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Richard Röjfors1e5db002009-09-22 16:46:34 -07001/*
Grant Likelyc103de22011-06-04 18:38:28 -06002 * MC33880 high-side/low-side switch GPIO driver
Richard Röjfors1e5db002009-09-22 16:46:34 -07003 * 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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090028#include <linux/slab.h>
Paul Gortmakerbb207ef2011-07-03 13:38:09 -040029#include <linux/module.h>
Richard Röjfors1e5db002009-09-22 16:46:34 -070030
31#define DRIVER_NAME "mc33880"
32
33/*
34 * Pin configurations, see MAX7301 datasheet page 6
35 */
36#define PIN_CONFIG_MASK 0x03
37#define PIN_CONFIG_IN_PULLUP 0x03
38#define PIN_CONFIG_IN_WO_PULLUP 0x02
39#define PIN_CONFIG_OUT 0x01
40
41#define PIN_NUMBER 8
42
43
44/*
45 * Some registers must be read back to modify.
46 * To save time we cache them here in memory
47 */
48struct mc33880 {
Lucas De Marchi25985ed2011-03-30 22:57:33 -030049 struct mutex lock; /* protect from simultaneous accesses */
Richard Röjfors1e5db002009-09-22 16:46:34 -070050 u8 port_config;
51 struct gpio_chip chip;
52 struct spi_device *spi;
53};
54
55static int mc33880_write_config(struct mc33880 *mc)
56{
57 return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));
58}
59
60
61static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value)
62{
63 if (value)
64 mc->port_config |= 1 << offset;
65 else
66 mc->port_config &= ~(1 << offset);
67
68 return mc33880_write_config(mc);
69}
70
71
72static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value)
73{
74 struct mc33880 *mc = container_of(chip, struct mc33880, chip);
75
76 mutex_lock(&mc->lock);
77
78 __mc33880_set(mc, offset, value);
79
80 mutex_unlock(&mc->lock);
81}
82
83static int __devinit mc33880_probe(struct spi_device *spi)
84{
85 struct mc33880 *mc;
86 struct mc33880_platform_data *pdata;
87 int ret;
88
89 pdata = spi->dev.platform_data;
90 if (!pdata || !pdata->base) {
91 dev_dbg(&spi->dev, "incorrect or missing platform data\n");
92 return -EINVAL;
93 }
94
95 /*
96 * bits_per_word cannot be configured in platform data
97 */
98 spi->bits_per_word = 8;
99
100 ret = spi_setup(spi);
101 if (ret < 0)
102 return ret;
103
104 mc = kzalloc(sizeof(struct mc33880), GFP_KERNEL);
105 if (!mc)
106 return -ENOMEM;
107
108 mutex_init(&mc->lock);
109
110 dev_set_drvdata(&spi->dev, mc);
111
112 mc->spi = spi;
113
114 mc->chip.label = DRIVER_NAME,
115 mc->chip.set = mc33880_set;
116 mc->chip.base = pdata->base;
117 mc->chip.ngpio = PIN_NUMBER;
118 mc->chip.can_sleep = 1;
119 mc->chip.dev = &spi->dev;
120 mc->chip.owner = THIS_MODULE;
121
122 mc->port_config = 0x00;
123 /* write twice, because during initialisation the first setting
124 * is just for testing SPI communication, and the second is the
125 * "real" configuration
126 */
127 ret = mc33880_write_config(mc);
128 mc->port_config = 0x00;
129 if (!ret)
130 ret = mc33880_write_config(mc);
131
132 if (ret) {
133 printk(KERN_ERR "Failed writing to " DRIVER_NAME ": %d\n", ret);
134 goto exit_destroy;
135 }
136
137 ret = gpiochip_add(&mc->chip);
138 if (ret)
139 goto exit_destroy;
140
141 return ret;
142
143exit_destroy:
144 dev_set_drvdata(&spi->dev, NULL);
145 mutex_destroy(&mc->lock);
146 kfree(mc);
147 return ret;
148}
149
Axel Linfc1599f2011-03-10 17:10:45 +0800150static int __devexit mc33880_remove(struct spi_device *spi)
Richard Röjfors1e5db002009-09-22 16:46:34 -0700151{
152 struct mc33880 *mc;
153 int ret;
154
155 mc = dev_get_drvdata(&spi->dev);
156 if (mc == NULL)
157 return -ENODEV;
158
159 dev_set_drvdata(&spi->dev, NULL);
160
161 ret = gpiochip_remove(&mc->chip);
162 if (!ret) {
163 mutex_destroy(&mc->lock);
164 kfree(mc);
165 } else
166 dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
167 ret);
168
169 return ret;
170}
171
172static struct spi_driver mc33880_driver = {
173 .driver = {
174 .name = DRIVER_NAME,
175 .owner = THIS_MODULE,
176 },
177 .probe = mc33880_probe,
178 .remove = __devexit_p(mc33880_remove),
179};
180
181static int __init mc33880_init(void)
182{
183 return spi_register_driver(&mc33880_driver);
184}
185/* register after spi postcore initcall and before
186 * subsys initcalls that may rely on these GPIOs
187 */
188subsys_initcall(mc33880_init);
189
190static void __exit mc33880_exit(void)
191{
192 spi_unregister_driver(&mc33880_driver);
193}
194module_exit(mc33880_exit);
195
196MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
197MODULE_LICENSE("GPL v2");
198