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 void mc33880_set(struct gpio_chip *chip, unsigned offset, int value)
61{
62	struct mc33880 *mc = gpiochip_get_data(chip);
63
64	mutex_lock(&mc->lock);
65
66	__mc33880_set(mc, offset, value);
67
68	mutex_unlock(&mc->lock);
69}
70
71static int mc33880_probe(struct spi_device *spi)
72{
73	struct mc33880 *mc;
74	struct mc33880_platform_data *pdata;
75	int ret;
76
77	pdata = dev_get_platdata(&spi->dev);
78	if (!pdata || !pdata->base) {
79		dev_dbg(&spi->dev, "incorrect or missing platform data\n");
80		return -EINVAL;
81	}
82
83	/*
84	 * bits_per_word cannot be configured in platform data
85	 */
86	spi->bits_per_word = 8;
87
88	ret = spi_setup(spi);
89	if (ret < 0)
90		return ret;
91
92	mc = devm_kzalloc(&spi->dev, sizeof(struct mc33880), GFP_KERNEL);
93	if (!mc)
94		return -ENOMEM;
95
96	mutex_init(&mc->lock);
97
98	spi_set_drvdata(spi, mc);
99
100	mc->spi = spi;
101
102	mc->chip.label = DRIVER_NAME,
103	mc->chip.set = mc33880_set;
104	mc->chip.base = pdata->base;
105	mc->chip.ngpio = PIN_NUMBER;
106	mc->chip.can_sleep = true;
107	mc->chip.parent = &spi->dev;
108	mc->chip.owner = THIS_MODULE;
109
110	mc->port_config = 0x00;
111	/* write twice, because during initialisation the first setting
112	 * is just for testing SPI communication, and the second is the
113	 * "real" configuration
114	 */
115	ret = mc33880_write_config(mc);
116	mc->port_config = 0x00;
117	if (!ret)
118		ret = mc33880_write_config(mc);
119
120	if (ret) {
121		dev_err(&spi->dev, "Failed writing to " DRIVER_NAME ": %d\n",
122			ret);
123		goto exit_destroy;
124	}
125
126	ret = gpiochip_add_data(&mc->chip, mc);
127	if (ret)
128		goto exit_destroy;
129
130	return ret;
131
132exit_destroy:
133	mutex_destroy(&mc->lock);
134	return ret;
135}
136
137static void mc33880_remove(struct spi_device *spi)
138{
139	struct mc33880 *mc;
140
141	mc = spi_get_drvdata(spi);
142
143	gpiochip_remove(&mc->chip);
144	mutex_destroy(&mc->lock);
145}
146
147static struct spi_driver mc33880_driver = {
148	.driver = {
149		.name		= DRIVER_NAME,
150	},
151	.probe		= mc33880_probe,
152	.remove		= mc33880_remove,
153};
154
155static int __init mc33880_init(void)
156{
157	return spi_register_driver(&mc33880_driver);
158}
159/* register after spi postcore initcall and before
160 * subsys initcalls that may rely on these GPIOs
161 */
162subsys_initcall(mc33880_init);
163
164static void __exit mc33880_exit(void)
165{
166	spi_unregister_driver(&mc33880_driver);
167}
168module_exit(mc33880_exit);
169
170MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
171MODULE_LICENSE("GPL v2");
172
173