On 03/07/2012 11:22 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:

On 11:16 Wed 07 Mar     , Rob Herring wrote:

quoted

On 02/29/2012 08:20 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:

quoted

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>
Cc: Nicolas Ferre <redacted>
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
---
v2:

	use devm_kzalloc
	use i2c-gpio
	use time name in the properties

Best Regars,
J.
 .../devicetree/bindings/gpio/gpio_i2c.txt          |   32 +++++++
 drivers/i2c/busses/i2c-gpio.c                      |   95 +++++++++++++++----
 2 files changed, 107 insertions(+), 20 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio_i2c.txt

diff --git a/Documentation/devicetree/bindings/gpio/gpio_i2c.txt b/Documentation/devicetree/bindings/gpio/gpio_i2c.txt
new file mode 100644
index 0000000..27e1b1a
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio_i2c.txt

@@ -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
+	- udelay: delay between GPIO operations (may depend on each platform)

i2c-gpio,delay-us

quoted

+	- i2c-algo-bit,timeout-milliseconds: timeout to get data

i2c-gpio,timeout-ms

it's algo-bit speficic no i2c-gpio that's why I use i2c-algo-bit

Don't bring Linux into the binding. I would have to look at the Linux
driver to understand your reasoning.

quoted

quoted

+
+Example nodes:
+
+i2c-gpio@0 {

Should be "i2c@0"

ok

quoted

quoted

+	compatible = "i2c-gpio";
+	gpios = <&pioA 23 0 /* sda */
+		 &pioA 24 0 /* scl */
+		>;
+	i2c-gpio,sda-open-drain;
+	i2c-gpio,scl-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..71adba5 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c

@@ -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 +85,63 @@ 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 (pdata->sda_pin < 0 || pdata->scl_pin < 0) {
+		pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
+		       np->full_name, pdata->sda_pin, pdata->scl_pin);
+		return -ENODEV;
+	}
+
+	if (of_property_read_u32(np, "udelay", &reg))
+		pdata->udelay = reg;

Why not of_property_read_u32(np, "udelay", &pdata->udelay)?

Also, reg may not be initialized here.

if udelay have any error we keep udelay as 0

Right, so there is no init issue with reg, but still you can just right
this and get rid of the if:

of_property_read_u32(np, "udelay", &pdata->udelay);

If there's an error, the value will be unchanged.

Rob

Best Regards,
J.