On 05.02.2012 11:38, Jean-Christophe PLAGNIOL-VILLARD wrote:
Hi!
+Device-Tree bindings for i2c gpio driver
+
+Required properties:
+ - compatible = "gpio-i2c";
Driver name is "i2c-gpio" in file i2c-gpio.c. Previous version of patch
adding DT-support (prepared by Thomas Chou[1]) used i2c-gpio - could we
stick to that name?
[1] https://lkml.org/lkml/2011/2/23/584
+ - gpios: sda and scl gpio
+
+
+Optional properties:
+ - gpio-i2c,sda_is_open_drain: sda as open drain
+ - gpio-i2c,scl_is_open_drain: scl as open drain
+ - gpio-i2c,scl_is_output_only: scl as output only
Most of DT-properties I've seen used hyphen, not underscore. Could we
stick to that convention?
(Nitpick: I think that "is" in property names is redundant too.)
+ - udelay: half clock cycle time in us (may depend on each platform)
Could we use "clock-frequency" as Grant have suggested during review of
previous patch to i2c-gpio?
https://lkml.org/lkml/2011/2/24/220
+ - timeout: timeout to get data
+
+
+Example nodes:
+
+i2c-gpio@0 {
+ compatible = "gpio-i2c";
+ gpios =<&pioA 23 0 /* sda */
+ &pioA 24 0 /* scl */
+ >;
+ gpio-i2c,sda_is_open_drain;
+ gpio-i2c,scl_is_open_drain;
+ udelay =<2>; /* ~100 kHz */
+ #address-cells =<1>;
+ #size-cells =<0>;
+
+ rv3029c2@56 {
+ compatible = "rv3029c2";
+ reg =<0x56>;
+ };
+};
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index a651779..6b5d794 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -14,6 +14,8 @@
#include<linux/module.h>
#include<linux/slab.h>
#include<linux/platform_device.h>
+#include<linux/of_gpio.h>
+#include<linux/of_i2c.h>
#include<asm/gpio.h>
@@ -78,16 +80,51 @@ static int i2c_gpio_getscl(void *data)
return gpio_get_value(pdata->scl_pin);
}
+static int of_i2c_gpio_probe(struct device_node *np,
+ struct i2c_gpio_platform_data *pdata)
+{
+ u32 reg;
+
if (of_gpio_count(np) < 2)
return -EINVAL;
+ pdata->sda_pin = of_get_gpio(np, 0);
+ pdata->scl_pin = of_get_gpio(np, 1);
if (pdata->sda_pin < 0 || pdata->scl_pin < 0)
return -EINVAL;
+
+ if (of_property_read_u32(np, "udelay",®))
+ pdata->udelay = reg;
+
+ if (of_property_read_u32(np, "timeout",®))
+ pdata->timeout = reg;
+
+ pdata->sda_is_open_drain =
+ !!of_get_property(np, "gpio-i2c,sda_is_open_drain", NULL);
+ pdata->scl_is_open_drain =
+ !!of_get_property(np, "gpio-i2c,scl_is_open_drain", NULL);
+ pdata->scl_is_output_only =
+ !!of_get_property(np, "gpio-i2c,scl_is_output_only", NULL);
+
+ return 0;
+}
+
static int __devinit i2c_gpio_probe(struct platform_device *pdev)
{
struct i2c_gpio_platform_data *pdata;
struct i2c_algo_bit_data *bit_data;
struct i2c_adapter *adap;
int ret;
+ int len = sizeof(struct i2c_gpio_platform_data);
- pdata = pdev->dev.platform_data;
+ pdata = kzalloc(len, GFP_KERNEL);
Could you also take into account Grant's comment about private/platform
data?
https://lkml.org/lkml/2011/2/3/221
if (!pdata)
- return -ENXIO;
+ return -ENOMEM;
+
+ if (pdev->dev.of_node) {
+ of_i2c_gpio_probe(pdev->dev.of_node, pdata);
Above might fail if configuration is corrupted.
+ } else {
+ if (!pdev->dev.platform_data) {
+ ret = -ENXIO;
+ goto err_alloc_adap;
+ }
+ memcpy(pdata, pdev->dev.platform_data, len);
+ }
ret = -ENOMEM;
adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
@@ -143,6 +180,7 @@ 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.
@@ -154,6 +192,8 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
if (ret)
goto err_add_bus;
+ of_i2c_register_devices(adap);
+
platform_set_drvdata(pdev, adap);
dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n",
@@ -172,6 +212,7 @@ err_request_sda:
err_alloc_bit_data:
kfree(adap);
err_alloc_adap:
+ kfree(pdata);
return ret;
}
@@ -192,10 +233,20 @@ static int __devexit i2c_gpio_remove(struct platform_device *pdev)
return 0;
}
+#if defined(CONFIG_OF)
+static const struct of_device_id gpio_i2c_dt_ids[] = {
+ { .compatible = "gpio-i2c", },
There seem to be no good reason to make DT-compatible string different
from driver's name that's already in use:
static struct platform_driver i2c_gpio_driver = {
.driver = {
.name = "i2c-gpio",
Regards,
--
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform
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