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

 /*
  * Copyright (C) ST-Ericsson SA 2010
  *
  * License Terms: GNU General Public License, version 2
  * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/gpio.h>
 #include <linux/interrupt.h>
 #include <linux/of.h>
 #include <linux/mfd/stmpe.h>
 #include <linux/seq_file.h>

 /*
  * These registers are modified under the irq bus lock and cached to avoid
  * unnecessary writes in bus_sync_unlock.
  */
 enum { REG_RE, REG_FE, REG_IE };

 #define CACHE_NR_REGS	3
 /* No variant has more than 24 GPIOs */
 #define CACHE_NR_BANKS	(24 / 8)

 struct stmpe_gpio {
 	struct gpio_chip chip;
 	struct stmpe *stmpe;
 	struct device *dev;
 	struct mutex irq_lock;
 	u32 norequest_mask;
 	/* Caches of interrupt control registers for bus_lock */
 	u8 regs[CACHE_NR_REGS][CACHE_NR_BANKS];
 	u8 oldregs[CACHE_NR_REGS][CACHE_NR_BANKS];
 };

 static int stmpe_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
 	u8 reg = stmpe->regs[STMPE_IDX_GPMR_LSB] - (offset / 8);
 	u8 mask = 1 << (offset % 8);
 	int ret;

 	ret = stmpe_reg_read(stmpe, reg);
 	if (ret < 0)
 		return ret;

 	return !!(ret & mask);
 }

 static void stmpe_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
 {
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
 	int which = val ? STMPE_IDX_GPSR_LSB : STMPE_IDX_GPCR_LSB;
 	u8 reg = stmpe->regs[which] - (offset / 8);
 	u8 mask = 1 << (offset % 8);

 	/*
 	 * Some variants have single register for gpio set/clear functionality.
 	 * For them we need to write 0 to clear and 1 to set.
 	 */
 	if (stmpe->regs[STMPE_IDX_GPSR_LSB] == stmpe->regs[STMPE_IDX_GPCR_LSB])
 		stmpe_set_bits(stmpe, reg, mask, val ? mask : 0);
 	else
 		stmpe_reg_write(stmpe, reg, mask);
 }

 static int stmpe_gpio_direction_output(struct gpio_chip *chip,
 					 unsigned offset, int val)
 {
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
 	u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
 	u8 mask = 1 << (offset % 8);

 	stmpe_gpio_set(chip, offset, val);

 	return stmpe_set_bits(stmpe, reg, mask, mask);
 }

 static int stmpe_gpio_direction_input(struct gpio_chip *chip,
 					unsigned offset)
 {
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
 	u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
 	u8 mask = 1 << (offset % 8);

 	return stmpe_set_bits(stmpe, reg, mask, 0);
 }

 static int stmpe_gpio_request(struct gpio_chip *chip, unsigned offset)
 {
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;

 	if (stmpe_gpio->norequest_mask & (1 << offset))
 		return -EINVAL;

 	return stmpe_set_altfunc(stmpe, 1 << offset, STMPE_BLOCK_GPIO);
 }

 static struct gpio_chip template_chip = {
 	.label			= "stmpe",
 	.owner			= THIS_MODULE,
 	.direction_input	= stmpe_gpio_direction_input,
 	.get			= stmpe_gpio_get,
 	.direction_output	= stmpe_gpio_direction_output,
 	.set			= stmpe_gpio_set,
 	.request		= stmpe_gpio_request,
 	.can_sleep		= true,
 };

 static int stmpe_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
 	int offset = d->hwirq;
 	int regoffset = offset / 8;
 	int mask = 1 << (offset % 8);

 	if (type & IRQ_TYPE_LEVEL_LOW || type & IRQ_TYPE_LEVEL_HIGH)
 		return -EINVAL;

