[PATCH 2/2] ARM: dts: exynos: arndale: fix HDMI-HPD line handling

[Andrzej Hajda]

On 26.07.2018 12:44, Krzysztof Kozlowski wrote:
> On 26 July 2018 at 12:12, Andrzej Hajda <a.hajda at samsung.com> wrote:
>> HDMI-HPD was set active low, moreover by default pincontrol
>> chip sets pull-down on the pin. As a result HDMI driver
>> assumes TV is always connected regardless of actual state.
>> The patch fixes it.
>>
>> Signed-off-by: Andrzej Hajda <a.hajda at samsung.com>
>> ---
>>  arch/arm/boot/dts/exynos5250-arndale.dts  | 4 +++-
>>  arch/arm/boot/dts/exynos5250-pinctrl.dtsi | 5 +++++
>>  2 files changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/boot/dts/exynos5250-arndale.dts b/arch/arm/boot/dts/exynos5250-arndale.dts
>> index 591023391f7d..26bae5157177 100644
>> --- a/arch/arm/boot/dts/exynos5250-arndale.dts
>> +++ b/arch/arm/boot/dts/exynos5250-arndale.dts
>> @@ -210,9 +210,11 @@
>>  };
>>
>>  &hdmi {
>> +       pinctrl-names = "default";
>> +       pinctrl-0 = <&hdmi_hpd>;
>>         status = "okay";
>>         ddc = <&i2c_ddc>;
>> -       hpd-gpios = <&gpx3 7 GPIO_ACTIVE_LOW>;
>> +       hpd-gpios = <&gpx3 7 GPIO_ACTIVE_HIGH>;
> The gpx3-7 (HDMI-HPD) has external pull up to... so maybe it should be
> active low? How can it go high if it is already high?
> I am not sure if this matters because the driver ignores the flags and
> responds on both falling and rising edge.

HDMI specification says HPD is active high!
Arndale schematics are quite misleading - pull-up resistors near level
shifter are marked as not-connected :) so there are no pull-ups.
And there is pull-down resistor on right side of the level shifter.
And finally with this patch it works as expected, without it it works
sometimes.

Regards
Andrzej

>
> Best regards,
> Krzysztof
>
>>         vdd_osc-supply = <&ldo10_reg>;
>>         vdd_pll-supply = <&ldo8_reg>;
>>         vdd-supply = <&ldo8_reg>;
>> diff --git a/arch/arm/boot/dts/exynos5250-pinctrl.dtsi b/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
>> index b25d520393b8..d31a68672bfa 100644
>> --- a/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
>> +++ b/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
>> @@ -599,6 +599,11 @@
>>                 samsung,pin-pud = <EXYNOS_PIN_PULL_NONE>;
>>                 samsung,pin-drv = <EXYNOS4_PIN_DRV_LV1>;
>>         };
>> +
>> +       hdmi_hpd: hdmi-hpd {
>> +               samsung,pins = "gpx3-7";
>> +               samsung,pin-pud = <EXYNOS_PIN_PULL_NONE>;
>> +       };
>>  };
>>
>>  &pinctrl_1 {
>> --
>> 2.18.0
>>
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