video: Add support for SSD2828 (parallel LCD to MIPI bridge)

SSD2828 can take pixel data coming from a parallel LCD interface
and translate it on the fly into MIPI DSI interface for driving
a MIPI compatible TFT display. SSD2828 is configured over SPI
interface, which may or may not have MISO pin wired up on some
hardware. So a write-only SPI mode also has to be supported.

The SSD2828 support code is implemented as a utility function
and needs to be called from real display drivers, which are
responsible for driving parallel LCD hardware in front of the
video pipeline. The usage instructions are provided as comments
in the header file.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index fdbf3f6..ec14a37 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -6,3 +6,73 @@ config VIDEO_X86
 	  Turn on this option to enable a very simple driver which uses vesa
 	  to discover the video mode and then provides a frame buffer for use
 	  by U-Boot.
+
+config VIDEO_LCD_SSD2828
+	bool "SSD2828 bridge chip"
+	default n
+	---help---
+	Support for the SSD2828 bridge chip, which can take pixel data coming
+	from a parallel LCD interface and translate it on the fly into MIPI DSI
+	interface for driving a MIPI compatible LCD panel. It uses SPI for
+	configuration.
+
+config VIDEO_LCD_SSD2828_TX_CLK
+	int "SSD2828 TX_CLK frequency (in MHz)"
+	depends on VIDEO_LCD_SSD2828
+	---help---
+	The frequency of the crystal, which is clocking SSD2828. It may be
+	anything in the 8MHz-30MHz range and the exact value should be
+	retrieved from the board schematics. Or in the case of Allwinner
+	hardware, it can be usually found as 'lcd_xtal_freq' variable in
+	FEX files.
+
+config VIDEO_LCD_SSD2828_RESET
+	string "RESET pin of SSD2828"
+	depends on VIDEO_LCD_SSD2828
+	default ""
+	---help---
+	The reset pin of SSD2828 chip. This takes a string in the format
+	understood by 'name_to_gpio' function, e.g. PH1 for pin 1 of port H.
+
+config VIDEO_LCD_SPI_CS
+	string "SPI CS pin for LCD related config job"
+	depends on VIDEO_LCD_SSD2828
+	default ""
+	---help---
+	This is one of the SPI communication pins, involved in setting up a
+	working LCD configuration. The exact role of SPI may differ for
+	different hardware setups. The option takes a string in the format
+	understood by 'name_to_gpio' function, e.g. PH1 for pin 1 of port H.
+
+config VIDEO_LCD_SPI_SCLK
+	string "SPI SCLK pin for LCD related config job"
+	depends on VIDEO_LCD_SSD2828
+	default ""
+	---help---
+	This is one of the SPI communication pins, involved in setting up a
+	working LCD configuration. The exact role of SPI may differ for
+	different hardware setups. The option takes a string in the format
+	understood by 'name_to_gpio' function, e.g. PH1 for pin 1 of port H.
+
+config VIDEO_LCD_SPI_MOSI
+	string "SPI MOSI pin for LCD related config job"
+	depends on VIDEO_LCD_SSD2828
+	default ""
+	---help---
+	This is one of the SPI communication pins, involved in setting up a
+	working LCD configuration. The exact role of SPI may differ for
+	different hardware setups. The option takes a string in the format
+	understood by 'name_to_gpio' function, e.g. PH1 for pin 1 of port H.
+
+config VIDEO_LCD_SPI_MISO
+	string "SPI MISO pin for LCD related config job (optional)"
+	depends on VIDEO_LCD_SSD2828
+	default ""
+	---help---
+	This is one of the SPI communication pins, involved in setting up a
+	working LCD configuration. The exact role of SPI may differ for
+	different hardware setups. If wired up, this pin may provide additional
+	useful functionality. Such as bi-directional communication with the
+	hardware and LCD panel id retrieval (if the panel can report it). The
+	option takes a string in the format understood by 'name_to_gpio'
+	function, e.g. PH1 for pin 1 of port H.