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 */
36 struct 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
mc33880_write_config(struct mc33880 * mc)43 static int mc33880_write_config(struct mc33880 *mc)
44 {
45 return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));
46 }
47
48
__mc33880_set(struct mc33880 * mc,unsigned offset,int value)49 static 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
mc33880_set(struct gpio_chip * chip,unsigned int offset,int value)60 static 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
mc33880_probe(struct spi_device * spi)74 static 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_rv = 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
135 exit_destroy:
136 mutex_destroy(&mc->lock);
137 return ret;
138 }
139
mc33880_remove(struct spi_device * spi)140 static 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
150 static struct spi_driver mc33880_driver = {
151 .driver = {
152 .name = DRIVER_NAME,
153 },
154 .probe = mc33880_probe,
155 .remove = mc33880_remove,
156 };
157
mc33880_init(void)158 static 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 */
165 subsys_initcall(mc33880_init);
166
mc33880_exit(void)167 static void __exit mc33880_exit(void)
168 {
169 spi_unregister_driver(&mc33880_driver);
170 }
171 module_exit(mc33880_exit);
172
173 MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
174 MODULE_DESCRIPTION("MC33880 high-side/low-side switch GPIO driver");
175 MODULE_LICENSE("GPL v2");
176
177