 	/* STMPE801 doesn't have RE and FE registers */
 	if (stmpe_gpio->stmpe->partnum == STMPE801)
 		return 0;

 	if (type & IRQ_TYPE_EDGE_RISING)
 		stmpe_gpio->regs[REG_RE][regoffset] |= mask;
 	else
 		stmpe_gpio->regs[REG_RE][regoffset] &= ~mask;

 	if (type & IRQ_TYPE_EDGE_FALLING)
 		stmpe_gpio->regs[REG_FE][regoffset] |= mask;
 	else
 		stmpe_gpio->regs[REG_FE][regoffset] &= ~mask;

 	return 0;
 }

 static void stmpe_gpio_irq_lock(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);

 	mutex_lock(&stmpe_gpio->irq_lock);
 }

 static void stmpe_gpio_irq_sync_unlock(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
 	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
 	static const u8 regmap[] = {
 		[REG_RE]	= STMPE_IDX_GPRER_LSB,
 		[REG_FE]	= STMPE_IDX_GPFER_LSB,
 		[REG_IE]	= STMPE_IDX_IEGPIOR_LSB,
 	};
 	int i, j;

 	for (i = 0; i < CACHE_NR_REGS; i++) {
 		/* STMPE801 doesn't have RE and FE registers */
 		if ((stmpe->partnum == STMPE801) &&
 				(i != REG_IE))
 			continue;

 		for (j = 0; j < num_banks; j++) {
 			u8 old = stmpe_gpio->oldregs[i][j];
 			u8 new = stmpe_gpio->regs[i][j];

 			if (new == old)
 				continue;

 			stmpe_gpio->oldregs[i][j] = new;
 			stmpe_reg_write(stmpe, stmpe->regs[regmap[i]] - j, new);
 		}
 	}

 	mutex_unlock(&stmpe_gpio->irq_lock);
 }

 static void stmpe_gpio_irq_mask(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
 	int offset = d->hwirq;
 	int regoffset = offset / 8;
 	int mask = 1 << (offset % 8);

 	stmpe_gpio->regs[REG_IE][regoffset] &= ~mask;
 }

 static void stmpe_gpio_irq_unmask(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
 	int offset = d->hwirq;
 	int regoffset = offset / 8;
 	int mask = 1 << (offset % 8);

 	stmpe_gpio->regs[REG_IE][regoffset] |= mask;
 }

 static void stmpe_dbg_show_one(struct seq_file *s,
 			       struct gpio_chip *gc,
 			       unsigned offset, unsigned gpio)
 {
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
 	const char *label = gpiochip_is_requested(gc, offset);
 	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
 	bool val = !!stmpe_gpio_get(gc, offset);
 	u8 dir_reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
 	u8 mask = 1 << (offset % 8);
 	int ret;
 	u8 dir;

 	ret = stmpe_reg_read(stmpe, dir_reg);
 	if (ret < 0)
 		return;
 	dir = !!(ret & mask);

 	if (dir) {
 		seq_printf(s, " gpio-%-3d (%-20.20s) out %s",
 			   gpio, label ?: "(none)",
 			   val ? "hi" : "lo");
 	} else {
 		u8 edge_det_reg = stmpe->regs[STMPE_IDX_GPEDR_MSB] + num_banks - 1 - (offset / 8);
 		u8 rise_reg = stmpe->regs[STMPE_IDX_GPRER_LSB] - (offset / 8);
 		u8 fall_reg = stmpe->regs[STMPE_IDX_GPFER_LSB] - (offset / 8);
 		u8 irqen_reg = stmpe->regs[STMPE_IDX_IEGPIOR_LSB] - (offset / 8);
 		bool edge_det;
 		bool rise;
 		bool fall;
 		bool irqen;

 		ret = stmpe_reg_read(stmpe, edge_det_reg);
 		if (ret < 0)
 			return;
 		edge_det = !!(ret & mask);
 		ret = stmpe_reg_read(stmpe, rise_reg);
 		if (ret < 0)
 			return;
 		rise = !!(ret & mask);
 		ret = stmpe_reg_read(stmpe, fall_reg);
 		if (ret < 0)
 			return;
 		fall = !!(ret & mask);
 		ret = stmpe_reg_read(stmpe, irqen_reg);
 		if (ret < 0)
 			return;
 		irqen = !!(ret & mask);

