Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 | /*
* w1-gpio - GPIO w1 bus master driver
*
* Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/w1-gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/of_platform.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/delay.h>
#include <linux/w1.h>
static u8 w1_gpio_set_pullup(void *data, int delay)
{
struct w1_gpio_platform_data *pdata = data;
if (delay) {
pdata->pullup_duration = delay;
} else {
if (pdata->pullup_duration) {
/*
* This will OVERRIDE open drain emulation and force-pull
* the line high for some time.
*/
gpiod_set_raw_value(pdata->gpiod, 1);
msleep(pdata->pullup_duration);
/*
* This will simply set the line as input since we are doing
* open drain emulation in the GPIO library.
*/
gpiod_set_value(pdata->gpiod, 1);
}
pdata->pullup_duration = 0;
}
return 0;
}
static void w1_gpio_write_bit(void *data, u8 bit)
{
struct w1_gpio_platform_data *pdata = data;
gpiod_set_value(pdata->gpiod, bit);
}
static u8 w1_gpio_read_bit(void *data)
{
struct w1_gpio_platform_data *pdata = data;
return gpiod_get_value(pdata->gpiod) ? 1 : 0;
}
#if defined(CONFIG_OF)
static const struct of_device_id w1_gpio_dt_ids[] = {
{ .compatible = "w1-gpio" },
{}
};
MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
#endif
static int w1_gpio_probe(struct platform_device *pdev)
{
struct w1_bus_master *master;
struct w1_gpio_platform_data *pdata;
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
/* Enforce open drain mode by default */
enum gpiod_flags gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
int err;
if (of_have_populated_dt()) {
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
/*
* This parameter means that something else than the gpiolib has
* already set the line into open drain mode, so we should just
* driver it high/low like we are in full control of the line and
* open drain will happen transparently.
*/
if (of_get_property(np, "linux,open-drain", NULL))
gflags = GPIOD_OUT_LOW;
pdev->dev.platform_data = pdata;
}
pdata = dev_get_platdata(dev);
if (!pdata) {
dev_err(dev, "No configuration data\n");
return -ENXIO;
}
master = devm_kzalloc(dev, sizeof(struct w1_bus_master),
GFP_KERNEL);
if (!master) {
dev_err(dev, "Out of memory\n");
return -ENOMEM;
}
pdata->gpiod = devm_gpiod_get_index(dev, NULL, 0, gflags);
if (IS_ERR(pdata->gpiod)) {
dev_err(dev, "gpio_request (pin) failed\n");
return PTR_ERR(pdata->gpiod);
}
pdata->pullup_gpiod =
devm_gpiod_get_index_optional(dev, NULL, 1, GPIOD_OUT_LOW);
if (IS_ERR(pdata->pullup_gpiod)) {
dev_err(dev, "gpio_request_one "
"(ext_pullup_enable_pin) failed\n");
return PTR_ERR(pdata->pullup_gpiod);
}
master->data = pdata;
master->read_bit = w1_gpio_read_bit;
gpiod_direction_output(pdata->gpiod, 1);
master->write_bit = w1_gpio_write_bit;
/*
* If we are using open drain emulation from the GPIO library,
* we need to use this pullup function that hammers the line
* high using a raw accessor to provide pull-up for the w1
* line.
*/
if (gflags == GPIOD_OUT_LOW_OPEN_DRAIN)
master->set_pullup = w1_gpio_set_pullup;
err = w1_add_master_device(master);
if (err) {
dev_err(dev, "w1_add_master device failed\n");
return err;
}
if (pdata->enable_external_pullup)
pdata->enable_external_pullup(1);
if (pdata->pullup_gpiod)
gpiod_set_value(pdata->pullup_gpiod, 1);
platform_set_drvdata(pdev, master);
return 0;
}
static int w1_gpio_remove(struct platform_device *pdev)
{
struct w1_bus_master *master = platform_get_drvdata(pdev);
struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
if (pdata->enable_external_pullup)
pdata->enable_external_pullup(0);
if (pdata->pullup_gpiod)
gpiod_set_value(pdata->pullup_gpiod, 0);
w1_remove_master_device(master);
return 0;
}
static int __maybe_unused w1_gpio_suspend(struct device *dev)
{
struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
if (pdata->enable_external_pullup)
pdata->enable_external_pullup(0);
return 0;
}
static int __maybe_unused w1_gpio_resume(struct device *dev)
{
struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
if (pdata->enable_external_pullup)
pdata->enable_external_pullup(1);
return 0;
}
static SIMPLE_DEV_PM_OPS(w1_gpio_pm_ops, w1_gpio_suspend, w1_gpio_resume);
static struct platform_driver w1_gpio_driver = {
.driver = {
.name = "w1-gpio",
.pm = &w1_gpio_pm_ops,
.of_match_table = of_match_ptr(w1_gpio_dt_ids),
},
.probe = w1_gpio_probe,
.remove = w1_gpio_remove,
};
module_platform_driver(w1_gpio_driver);
MODULE_DESCRIPTION("GPIO w1 bus master driver");
MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
MODULE_LICENSE("GPL");
|