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#include <linux/slab.h> 29 30#define DRIVER_NAME "mc33880" 31 32/* 33 * Pin configurations, see MAX7301 datasheet page 6 34 */ 35#define PIN_CONFIG_MASK 0x03 36#define PIN_CONFIG_IN_PULLUP 0x03 37#define PIN_CONFIG_IN_WO_PULLUP 0x02 38#define PIN_CONFIG_OUT 0x01 39 40#define PIN_NUMBER 8 41 42 43/* 44 * Some registers must be read back to modify. 45 * To save time we cache them here in memory 46 */ 47struct mc33880 { 48 struct mutex lock; /* protect from simultanous accesses */ 49 u8 port_config; 50 struct gpio_chip chip; 51 struct spi_device *spi; 52}; 53 54static int mc33880_write_config(struct mc33880 *mc) 55{ 56 return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config)); 57} 58 59 60static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value) 61{ 62 if (value) 63 mc->port_config |= 1 << offset; 64 else 65 mc->port_config &= ~(1 << offset); 66 67 return mc33880_write_config(mc); 68} 69 70 71static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value) 72{ 73 struct mc33880 *mc = container_of(chip, struct mc33880, chip); 74 75 mutex_lock(&mc->lock); 76 77 __mc33880_set(mc, offset, value); 78 79 mutex_unlock(&mc->lock); 80} 81 82static int __devinit mc33880_probe(struct spi_device *spi) 83{ 84 struct mc33880 *mc; 85 struct mc33880_platform_data *pdata; 86 int ret; 87 88 pdata = spi->dev.platform_data; 89 if (!pdata || !pdata->base) { 90 dev_dbg(&spi->dev, "incorrect or missing platform data\n"); 91 return -EINVAL; 92 } 93 94 /* 95 * bits_per_word cannot be configured in platform data 96 */ 97 spi->bits_per_word = 8; 98 99 ret = spi_setup(spi); 100 if (ret < 0) 101 return ret; 102 103 mc = kzalloc(sizeof(struct mc33880), GFP_KERNEL); 104 if (!mc) 105 return -ENOMEM; 106 107 mutex_init(&mc->lock); 108 109 dev_set_drvdata(&spi->dev, mc); 110 111 mc->spi = spi; 112 113 mc->chip.label = DRIVER_NAME, 114 mc->chip.set = mc33880_set; 115 mc->chip.base = pdata->base; 116 mc->chip.ngpio = PIN_NUMBER; 117 mc->chip.can_sleep = 1; 118 mc->chip.dev = &spi->dev; 119 mc->chip.owner = THIS_MODULE; 120 121 mc->port_config = 0x00; 122 /* write twice, because during initialisation the first setting 123 * is just for testing SPI communication, and the second is the 124 * "real" configuration 125 */ 126 ret = mc33880_write_config(mc); 127 mc->port_config = 0x00; 128 if (!ret) 129 ret = mc33880_write_config(mc); 130 131 if (ret) { 132 printk(KERN_ERR "Failed writing to " DRIVER_NAME ": %d\n", ret); 133 goto exit_destroy; 134 } 135 136 ret = gpiochip_add(&mc->chip); 137 if (ret) 138 goto exit_destroy; 139 140 return ret; 141 142exit_destroy: 143 dev_set_drvdata(&spi->dev, NULL); 144 mutex_destroy(&mc->lock); 145 kfree(mc); 146 return ret; 147} 148 149static int mc33880_remove(struct spi_device *spi) 150{ 151 struct mc33880 *mc; 152 int ret; 153 154 mc = dev_get_drvdata(&spi->dev); 155 if (mc == NULL) 156 return -ENODEV; 157 158 dev_set_drvdata(&spi->dev, NULL); 159 160 ret = gpiochip_remove(&mc->chip); 161 if (!ret) { 162 mutex_destroy(&mc->lock); 163 kfree(mc); 164 } else 165 dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n", 166 ret); 167 168 return ret; 169} 170 171static struct spi_driver mc33880_driver = { 172 .driver = { 173 .name = DRIVER_NAME, 174 .owner = THIS_MODULE, 175 }, 176 .probe = mc33880_probe, 177 .remove = __devexit_p(mc33880_remove), 178}; 179 180static int __init mc33880_init(void) 181{ 182 return spi_register_driver(&mc33880_driver); 183} 184/* register after spi postcore initcall and before 185 * subsys initcalls that may rely on these GPIOs 186 */ 187subsys_initcall(mc33880_init); 188 189static void __exit mc33880_exit(void) 190{ 191 spi_unregister_driver(&mc33880_driver); 192} 193module_exit(mc33880_exit); 194 195MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>"); 196MODULE_LICENSE("GPL v2"); 197