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); 142 143 gpiochip_remove(&mc->chip); 144 mutex_destroy(&mc->lock); 145 146 return 0; 147 } 148 149 static struct spi_driver mc33880_driver = { 150 .driver = { 151 .name = DRIVER_NAME, 152 }, 153 .probe = mc33880_probe, 154 .remove = mc33880_remove, 155 }; 156 157 static int __init mc33880_init(void) 158 { 159 return spi_register_driver(&mc33880_driver); 160 } 161 /* register after spi postcore initcall and before 162 * subsys initcalls that may rely on these GPIOs 163 */ 164 subsys_initcall(mc33880_init); 165 166 static void __exit mc33880_exit(void) 167 { 168 spi_unregister_driver(&mc33880_driver); 169 } 170 module_exit(mc33880_exit); 171 172 MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>"); 173 MODULE_LICENSE("GPL v2"); 174 175