[thirdparty/kernel/stable.git] / drivers / gpio / gpio-pisosr.c

/*
 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
 *	Andrew F. Davis <afd@ti.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 "as is" WITHOUT ANY WARRANTY of any
 * kind, whether expressed or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License version 2 for more details.
 */

#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/spi/spi.h>

#define DEFAULT_NGPIO 8

/**
 * struct pisosr_gpio - GPIO driver data
 * @chip: GPIO controller chip
 * @spi: SPI device pointer
 * @buffer: Buffer for device reads
 * @buffer_size: Size of buffer
 * @load_gpio: GPIO pin used to load input into device
 * @lock: Protects read sequences
 */
struct pisosr_gpio {
	struct gpio_chip chip;
	struct spi_device *spi;
	u8 *buffer;
	size_t buffer_size;
	struct gpio_desc *load_gpio;
	struct mutex lock;
};

static int pisosr_gpio_refresh(struct pisosr_gpio *gpio)
{
	int ret;

	mutex_lock(&gpio->lock);

	if (gpio->load_gpio) {
		gpiod_set_value_cansleep(gpio->load_gpio, 1);
		udelay(1); /* registers load time (~10ns) */
		gpiod_set_value_cansleep(gpio->load_gpio, 0);
		udelay(1); /* registers recovery time (~5ns) */
	}

	ret = spi_read(gpio->spi, gpio->buffer, gpio->buffer_size);

	mutex_unlock(&gpio->lock);

	return ret;
}

static int pisosr_gpio_get_direction(struct gpio_chip *chip,
				     unsigned offset)
{
	/* This device always input */
	return 1;
}

static int pisosr_gpio_direction_input(struct gpio_chip *chip,
				       unsigned offset)
{
	/* This device always input */
	return 0;
}

static int pisosr_gpio_direction_output(struct gpio_chip *chip,
					unsigned offset, int value)
{
	/* This device is input only */
	return -EINVAL;
}

static int pisosr_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct pisosr_gpio *gpio = gpiochip_get_data(chip);

	/* Refresh may not always be needed */
	pisosr_gpio_refresh(gpio);

	return (gpio->buffer[offset / 8] >> (offset % 8)) & 0x1;
}

static int pisosr_gpio_get_multiple(struct gpio_chip *chip,
				    unsigned long *mask, unsigned long *bits)
{
	struct pisosr_gpio *gpio = gpiochip_get_data(chip);
	unsigned int nbytes = DIV_ROUND_UP(chip->ngpio, 8);
	unsigned int i, j;

	pisosr_gpio_refresh(gpio);

	bitmap_zero(bits, chip->ngpio);
	for (i = 0; i < nbytes; i++) {
		j = i / sizeof(unsigned long);
		bits[j] |= ((unsigned long) gpio->buffer[i])
			   << (8 * (i % sizeof(unsigned long)));
	}

	return 0;
}

static const struct gpio_chip template_chip = {
	.label			= "pisosr-gpio",
	.owner			= THIS_MODULE,
	.get_direction		= pisosr_gpio_get_direction,
	.direction_input	= pisosr_gpio_direction_input,
	.direction_output	= pisosr_gpio_direction_output,
	.get			= pisosr_gpio_get,
	.get_multiple		= pisosr_gpio_get_multiple,
	.base			= -1,
	.ngpio			= DEFAULT_NGPIO,
	.can_sleep		= true,
};

static int pisosr_gpio_probe(struct spi_device *spi)
{
	struct device *dev = &spi->dev;
	struct pisosr_gpio *gpio;
	int ret;

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

	spi_set_drvdata(spi, gpio);

	gpio->chip = template_chip;
	gpio->chip.parent = dev;
	of_property_read_u16(dev->of_node, "ngpios", &gpio->chip.ngpio);

	gpio->spi = spi;

	gpio->buffer_size = DIV_ROUND_UP(gpio->chip.ngpio, 8);
	gpio->buffer = devm_kzalloc(dev, gpio->buffer_size, GFP_KERNEL);
	if (!gpio->buffer)
		return -ENOMEM;

	gpio->load_gpio = devm_gpiod_get_optional(dev, "load", GPIOD_OUT_LOW);
	if (IS_ERR(gpio->load_gpio)) {
		ret = PTR_ERR(gpio->load_gpio);
		if (ret != -EPROBE_DEFER)
			dev_err(dev, "Unable to allocate load GPIO\n");
		return ret;
	}

	mutex_init(&gpio->lock);

