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/*
* 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.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/delay.h>
#include "../w1.h"
#include "../w1_int.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) {
gpio_direction_output(pdata->pin, 1);
msleep(pdata->pullup_duration);
gpio_direction_input(pdata->pin);
}
pdata->pullup_duration = 0;
}
return 0;
}
static void w1_gpio_write_bit_dir(void *data, u8 bit)
{
struct w1_gpio_platform_data *pdata = data;
if (bit)
gpio_direction_input(pdata->pin);
else
gpio_direction_output(pdata->pin, 0);
}
static void w1_gpio_write_bit_val(void *data, u8 bit)
{
struct w1_gpio_platform_data *pdata = data;
gpio_set_value(pdata->pin, bit);
}
static u8 w1_gpio_read_bit(void *data)
{
struct w1_gpio_platform_data *pdata = data;
return gpio_get_value(pdata->pin) ? 1 : 0;
}
#if defined(CONFIG_OF)
static 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_dt(struct platform_device *pdev)
{
struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
struct device_node *np = pdev->dev.of_node;
int gpio;
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
if (of_get_property(np, "linux,open-drain", NULL))
pdata->is_open_drain = 1;
gpio = of_get_gpio(np, 0);
if (gpio < 0) {
if (gpio != -EPROBE_DEFER)
dev_err(&pdev->dev,
"Failed to parse gpio property for data pin (%d)\n",
gpio);
return gpio;
}
pdata->pin = gpio;
gpio = of_get_gpio(np, 1);
if (gpio == -EPROBE_DEFER)
return gpio;
/* ignore other errors as the pullup gpio is optional */
pdata->ext_pullup_enable_pin = gpio;
pdev->dev.platform_data = pdata;
return 0;
}
static int w1_gpio_probe(struct platform_device *pdev)
{
struct w1_bus_master *master;
struct w1_gpio_platform_data *pdata;
int err;
if (of_have_populated_dt()) {
err = w1_gpio_probe_dt(pdev);
if (err < 0)
return err;
}
pdata = dev_get_platdata(&pdev->dev);
if (!pdata) {
dev_err(&pdev->dev, "No configuration data\n");
return -ENXIO;
}
master = devm_kzalloc(&pdev->dev, sizeof(struct w1_bus_master),
GFP_KERNEL);
if (!master) {
dev_err(&pdev->dev, "Out of memory\n");
return -ENOMEM;
}
err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
if (err) {
dev_err(&pdev->dev, "gpio_request (pin) failed\n");
return err;
}
if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
err = devm_gpio_request_one(&pdev->dev,
pdata->ext_pullup_enable_pin, GPIOF_INIT_LOW,
"w1 pullup");
if (err < 0) {
dev_err(&pdev->dev, "gpio_request_one "
"(ext_pullup_enable_pin) failed\n");
return err;
}
}
master->data = pdata;
master->read_bit = w1_gpio_read_bit;
if (pdata->is_open_drain) {
gpio_direction_output(pdata->pin, 1);
master->write_bit = w1_gpio_write_bit_val;
} else {
gpio_direction_input(pdata->pin);
master->write_bit = w1_gpio_write_bit_dir;
master->set_pullup = w1_gpio_set_pullup;
}
err = w1_add_master_device(master);
if (err) {
dev_err(&pdev->dev, "w1_add_master device failed\n");
return err;
}
if (pdata->enable_external_pullup)
pdata->enable_external_pullup(1);
if (gpio_is_valid(pdata->ext_pullup_enable_pin))
gpio_set_value(pdata->ext_pullup_enable_pin, 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 (gpio_is_valid(pdata->ext_pullup_enable_pin))
gpio_set_value(pdata->ext_pullup_enable_pin, 0);
w1_remove_master_device(master);
return 0;
}
#ifdef CONFIG_PM
static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
{
struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
if (pdata->enable_external_pullup)
pdata->enable_external_pullup(0);
return 0;
}
static int w1_gpio_resume(struct platform_device *pdev)
{
struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
if (pdata->enable_external_pullup)
pdata->enable_external_pullup(1);
return 0;
}
#else
#define w1_gpio_suspend NULL
#define w1_gpio_resume NULL
#endif
static struct platform_driver w1_gpio_driver = {
.driver = {
.name = "w1-gpio",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(w1_gpio_dt_ids),
},
.probe = w1_gpio_probe,
.remove = w1_gpio_remove,
.suspend = w1_gpio_suspend,
.resume = w1_gpio_resume,
};
module_platform_driver(w1_gpio_driver);
MODULE_DESCRIPTION("GPIO w1 bus master driver");
MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
MODULE_LICENSE("GPL");
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