	u32 tmp = gpio_rcar_read(p, offs);

	if (value)
	tmp \|= BIT(bit);
	else
	tmp &= ~BIT(bit);

	gpio_rcar_write(p, offs, tmp);
	}

	static void gpio_rcar_irq_disable(struct irq_data *d)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct gpio_rcar_priv *p = gpiochip_get_data(gc);

	gpio_rcar_write(p, INTMSK, ~BIT(irqd_to_hwirq(d)));
	}

	static void gpio_rcar_irq_enable(struct irq_data *d)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct gpio_rcar_priv *p = gpiochip_get_data(gc);

	gpio_rcar_write(p, MSKCLR, BIT(irqd_to_hwirq(d)));
	}

	static void gpio_rcar_config_interrupt_input_mode(struct gpio_rcar_priv *p,
	unsigned int hwirq,
	bool active_high_rising_edge,
	bool level_trigger,
	bool both)
	{
	unsigned long flags;

	/* follow steps in the GPIO documentation for
	* "Setting Edge-Sensitive Interrupt Input Mode" and
	* "Setting Level-Sensitive Interrupt Input Mode"
	*/

	spin_lock_irqsave(&p->lock, flags);

	/* Configure postive or negative logic in POSNEG */
	gpio_rcar_modify_bit(p, POSNEG, hwirq, !active_high_rising_edge);

	/* Configure edge or level trigger in EDGLEVEL */
	gpio_rcar_modify_bit(p, EDGLEVEL, hwirq, !level_trigger);

	/* Select one edge or both edges in BOTHEDGE */
	if (p->has_both_edge_trigger)
	gpio_rcar_modify_bit(p, BOTHEDGE, hwirq, both);

	/* Select "Interrupt Input Mode" in IOINTSEL */
	gpio_rcar_modify_bit(p, IOINTSEL, hwirq, true);

	/* Write INTCLR in case of edge trigger */
	if (!level_trigger)
	gpio_rcar_write(p, INTCLR, BIT(hwirq));

	spin_unlock_irqrestore(&p->lock, flags);
	}

	static int gpio_rcar_irq_set_type(struct irq_data *d, unsigned int type)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct gpio_rcar_priv *p = gpiochip_get_data(gc);
	unsigned int hwirq = irqd_to_hwirq(d);

	dev_dbg(&p->pdev->dev, "sense irq = %d, type = %d\n", hwirq, type);

	switch (type & IRQ_TYPE_SENSE_MASK) {
	case IRQ_TYPE_LEVEL_HIGH:
	gpio_rcar_config_interrupt_input_mode(p, hwirq, true, true,
	false);
	break;
	case IRQ_TYPE_LEVEL_LOW:
	gpio_rcar_config_interrupt_input_mode(p, hwirq, false, true,
	false);
	break;
	case IRQ_TYPE_EDGE_RISING:
	gpio_rcar_config_interrupt_input_mode(p, hwirq, true, false,
	false);
	break;
	case IRQ_TYPE_EDGE_FALLING:
	gpio_rcar_config_interrupt_input_mode(p, hwirq, false, false,
	false);
	break;
	case IRQ_TYPE_EDGE_BOTH:
	if (!p->has_both_edge_trigger)
	return -EINVAL;
	gpio_rcar_config_interrupt_input_mode(p, hwirq, true, false,
	true);
	break;
	default:
	return -EINVAL;
	}
	return 0;
	}

	static int gpio_rcar_irq_set_wake(struct irq_data *d, unsigned int on)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct gpio_rcar_priv *p = gpiochip_get_data(gc);
	int error;

	if (p->irq_parent) {
	error = irq_set_irq_wake(p->irq_parent, on);
	if (error) {
	dev_dbg(&p->pdev->dev,
	"irq %u doesn't support irq_set_wake\n",
	p->irq_parent);
	p->irq_parent = 0;
	}
	}

	if (!p->clk)
	return 0;

	if (on)
	clk_enable(p->clk);
	else
	clk_disable(p->clk);

	return 0;
	}

	static irqreturn_t gpio_rcar_irq_handler(int irq, void *dev_id)
	{
	struct gpio_rcar_priv *p = dev_id;
	u32 pending;
	unsigned int offset, irqs_handled = 0;

	while ((pending = gpio_rcar_read(p, INTDT) &
	gpio_rcar_read(p, INTMSK))) {
	offset = __ffs(pending);
	gpio_rcar_write(p, INTCLR, BIT(offset));
	generic_handle_irq(irq_find_mapping(p->gpio_chip.irqdomain,
	offset));
	irqs_handled++;
	}

	return irqs_handled ? IRQ_HANDLED : IRQ_NONE;
	}

	static void gpio_rcar_config_general_input_output_mode(struct gpio_chip *chip,
	unsigned int gpio,
	bool output)
	{
	struct gpio_rcar_priv *p = gpiochip_get_data(chip);
	unsigned long flags;