 		seq_printf(s, " gpio-%-3d (%-20.20s) in  %s %s %s%s%s",
 			   gpio, label ?: "(none)",
 			   val ? "hi" : "lo",
 			   edge_det ? "edge-asserted" : "edge-inactive",
 			   irqen ? "IRQ-enabled" : "",
 			   rise ? " rising-edge-detection" : "",
 			   fall ? " falling-edge-detection" : "");
 	}
 }

 static void stmpe_dbg_show(struct seq_file *s, struct gpio_chip *gc)
 {
 	unsigned i;
 	unsigned gpio = gc->base;

 	for (i = 0; i < gc->ngpio; i++, gpio++) {
 		stmpe_dbg_show_one(s, gc, i, gpio);
 		seq_printf(s, "\n");
 	}
 }

 static struct irq_chip stmpe_gpio_irq_chip = {
 	.name			= "stmpe-gpio",
 	.irq_bus_lock		= stmpe_gpio_irq_lock,
 	.irq_bus_sync_unlock	= stmpe_gpio_irq_sync_unlock,
 	.irq_mask		= stmpe_gpio_irq_mask,
 	.irq_unmask		= stmpe_gpio_irq_unmask,
 	.irq_set_type		= stmpe_gpio_irq_set_type,
 };

 static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
 {
 	struct stmpe_gpio *stmpe_gpio = dev;
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
 	u8 statmsbreg = stmpe->regs[STMPE_IDX_ISGPIOR_MSB];
 	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
 	u8 status[num_banks];
 	int ret;
 	int i;

 	ret = stmpe_block_read(stmpe, statmsbreg, num_banks, status);
 	if (ret < 0)
 		return IRQ_NONE;

 	for (i = 0; i < num_banks; i++) {
 		int bank = num_banks - i - 1;
 		unsigned int enabled = stmpe_gpio->regs[REG_IE][bank];
 		unsigned int stat = status[i];

 		stat &= enabled;
 		if (!stat)
 			continue;

 		while (stat) {
 			int bit = __ffs(stat);
 			int line = bank * 8 + bit;
 			int child_irq = irq_find_mapping(stmpe_gpio->chip.irqdomain,
 							 line);

 			handle_nested_irq(child_irq);
 			stat &= ~(1 << bit);
 		}

 		stmpe_reg_write(stmpe, statmsbreg + i, status[i]);

 		/* Edge detect register is not present on 801 */
 		if (stmpe->partnum != STMPE801)
 			stmpe_reg_write(stmpe, stmpe->regs[STMPE_IDX_GPEDR_MSB]
 					+ i, status[i]);
 	}

 	return IRQ_HANDLED;
 }

 static int stmpe_gpio_probe(struct platform_device *pdev)
 {
 	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
 	struct device_node *np = pdev->dev.of_node;
 	struct stmpe_gpio *stmpe_gpio;
 	int ret;
 	int irq = 0;

 	irq = platform_get_irq(pdev, 0);

 	stmpe_gpio = kzalloc(sizeof(struct stmpe_gpio), GFP_KERNEL);
 	if (!stmpe_gpio)
 		return -ENOMEM;

 	mutex_init(&stmpe_gpio->irq_lock);

 	stmpe_gpio->dev = &pdev->dev;
 	stmpe_gpio->stmpe = stmpe;
 	stmpe_gpio->chip = template_chip;
 	stmpe_gpio->chip.ngpio = stmpe->num_gpios;
 	stmpe_gpio->chip.parent = &pdev->dev;
 	stmpe_gpio->chip.of_node = np;
 	stmpe_gpio->chip.base = -1;

 	if (IS_ENABLED(CONFIG_DEBUG_FS))
                 stmpe_gpio->chip.dbg_show = stmpe_dbg_show;

 	of_property_read_u32(np, "st,norequest-mask",
 			&stmpe_gpio->norequest_mask);

 	if (irq < 0)
 		dev_info(&pdev->dev,
 			"device configured in no-irq mode: "
 			"irqs are not available\n");

 	ret = stmpe_enable(stmpe, STMPE_BLOCK_GPIO);
 	if (ret)
 		goto out_free;

