Re: [PATCH 15/26] ARM: omap4-panda.dts: add display information

Hi Tomi,

On Mon, Dec 9, 2013 at 4:30 PM, Tomi Valkeinen [off-list ref] wrote:

On 2013-12-09 17:09, Javier Martinez Canillas wrote:

quoted

Hi Tomi,

On Mon, Dec 9, 2013 at 1:56 PM, Tomi Valkeinen [off-list ref] wrote:

quoted

On 2013-12-06 10:57, Javier Martinez Canillas wrote:

quoted

quoted

+       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