drivers/gpio/gpio-mc33880.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * MC33880 high-side/low-side switch GPIO driver
0004  * Copyright (c) 2009 Intel Corporation
0005  */
0006
0007 /* Supports:
0008  * Freescale MC33880 high-side/low-side switch
0009  */
0010
0011 #include <linux/init.h>
0012 #include <linux/mutex.h>
0013 #include <linux/spi/spi.h>
0014 #include <linux/spi/mc33880.h>
0015 #include <linux/gpio/driver.h>
0016 #include <linux/slab.h>
0017 #include <linux/module.h>
0018
0019 #define DRIVER_NAME "mc33880"
0020
0021 /*
0022  * Pin configurations, see MAX7301 datasheet page 6
0023  */
0024 #define PIN_CONFIG_MASK 0x03
0025 #define PIN_CONFIG_IN_PULLUP 0x03
0026 #define PIN_CONFIG_IN_WO_PULLUP 0x02
0027 #define PIN_CONFIG_OUT 0x01
0028
0029 #define PIN_NUMBER 8
0030
0031
0032 /*
0033  * Some registers must be read back to modify.
0034  * To save time we cache them here in memory
0035  */
0036 struct mc33880 {
0037     struct mutex    lock;   /* protect from simultaneous accesses */
0038     u8      port_config;
0039     struct gpio_chip chip;
0040     struct spi_device *spi;
0041 };
0042
0043 static int mc33880_write_config(struct mc33880 *mc)
0044 {
0045     return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));
0046 }
0047
0048
0049 static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value)
0050 {
0051     if (value)
0052         mc->port_config |= 1 << offset;
0053     else
0054         mc->port_config &= ~(1 << offset);
0055
0056     return mc33880_write_config(mc);
0057 }
0058
0059
0060 static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value)
0061 {
0062     struct mc33880 *mc = gpiochip_get_data(chip);
0063
0064     mutex_lock(&mc->lock);
0065
0066     __mc33880_set(mc, offset, value);
0067
0068     mutex_unlock(&mc->lock);
0069 }
0070
0071 static int mc33880_probe(struct spi_device *spi)
0072 {
0073     struct mc33880 *mc;
0074     struct mc33880_platform_data *pdata;
0075     int ret;
0076
0077     pdata = dev_get_platdata(&spi->dev);
0078     if (!pdata || !pdata->base) {
0079         dev_dbg(&spi->dev, "incorrect or missing platform data\n");
0080         return -EINVAL;
0081     }
0082
0083     /*
0084      * bits_per_word cannot be configured in platform data
0085      */
0086     spi->bits_per_word = 8;
0087
0088     ret = spi_setup(spi);
0089     if (ret < 0)
0090         return ret;
0091
0092     mc = devm_kzalloc(&spi->dev, sizeof(struct mc33880), GFP_KERNEL);
0093     if (!mc)
0094         return -ENOMEM;
0095
0096     mutex_init(&mc->lock);
0097
0098     spi_set_drvdata(spi, mc);
0099
0100     mc->spi = spi;
0101
0102     mc->chip.label = DRIVER_NAME,
0103     mc->chip.set = mc33880_set;
0104     mc->chip.base = pdata->base;
0105     mc->chip.ngpio = PIN_NUMBER;
0106     mc->chip.can_sleep = true;
0107     mc->chip.parent = &spi->dev;
0108     mc->chip.owner = THIS_MODULE;
0109
0110     mc->port_config = 0x00;
0111     /* write twice, because during initialisation the first setting
0112      * is just for testing SPI communication, and the second is the
0113      * "real" configuration
0114      */
0115     ret = mc33880_write_config(mc);
0116     mc->port_config = 0x00;
0117     if (!ret)
0118         ret = mc33880_write_config(mc);
0119
0120     if (ret) {
0121         dev_err(&spi->dev, "Failed writing to " DRIVER_NAME ": %d\n",
0122             ret);
0123         goto exit_destroy;
0124     }
0125
0126     ret = gpiochip_add_data(&mc->chip, mc);
0127     if (ret)
0128         goto exit_destroy;
0129
0130     return ret;
0131
0132 exit_destroy:
0133     mutex_destroy(&mc->lock);
0134     return ret;
0135 }
0136
0137 static void mc33880_remove(struct spi_device *spi)
0138 {
0139     struct mc33880 *mc;
0140
0141     mc = spi_get_drvdata(spi);
0142
0143     gpiochip_remove(&mc->chip);
0144     mutex_destroy(&mc->lock);
0145 }
0146
0147 static struct spi_driver mc33880_driver = {
0148     .driver = {
0149         .name       = DRIVER_NAME,
0150     },
0151     .probe      = mc33880_probe,
0152     .remove     = mc33880_remove,
0153 };
0154
0155 static int __init mc33880_init(void)
0156 {
0157     return spi_register_driver(&mc33880_driver);
0158 }
0159 /* register after spi postcore initcall and before
0160  * subsys initcalls that may rely on these GPIOs
0161  */
0162 subsys_initcall(mc33880_init);
0163
0164 static void __exit mc33880_exit(void)
0165 {
0166     spi_unregister_driver(&mc33880_driver);
0167 }
0168 module_exit(mc33880_exit);
0169
0170 MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
0171 MODULE_LICENSE("GPL v2");
0172