2023-01-16 23:00:06

by Richard Acayan

Subject: [RFC PATCH v3 2/3] drm/panel: sofef00: Use 16-bit brightness function

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 <[email protected]>
Tested-by: Caleb Connolly <[email protected]>
---
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

2023-01-18 10:51:15

by Neil Armstrong

Subject: Re: [RFC PATCH v3 2/3] drm/panel: sofef00: Use 16-bit brightness function

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 <[email protected]>
> Tested-by: Caleb Connolly <[email protected]>
> ---
> 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 <[email protected]>