	ret = gpiochip_add_data(&gpio->chip, gpio);
	if (ret < 0) {
		dev_err(dev, "Unable to register gpiochip\n");
		return ret;
	}

	return 0;
}

static int pisosr_gpio_remove(struct spi_device *spi)
{
	struct pisosr_gpio *gpio = spi_get_drvdata(spi);

	gpiochip_remove(&gpio->chip);

	mutex_destroy(&gpio->lock);

	return 0;
}

static const struct spi_device_id pisosr_gpio_id_table[] = {
	{ "pisosr-gpio", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(spi, pisosr_gpio_id_table);

static const struct of_device_id pisosr_gpio_of_match_table[] = {
	{ .compatible = "pisosr-gpio", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pisosr_gpio_of_match_table);

static struct spi_driver pisosr_gpio_driver = {
	.driver = {
		.name = "pisosr-gpio",
		.of_match_table = pisosr_gpio_of_match_table,
	},
	.probe = pisosr_gpio_probe,
	.remove = pisosr_gpio_remove,
	.id_table = pisosr_gpio_id_table,
};
module_spi_driver(pisosr_gpio_driver);

MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
MODULE_DESCRIPTION("SPI Compatible PISO Shift Register GPIO Driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
df6df93c AD	1	/*
	2	* Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
	3	* Andrew F. Davis <afd@ti.com>
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*
	9	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	10	* kind, whether expressed or implied; without even the implied warranty
	11	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License version 2 for more details.
	13	*/
	14
40bb5d72 MHT	15	#include <linux/bitmap.h>
40bb5d72 MHT	16	#include <linux/bitops.h>
df6df93c AD	17	#include <linux/delay.h>
	18	#include <linux/gpio/consumer.h>
	19	#include <linux/gpio/driver.h>
	20	#include <linux/module.h>
	21	#include <linux/mutex.h>
	22	#include <linux/spi/spi.h>
	23
	24	#define DEFAULT_NGPIO 8
	25
	26	/**
	27	* struct pisosr_gpio - GPIO driver data
	28	* @chip: GPIO controller chip
	29	* @spi: SPI device pointer
	30	* @buffer: Buffer for device reads
	31	* @buffer_size: Size of buffer
	32	* @load_gpio: GPIO pin used to load input into device
	33	* @lock: Protects read sequences
	34	*/
	35	struct pisosr_gpio {
	36	struct gpio_chip chip;
	37	struct spi_device *spi;
	38	u8 *buffer;
	39	size_t buffer_size;
	40	struct gpio_desc *load_gpio;
	41	struct mutex lock;
	42	};
	43
	44	static int pisosr_gpio_refresh(struct pisosr_gpio *gpio)
	45	{
	46	int ret;
	47
	48	mutex_lock(&gpio->lock);
	49
	50	if (gpio->load_gpio) {
ea04a7ca	51	gpiod_set_value_cansleep(gpio->load_gpio, 1);
df6df93c	52	udelay(1); /* registers load time (~10ns) */
ea04a7ca	53	gpiod_set_value_cansleep(gpio->load_gpio, 0);
df6df93c AD	54	udelay(1); /* registers recovery time (~5ns) */
	55	}
	56
	57	ret = spi_read(gpio->spi, gpio->buffer, gpio->buffer_size);
df6df93c AD	58
	59	mutex_unlock(&gpio->lock);
	60
3e089d9f	61	return ret;
df6df93c AD	62	}
	63
	64	static int pisosr_gpio_get_direction(struct gpio_chip *chip,
	65	unsigned offset)
	66	{
	67	/* This device always input */
	68	return 1;
	69	}
	70
	71	static int pisosr_gpio_direction_input(struct gpio_chip *chip,
	72	unsigned offset)
	73	{
	74	/* This device always input */
	75	return 0;
	76	}
	77
	78	static int pisosr_gpio_direction_output(struct gpio_chip *chip,
	79	unsigned offset, int value)
	80	{
	81	/* This device is input only */
	82	return -EINVAL;
	83	}
	84
	85	static int pisosr_gpio_get(struct gpio_chip *chip, unsigned offset)
	86	{
	87	struct pisosr_gpio *gpio = gpiochip_get_data(chip);
