On 03/07/2012 11:22 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 11:16 Wed 07 Mar , Rob Herring wrote:
>> On 02/29/2012 08:20 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
>>> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@xxxxxxxxxxxx>
>>> Cc: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
>>> Cc: linux-i2c@xxxxxxxxxxxxxxx
>>> Cc: devicetree-discuss@xxxxxxxxxxxxxxxx
>>> ---
>>> 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
>>
>>> + - 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.
>>
>>> +
>>> +Example nodes:
>>> +
>>> +i2c-gpio@0 {
>>
>> Should be "i2c@0"
> ok
>>
>>> + 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", ®))
>>> + 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.
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