[mirror_ubuntu-bionic-kernel.git] / drivers / gpio / gpio-max7301.c

/*
 * Copyright (C) 2006 Juergen Beisert, Pengutronix
 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
 * Copyright (C) 2009 Wolfram Sang, Pengutronix
 *
 * 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.
 *
 * Check max730x.c for further details.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spi/max7301.h>

/* A write to the MAX7301 means one message with one transfer */
static int max7301_spi_write(struct device *dev, unsigned int reg,
				unsigned int val)
{
	struct spi_device *spi = to_spi_device(dev);
	u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);

	return spi_write_then_read(spi, &word, sizeof(word), NULL, 0);
}

/* A read from the MAX7301 means two transfers; here, one message each */

static int max7301_spi_read(struct device *dev, unsigned int reg)
{
	int ret;
	u16 word;
	struct spi_device *spi = to_spi_device(dev);

	word = 0x8000 | (reg << 8);
	ret = spi_write_then_read(spi, &word, sizeof(word), &word,
				  sizeof(word));
	if (ret)
		return ret;
	return word & 0xff;
}

static int max7301_probe(struct spi_device *spi)
{
	struct max7301 *ts;
	int ret;

	/* bits_per_word cannot be configured in platform data */
	spi->bits_per_word = 16;
	ret = spi_setup(spi);
	if (ret < 0)
		return ret;

	ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);
	if (!ts)
		return -ENOMEM;

	ts->read = max7301_spi_read;
	ts->write = max7301_spi_write;
	ts->dev = &spi->dev;

	ret = __max730x_probe(ts);
	return ret;
}

static int max7301_remove(struct spi_device *spi)
{
	return __max730x_remove(&spi->dev);
}

static const struct spi_device_id max7301_id[] = {
	{ "max7301", 0 },
	{ }
};
MODULE_DEVICE_TABLE(spi, max7301_id);

static struct spi_driver max7301_driver = {
	.driver = {
		.name = "max7301",
	},
	.probe = max7301_probe,
	.remove = max7301_remove,
	.id_table = max7301_id,
};

static int __init max7301_init(void)
{
	return spi_register_driver(&max7301_driver);
}
/* register after spi postcore initcall and before
 * subsys initcalls that may rely on these GPIOs
 */
subsys_initcall(max7301_init);

static void __exit max7301_exit(void)
{
	spi_unregister_driver(&max7301_driver);
}
module_exit(max7301_exit);

MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("MAX7301 GPIO-Expander");
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2006 Juergen Beisert, Pengutronix
	3	* Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
	4	* Copyright (C) 2009 Wolfram Sang, Pengutronix
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* Check max730x.c for further details.
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/init.h>
	15	#include <linux/platform_device.h>
	16	#include <linux/mutex.h>
	17	#include <linux/slab.h>
	18	#include <linux/spi/spi.h>
	19	#include <linux/spi/max7301.h>
	20
	21	/* A write to the MAX7301 means one message with one transfer */
	22	static int max7301_spi_write(struct device *dev, unsigned int reg,
	23	unsigned int val)
	24	{
	25	struct spi_device *spi = to_spi_device(dev);
	26	u16 word = ((reg & 0x7F) << 8) \| (val & 0xFF);
	27
	28	return spi_write_then_read(spi, &word, sizeof(word), NULL, 0);
	29	}
	30
	31	/* A read from the MAX7301 means two transfers; here, one message each */
	32
	33	static int max7301_spi_read(struct device *dev, unsigned int reg)
	34	{
	35	int ret;
	36	u16 word;
	37	struct spi_device *spi = to_spi_device(dev);
	38
	39	word = 0x8000 \| (reg << 8);
	40	ret = spi_write_then_read(spi, &word, sizeof(word), &word,
	41	sizeof(word));
	42	if (ret)
	43	return ret;
	44	return word & 0xff;
	45	}
	46
	47	static int max7301_probe(struct spi_device *spi)
	48	{
	49	struct max7301 *ts;
	50	int ret;
	51
	52	/* bits_per_word cannot be configured in platform data */
	53	spi->bits_per_word = 16;
	54	ret = spi_setup(spi);
	55	if (ret < 0)
	56	return ret;
	57
	58	ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);
	59	if (!ts)
	60	return -ENOMEM;
	61
	62	ts->read = max7301_spi_read;
	63	ts->write = max7301_spi_write;
	64	ts->dev = &spi->dev;
	65
	66	ret = __max730x_probe(ts);
	67	return ret;
	68	}
	69
	70	static int max7301_remove(struct spi_device *spi)
	71	{
	72	return __max730x_remove(&spi->dev);
	73	}
	74
	75	static const struct spi_device_id max7301_id[] = {
	76	{ "max7301", 0 },
	77	{ }
	78	};
	79	MODULE_DEVICE_TABLE(spi, max7301_id);
	80
	81	static struct spi_driver max7301_driver = {
	82	.driver = {
	83	.name = "max7301",
	84	},
	85	.probe = max7301_probe,
	86	.remove = max7301_remove,
	87	.id_table = max7301_id,
	88	};
	89
	90	static int __init max7301_init(void)
	91	{
	92	return spi_register_driver(&max7301_driver);
	93	}
	94	/* register after spi postcore initcall and before
	95	* subsys initcalls that may rely on these GPIOs
	96	*/
	97	subsys_initcall(max7301_init);
	98
	99	static void __exit max7301_exit(void)
	100	{
	101	spi_unregister_driver(&max7301_driver);
	102	}
	103	module_exit(max7301_exit);
	104
	105	MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
	106	MODULE_LICENSE("GPL v2");
	107	MODULE_DESCRIPTION("MAX7301 GPIO-Expander");