On Mon, May 14, 2018 at 12:29 AM, Sekhar Nori <nsekhar@xxxxxx> wrote:
> Hi Adam,
>
> On Monday 14 May 2018 04:50 AM, Adam Ford wrote:
>> When using the board files the LCD works, but not with the DT.
>> This adds enables the original da850-evm to work with the same
>> LCD in device tree mode.
>>
>> The EVM has a gpio for the regulator and a gpio enable. The LCD and
>> the vpif display pins are mutually exclusive, so if using the LCD,
>> do not load the vpif driver.
>
> Its not sufficient just note this in patch description.
>
> a) Disable (status = "disabled") the VPIF node which clashes for pins
> with LCD.
> b) Add a comment on top of the status = "disabled" giving information on
> how user can enable it (disable lcdc node and then change to status =
> "okay").
>
>>
>> Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
>> ---
>> V3: Fix errant GPIO, label GPIO pins, and rename the regulator to be more explict to
>> backlight which better matches the schematic. Updated the description to explain
>> that it cannot be used at the same time as the vpif driver.
>>
>> V2: Add regulator and GPIO enable pins. Remove PWM backlight and replace with GPIO
>>
>> diff --git a/arch/arm/boot/dts/da850-evm.dts b/arch/arm/boot/dts/da850-evm.dts
>> index 2e817da37fdb..3f1c8be07efe 100644
>> --- a/arch/arm/boot/dts/da850-evm.dts
>> +++ b/arch/arm/boot/dts/da850-evm.dts
>> @@ -27,6 +27,50 @@
>> spi0 = &spi1;
>> };
>>
>> + backlight {
>> + compatible = "gpio-backlight";
>> + enable-gpios = <&gpio 7 GPIO_ACTIVE_HIGH>; /* GP0[7] */
>
> The gpio-backlight binding does not describe a property called
> enable-gpios. It should just be gpios.
I will fix that.
>
> a) Are you using gpio-backlight because you are not able to get the PWM
> to work?
>
Yes, You told me not to worry about doing a PWM backlight because the
legacy board does not PWM either.
> b) What is GP0[7] connected to in the schematic you have? In the
> schematic I have I see LCD_PWM0 is connected to
> SPI1_SCS[0]/EPWM1B/GP2[14]/TM64P3_IN12.
I have schematic 1016572 dated Wednesday, August 18, 2010. According
to it, AXR15 / EPWMN0_TZ[0] / ECAP2_APWM2 / GPIO0[7] connects to U25,
Pin 46 to generate M_LCD_PWM0. You might have one of the early,
pre-release versions.
>
> c) The /* GP0[7] */ comment is not really useful on its own as it can be
> computed. What I wanted to see is the schematic symbol like "LCD_PWM0".
> Same for other places like this below.
I can do that.
>
>> @@ -35,6 +79,16 @@
>> regulator-boot-on;
>> };
>>
>> + backlight_reg: backlight-regulator {
>> + compatible = "regulator-fixed";
>> + regulator-name = "lcd_backlight_pwr";
>> + regulator-min-microvolt = <3300000>;
>> + regulator-max-microvolt = <3300000>;
>> + gpio = <&gpio 47 GPIO_ACTIVE_HIGH>; /* GP2[15] */
>> + regulator-always-on;
>
> Why should this regulator never be disabled?
The gpio-backlight does not have a way that I can see to associate the
regulator to it. I read through the bindings, but I didn't see an
option to associate a regulator it. I use this regulator to drive
lcd_backlight_pwr and the backlight driver to write lcd_pwm0. Without
this option, the system disables lcd_backlight_pwr and the screen is
blank
adam
>
> Thanks,
> Sekhar
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