linux-kernel - Re: [PATCH 1/3] drm/panel: ld9040: Use better magic values

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Message-ID: <f7bf6f1a-1cc6-55e3-82a2-ecc6818be5c4@linaro.org>
Date:   Wed, 5 Jul 2023 15:55:24 +0200
From:   Neil Armstrong <neil.armstrong@...aro.org>
To:     Paul Cercueil <paul@...pouillou.net>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Sam Ravnborg <sam@...nborg.org>
Cc:     devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 1/3] drm/panel: ld9040: Use better magic values

Hi

On 03/07/2023 23:47, Paul Cercueil wrote:
> I have no idea what the prior magic values mean, and I have no idea
> what my replacement (extracted from [1]) magic values mean.
> 
> What I do know, is that these new values result in a much better
> picture, where the blacks are really black (as you would expect on an
> AMOLED display) instead of grey-ish.
> 
> [1] https://github.com/dorimanx/Dorimanx-SG2-I9100-Kernel/blob/master-jelly-bean/arch/arm/mach-exynos/u1-panel.h
> 
> Signed-off-by: Paul Cercueil <paul@...pouillou.net>
> ---
>   drivers/gpu/drm/panel/panel-samsung-ld9040.c | 11 ++++++-----
>   1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panel/panel-samsung-ld9040.c b/drivers/gpu/drm/panel/panel-samsung-ld9040.c
> index 01eb211f32f7..7fd9444b42c5 100644
> --- a/drivers/gpu/drm/panel/panel-samsung-ld9040.c
> +++ b/drivers/gpu/drm/panel/panel-samsung-ld9040.c
> @@ -180,17 +180,18 @@ static void ld9040_init(struct ld9040 *ctx)
>   {
>   	ld9040_dcs_write_seq_static(ctx, MCS_USER_SETTING, 0x5a, 0x5a);
>   	ld9040_dcs_write_seq_static(ctx, MCS_PANEL_CONDITION,
> -		0x05, 0x65, 0x96, 0x71, 0x7d, 0x19, 0x3b, 0x0d,
> -		0x19, 0x7e, 0x0d, 0xe2, 0x00, 0x00, 0x7e, 0x7d,
> -		0x07, 0x07, 0x20, 0x20, 0x20, 0x02, 0x02);
> +		0x05, 0x5e, 0x96, 0x6b, 0x7d, 0x0d, 0x3f, 0x00,
> +		0x00, 0x32, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> +		0x07, 0x05, 0x1f, 0x1f, 0x1f, 0x00, 0x00);
>   	ld9040_dcs_write_seq_static(ctx, MCS_DISPCTL,
> -		0x02, 0x08, 0x08, 0x10, 0x10);
> +		0x02, 0x06, 0x0a, 0x10, 0x10);
>   	ld9040_dcs_write_seq_static(ctx, MCS_MANPWR, 0x04);
>   	ld9040_dcs_write_seq_static(ctx, MCS_POWER_CTRL,
>   		0x0a, 0x87, 0x25, 0x6a, 0x44, 0x02, 0x88);
> -	ld9040_dcs_write_seq_static(ctx, MCS_ELVSS_ON, 0x0d, 0x00, 0x16);
> +	ld9040_dcs_write_seq_static(ctx, MCS_ELVSS_ON, 0x0f, 0x00, 0x16);
>   	ld9040_dcs_write_seq_static(ctx, MCS_GTCON, 0x09, 0x00, 0x00);
>   	ld9040_brightness_set(ctx);
> +

You can drop this spurious new line for v2

>   	ld9040_dcs_write_seq_static(ctx, MIPI_DCS_EXIT_SLEEP_MODE);
>   	ld9040_dcs_write_seq_static(ctx, MIPI_DCS_SET_DISPLAY_ON);
>   }

And add

Reviewed-by: Neil Armstrong <neil.armstrong@...aro.org>

Neil