Hi Tomi,
On Mon, Dec 9, 2013 at 4:30 PM, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
> On 2013-12-09 17:09, Javier Martinez Canillas wrote:
>> Hi Tomi,
>>
>> On Mon, Dec 9, 2013 at 1:56 PM, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
>>> On 2013-12-06 10:57, Javier Martinez Canillas wrote:
>>>
>>>>> + tfp410: encoder@0 {
>>>>> + compatible = "ti,tfp410";
>>>>> + gpios = <&gpio1 0 0>; /* 0, power-down */
>>>>> +
>>>>
>>>> Please use the constants from include/dt-bindings/ instead of magic
>>>> numbers, i.e:
>>>>
>>>> gpios = <&gpio1 0 GPIO_ACTIVE_HIGH>; /* 0, power-down */
>>>
>>> Thanks, fixed now (for all .dts files)
>>>
>>> However... The TFP410 gpio is "power-down". I think we should actually
>>> mark it as GPIO_ACTIVE_LOW, as setting it to 0 powers down the device.
>>>
>>
>> yes, I looked at the TFP410 datasheet [0] and the Power Down pin is
>> indeed an active-low, I just replaced to GPIO_ACTIVE_HIGH since you
>> were using a constant 0 and include/dt-bindings/gpio/gpio.h defines
>> GPIO_ACTIVE_HIGH as 0.
>>
>> I just asked to Enric why we use GPIO_ACTIVE_HIGH for the PD pin on
>> the IGEPv2 DTS instad and is because the IGEP board uses a hardware
>> signal inverter but that is a special case. I don't know about the
>> Panda board since I haven't looked at its datasheet.
>
> Oh. Does it work on igep? The TFP410 driver always handles the PD GPIO
> as it were active-low. The flag is ignored.
>
How weird, it does work on the IGEPv2 but you are right I just looked
at at drivers/video/omap2/displays-new/encoder-tfp410.c and I see
that it indeed just does:
r = devm_gpio_request_one(&pdev->dev, ddata->pd_gpio,
GPIOF_OUT_INIT_LOW, "tfp410 PD");
So I don't know how it is working... I'm on the road and won't have
access to my IGEPv2 to dig further on this. Maybe Enric can shed more
light on this.
> Tomi
>
>
Thanks a lot and best regards,
Javier
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