	/* follow steps in the GPIO documentation for
	* "Setting General Output Mode" and
	* "Setting General Input Mode"
	*/

	spin_lock_irqsave(&p->lock, flags);

	/* Configure postive logic in POSNEG */
	gpio_rcar_modify_bit(p, POSNEG, gpio, false);

	/* Select "General Input/Output Mode" in IOINTSEL */
	gpio_rcar_modify_bit(p, IOINTSEL, gpio, false);

	/* Select Input Mode or Output Mode in INOUTSEL */
	gpio_rcar_modify_bit(p, INOUTSEL, gpio, output);

	spin_unlock_irqrestore(&p->lock, flags);
	}

	static int gpio_rcar_request(struct gpio_chip *chip, unsigned offset)
	{
	return pinctrl_request_gpio(chip->base + offset);
	}

	static void gpio_rcar_free(struct gpio_chip *chip, unsigned offset)
	{
	pinctrl_free_gpio(chip->base + offset);

	/*
	* Set the GPIO as an input to ensure that the next GPIO request won't
	* drive the GPIO pin as an output.
	*/
	gpio_rcar_config_general_input_output_mode(chip, offset, false);
	}

	static int gpio_rcar_direction_input(struct gpio_chip *chip, unsigned offset)
	{
	gpio_rcar_config_general_input_output_mode(chip, offset, false);
	return 0;
	}

	static int gpio_rcar_get(struct gpio_chip *chip, unsigned offset)
	{
	u32 bit = BIT(offset);

	/* testing on r8a7790 shows that INDT does not show correct pin state
	* when configured as output, so use OUTDT in case of output pins */
	if (gpio_rcar_read(gpiochip_get_data(chip), INOUTSEL) & bit)
	return !!(gpio_rcar_read(gpiochip_get_data(chip), OUTDT) & bit);
	else
	return !!(gpio_rcar_read(gpiochip_get_data(chip), INDT) & bit);
	}

	static void gpio_rcar_set(struct gpio_chip *chip, unsigned offset, int value)
	{
	struct gpio_rcar_priv *p = gpiochip_get_data(chip);
	unsigned long flags;

	spin_lock_irqsave(&p->lock, flags);
	gpio_rcar_modify_bit(p, OUTDT, offset, value);
	spin_unlock_irqrestore(&p->lock, flags);
	}

	static int gpio_rcar_direction_output(struct gpio_chip *chip, unsigned offset,
	int value)
	{
	/* write GPIO value to output before selecting output mode of pin */
	gpio_rcar_set(chip, offset, value);
	gpio_rcar_config_general_input_output_mode(chip, offset, true);
	return 0;
	}

	struct gpio_rcar_info {
	bool has_both_edge_trigger;
	bool needs_clk;
	};

	static const struct gpio_rcar_info gpio_rcar_info_gen1 = {
	.has_both_edge_trigger = false,
	.needs_clk = false,
	};

	static const struct gpio_rcar_info gpio_rcar_info_gen2 = {
	.has_both_edge_trigger = true,
	.needs_clk = true,
	};

	static const struct of_device_id gpio_rcar_of_table[] = {
	{
	.compatible = "renesas,gpio-r8a7790",
	.data = &gpio_rcar_info_gen2,
	}, {
	.compatible = "renesas,gpio-r8a7791",
	.data = &gpio_rcar_info_gen2,
	}, {
	.compatible = "renesas,gpio-r8a7793",
	.data = &gpio_rcar_info_gen2,
	}, {
	.compatible = "renesas,gpio-r8a7794",
	.data = &gpio_rcar_info_gen2,
	}, {
	.compatible = "renesas,gpio-r8a7795",
	/* Gen3 GPIO is identical to Gen2. */
	.data = &gpio_rcar_info_gen2,
	}, {
	.compatible = "renesas,gpio-rcar",
	.data = &gpio_rcar_info_gen1,
	}, {
	/* Terminator */
	},
	};

	MODULE_DEVICE_TABLE(of, gpio_rcar_of_table);

	static int gpio_rcar_parse_dt(struct gpio_rcar_priv p, unsigned int npins)
	{
	struct device_node *np = p->pdev->dev.of_node;
	const struct of_device_id *match;
	const struct gpio_rcar_info *info;
	struct of_phandle_args args;
	int ret;

	match = of_match_node(gpio_rcar_of_table, np);
	if (!match)
	return -EINVAL;

	info = match->data;

	ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 0, &args);
	*npins = ret == 0 ? args.args[2] : RCAR_MAX_GPIO_PER_BANK;
	p->has_both_edge_trigger = info->has_both_edge_trigger;
	p->needs_clk = info->needs_clk;

	if (npins == 0 \|\| npins > RCAR_MAX_GPIO_PER_BANK) {
	dev_warn(&p->pdev->dev,
	"Invalid number of gpio lines %u, using %u\n", *npins,
	RCAR_MAX_GPIO_PER_BANK);
	*npins = RCAR_MAX_GPIO_PER_BANK;
	}

	return 0;
	}

	static int gpio_rcar_probe(struct platform_device *pdev)
	{
	struct gpio_rcar_priv *p;
	struct resource io, irq;
	struct gpio_chip *gpio_chip;
	struct irq_chip *irq_chip;
	struct device *dev = &pdev->dev;
	const char *name = dev_name(dev);
	unsigned int npins;
	int ret;

	p = devm_kzalloc(dev, sizeof(*p), GFP_KERNEL);
	if (!p)
	return -ENOMEM;

	p->pdev = pdev;
	spin_lock_init(&p->lock);

	/* Get device configuration from DT node */
	ret = gpio_rcar_parse_dt(p, &npins);
	if (ret < 0)
	return ret;

	platform_set_drvdata(pdev, p);

	p->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(p->clk)) {
	if (p->needs_clk) {
	dev_err(dev, "unable to get clock\n");
	ret = PTR_ERR(p->clk);
	goto err0;
	}
	p->clk = NULL;
	}

	pm_runtime_enable(dev);
	pm_runtime_get_sync(dev);

	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

	if (!io \|\| !irq) {
	dev_err(dev, "missing IRQ or IOMEM\n");
	ret = -EINVAL;
	goto err0;
	}

	p->base = devm_ioremap_nocache(dev, io->start, resource_size(io));
	if (!p->base) {
	dev_err(dev, "failed to remap I/O memory\n");
	ret = -ENXIO;
	goto err0;
	}

	gpio_chip = &p->gpio_chip;
	gpio_chip->request = gpio_rcar_request;
	gpio_chip->free = gpio_rcar_free;
	gpio_chip->direction_input = gpio_rcar_direction_input;
	gpio_chip->get = gpio_rcar_get;
	gpio_chip->direction_output = gpio_rcar_direction_output;
	gpio_chip->set = gpio_rcar_set;
	gpio_chip->label = name;
	gpio_chip->parent = dev;
	gpio_chip->owner = THIS_MODULE;
	gpio_chip->base = -1;
	gpio_chip->ngpio = npins;

	irq_chip = &p->irq_chip;
	irq_chip->name = name;
	irq_chip->irq_mask = gpio_rcar_irq_disable;
	irq_chip->irq_unmask = gpio_rcar_irq_enable;
	irq_chip->irq_set_type = gpio_rcar_irq_set_type;
	irq_chip->irq_set_wake = gpio_rcar_irq_set_wake;
	irq_chip->flags = IRQCHIP_SET_TYPE_MASKED \| IRQCHIP_MASK_ON_SUSPEND;

	ret = gpiochip_add_data(gpio_chip, p);
	if (ret) {
	dev_err(dev, "failed to add GPIO controller\n");
	goto err0;
	}

	ret = gpiochip_irqchip_add(gpio_chip, irq_chip, 0, handle_level_irq,
	IRQ_TYPE_NONE);
	if (ret) {
	dev_err(dev, "cannot add irqchip\n");
	goto err1;
	}

	p->irq_parent = irq->start;
	if (devm_request_irq(dev, irq->start, gpio_rcar_irq_handler,
	IRQF_SHARED, name, p)) {
	dev_err(dev, "failed to request IRQ\n");
	ret = -ENOENT;
	goto err1;
	}

	dev_info(dev, "driving %d GPIOs\n", npins);

	return 0;

	err1:
	gpiochip_remove(gpio_chip);
	err0:
	pm_runtime_put(dev);
	pm_runtime_disable(dev);
	return ret;
	}

	static int gpio_rcar_remove(struct platform_device *pdev)
	{
	struct gpio_rcar_priv *p = platform_get_drvdata(pdev);

	gpiochip_remove(&p->gpio_chip);

	pm_runtime_put(&pdev->dev);
	pm_runtime_disable(&pdev->dev);
	return 0;
	}

	static struct platform_driver gpio_rcar_device_driver = {
	.probe = gpio_rcar_probe,
	.remove = gpio_rcar_remove,
	.driver = {
	.name = "gpio_rcar",
	.of_match_table = of_match_ptr(gpio_rcar_of_table),
	}
	};

	module_platform_driver(gpio_rcar_device_driver);

	MODULE_AUTHOR("Magnus Damm");
	MODULE_DESCRIPTION("Renesas R-Car GPIO Driver");
	MODULE_LICENSE("GPL v2");