gpio-mc33880.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * MC33880 high-side/low-side switch GPIO driver
  4 * Copyright (c) 2009 Intel Corporation
  5 */
  6
  7/* Supports:
  8 * Freescale MC33880 high-side/low-side switch
  9 */
 10
 11#include <linux/init.h>
 12#include <linux/mutex.h>
 13#include <linux/spi/spi.h>
 14#include <linux/spi/mc33880.h>
 15#include <linux/gpio/driver.h>
 16#include <linux/slab.h>
 17#include <linux/module.h>
 18
 19#define DRIVER_NAME "mc33880"
 20
 21/*
 22 * Pin configurations, see MAX7301 datasheet page 6
 23 */
 24#define PIN_CONFIG_MASK 0x03
 25#define PIN_CONFIG_IN_PULLUP 0x03
 26#define PIN_CONFIG_IN_WO_PULLUP 0x02
 27#define PIN_CONFIG_OUT 0x01
 28
 29#define PIN_NUMBER 8
 30
 31
 32/*
 33 * Some registers must be read back to modify.
 34 * To save time we cache them here in memory
 35 */
 36struct mc33880 {
 37	struct mutex	lock;	/* protect from simultaneous accesses */
 38	u8		port_config;
 39	struct gpio_chip chip;
 40	struct spi_device *spi;
 41};
 42
 43static int mc33880_write_config(struct mc33880 *mc)
 44{
 45	return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));
 46}
 47
 48
 49static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value)
 50{
 51	if (value)
 52		mc->port_config |= 1 << offset;
 53	else
 54		mc->port_config &= ~(1 << offset);
 55
 56	return mc33880_write_config(mc);
 57}
 58
 59
 60static int mc33880_set(struct gpio_chip *chip, unsigned int offset, int value)
 61{
 62	struct mc33880 *mc = gpiochip_get_data(chip);
 63	int ret;
 64
 65	mutex_lock(&mc->lock);
 66
 67	ret = __mc33880_set(mc, offset, value);
 68
 69	mutex_unlock(&mc->lock);
 70
 71	return ret;
 72}
 73
 74static int mc33880_probe(struct spi_device *spi)
 75{
 76	struct mc33880 *mc;
 77	struct mc33880_platform_data *pdata;
 78	int ret;
 79
 80	pdata = dev_get_platdata(&spi->dev);
 81	if (!pdata || !pdata->base) {
 82		dev_dbg(&spi->dev, "incorrect or missing platform data\n");
 83		return -EINVAL;
 84	}
 85
 86	/*
 87	 * bits_per_word cannot be configured in platform data
 88	 */
 89	spi->bits_per_word = 8;
 90
 91	ret = spi_setup(spi);
 92	if (ret < 0)
 93		return ret;
 94
 95	mc = devm_kzalloc(&spi->dev, sizeof(struct mc33880), GFP_KERNEL);
 96	if (!mc)
 97		return -ENOMEM;
 98
 99	mutex_init(&mc->lock);
100
101	spi_set_drvdata(spi, mc);
102
103	mc->spi = spi;
104
105	mc->chip.label = DRIVER_NAME;
106	mc->chip.set = mc33880_set;
107	mc->chip.base = pdata->base;
108	mc->chip.ngpio = PIN_NUMBER;
109	mc->chip.can_sleep = true;
110	mc->chip.parent = &spi->dev;
111	mc->chip.owner = THIS_MODULE;
112
113	mc->port_config = 0x00;
114	/* write twice, because during initialisation the first setting
115	 * is just for testing SPI communication, and the second is the
116	 * "real" configuration
117	 */
118	ret = mc33880_write_config(mc);
119	mc->port_config = 0x00;
120	if (!ret)
121		ret = mc33880_write_config(mc);
122
123	if (ret) {
124		dev_err(&spi->dev, "Failed writing to " DRIVER_NAME ": %d\n",
125			ret);
126		goto exit_destroy;
127	}
128
129	ret = gpiochip_add_data(&mc->chip, mc);
130	if (ret)
131		goto exit_destroy;
132
133	return ret;
134
135exit_destroy:
136	mutex_destroy(&mc->lock);
137	return ret;
138}
139
140static void mc33880_remove(struct spi_device *spi)
141{
142	struct mc33880 *mc;
143
144	mc = spi_get_drvdata(spi);
145
146	gpiochip_remove(&mc->chip);
147	mutex_destroy(&mc->lock);
148}
149
150static struct spi_driver mc33880_driver = {
151	.driver = {
152		.name		= DRIVER_NAME,
153	},
154	.probe		= mc33880_probe,
155	.remove		= mc33880_remove,
156};
157
158static int __init mc33880_init(void)
159{
160	return spi_register_driver(&mc33880_driver);
161}
162/* register after spi postcore initcall and before
163 * subsys initcalls that may rely on these GPIOs
164 */
165subsys_initcall(mc33880_init);
166
167static void __exit mc33880_exit(void)
168{
169	spi_unregister_driver(&mc33880_driver);
170}
171module_exit(mc33880_exit);
172
173MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
174MODULE_DESCRIPTION("MC33880 high-side/low-side switch GPIO driver");
175MODULE_LICENSE("GPL v2");
176