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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 | // SPDX-License-Identifier: GPL-2.0-only /* * MC33880 high-side/low-side switch GPIO driver * Copyright (c) 2009 Intel Corporation */ /* Supports: * Freescale MC33880 high-side/low-side switch */ #include <linux/init.h> #include <linux/mutex.h> #include <linux/spi/spi.h> #include <linux/spi/mc33880.h> #include <linux/gpio/driver.h> #include <linux/slab.h> #include <linux/module.h> #define DRIVER_NAME "mc33880" /* * Pin configurations, see MAX7301 datasheet page 6 */ #define PIN_CONFIG_MASK 0x03 #define PIN_CONFIG_IN_PULLUP 0x03 #define PIN_CONFIG_IN_WO_PULLUP 0x02 #define PIN_CONFIG_OUT 0x01 #define PIN_NUMBER 8 /* * Some registers must be read back to modify. * To save time we cache them here in memory */ struct mc33880 { struct mutex lock; /* protect from simultaneous accesses */ u8 port_config; struct gpio_chip chip; struct spi_device *spi; }; static int mc33880_write_config(struct mc33880 *mc) { return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config)); } static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value) { if (value) mc->port_config |= 1 << offset; else mc->port_config &= ~(1 << offset); return mc33880_write_config(mc); } static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value) { struct mc33880 *mc = gpiochip_get_data(chip); mutex_lock(&mc->lock); __mc33880_set(mc, offset, value); mutex_unlock(&mc->lock); } static int mc33880_probe(struct spi_device *spi) { struct mc33880 *mc; struct mc33880_platform_data *pdata; int ret; pdata = dev_get_platdata(&spi->dev); 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; mc = devm_kzalloc(&spi->dev, sizeof(struct mc33880), GFP_KERNEL); if (!mc) return -ENOMEM; mutex_init(&mc->lock); spi_set_drvdata(spi, mc); mc->spi = spi; mc->chip.label = DRIVER_NAME, mc->chip.set = mc33880_set; mc->chip.base = pdata->base; mc->chip.ngpio = PIN_NUMBER; mc->chip.can_sleep = true; mc->chip.parent = &spi->dev; mc->chip.owner = THIS_MODULE; mc->port_config = 0x00; /* write twice, because during initialisation the first setting * is just for testing SPI communication, and the second is the * "real" configuration */ ret = mc33880_write_config(mc); mc->port_config = 0x00; if (!ret) ret = mc33880_write_config(mc); if (ret) { dev_err(&spi->dev, "Failed writing to " DRIVER_NAME ": %d\n", ret); goto exit_destroy; } ret = gpiochip_add_data(&mc->chip, mc); if (ret) goto exit_destroy; return ret; exit_destroy: mutex_destroy(&mc->lock); return ret; } static void mc33880_remove(struct spi_device *spi) { struct mc33880 *mc; mc = spi_get_drvdata(spi); gpiochip_remove(&mc->chip); mutex_destroy(&mc->lock); } static struct spi_driver mc33880_driver = { .driver = { .name = DRIVER_NAME, }, .probe = mc33880_probe, .remove = mc33880_remove, }; static int __init mc33880_init(void) { return spi_register_driver(&mc33880_driver); } /* register after spi postcore initcall and before * subsys initcalls that may rely on these GPIOs */ subsys_initcall(mc33880_init); static void __exit mc33880_exit(void) { spi_unregister_driver(&mc33880_driver); } module_exit(mc33880_exit); MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>"); MODULE_LICENSE("GPL v2"); |