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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 | /* * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver * * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org> * Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/init.h> #include <linux/mutex.h> #include <linux/spi/spi.h> #include <linux/spi/74x164.h> #include <linux/gpio.h> #include <linux/slab.h> #include <linux/module.h> struct gen_74x164_chip { struct spi_device *spi; struct gpio_chip gpio_chip; struct mutex lock; u8 port_config; }; static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc) { return container_of(gc, struct gen_74x164_chip, gpio_chip); } static int __gen_74x164_write_config(struct gen_74x164_chip *chip) { return spi_write(chip->spi, &chip->port_config, sizeof(chip->port_config)); } static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset) { struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc); int ret; mutex_lock(&chip->lock); ret = (chip->port_config >> offset) & 0x1; mutex_unlock(&chip->lock); return ret; } static void gen_74x164_set_value(struct gpio_chip *gc, unsigned offset, int val) { struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc); mutex_lock(&chip->lock); if (val) chip->port_config |= (1 << offset); else chip->port_config &= ~(1 << offset); __gen_74x164_write_config(chip); mutex_unlock(&chip->lock); } static int gen_74x164_direction_output(struct gpio_chip *gc, unsigned offset, int val) { gen_74x164_set_value(gc, offset, val); return 0; } static int __devinit gen_74x164_probe(struct spi_device *spi) { struct gen_74x164_chip *chip; struct gen_74x164_chip_platform_data *pdata; int ret; pdata = spi->dev.platform_data; if (!pdata || !pdata->base) { dev_dbg(&spi->dev, "incorrect or missing platform data\n"); return -EINVAL; } /* * bits_per_word cannot be configured in platform data */ spi->bits_per_word = 8; ret = spi_setup(spi); if (ret < 0) return ret; chip = kzalloc(sizeof(*chip), GFP_KERNEL); if (!chip) return -ENOMEM; mutex_init(&chip->lock); dev_set_drvdata(&spi->dev, chip); chip->spi = spi; chip->gpio_chip.label = spi->modalias; chip->gpio_chip.direction_output = gen_74x164_direction_output; chip->gpio_chip.get = gen_74x164_get_value; chip->gpio_chip.set = gen_74x164_set_value; chip->gpio_chip.base = pdata->base; chip->gpio_chip.ngpio = 8; chip->gpio_chip.can_sleep = 1; chip->gpio_chip.dev = &spi->dev; chip->gpio_chip.owner = THIS_MODULE; ret = __gen_74x164_write_config(chip); if (ret) { dev_err(&spi->dev, "Failed writing: %d\n", ret); goto exit_destroy; } ret = gpiochip_add(&chip->gpio_chip); if (ret) goto exit_destroy; return ret; exit_destroy: dev_set_drvdata(&spi->dev, NULL); mutex_destroy(&chip->lock); kfree(chip); return ret; } static int __devexit gen_74x164_remove(struct spi_device *spi) { struct gen_74x164_chip *chip; int ret; chip = dev_get_drvdata(&spi->dev); if (chip == NULL) return -ENODEV; dev_set_drvdata(&spi->dev, NULL); ret = gpiochip_remove(&chip->gpio_chip); if (!ret) { mutex_destroy(&chip->lock); kfree(chip); } else dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n", ret); return ret; } static struct spi_driver gen_74x164_driver = { .driver = { .name = "74x164", .owner = THIS_MODULE, }, .probe = gen_74x164_probe, .remove = __devexit_p(gen_74x164_remove), }; static int __init gen_74x164_init(void) { return spi_register_driver(&gen_74x164_driver); } subsys_initcall(gen_74x164_init); static void __exit gen_74x164_exit(void) { spi_unregister_driver(&gen_74x164_driver); } module_exit(gen_74x164_exit); MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>"); MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>"); MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register"); MODULE_LICENSE("GPL v2"); |