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  */
  36 struct 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
  43 static int mc33880_write_config(struct mc33880 *mc)
  44 {
  45         return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));
  46 }
  47
  48
  49 static 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
  60 static 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
  71 static 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
 132 exit_destroy:
 133         mutex_destroy(&mc->lock);
 134         return ret;
 135 }
 136
 137 static 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
 151 static struct spi_driver mc33880_driver = {
 152         .driver = {
 153                 .name           = DRIVER_NAME,
 154         },
 155         .probe          = mc33880_probe,
 156         .remove         = mc33880_remove,
 157 };
 158
 159 static 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  */
 166 subsys_initcall(mc33880_init);
 167
 168 static void __exit mc33880_exit(void)
 169 {
 170         spi_unregister_driver(&mc33880_driver);
 171 }
 172 module_exit(mc33880_exit);
 173
 174 MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
 175 MODULE_LICENSE("GPL v2");
 176