[PATCH v1 2/2] drm/tinydrm: add driver for ST7735R panels
david at lechnology.com
Fri Dec 8 21:25:09 UTC 2017
On 12/06/2017 12:27 PM, Noralf Trønnes wrote:
> Den 29.11.2017 04.01, skrev David Lechner:
>> This adds a new driver for Sitronix ST7735R display panels.
>> This has been tested using an Adafruit 1.8" TFT.
>> Signed-off-by: David Lechner <david at lechnology.com>
>> MAINTAINERS | 6 +
>> drivers/gpu/drm/tinydrm/Kconfig | 10 ++
>> drivers/gpu/drm/tinydrm/Makefile | 1 +
>> drivers/gpu/drm/tinydrm/st7735r.c | 237
>> 4 files changed, 254 insertions(+)
>> create mode 100644 drivers/gpu/drm/tinydrm/st7735r.c
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index a174632..9c7707e 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -4462,6 +4462,12 @@ S: Maintained
>> F: drivers/gpu/drm/tinydrm/st7586.c
>> F: Documentation/devicetree/bindings/display/st7586.txt
>> +DRM DRIVER FOR SITRONIX ST7735R PANELS
>> +M: David Lechner <david at lechnology.com>
> I know we haven't done this in the other tinydrm drivers, but I think
> we should start adding which tree the development is happening in:
> T: git git://anongit.freedesktop.org/drm/drm-misc
This is inherited, just like L:, so get_maintainers.pl --scm returns git
git://anongit.freedesktop.org/drm/drm-misc already. So there doesn't
seem to be a need to add this line.
>> +S: Maintained
>> +F: drivers/gpu/drm/tinydrm/st7735r.c
>> +F: Documentation/devicetree/bindings/display/st7735r.txt
>> +static void st7735r_pipe_disable(struct drm_simple_display_pipe *pipe)
>> + struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
>> + struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
> Please use mipi_dbi_pipe_disable() here.
>> + DRM_DEBUG_KMS("\n");
>> + if (!mipi->enabled)
>> + return;
>> + tinydrm_disable_backlight(mipi->backlight);
>> + mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
> You turn off the panel, have you checked what it looks like if you don't
> turn off backlight (which is optional in this driver)?
> On the displays I have tried this on, all pixels turn white when they're
> not driven, letting backlight through, giving an all white display.
> That's why I have that blanking code in mipi_dbi_pipe_disable() when we
> don't have backlight control and the reason I don't turn off the panel.
> The power savings of not driving the panel is negligible AFAICR.
> If you don't need DISPLAY_OFF, you can just use mipi_dbi_pipe_disable()
> directly as the callback.
I tested this and you are right, it causes the panel to go white when a
backlight is not specified, so I will just use mipi_dbi_pipe_disable().
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