1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/*
* 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
*
* Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.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.
*/
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/spi/spi.h>
#include <linux/spi/74x164.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/module.h>
struct gen_74x164_chip {
struct spi_device *spi;
struct gpio_chip gpio_chip;
struct mutex lock;
u8 port_config;
};
static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc)
{
return container_of(gc, struct gen_74x164_chip, gpio_chip);
}
static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
{
return spi_write(chip->spi,
&chip->port_config, sizeof(chip->port_config));
}
static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
{
struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
int ret;
mutex_lock(&chip->lock);
ret = (chip->port_config >> offset) & 0x1;
mutex_unlock(&chip->lock);
return ret;
}
static void gen_74x164_set_value(struct gpio_chip *gc,
unsigned offset, int val)
{
struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
mutex_lock(&chip->lock);
if (val)
chip->port_config |= (1 << offset);
else
chip->port_config &= ~(1 << offset);
__gen_74x164_write_config(chip);
mutex_unlock(&chip->lock);
}
static int gen_74x164_direction_output(struct gpio_chip *gc,
unsigned offset, int val)
{
gen_74x164_set_value(gc, offset, val);
return 0;
}
static int __devinit gen_74x164_probe(struct spi_device *spi)
{
struct gen_74x164_chip *chip;
struct gen_74x164_chip_platform_data *pdata;
int ret;
pdata = spi->dev.platform_data;
if (!pdata || !pdata->base) {
dev_dbg(&spi->dev, "incorrect or missing platform data\n");
return -EINVAL;
}
/*
* bits_per_word cannot be configured in platform data
*/
spi->bits_per_word = 8;
ret = spi_setup(spi);
if (ret < 0)
return ret;
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
mutex_init(&chip->lock);
dev_set_drvdata(&spi->dev, chip);
chip->spi = spi;
chip->gpio_chip.label = spi->modalias;
chip->gpio_chip.direction_output = gen_74x164_direction_output;
chip->gpio_chip.get = gen_74x164_get_value;
chip->gpio_chip.set = gen_74x164_set_value;
chip->gpio_chip.base = pdata->base;
chip->gpio_chip.ngpio = 8;
chip->gpio_chip.can_sleep = 1;
chip->gpio_chip.dev = &spi->dev;
chip->gpio_chip.owner = THIS_MODULE;
ret = __gen_74x164_write_config(chip);
if (ret) {
dev_err(&spi->dev, "Failed writing: %d\n", ret);
goto exit_destroy;
}
ret = gpiochip_add(&chip->gpio_chip);
if (ret)
goto exit_destroy;
return ret;
exit_destroy:
dev_set_drvdata(&spi->dev, NULL);
mutex_destroy(&chip->lock);
kfree(chip);
return ret;
}
static int __devexit gen_74x164_remove(struct spi_device *spi)
{
struct gen_74x164_chip *chip;
int ret;
chip = dev_get_drvdata(&spi->dev);
if (chip == NULL)
return -ENODEV;
dev_set_drvdata(&spi->dev, NULL);
ret = gpiochip_remove(&chip->gpio_chip);
if (!ret) {
mutex_destroy(&chip->lock);
kfree(chip);
} else
dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
ret);
return ret;
}
static struct spi_driver gen_74x164_driver = {
.driver = {
.name = "74x164",
.owner = THIS_MODULE,
},
.probe = gen_74x164_probe,
.remove = __devexit_p(gen_74x164_remove),
};
static int __init gen_74x164_init(void)
{
return spi_register_driver(&gen_74x164_driver);
}
subsys_initcall(gen_74x164_init);
static void __exit gen_74x164_exit(void)
{
spi_unregister_driver(&gen_74x164_driver);
}
module_exit(gen_74x164_exit);
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
MODULE_LICENSE("GPL v2");
|
