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1e5db006 RR |
1 | /* |
2 | * mc33880.c MC33880 high-side/low-side switch GPIO driver | |
3 | * Copyright (c) 2009 Intel Corporation | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
17 | */ | |
18 | ||
19 | /* Supports: | |
20 | * Freescale MC33880 high-side/low-side switch | |
21 | */ | |
22 | ||
23 | #include <linux/init.h> | |
24 | #include <linux/mutex.h> | |
25 | #include <linux/spi/spi.h> | |
26 | #include <linux/spi/mc33880.h> | |
27 | #include <linux/gpio.h> | |
28 | ||
29 | #define DRIVER_NAME "mc33880" | |
30 | ||
31 | /* | |
32 | * Pin configurations, see MAX7301 datasheet page 6 | |
33 | */ | |
34 | #define PIN_CONFIG_MASK 0x03 | |
35 | #define PIN_CONFIG_IN_PULLUP 0x03 | |
36 | #define PIN_CONFIG_IN_WO_PULLUP 0x02 | |
37 | #define PIN_CONFIG_OUT 0x01 | |
38 | ||
39 | #define PIN_NUMBER 8 | |
40 | ||
41 | ||
42 | /* | |
43 | * Some registers must be read back to modify. | |
44 | * To save time we cache them here in memory | |
45 | */ | |
46 | struct mc33880 { | |
47 | struct mutex lock; /* protect from simultanous accesses */ | |
48 | u8 port_config; | |
49 | struct gpio_chip chip; | |
50 | struct spi_device *spi; | |
51 | }; | |
52 | ||
53 | static int mc33880_write_config(struct mc33880 *mc) | |
54 | { | |
55 | return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config)); | |
56 | } | |
57 | ||
58 | ||
59 | static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value) | |
60 | { | |
61 | if (value) | |
62 | mc->port_config |= 1 << offset; | |
63 | else | |
64 | mc->port_config &= ~(1 << offset); | |
65 | ||
66 | return mc33880_write_config(mc); | |
67 | } | |
68 | ||
69 | ||
70 | static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value) | |
71 | { | |
72 | struct mc33880 *mc = container_of(chip, struct mc33880, chip); | |
73 | ||
74 | mutex_lock(&mc->lock); | |
75 | ||
76 | __mc33880_set(mc, offset, value); | |
77 | ||
78 | mutex_unlock(&mc->lock); | |
79 | } | |
80 | ||
81 | static int __devinit mc33880_probe(struct spi_device *spi) | |
82 | { | |
83 | struct mc33880 *mc; | |
84 | struct mc33880_platform_data *pdata; | |
85 | int ret; | |
86 | ||
87 | pdata = spi->dev.platform_data; | |
88 | if (!pdata || !pdata->base) { | |
89 | dev_dbg(&spi->dev, "incorrect or missing platform data\n"); | |
90 | return -EINVAL; | |
91 | } | |
92 | ||
93 | /* | |
94 | * bits_per_word cannot be configured in platform data | |
95 | */ | |
96 | spi->bits_per_word = 8; | |
97 | ||
98 | ret = spi_setup(spi); | |
99 | if (ret < 0) | |
100 | return ret; | |
101 | ||
102 | mc = kzalloc(sizeof(struct mc33880), GFP_KERNEL); | |
103 | if (!mc) | |
104 | return -ENOMEM; | |
105 | ||
106 | mutex_init(&mc->lock); | |
107 | ||
108 | dev_set_drvdata(&spi->dev, mc); | |
109 | ||
110 | mc->spi = spi; | |
111 | ||
112 | mc->chip.label = DRIVER_NAME, | |
113 | mc->chip.set = mc33880_set; | |
114 | mc->chip.base = pdata->base; | |
115 | mc->chip.ngpio = PIN_NUMBER; | |
116 | mc->chip.can_sleep = 1; | |
117 | mc->chip.dev = &spi->dev; | |
118 | mc->chip.owner = THIS_MODULE; | |
119 | ||
120 | mc->port_config = 0x00; | |
121 | /* write twice, because during initialisation the first setting | |
122 | * is just for testing SPI communication, and the second is the | |
123 | * "real" configuration | |
124 | */ | |
125 | ret = mc33880_write_config(mc); | |
126 | mc->port_config = 0x00; | |
127 | if (!ret) | |
128 | ret = mc33880_write_config(mc); | |
129 | ||
130 | if (ret) { | |
131 | printk(KERN_ERR "Failed writing to " DRIVER_NAME ": %d\n", ret); | |
132 | goto exit_destroy; | |
133 | } | |
134 | ||
135 | ret = gpiochip_add(&mc->chip); | |
136 | if (ret) | |
137 | goto exit_destroy; | |
138 | ||
139 | return ret; | |
140 | ||
141 | exit_destroy: | |
142 | dev_set_drvdata(&spi->dev, NULL); | |
143 | mutex_destroy(&mc->lock); | |
144 | kfree(mc); | |
145 | return ret; | |
146 | } | |
147 | ||
148 | static int mc33880_remove(struct spi_device *spi) | |
149 | { | |
150 | struct mc33880 *mc; | |
151 | int ret; | |
152 | ||
153 | mc = dev_get_drvdata(&spi->dev); | |
154 | if (mc == NULL) | |
155 | return -ENODEV; | |
156 | ||
157 | dev_set_drvdata(&spi->dev, NULL); | |
158 | ||
159 | ret = gpiochip_remove(&mc->chip); | |
160 | if (!ret) { | |
161 | mutex_destroy(&mc->lock); | |
162 | kfree(mc); | |
163 | } else | |
164 | dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n", | |
165 | ret); | |
166 | ||
167 | return ret; | |
168 | } | |
169 | ||
170 | static struct spi_driver mc33880_driver = { | |
171 | .driver = { | |
172 | .name = DRIVER_NAME, | |
173 | .owner = THIS_MODULE, | |
174 | }, | |
175 | .probe = mc33880_probe, | |
176 | .remove = __devexit_p(mc33880_remove), | |
177 | }; | |
178 | ||
179 | static int __init mc33880_init(void) | |
180 | { | |
181 | return spi_register_driver(&mc33880_driver); | |
182 | } | |
183 | /* register after spi postcore initcall and before | |
184 | * subsys initcalls that may rely on these GPIOs | |
185 | */ | |
186 | subsys_initcall(mc33880_init); | |
187 | ||
188 | static void __exit mc33880_exit(void) | |
189 | { | |
190 | spi_unregister_driver(&mc33880_driver); | |
191 | } | |
192 | module_exit(mc33880_exit); | |
193 | ||
194 | MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>"); | |
195 | MODULE_LICENSE("GPL v2"); | |
196 |