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Javier Martinez Canillas
74373977d2
The ssd130x driver only provides the core support for these devices but it does not have any bus transport logic. Add a driver to interface over SPI. There is a difference in the communication protocol when using 4-wire SPI instead of I2C. For the latter, a control byte that contains a D/C# field has to be sent. This field tells the controller whether the data has to be written to the command register or to the graphics display data memory. But for 4-wire SPI that control byte is not used, instead a real D/C# line must be pulled HIGH for commands data and LOW for graphics display data. For this reason the standard SPI regmap can't be used and a custom .write bus handler is needed. Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Acked-by: Mark Brown <broonie@kernel.org> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Link: https://patchwork.freedesktop.org/patch/msgid/20220419214824.335075-6-javierm@redhat.com
Linux kernel
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