8d0df7a3d1
W1 master implementations are expected to return 0 or 1 from their read_bit() function. However, not all platforms do return these values from gpio_get_value() - namely PXAs won't. Hence the w1 gpio-master needs to break the result down to 0 or 1 itself. Signed-off-by: Daniel Mack <daniel@caiaq.de> Cc: Ville Syrjala <syrjala@sci.fi> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
124 lines
2.5 KiB
C
124 lines
2.5 KiB
C
/*
|
|
* 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/w1-gpio.h>
|
|
|
|
#include "../w1.h"
|
|
#include "../w1_int.h"
|
|
|
|
#include <asm/gpio.h>
|
|
|
|
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;
|
|
}
|
|
|
|
static int __init w1_gpio_probe(struct platform_device *pdev)
|
|
{
|
|
struct w1_bus_master *master;
|
|
struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
|
|
int err;
|
|
|
|
if (!pdata)
|
|
return -ENXIO;
|
|
|
|
master = kzalloc(sizeof(struct w1_bus_master), GFP_KERNEL);
|
|
if (!master)
|
|
return -ENOMEM;
|
|
|
|
err = gpio_request(pdata->pin, "w1");
|
|
if (err)
|
|
goto free_master;
|
|
|
|
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;
|
|
}
|
|
|
|
err = w1_add_master_device(master);
|
|
if (err)
|
|
goto free_gpio;
|
|
|
|
platform_set_drvdata(pdev, master);
|
|
|
|
return 0;
|
|
|
|
free_gpio:
|
|
gpio_free(pdata->pin);
|
|
free_master:
|
|
kfree(master);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int __exit w1_gpio_remove(struct platform_device *pdev)
|
|
{
|
|
struct w1_bus_master *master = platform_get_drvdata(pdev);
|
|
struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
|
|
|
|
w1_remove_master_device(master);
|
|
gpio_free(pdata->pin);
|
|
kfree(master);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver w1_gpio_driver = {
|
|
.driver = {
|
|
.name = "w1-gpio",
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.remove = __exit_p(w1_gpio_remove),
|
|
};
|
|
|
|
static int __init w1_gpio_init(void)
|
|
{
|
|
return platform_driver_probe(&w1_gpio_driver, w1_gpio_probe);
|
|
}
|
|
|
|
static void __exit w1_gpio_exit(void)
|
|
{
|
|
platform_driver_unregister(&w1_gpio_driver);
|
|
}
|
|
|
|
module_init(w1_gpio_init);
|
|
module_exit(w1_gpio_exit);
|
|
|
|
MODULE_DESCRIPTION("GPIO w1 bus master driver");
|
|
MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
|
|
MODULE_LICENSE("GPL");
|