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i2c/gpio: add DT support 

To achieve DT support, we need to populate a custom platform_data in a
private struct from DT information. To simplify code, the adapter and
algorithm are also put into the private struct.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
This commit is contained in:
Jean-Christophe PLAGNIOL-VILLARD 2012-02-05 18:22:34 +08:00
parent 86a89f4ff6
commit 8ffaa0f40d
2 changed files with 106 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
Documentation/devicetree/bindings/gpio/gpio_i2c.txt Normal file
View File

@ -0,0 +1,32 @@
Device-Tree bindings for i2c gpio driver
Required properties:
- compatible = "i2c-gpio";
- gpios: sda and scl gpio
Optional properties:
- i2c-gpio,sda-open-drain: sda as open drain
- i2c-gpio,scl-open-drain: scl as open drain
- i2c-gpio,scl-output-only: scl as output only
- i2c-gpio,delay-us: delay between GPIO operations (may depend on each platform)
- i2c-gpio,timeout-ms: timeout to get data
Example nodes:
i2c@0 {
compatible = "i2c-gpio";
gpios = <&pioA 23 0 /* sda */
&pioA 24 0 /* scl */
>;
i2c-gpio,sda-open-drain;
i2c-gpio,scl-open-drain;
i2c-gpio,delay-us = <2>; /* ~100 kHz */
#address-cells = <1>;
#size-cells = <0>;
rv3029c2@56 {
compatible = "rv3029c2";
reg = <0x56>;
};
};

94
drivers/i2c/busses/i2c-gpio.c
View File

@ -14,8 +14,15 @@
#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>
#include <asm/gpio.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)
@ -78,24 +85,62 @@ static int i2c_gpio_getscl(void *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;
pdata = pdev->dev.platform_data;
if (!pdata)
return -ENXIO;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
adap = &priv->adap;
bit_data = &priv->bit_data;
pdata = &priv->pdata;
ret = -ENOMEM;
adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
if (!adap)
goto err_alloc_adap;
bit_data = kzalloc(sizeof(struct i2c_algo_bit_data), GFP_KERNEL);
if (!bit_data)
goto err_alloc_bit_data;
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)
@ -143,6 +188,7 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
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;
/*
* If "dev->id" is negative we consider it as zero.
@ -154,7 +200,9 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
if (ret)
goto err_add_bus;
platform_set_drvdata(pdev, adap);
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,
@ -168,34 +216,40 @@ err_add_bus:
err_request_scl:
gpio_free(pdata->sda_pin);
err_request_sda:
kfree(bit_data);
err_alloc_bit_data:
kfree(adap);
err_alloc_adap:
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;
adap = platform_get_drvdata(pdev);
pdata = pdev->dev.platform_data;
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);
kfree(adap->algo_data);
kfree(adap);
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),