 	ret = gpiochip_add_data(&stmpe_gpio->chip, stmpe_gpio);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
 		goto out_disable;
 	}

 	if (irq > 0) {
 		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
 				stmpe_gpio_irq, IRQF_ONESHOT,
 				"stmpe-gpio", stmpe_gpio);
 		if (ret) {
 			dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
 			goto out_disable;
 		}
 		ret =  gpiochip_irqchip_add(&stmpe_gpio->chip,
 					    &stmpe_gpio_irq_chip,
 					    0,
 					    handle_simple_irq,
 					    IRQ_TYPE_NONE);
 		if (ret) {
 			dev_err(&pdev->dev,
 				"could not connect irqchip to gpiochip\n");
 			goto out_disable;
 		}

 		gpiochip_set_chained_irqchip(&stmpe_gpio->chip,
 					     &stmpe_gpio_irq_chip,
 					     irq,
 					     NULL);
 	}

 	platform_set_drvdata(pdev, stmpe_gpio);

 	return 0;

 out_disable:
 	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
 	gpiochip_remove(&stmpe_gpio->chip);
 out_free:
 	kfree(stmpe_gpio);
 	return ret;
 }

 static int stmpe_gpio_remove(struct platform_device *pdev)
 {
 	struct stmpe_gpio *stmpe_gpio = platform_get_drvdata(pdev);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;

 	gpiochip_remove(&stmpe_gpio->chip);
 	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
 	kfree(stmpe_gpio);

 	return 0;
 }

 static struct platform_driver stmpe_gpio_driver = {
 	.driver.name	= "stmpe-gpio",
 	.driver.owner	= THIS_MODULE,
 	.probe		= stmpe_gpio_probe,
 	.remove		= stmpe_gpio_remove,
 };

 static int __init stmpe_gpio_init(void)
 {
 	return platform_driver_register(&stmpe_gpio_driver);
 }
 subsys_initcall(stmpe_gpio_init);

 static void __exit stmpe_gpio_exit(void)
 {
 	platform_driver_unregister(&stmpe_gpio_driver);
 }
 module_exit(stmpe_gpio_exit);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("STMPExxxx GPIO driver");
 MODULE_AUTHOR("Rabin Vincent <rabin.vincent@stericsson.com>");
	/*
	* Copyright (C) ST-Ericsson SA 2010
	*
	* License Terms: GNU General Public License, version 2
	* Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/gpio.h>
	#include <linux/interrupt.h>
	#include <linux/of.h>
	#include <linux/mfd/stmpe.h>
	#include <linux/seq_file.h>

	/*
	* These registers are modified under the irq bus lock and cached to avoid
	* unnecessary writes in bus_sync_unlock.
	*/
	enum { REG_RE, REG_FE, REG_IE };

	#define CACHE_NR_REGS 3
	/* No variant has more than 24 GPIOs */
	#define CACHE_NR_BANKS (24 / 8)

	struct stmpe_gpio {
	struct gpio_chip chip;
	struct stmpe *stmpe;
	struct device *dev;
	struct mutex irq_lock;
	u32 norequest_mask;
	/* Caches of interrupt control registers for bus_lock */
	u8 regs[CACHE_NR_REGS][CACHE_NR_BANKS];
	u8 oldregs[CACHE_NR_REGS][CACHE_NR_BANKS];
	};

	static int stmpe_gpio_get(struct gpio_chip *chip, unsigned offset)
	{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	u8 reg = stmpe->regs[STMPE_IDX_GPMR_LSB] - (offset / 8);
	u8 mask = 1 << (offset % 8);
	int ret;

	ret = stmpe_reg_read(stmpe, reg);
	if (ret < 0)
	return ret;

	return !!(ret & mask);
	}

	static void stmpe_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
	{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	int which = val ? STMPE_IDX_GPSR_LSB : STMPE_IDX_GPCR_LSB;
	u8 reg = stmpe->regs[which] - (offset / 8);
	u8 mask = 1 << (offset % 8);

