LXR linux/drivers/gpio/gpio-mc33880.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * MC33880 high-side/low-side switch GPIO driver
   4 * Copyright (c) 2009 Intel Corporation
   5 */
   6
   7/* Supports:
   8 * Freescale MC33880 high-side/low-side switch
   9 */
  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 6
  23 */
  24#define PIN_CONFIG_MASK 0x03
  25#define PIN_CONFIG_IN_PULLUP 0x03
  26#define PIN_CONFIG_IN_WO_PULLUP 0x02
  27#define PIN_CONFIG_OUT 0x01
  28
  29#define PIN_NUMBER 8
  30
  31
  32/*
  33 * Some registers must be read back to modify.
  34 * To save time we cache them here in memory
  35 */
  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        else
  54                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 data
  85         */
  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 setting
 112         * is just for testing SPI communication, and the second is the
 113         * "real" configuration
 114         */
 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 int mc33880_remove(struct spi_device *spi)
 138{
 139        struct mc33880 *mc;
 140
 141        mc = spi_get_drvdata(spi);
 142        if (!mc)
 143                return -ENODEV;
 144
 145        gpiochip_remove(&mc->chip);
 146        mutex_destroy(&mc->lock);
 147
 148        return 0;
 149}
 150
 151static struct spi_driver mc33880_driver = {
 152        .driver = {
 153                .name           = DRIVER_NAME,
 154        },
 155        .probe          = mc33880_probe,
 156        .remove         = mc33880_remove,
 157};
 158
 159static int __init mc33880_init(void)
 160{
 161        return spi_register_driver(&mc33880_driver);
 162}
 163/* register after spi postcore initcall and before
 164 * subsys initcalls that may rely on these GPIOs
 165 */
 166subsys_initcall(mc33880_init);
 167
 168static void __exit mc33880_exit(void)
 169{
 170        spi_unregister_driver(&mc33880_driver);
 171}
 172module_exit(mc33880_exit);
 173
 174MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
 175MODULE_LICENSE("GPL v2");
 176
 177