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ead6db08 MG |
1 | /* |
2 | * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver | |
3 | * | |
4 | * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org> | |
5 | * Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #include <linux/init.h> | |
13 | #include <linux/mutex.h> | |
14 | #include <linux/spi/spi.h> | |
15 | #include <linux/spi/74x164.h> | |
16 | #include <linux/gpio.h> | |
17 | #include <linux/slab.h> | |
18 | ||
ead6db08 MG |
19 | struct gen_74x164_chip { |
20 | struct spi_device *spi; | |
21 | struct gpio_chip gpio_chip; | |
22 | struct mutex lock; | |
23 | u8 port_config; | |
24 | }; | |
25 | ||
ead6db08 MG |
26 | static struct gen_74x164_chip *gpio_to_chip(struct gpio_chip *gc) |
27 | { | |
28 | return container_of(gc, struct gen_74x164_chip, gpio_chip); | |
29 | } | |
30 | ||
31 | static int __gen_74x164_write_config(struct gen_74x164_chip *chip) | |
32 | { | |
33 | return spi_write(chip->spi, | |
34 | &chip->port_config, sizeof(chip->port_config)); | |
35 | } | |
36 | ||
ead6db08 MG |
37 | static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset) |
38 | { | |
39 | struct gen_74x164_chip *chip = gpio_to_chip(gc); | |
40 | int ret; | |
41 | ||
42 | mutex_lock(&chip->lock); | |
43 | ret = (chip->port_config >> offset) & 0x1; | |
44 | mutex_unlock(&chip->lock); | |
45 | ||
46 | return ret; | |
47 | } | |
48 | ||
49 | static void gen_74x164_set_value(struct gpio_chip *gc, | |
50 | unsigned offset, int val) | |
51 | { | |
52 | struct gen_74x164_chip *chip = gpio_to_chip(gc); | |
53 | ||
54 | mutex_lock(&chip->lock); | |
55 | if (val) | |
56 | chip->port_config |= (1 << offset); | |
57 | else | |
58 | chip->port_config &= ~(1 << offset); | |
59 | ||
60 | __gen_74x164_write_config(chip); | |
61 | mutex_unlock(&chip->lock); | |
62 | } | |
63 | ||
a3cc68c3 HS |
64 | static int gen_74x164_direction_output(struct gpio_chip *gc, |
65 | unsigned offset, int val) | |
66 | { | |
67 | gen_74x164_set_value(gc, offset, val); | |
68 | return 0; | |
69 | } | |
70 | ||
ead6db08 MG |
71 | static int __devinit gen_74x164_probe(struct spi_device *spi) |
72 | { | |
73 | struct gen_74x164_chip *chip; | |
74 | struct gen_74x164_chip_platform_data *pdata; | |
75 | int ret; | |
76 | ||
77 | pdata = spi->dev.platform_data; | |
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 | chip = kzalloc(sizeof(*chip), GFP_KERNEL); | |
93 | if (!chip) | |
94 | return -ENOMEM; | |
95 | ||
96 | mutex_init(&chip->lock); | |
97 | ||
98 | dev_set_drvdata(&spi->dev, chip); | |
99 | ||
100 | chip->spi = spi; | |
101 | ||
a3cc68c3 HS |
102 | chip->gpio_chip.label = spi->modalias; |
103 | chip->gpio_chip.direction_output = gen_74x164_direction_output; | |
ead6db08 MG |
104 | chip->gpio_chip.get = gen_74x164_get_value; |
105 | chip->gpio_chip.set = gen_74x164_set_value; | |
106 | chip->gpio_chip.base = pdata->base; | |
a3cc68c3 | 107 | chip->gpio_chip.ngpio = 8; |
ead6db08 MG |
108 | chip->gpio_chip.can_sleep = 1; |
109 | chip->gpio_chip.dev = &spi->dev; | |
110 | chip->gpio_chip.owner = THIS_MODULE; | |
111 | ||
112 | ret = __gen_74x164_write_config(chip); | |
113 | if (ret) { | |
114 | dev_err(&spi->dev, "Failed writing: %d\n", ret); | |
115 | goto exit_destroy; | |
116 | } | |
117 | ||
118 | ret = gpiochip_add(&chip->gpio_chip); | |
119 | if (ret) | |
120 | goto exit_destroy; | |
121 | ||
122 | return ret; | |
123 | ||
124 | exit_destroy: | |
125 | dev_set_drvdata(&spi->dev, NULL); | |
126 | mutex_destroy(&chip->lock); | |
127 | kfree(chip); | |
128 | return ret; | |
129 | } | |
130 | ||
fc1599f7 | 131 | static int __devexit gen_74x164_remove(struct spi_device *spi) |
ead6db08 MG |
132 | { |
133 | struct gen_74x164_chip *chip; | |
134 | int ret; | |
135 | ||
136 | chip = dev_get_drvdata(&spi->dev); | |
137 | if (chip == NULL) | |
138 | return -ENODEV; | |
139 | ||
140 | dev_set_drvdata(&spi->dev, NULL); | |
141 | ||
142 | ret = gpiochip_remove(&chip->gpio_chip); | |
143 | if (!ret) { | |
144 | mutex_destroy(&chip->lock); | |
145 | kfree(chip); | |
146 | } else | |
147 | dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n", | |
148 | ret); | |
149 | ||
150 | return ret; | |
151 | } | |
152 | ||
153 | static struct spi_driver gen_74x164_driver = { | |
154 | .driver = { | |
a3cc68c3 | 155 | .name = "74x164", |
ead6db08 MG |
156 | .owner = THIS_MODULE, |
157 | }, | |
158 | .probe = gen_74x164_probe, | |
159 | .remove = __devexit_p(gen_74x164_remove), | |
160 | }; | |
161 | ||
162 | static int __init gen_74x164_init(void) | |
163 | { | |
164 | return spi_register_driver(&gen_74x164_driver); | |
165 | } | |
166 | subsys_initcall(gen_74x164_init); | |
167 | ||
168 | static void __exit gen_74x164_exit(void) | |
169 | { | |
170 | spi_unregister_driver(&gen_74x164_driver); | |
171 | } | |
172 | module_exit(gen_74x164_exit); | |
173 | ||
174 | MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>"); | |
175 | MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>"); | |
176 | MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register"); | |
177 | MODULE_LICENSE("GPL v2"); |