	/*
	* Some variants have single register for gpio set/clear functionality.
	* For them we need to write 0 to clear and 1 to set.
	*/
	if (stmpe->regs[STMPE_IDX_GPSR_LSB] == stmpe->regs[STMPE_IDX_GPCR_LSB])
	stmpe_set_bits(stmpe, reg, mask, val ? mask : 0);
	else
	stmpe_reg_write(stmpe, reg, mask);
	}

	static int stmpe_gpio_direction_output(struct gpio_chip *chip,
	unsigned offset, int val)
	{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
	u8 mask = 1 << (offset % 8);

	stmpe_gpio_set(chip, offset, val);

	return stmpe_set_bits(stmpe, reg, mask, mask);
	}

	static int stmpe_gpio_direction_input(struct gpio_chip *chip,
	unsigned offset)
	{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
	u8 mask = 1 << (offset % 8);

	return stmpe_set_bits(stmpe, reg, mask, 0);
	}

	static int stmpe_gpio_request(struct gpio_chip *chip, unsigned offset)
	{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
	struct stmpe *stmpe = stmpe_gpio->stmpe;

	if (stmpe_gpio->norequest_mask & (1 << offset))
	return -EINVAL;

	return stmpe_set_altfunc(stmpe, 1 << offset, STMPE_BLOCK_GPIO);
	}

	static struct gpio_chip template_chip = {
	.label = "stmpe",
	.owner = THIS_MODULE,
	.direction_input = stmpe_gpio_direction_input,
	.get = stmpe_gpio_get,
	.direction_output = stmpe_gpio_direction_output,
	.set = stmpe_gpio_set,
	.request = stmpe_gpio_request,
	.can_sleep = true,
	};

	static int stmpe_gpio_irq_set_type(struct irq_data *d, unsigned int type)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	int offset = d->hwirq;
	int regoffset = offset / 8;
	int mask = 1 << (offset % 8);

	if (type & IRQ_TYPE_LEVEL_LOW \|\| type & IRQ_TYPE_LEVEL_HIGH)
	return -EINVAL;

	/* STMPE801 doesn't have RE and FE registers */
	if (stmpe_gpio->stmpe->partnum == STMPE801)
	return 0;

	if (type & IRQ_TYPE_EDGE_RISING)
	stmpe_gpio->regs[REG_RE][regoffset] \|= mask;
	else
	stmpe_gpio->regs[REG_RE][regoffset] &= ~mask;

	if (type & IRQ_TYPE_EDGE_FALLING)
	stmpe_gpio->regs[REG_FE][regoffset] \|= mask;
	else
	stmpe_gpio->regs[REG_FE][regoffset] &= ~mask;

	return 0;
	}

	static void stmpe_gpio_irq_lock(struct irq_data *d)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);

	mutex_lock(&stmpe_gpio->irq_lock);
	}

	static void stmpe_gpio_irq_sync_unlock(struct irq_data *d)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
	static const u8 regmap[] = {
	[REG_RE] = STMPE_IDX_GPRER_LSB,
	[REG_FE] = STMPE_IDX_GPFER_LSB,
	[REG_IE] = STMPE_IDX_IEGPIOR_LSB,
	};
	int i, j;

	for (i = 0; i < CACHE_NR_REGS; i++) {
	/* STMPE801 doesn't have RE and FE registers */
	if ((stmpe->partnum == STMPE801) &&
	(i != REG_IE))
	continue;

	for (j = 0; j < num_banks; j++) {
	u8 old = stmpe_gpio->oldregs[i][j];
	u8 new = stmpe_gpio->regs[i][j];

	if (new == old)
	continue;

	stmpe_gpio->oldregs[i][j] = new;
	stmpe_reg_write(stmpe, stmpe->regs[regmap[i]] - j, new);
	}
	}

	mutex_unlock(&stmpe_gpio->irq_lock);
	}

	static void stmpe_gpio_irq_mask(struct irq_data *d)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	int offset = d->hwirq;
	int regoffset = offset / 8;
	int mask = 1 << (offset % 8);

	stmpe_gpio->regs[REG_IE][regoffset] &= ~mask;
	}

	static void stmpe_gpio_irq_unmask(struct irq_data *d)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	int offset = d->hwirq;
	int regoffset = offset / 8;
	int mask = 1 << (offset % 8);

