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 int mc33880_set(struct gpio_chip *chip, unsigned int offset, int value) 61 { 62 struct mc33880 *mc = gpiochip_get_data(chip); 63 int ret; 64 65 mutex_lock(&mc->lock); 66 67 ret = __mc33880_set(mc, offset, value); 68 69 mutex_unlock(&mc->lock); 70 71 return ret; 72 } 73 74 static int mc33880_probe(struct spi_device *spi) 75 { 76 struct mc33880 *mc; 77 struct mc33880_platform_data *pdata; 78 int ret; 79 80 pdata = dev_get_platdata(&spi->dev); 81 if (!pdata || !pdata->base) { 82 dev_dbg(&spi->dev, "incorrect or missing platform data\n"); 83 return -EINVAL; 84 } 85 86 /* 87 * bits_per_word cannot be configured in platform data 88 */ 89 spi->bits_per_word = 8; 90 91 ret = spi_setup(spi); 92 if (ret < 0) 93 return ret; 94 95 mc = devm_kzalloc(&spi->dev, sizeof(struct mc33880), GFP_KERNEL); 96 if (!mc) 97 return -ENOMEM; 98 99 mutex_init(&mc->lock); 100 101 spi_set_drvdata(spi, mc); 102 103 mc->spi = spi; 104 105 mc->chip.label = DRIVER_NAME; 106 mc->chip.set = mc33880_set; 107 mc->chip.base = pdata->base; 108 mc->chip.ngpio = PIN_NUMBER; 109 mc->chip.can_sleep = true; 110 mc->chip.parent = &spi->dev; 111 mc->chip.owner = THIS_MODULE; 112 113 mc->port_config = 0x00; 114 /* write twice, because during initialisation the first setting 115 * is just for testing SPI communication, and the second is the 116 * "real" configuration 117 */ 118 ret = mc33880_write_config(mc); 119 mc->port_config = 0x00; 120 if (!ret) 121 ret = mc33880_write_config(mc); 122 123 if (ret) { 124 dev_err(&spi->dev, "Failed writing to " DRIVER_NAME ": %d\n", 125 ret); 126 goto exit_destroy; 127 } 128 129 ret = gpiochip_add_data(&mc->chip, mc); 130 if (ret) 131 goto exit_destroy; 132 133 return ret; 134 135 exit_destroy: 136 mutex_destroy(&mc->lock); 137 return ret; 138 } 139 140 static void mc33880_remove(struct spi_device *spi) 141 { 142 struct mc33880 *mc; 143 144 mc = spi_get_drvdata(spi); 145 146 gpiochip_remove(&mc->chip); 147 mutex_destroy(&mc->lock); 148 } 149 150 static struct spi_driver mc33880_driver = { 151 .driver = { 152 .name = DRIVER_NAME, 153 }, 154 .probe = mc33880_probe, 155 .remove = mc33880_remove, 156 }; 157 158 static int __init mc33880_init(void) 159 { 160 return spi_register_driver(&mc33880_driver); 161 } 162 /* register after spi postcore initcall and before 163 * subsys initcalls that may rely on these GPIOs 164 */ 165 subsys_initcall(mc33880_init); 166 167 static void __exit mc33880_exit(void) 168 { 169 spi_unregister_driver(&mc33880_driver); 170 } 171 module_exit(mc33880_exit); 172 173 MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>"); 174 MODULE_DESCRIPTION("MC33880 high-side/low-side switch GPIO driver"); 175 MODULE_LICENSE("GPL v2"); 176 177