linux/drivers/i2c/busses/i2c-gpio.c
Karol Lewandowski 44454baa7c i2c: Dynamically assign adapter id if it wasn't explictly specified
Commit 488bf314b ("i2c: Allow i2c_add_numbered_adapter() to assign a
bus id") reworked i2c_add_numbered_adapter() to call i2c_add_adapter()
if requested bus was -1.

This allows to simplify driver's initialization procedure by using
just one function for static and dynamic adapter id registration.

This patch updates few more drivers (missed out in original patch)
to use this functionality.

Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-05-12 14:28:11 +02:00

274 lines
6.6 KiB
C

/*
* Bitbanging I2C bus driver using the GPIO API
*
* Copyright (C) 2007 Atmel Corporation
*
* 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/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/i2c-gpio.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/of_i2c.h>
struct i2c_gpio_private_data {
struct i2c_adapter adap;
struct i2c_algo_bit_data bit_data;
struct i2c_gpio_platform_data pdata;
};
/* Toggle SDA by changing the direction of the pin */
static void i2c_gpio_setsda_dir(void *data, int state)
{
struct i2c_gpio_platform_data *pdata = data;
if (state)
gpio_direction_input(pdata->sda_pin);
else
gpio_direction_output(pdata->sda_pin, 0);
}
/*
* Toggle SDA by changing the output value of the pin. This is only
* valid for pins configured as open drain (i.e. setting the value
* high effectively turns off the output driver.)
*/
static void i2c_gpio_setsda_val(void *data, int state)
{
struct i2c_gpio_platform_data *pdata = data;
gpio_set_value(pdata->sda_pin, state);
}
/* Toggle SCL by changing the direction of the pin. */
static void i2c_gpio_setscl_dir(void *data, int state)
{
struct i2c_gpio_platform_data *pdata = data;
if (state)
gpio_direction_input(pdata->scl_pin);
else
gpio_direction_output(pdata->scl_pin, 0);
}
/*
* Toggle SCL by changing the output value of the pin. This is used
* for pins that are configured as open drain and for output-only
* pins. The latter case will break the i2c protocol, but it will
* often work in practice.
*/
static void i2c_gpio_setscl_val(void *data, int state)
{
struct i2c_gpio_platform_data *pdata = data;
gpio_set_value(pdata->scl_pin, state);
}
static int i2c_gpio_getsda(void *data)
{
struct i2c_gpio_platform_data *pdata = data;
return gpio_get_value(pdata->sda_pin);
}
static int i2c_gpio_getscl(void *data)
{
struct i2c_gpio_platform_data *pdata = data;
return gpio_get_value(pdata->scl_pin);
}
static int __devinit of_i2c_gpio_probe(struct device_node *np,
struct i2c_gpio_platform_data *pdata)
{
u32 reg;
if (of_gpio_count(np) < 2)
return -ENODEV;
pdata->sda_pin = of_get_gpio(np, 0);
pdata->scl_pin = of_get_gpio(np, 1);
if (!gpio_is_valid(pdata->sda_pin) || !gpio_is_valid(pdata->scl_pin)) {
pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
np->full_name, pdata->sda_pin, pdata->scl_pin);
return -ENODEV;
}
of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", &reg))
pdata->timeout = msecs_to_jiffies(reg);
pdata->sda_is_open_drain =
of_property_read_bool(np, "i2c-gpio,sda-open-drain");
pdata->scl_is_open_drain =
of_property_read_bool(np, "i2c-gpio,scl-open-drain");
pdata->scl_is_output_only =
of_property_read_bool(np, "i2c-gpio,scl-output-only");
return 0;
}
static int __devinit i2c_gpio_probe(struct platform_device *pdev)
{
struct i2c_gpio_private_data *priv;
struct i2c_gpio_platform_data *pdata;
struct i2c_algo_bit_data *bit_data;
struct i2c_adapter *adap;
int ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
adap = &priv->adap;
bit_data = &priv->bit_data;
pdata = &priv->pdata;
if (pdev->dev.of_node) {
ret = of_i2c_gpio_probe(pdev->dev.of_node, pdata);
if (ret)
return ret;
} else {
if (!pdev->dev.platform_data)
return -ENXIO;
memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
}
ret = gpio_request(pdata->sda_pin, "sda");
if (ret)
goto err_request_sda;
ret = gpio_request(pdata->scl_pin, "scl");
if (ret)
goto err_request_scl;
if (pdata->sda_is_open_drain) {
gpio_direction_output(pdata->sda_pin, 1);
bit_data->setsda = i2c_gpio_setsda_val;
} else {
gpio_direction_input(pdata->sda_pin);
bit_data->setsda = i2c_gpio_setsda_dir;
}
if (pdata->scl_is_open_drain || pdata->scl_is_output_only) {
gpio_direction_output(pdata->scl_pin, 1);
bit_data->setscl = i2c_gpio_setscl_val;
} else {
gpio_direction_input(pdata->scl_pin);
bit_data->setscl = i2c_gpio_setscl_dir;
}
if (!pdata->scl_is_output_only)
bit_data->getscl = i2c_gpio_getscl;
bit_data->getsda = i2c_gpio_getsda;
if (pdata->udelay)
bit_data->udelay = pdata->udelay;
else if (pdata->scl_is_output_only)
bit_data->udelay = 50; /* 10 kHz */
else
bit_data->udelay = 5; /* 100 kHz */
if (pdata->timeout)
bit_data->timeout = pdata->timeout;
else
bit_data->timeout = HZ / 10; /* 100 ms */
bit_data->data = pdata;
adap->owner = THIS_MODULE;
snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);
adap->algo_data = bit_data;
adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
adap->dev.parent = &pdev->dev;
adap->dev.of_node = pdev->dev.of_node;
adap->nr = pdev->id;
ret = i2c_bit_add_numbered_bus(adap);
if (ret)
goto err_add_bus;
of_i2c_register_devices(adap);
platform_set_drvdata(pdev, priv);
dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n",
pdata->sda_pin, pdata->scl_pin,
pdata->scl_is_output_only
? ", no clock stretching" : "");
return 0;
err_add_bus:
gpio_free(pdata->scl_pin);
err_request_scl:
gpio_free(pdata->sda_pin);
err_request_sda:
return ret;
}
static int __devexit i2c_gpio_remove(struct platform_device *pdev)
{
struct i2c_gpio_private_data *priv;
struct i2c_gpio_platform_data *pdata;
struct i2c_adapter *adap;
priv = platform_get_drvdata(pdev);
adap = &priv->adap;
pdata = &priv->pdata;
i2c_del_adapter(adap);
gpio_free(pdata->scl_pin);
gpio_free(pdata->sda_pin);
return 0;
}
#if defined(CONFIG_OF)
static const struct of_device_id i2c_gpio_dt_ids[] = {
{ .compatible = "i2c-gpio", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
#endif
static struct platform_driver i2c_gpio_driver = {
.driver = {
.name = "i2c-gpio",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(i2c_gpio_dt_ids),
},
.probe = i2c_gpio_probe,
.remove = __devexit_p(i2c_gpio_remove),
};
static int __init i2c_gpio_init(void)
{
int ret;
ret = platform_driver_register(&i2c_gpio_driver);
if (ret)
printk(KERN_ERR "i2c-gpio: probe failed: %d\n", ret);
return ret;
}
subsys_initcall(i2c_gpio_init);
static void __exit i2c_gpio_exit(void)
{
platform_driver_unregister(&i2c_gpio_driver);
}
module_exit(i2c_gpio_exit);
MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
MODULE_DESCRIPTION("Platform-independent bitbanging I2C driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:i2c-gpio");