	stmpe_gpio->regs[REG_IE][regoffset] \|= mask;
	}

	static void stmpe_dbg_show_one(struct seq_file *s,
	struct gpio_chip *gc,
	unsigned offset, unsigned gpio)
	{
	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	const char *label = gpiochip_is_requested(gc, offset);
	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
	bool val = !!stmpe_gpio_get(gc, offset);
	u8 dir_reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
	u8 mask = 1 << (offset % 8);
	int ret;
	u8 dir;

	ret = stmpe_reg_read(stmpe, dir_reg);
	if (ret < 0)
	return;
	dir = !!(ret & mask);

	if (dir) {
	seq_printf(s, " gpio-%-3d (%-20.20s) out %s",
	gpio, label ?: "(none)",
	val ? "hi" : "lo");
	} else {
	u8 edge_det_reg = stmpe->regs[STMPE_IDX_GPEDR_MSB] + num_banks - 1 - (offset / 8);
	u8 rise_reg = stmpe->regs[STMPE_IDX_GPRER_LSB] - (offset / 8);
	u8 fall_reg = stmpe->regs[STMPE_IDX_GPFER_LSB] - (offset / 8);
	u8 irqen_reg = stmpe->regs[STMPE_IDX_IEGPIOR_LSB] - (offset / 8);
	bool edge_det;
	bool rise;
	bool fall;
	bool irqen;

	ret = stmpe_reg_read(stmpe, edge_det_reg);
	if (ret < 0)
	return;
	edge_det = !!(ret & mask);
	ret = stmpe_reg_read(stmpe, rise_reg);
	if (ret < 0)
	return;
	rise = !!(ret & mask);
	ret = stmpe_reg_read(stmpe, fall_reg);
	if (ret < 0)
	return;
	fall = !!(ret & mask);
	ret = stmpe_reg_read(stmpe, irqen_reg);
	if (ret < 0)
	return;
	irqen = !!(ret & mask);

	seq_printf(s, " gpio-%-3d (%-20.20s) in %s %s %s%s%s",
	gpio, label ?: "(none)",
	val ? "hi" : "lo",
	edge_det ? "edge-asserted" : "edge-inactive",
	irqen ? "IRQ-enabled" : "",
	rise ? " rising-edge-detection" : "",
	fall ? " falling-edge-detection" : "");
	}
	}

	static void stmpe_dbg_show(struct seq_file s, struct gpio_chip gc)
	{
	unsigned i;
	unsigned gpio = gc->base;

	for (i = 0; i < gc->ngpio; i++, gpio++) {
	stmpe_dbg_show_one(s, gc, i, gpio);
	seq_printf(s, "\n");
	}
	}

	static struct irq_chip stmpe_gpio_irq_chip = {
	.name = "stmpe-gpio",
	.irq_bus_lock = stmpe_gpio_irq_lock,
	.irq_bus_sync_unlock = stmpe_gpio_irq_sync_unlock,
	.irq_mask = stmpe_gpio_irq_mask,
	.irq_unmask = stmpe_gpio_irq_unmask,
	.irq_set_type = stmpe_gpio_irq_set_type,
	};

	static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
	{
	struct stmpe_gpio *stmpe_gpio = dev;
	struct stmpe *stmpe = stmpe_gpio->stmpe;
	u8 statmsbreg = stmpe->regs[STMPE_IDX_ISGPIOR_MSB];
	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
	u8 status[num_banks];
	int ret;
	int i;

	ret = stmpe_block_read(stmpe, statmsbreg, num_banks, status);
	if (ret < 0)
	return IRQ_NONE;

	for (i = 0; i < num_banks; i++) {
	int bank = num_banks - i - 1;
	unsigned int enabled = stmpe_gpio->regs[REG_IE][bank];
	unsigned int stat = status[i];

	stat &= enabled;
	if (!stat)
	continue;

	while (stat) {
	int bit = __ffs(stat);
	int line = bank * 8 + bit;
	int child_irq = irq_find_mapping(stmpe_gpio->chip.irqdomain,
	line);

	handle_nested_irq(child_irq);
	stat &= ~(1 << bit);
	}

	stmpe_reg_write(stmpe, statmsbreg + i, status[i]);

