2 * mc33880.c MC33880 high-side/low-side switch GPIO driver
3 * Copyright (c) 2009 Intel Corporation
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.
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.
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.
20 * Freescale MC33880 high-side/low-side switch
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>
29 #define DRIVER_NAME "mc33880"
32 * Pin configurations, see MAX7301 datasheet page 6
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
43 * Some registers must be read back to modify.
44 * To save time we cache them here in memory
47 struct mutex lock; /* protect from simultanous accesses */
49 struct gpio_chip chip;
50 struct spi_device *spi;
53 static int mc33880_write_config(struct mc33880 *mc)
55 return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));
59 static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value)
62 mc->port_config |= 1 << offset;
64 mc->port_config &= ~(1 << offset);
66 return mc33880_write_config(mc);
70 static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value)
72 struct mc33880 *mc = container_of(chip, struct mc33880, chip);
74 mutex_lock(&mc->lock);
76 __mc33880_set(mc, offset, value);
78 mutex_unlock(&mc->lock);
81 static int __devinit mc33880_probe(struct spi_device *spi)
84 struct mc33880_platform_data *pdata;
87 pdata = spi->dev.platform_data;
88 if (!pdata || !pdata->base) {
89 dev_dbg(&spi->dev, "incorrect or missing platform data\n");
94 * bits_per_word cannot be configured in platform data
96 spi->bits_per_word = 8;
102 mc = kzalloc(sizeof(struct mc33880), GFP_KERNEL);
106 mutex_init(&mc->lock);
108 dev_set_drvdata(&spi->dev, mc);
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;
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
125 ret = mc33880_write_config(mc);
126 mc->port_config = 0x00;
128 ret = mc33880_write_config(mc);
131 printk(KERN_ERR "Failed writing to " DRIVER_NAME ": %d\n", ret);
135 ret = gpiochip_add(&mc->chip);
142 dev_set_drvdata(&spi->dev, NULL);
143 mutex_destroy(&mc->lock);
148 static int mc33880_remove(struct spi_device *spi)
153 mc = dev_get_drvdata(&spi->dev);
157 dev_set_drvdata(&spi->dev, NULL);
159 ret = gpiochip_remove(&mc->chip);
161 mutex_destroy(&mc->lock);
164 dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
170 static struct spi_driver mc33880_driver = {
173 .owner = THIS_MODULE,
175 .probe = mc33880_probe,
176 .remove = __devexit_p(mc33880_remove),
179 static int __init mc33880_init(void)
181 return spi_register_driver(&mc33880_driver);
183 /* register after spi postcore initcall and before
184 * subsys initcalls that may rely on these GPIOs
186 subsys_initcall(mc33880_init);
188 static void __exit mc33880_exit(void)
190 spi_unregister_driver(&mc33880_driver);
192 module_exit(mc33880_exit);
194 MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
195 MODULE_LICENSE("GPL v2");