	88
	89	/* Refresh may not always be needed */
	90	pisosr_gpio_refresh(gpio);
	91
	92	return (gpio->buffer[offset / 8] >> (offset % 8)) & 0x1;
	93	}
	94
40bb5d72 MHT	95	static int pisosr_gpio_get_multiple(struct gpio_chip *chip,
	96	unsigned long mask, unsigned long bits)
	97	{
	98	struct pisosr_gpio *gpio = gpiochip_get_data(chip);
	99	unsigned int nbytes = DIV_ROUND_UP(chip->ngpio, 8);
	100	unsigned int i, j;
	101
	102	pisosr_gpio_refresh(gpio);
	103
	104	bitmap_zero(bits, chip->ngpio);
	105	for (i = 0; i < nbytes; i++) {
	106	j = i / sizeof(unsigned long);
	107	bits[j] \|= ((unsigned long) gpio->buffer[i])
	108	<< (8 * (i % sizeof(unsigned long)));
	109	}
	110
	111	return 0;
	112	}
	113
e35b5ab0	114	static const struct gpio_chip template_chip = {
df6df93c AD	115	.label = "pisosr-gpio",
	116	.owner = THIS_MODULE,
	117	.get_direction = pisosr_gpio_get_direction,
	118	.direction_input = pisosr_gpio_direction_input,
	119	.direction_output = pisosr_gpio_direction_output,
	120	.get = pisosr_gpio_get,
40bb5d72	121	.get_multiple = pisosr_gpio_get_multiple,
df6df93c AD	122	.base = -1,
	123	.ngpio = DEFAULT_NGPIO,
	124	.can_sleep = true,
	125	};
	126
	127	static int pisosr_gpio_probe(struct spi_device *spi)
	128	{
	129	struct device *dev = &spi->dev;
	130	struct pisosr_gpio *gpio;
	131	int ret;
	132
	133	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
	134	if (!gpio)
	135	return -ENOMEM;
	136
	137	spi_set_drvdata(spi, gpio);
	138
	139	gpio->chip = template_chip;
	140	gpio->chip.parent = dev;
	141	of_property_read_u16(dev->of_node, "ngpios", &gpio->chip.ngpio);
	142
	143	gpio->spi = spi;
	144
	145	gpio->buffer_size = DIV_ROUND_UP(gpio->chip.ngpio, 8);
	146	gpio->buffer = devm_kzalloc(dev, gpio->buffer_size, GFP_KERNEL);
	147	if (!gpio->buffer)
	148	return -ENOMEM;
	149
21d08ab9	150	gpio->load_gpio = devm_gpiod_get_optional(dev, "load", GPIOD_OUT_LOW);
df6df93c AD	151	if (IS_ERR(gpio->load_gpio)) {
df6df93c AD	152	ret = PTR_ERR(gpio->load_gpio);
21d08ab9 AL	153	if (ret != -EPROBE_DEFER)
	154	dev_err(dev, "Unable to allocate load GPIO\n");
	155	return ret;
df6df93c AD	156	}
	157
	158	mutex_init(&gpio->lock);
	159
	160	ret = gpiochip_add_data(&gpio->chip, gpio);
	161	if (ret < 0) {
	162	dev_err(dev, "Unable to register gpiochip\n");
	163	return ret;
	164	}
	165
	166	return 0;
	167	}
	168
	169	static int pisosr_gpio_remove(struct spi_device *spi)
	170	{
	171	struct pisosr_gpio *gpio = spi_get_drvdata(spi);
	172
	173	gpiochip_remove(&gpio->chip);
	174
	175	mutex_destroy(&gpio->lock);
	176
	177	return 0;
	178	}
	179
	180	static const struct spi_device_id pisosr_gpio_id_table[] = {
	181	{ "pisosr-gpio", },
	182	{ /* sentinel */ }
	183	};
	184	MODULE_DEVICE_TABLE(spi, pisosr_gpio_id_table);
	185
	186	static const struct of_device_id pisosr_gpio_of_match_table[] = {
	187	{ .compatible = "pisosr-gpio", },
	188	{ /* sentinel */ }
	189	};
	190	MODULE_DEVICE_TABLE(of, pisosr_gpio_of_match_table);
	191
	192	static struct spi_driver pisosr_gpio_driver = {
	193	.driver = {
	194	.name = "pisosr-gpio",
	195	.of_match_table = pisosr_gpio_of_match_table,
	196	},
	197	.probe = pisosr_gpio_probe,
	198	.remove = pisosr_gpio_remove,
	199	.id_table = pisosr_gpio_id_table,
	200	};
	201	module_spi_driver(pisosr_gpio_driver);
	202
	203	MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
	204	MODULE_DESCRIPTION("SPI Compatible PISO Shift Register GPIO Driver");
	205	MODULE_LICENSE("GPL v2");