	/* Edge detect register is not present on 801 */
	if (stmpe->partnum != STMPE801)
	stmpe_reg_write(stmpe, stmpe->regs[STMPE_IDX_GPEDR_MSB]
	+ i, status[i]);
	}

	return IRQ_HANDLED;
	}

	static int stmpe_gpio_probe(struct platform_device *pdev)
	{
	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
	struct device_node *np = pdev->dev.of_node;
	struct stmpe_gpio *stmpe_gpio;
	int ret;
	int irq = 0;

	irq = platform_get_irq(pdev, 0);

	stmpe_gpio = kzalloc(sizeof(struct stmpe_gpio), GFP_KERNEL);
	if (!stmpe_gpio)
	return -ENOMEM;

	mutex_init(&stmpe_gpio->irq_lock);

	stmpe_gpio->dev = &pdev->dev;
	stmpe_gpio->stmpe = stmpe;
	stmpe_gpio->chip = template_chip;
	stmpe_gpio->chip.ngpio = stmpe->num_gpios;
	stmpe_gpio->chip.parent = &pdev->dev;
	stmpe_gpio->chip.of_node = np;
	stmpe_gpio->chip.base = -1;

	if (IS_ENABLED(CONFIG_DEBUG_FS))
	stmpe_gpio->chip.dbg_show = stmpe_dbg_show;

	of_property_read_u32(np, "st,norequest-mask",
	&stmpe_gpio->norequest_mask);

	if (irq < 0)
	dev_info(&pdev->dev,
	"device configured in no-irq mode: "
	"irqs are not available\n");

	ret = stmpe_enable(stmpe, STMPE_BLOCK_GPIO);
	if (ret)
	goto out_free;

	ret = gpiochip_add_data(&stmpe_gpio->chip, stmpe_gpio);
	if (ret) {
	dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
	goto out_disable;
	}

	if (irq > 0) {
	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
	stmpe_gpio_irq, IRQF_ONESHOT,
	"stmpe-gpio", stmpe_gpio);
	if (ret) {
	dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
	goto out_disable;
	}
	ret = gpiochip_irqchip_add(&stmpe_gpio->chip,
	&stmpe_gpio_irq_chip,
	0,
	handle_simple_irq,
	IRQ_TYPE_NONE);
	if (ret) {
	dev_err(&pdev->dev,
	"could not connect irqchip to gpiochip\n");
	goto out_disable;
	}

	gpiochip_set_chained_irqchip(&stmpe_gpio->chip,
	&stmpe_gpio_irq_chip,
	irq,
	NULL);
	}

	platform_set_drvdata(pdev, stmpe_gpio);

	return 0;

	out_disable:
	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
	gpiochip_remove(&stmpe_gpio->chip);
	out_free:
	kfree(stmpe_gpio);
	return ret;
	}

	static int stmpe_gpio_remove(struct platform_device *pdev)
	{
	struct stmpe_gpio *stmpe_gpio = platform_get_drvdata(pdev);
	struct stmpe *stmpe = stmpe_gpio->stmpe;

	gpiochip_remove(&stmpe_gpio->chip);
	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
	kfree(stmpe_gpio);

	return 0;
	}

	static struct platform_driver stmpe_gpio_driver = {
	.driver.name = "stmpe-gpio",
	.driver.owner = THIS_MODULE,
	.probe = stmpe_gpio_probe,
	.remove = stmpe_gpio_remove,
	};

	static int __init stmpe_gpio_init(void)
	{
	return platform_driver_register(&stmpe_gpio_driver);
	}
	subsys_initcall(stmpe_gpio_init);

	static void __exit stmpe_gpio_exit(void)
	{
	platform_driver_unregister(&stmpe_gpio_driver);
	}
	module_exit(stmpe_gpio_exit);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("STMPExxxx GPIO driver");
	MODULE_AUTHOR("Rabin Vincent <rabin.vincent@stericsson.com>");