linux-kernel - [RFC PATCH v2 2/2] drm/panel: sofef00: Use 16-bit panel brightness

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Message-Id: <20230114010006.50471-3-mailingradian@gmail.com>
Date:   Fri, 13 Jan 2023 20:00:06 -0500
From:   Richard Acayan <mailingradian@...il.com>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Thierry Reding <thierry.reding@...il.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Emil Velikov <emil.l.velikov@...il.com>,
        Vinay Simha BN <simhavcs@...il.com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc:     Daniel Mentz <danielmentz@...gle.com>,
        Caleb Connolly <caleb@...nolly.tech>,
        Richard Acayan <mailingradian@...il.com>
Subject: [RFC PATCH v2 2/2] drm/panel: sofef00: Use 16-bit panel brightness

These panels communicate brightness in big endian. This is not a quirk
of the panels themselves, but rather, a part of the MIPI standard. Use
the new mipi_dsi_dcs_set_display_brightness_wide() function that
properly handles 16-bit brightness instead of doing special processing
of the brightness values.

Signed-off-by: Richard Acayan <mailingradian@...il.com>
---
 drivers/gpu/drm/panel/panel-samsung-sofef00.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-samsung-sofef00.c b/drivers/gpu/drm/panel/panel-samsung-sofef00.c
index 1a0d24595faa..014fe350bc59 100644
--- a/drivers/gpu/drm/panel/panel-samsung-sofef00.c
+++ b/drivers/gpu/drm/panel/panel-samsung-sofef00.c
@@ -10,7 +10,6 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/regulator/consumer.h>
-#include <linux/swab.h>
 #include <linux/backlight.h>
 
 #include <video/mipi_display.h>
@@ -221,13 +220,9 @@ static int sofef00_panel_bl_update_status(struct backlight_device *bl)
 {
 	struct mipi_dsi_device *dsi = bl_get_data(bl);
 	int err;
-	u16 brightness;
+	u16 brightness = (u16)backlight_get_brightness(bl);
 
-	brightness = (u16)backlight_get_brightness(bl);
-	// This panel needs the high and low bytes swapped for the brightness value
-	brightness = __swab16(brightness);
-
-	err = mipi_dsi_dcs_set_display_brightness(dsi, brightness);
+	err = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
 	if (err < 0)
 		return err;
 
-- 
2.39.0