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_large() function that
properly handles 16-bit brightness instead of doing special processing
of the brightness values.

Signed-off-by: Richard Acayan <mailingradian@gmail.com>
Tested-by: Caleb Connolly <caleb@connolly.tech>
---
 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 9db49a028930..1ebb79e3103c 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>
@@ -213,13 +212,9 @@ 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

On 16/01/2023 23:49, Richard Acayan wrote:
> 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_large() function that
> properly handles 16-bit brightness instead of doing special processing
> of the brightness values.
> 
> Signed-off-by: Richard Acayan <mailingradian@gmail.com>
> Tested-by: Caleb Connolly <caleb@connolly.tech>
> ---
>   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 9db49a028930..1ebb79e3103c 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>
> @@ -213,13 +212,9 @@ 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;
>   

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