174 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * MC33880 high-side/low-side switch GPIO driver4 * Copyright (c) 2009 Intel Corporation5 */6 7/* Supports:8 * Freescale MC33880 high-side/low-side switch9 */10 11#include <linux/init.h>12#include <linux/mutex.h>13#include <linux/spi/spi.h>14#include <linux/spi/mc33880.h>15#include <linux/gpio/driver.h>16#include <linux/slab.h>17#include <linux/module.h>18 19#define DRIVER_NAME "mc33880"20 21/*22 * Pin configurations, see MAX7301 datasheet page 623 */24#define PIN_CONFIG_MASK 0x0325#define PIN_CONFIG_IN_PULLUP 0x0326#define PIN_CONFIG_IN_WO_PULLUP 0x0227#define PIN_CONFIG_OUT 0x0128 29#define PIN_NUMBER 830 31 32/*33 * Some registers must be read back to modify.34 * To save time we cache them here in memory35 */36struct mc33880 {37 struct mutex lock; /* protect from simultaneous accesses */38 u8 port_config;39 struct gpio_chip chip;40 struct spi_device *spi;41};42 43static int mc33880_write_config(struct mc33880 *mc)44{45 return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));46}47 48 49static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value)50{51 if (value)52 mc->port_config |= 1 << offset;53 else54 mc->port_config &= ~(1 << offset);55 56 return mc33880_write_config(mc);57}58 59 60static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value)61{62 struct mc33880 *mc = gpiochip_get_data(chip);63 64 mutex_lock(&mc->lock);65 66 __mc33880_set(mc, offset, value);67 68 mutex_unlock(&mc->lock);69}70 71static int mc33880_probe(struct spi_device *spi)72{73 struct mc33880 *mc;74 struct mc33880_platform_data *pdata;75 int ret;76 77 pdata = dev_get_platdata(&spi->dev);78 if (!pdata || !pdata->base) {79 dev_dbg(&spi->dev, "incorrect or missing platform data\n");80 return -EINVAL;81 }82 83 /*84 * bits_per_word cannot be configured in platform data85 */86 spi->bits_per_word = 8;87 88 ret = spi_setup(spi);89 if (ret < 0)90 return ret;91 92 mc = devm_kzalloc(&spi->dev, sizeof(struct mc33880), GFP_KERNEL);93 if (!mc)94 return -ENOMEM;95 96 mutex_init(&mc->lock);97 98 spi_set_drvdata(spi, mc);99 100 mc->spi = spi;101 102 mc->chip.label = DRIVER_NAME;103 mc->chip.set = mc33880_set;104 mc->chip.base = pdata->base;105 mc->chip.ngpio = PIN_NUMBER;106 mc->chip.can_sleep = true;107 mc->chip.parent = &spi->dev;108 mc->chip.owner = THIS_MODULE;109 110 mc->port_config = 0x00;111 /* write twice, because during initialisation the first setting112 * is just for testing SPI communication, and the second is the113 * "real" configuration114 */115 ret = mc33880_write_config(mc);116 mc->port_config = 0x00;117 if (!ret)118 ret = mc33880_write_config(mc);119 120 if (ret) {121 dev_err(&spi->dev, "Failed writing to " DRIVER_NAME ": %d\n",122 ret);123 goto exit_destroy;124 }125 126 ret = gpiochip_add_data(&mc->chip, mc);127 if (ret)128 goto exit_destroy;129 130 return ret;131 132exit_destroy:133 mutex_destroy(&mc->lock);134 return ret;135}136 137static void mc33880_remove(struct spi_device *spi)138{139 struct mc33880 *mc;140 141 mc = spi_get_drvdata(spi);142 143 gpiochip_remove(&mc->chip);144 mutex_destroy(&mc->lock);145}146 147static struct spi_driver mc33880_driver = {148 .driver = {149 .name = DRIVER_NAME,150 },151 .probe = mc33880_probe,152 .remove = mc33880_remove,153};154 155static int __init mc33880_init(void)156{157 return spi_register_driver(&mc33880_driver);158}159/* register after spi postcore initcall and before160 * subsys initcalls that may rely on these GPIOs161 */162subsys_initcall(mc33880_init);163 164static void __exit mc33880_exit(void)165{166 spi_unregister_driver(&mc33880_driver);167}168module_exit(mc33880_exit);169 170MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");171MODULE_DESCRIPTION("MC33880 high-side/low-side switch GPIO driver");172MODULE_LICENSE("GPL v2");173 174