avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/drivers/video/ssd2828.h

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+/*
+ * (C) 2015 Siarhei Siamashka <siarhei.siamashka@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/*
+ * Support for the SSD2828 bridge chip, which can take pixel data coming
+ * from a parallel LCD interface and translate it on the flight into MIPI DSI
+ * interface for driving a MIPI compatible TFT display.
+ *
+ * Implemented as a utility function. To be used from display drivers, which are
+ * responsible for driving parallel LCD hardware in front of the video pipeline.
+ */
+
+#ifndef _SSD2828_H
+#define _SSD2828_H
+
+struct ctfb_res_modes;
+
+struct ssd2828_config {
+	/*********************************************************************/
+	/* SSD2828 configuration                                             */
+	/*********************************************************************/
+
+	/*
+	 * The pins, which are used for SPI communication. This is only used
+	 * for configuring SSD2828, so the performance is irrelevant (only
+	 * around a hundred of bytes is moved). Also these can be any arbitrary
+	 * GPIO pins (not necessarily the pins having hardware SPI function).
+	 * Moreover, the 'sdo' pin may be even not wired up in some devices.
+	 *
+	 * These configuration variables need to be set as pin numbers for
+	 * the standard u-boot GPIO interface (gpio_get_value/gpio_set_value
+	 * functions). Note that -1 value can be used for the pins, which are
+	 * not really wired up.
+	 */
+	int csx_pin;
+	int sck_pin;
+	int sdi_pin;
+	int sdo_pin;
+	/* SSD2828 reset pin (shared with LCD panel reset) */
+	int reset_pin;
+
+	/*
+	 * The SSD2828 has its own dedicated clock source 'tx_clk' (connected
+	 * to TX_CLK_XIO/TX_CLK_XIN pins), which is necessary at least for
+	 * clocking SPI after reset. The exact clock speed is not strictly,
+	 * defined, but the datasheet says that it must be somewhere in the
+	 * 8MHz - 30MHz range (see "TX_CLK Timing" section). It can be also
+	 * used as a reference clock for PLL. If the exact clock frequency
+	 * is known, then it can be specified here. If it is unknown, or the
+	 * information is not trustworthy, then it can be set to 0.
+	 *
+	 * If unsure, set to 0.
+	 */
+	int ssd2828_tx_clk_khz;
+
+	/*
+	 * This is not a property of the used LCD panel, but more like a
+	 * property of the SSD2828 wiring. See the "SSD2828QN4 RGB data
+	 * arrangement" table in the datasheet. The SSD2828 pins are arranged
+	 * in such a way that 18bpp and 24bpp configurations are completely
+	 * incompatible with each other.
+	 *
+	 * Depending on the color depth, this must be set to 16, 18 or 24.
+	 */
+	int ssd2828_color_depth;
+
+	/*********************************************************************/
+	/* LCD panel configuration                                           */
+	/*********************************************************************/
+
+	/*
+	 * The number of lanes in the MIPI DSI interface. May vary from 1 to 4.
+	 *
+	 * This information can be found in the LCD panel datasheet.
+	 */
+	int mipi_dsi_number_of_data_lanes;
+
+	/*
+	 * Data transfer bit rate per lane. Please note that it is expected
+	 * to be higher than the pixel clock rate of the used video mode when
+	 * multiplied by the number of lanes. This is perfectly normal because
+	 * MIPI DSI handles data transfers in periodic bursts, and uses the
+	 * idle time between bursts for sending configuration information and
+	 * commands. Or just for saving power.
+	 *
+	 * The necessary Mbps/lane information can be found in the LCD panel
+	 * datasheet. Note that the transfer rate can't be always set precisely
+	 * and it may be rounded *up* (introducing no more than 10Mbps error).
+	 */
+	int mipi_dsi_bitrate_per_data_lane_mbps;
+
+	/*
+	 * Setting this to 1 enforces packing of 18bpp pixel data in 24bpp
+	 * envelope when sending it over the MIPI DSI link.
+	 *
+	 * If unsure, set to 0.
+	 */
+	int mipi_dsi_loosely_packed_pixel_format;
+
+	/*
+	 * According to the "Example for system sleep in and out" section in
+	 * the SSD2828 datasheet, some LCD panel specific delays are necessary
+	 * after MIPI DCS commands EXIT_SLEEP_MODE and SET_DISPLAY_ON.
+	 *
+	 * For example, Allwinner uses 100 milliseconds delay after
+	 * EXIT_SLEEP_MODE and 200 milliseconds delay after SET_DISPLAY_ON.
+	 */
+	int mipi_dsi_delay_after_exit_sleep_mode_ms;
+	int mipi_dsi_delay_after_set_display_on_ms;
+};
+
+/*
+ * Initialize the SSD2828 chip. It needs the 'ssd2828_config' structure
+ * and also the video mode timings.
+ *
+ * The right place to insert this function call is after the parallel LCD
+ * interface is initialized and before turning on the backlight. This is
+ * advised in the "Example for system sleep in and out" section of the
+ * SSD2828 datasheet. And also SS2828 may use 'pclk' as the clock source
+ * for PLL, which means that the input signal must be already there.
+ */
+int ssd2828_init(const struct ssd2828_config *cfg,
+		 const struct ctfb_res_modes *mode);
+
+#endif