linux-kernel - [PATCH v3 17/19] drm/panel: sitronix-st7789v: Clarify a definition

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Message-Id: <20230714013756.1546769-18-sre@kernel.org>
Date:   Fri, 14 Jul 2023 03:37:54 +0200
From:   Sebastian Reichel <sre@...nel.org>
To:     Sebastian Reichel <sre@...nel.org>
Cc:     Gerald Loacker <gerald.loacker@...fvision.net>,
        Michael Riesch <michael.riesch@...fvision.net>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Sam Ravnborg <sam@...nborg.org>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        devicetree@...r.kernel.org, Maxime Ripard <mripard@...nel.org>
Subject: [PATCH v3 17/19] drm/panel: sitronix-st7789v: Clarify a definition

From: Miquel Raynal <miquel.raynal@...tlin.com>

The Sitronix datasheet explains BIT(1) of the RGBCTRL register as the
DOTCLK/PCLK edge used to sample the data lines:

    “0” The data is input on the positive edge of DOTCLK
    “1” The data is input on the negative edge of DOTCLK

IOW, this bit implies a falling edge and not a high state. Correct the
definition to ease the comparison with the datasheet.

Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
Acked-by: Maxime Ripard <mripard@...nel.org>
Reviewed-by: Sebastian Reichel <sre@...nel.org>
Tested-by: Sebastian Reichel <sre@...nel.org>
Signed-off-by: Sebastian Reichel <sre@...nel.org>
---
 drivers/gpu/drm/panel/panel-sitronix-st7789v.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7789v.c b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
index 33bdf9ee4085..3d24690e891b 100644
--- a/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
+++ b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
@@ -27,7 +27,7 @@
 #define ST7789V_RGBCTRL_RCM(n)			(((n) & 3) << 5)
 #define ST7789V_RGBCTRL_VSYNC_HIGH		BIT(3)
 #define ST7789V_RGBCTRL_HSYNC_HIGH		BIT(2)
-#define ST7789V_RGBCTRL_PCLK_HIGH		BIT(1)
+#define ST7789V_RGBCTRL_PCLK_FALLING		BIT(1)
 #define ST7789V_RGBCTRL_DE_LOW			BIT(0)
 #define ST7789V_RGBCTRL_VBP(n)			((n) & 0x7f)
 #define ST7789V_RGBCTRL_HBP(n)			((n) & 0x1f)
@@ -259,7 +259,7 @@ static int st7789v_prepare(struct drm_panel *panel)
 	if (ctx->info->mode->flags & DRM_MODE_FLAG_PHSYNC)
 		polarity |= ST7789V_RGBCTRL_HSYNC_HIGH;
 	if (ctx->info->bus_flags & DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE)
-		polarity |= ST7789V_RGBCTRL_PCLK_HIGH;
+		polarity |= ST7789V_RGBCTRL_PCLK_FALLING;
 	if (ctx->info->bus_flags & DRM_BUS_FLAG_DE_LOW)
 		polarity |= ST7789V_RGBCTRL_DE_LOW;
 
-- 
2.40.1