This interface supports sending MIPI commands over an SPI bus. This driver only implements the Type C1 protocol for now.
Signed-off-by: John Watts contact@jookia.org --- drivers/video/Kconfig | 6 ++++ drivers/video/Makefile | 1 + drivers/video/mipi_dbi.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++ include/mipi_dbi.h | 73 ++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 150 insertions(+)
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig index 7808ae7919..e9d069d440 100644 --- a/drivers/video/Kconfig +++ b/drivers/video/Kconfig @@ -157,6 +157,12 @@ config VIDEO_MIPI_DSI The MIPI Display Serial Interface (MIPI DSI) defines a high-speed serial interface between a host processor and a display module.
+config VIDEO_MIPI_DBI + bool "Support MIPI DBI interface" + help + Support MIPI DBI interface for driving a MIPI compatible device + over a SPI interface. + config CONSOLE_NORMAL bool "Support a simple text console" default y diff --git a/drivers/video/Makefile b/drivers/video/Makefile index f3f70cd04a..ad77c60973 100644 --- a/drivers/video/Makefile +++ b/drivers/video/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_VIDEO_LCD_TDO_TL070WSH30) += tdo-tl070wsh30.o obj-$(CONFIG_VIDEO_MCDE_SIMPLE) += mcde_simple.o obj-${CONFIG_VIDEO_MESON} += meson/ obj-${CONFIG_VIDEO_MIPI_DSI} += mipi_dsi.o +obj-${CONFIG_VIDEO_MIPI_DBI} += mipi_dbi.o obj-$(CONFIG_VIDEO_MVEBU) += mvebu_lcd.o obj-$(CONFIG_VIDEO_MXS) += mxsfb.o videomodes.o obj-$(CONFIG_VIDEO_NX) += nexell_display.o videomodes.o nexell/ diff --git a/drivers/video/mipi_dbi.c b/drivers/video/mipi_dbi.c new file mode 100644 index 0000000000..d7457bb6e2 --- /dev/null +++ b/drivers/video/mipi_dbi.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * MIPI DBI Bus support + * + * Copyright 2024 John Watts contact@jookia.org + */ + +#include <mipi_dbi.h> + +int mipi_dbi_spi_init(struct spi_slave *slave, struct mipi_dbi *dbi, + struct gpio_desc *dc) +{ + /* D/C GPIO isn't supported yet */ + if (dc) + return -1; + + dbi->spi = slave; + + return 0; +} + +int mipi_dbi_xfer(struct mipi_dbi *dbi, u8 data, int pos, int len) +{ + struct spi_slave *spi = dbi->spi; + bool is_data = (pos != 0); + int flags = 0; + u8 buf[2]; + + /* Mimic Linux's behaviour of pulling CS active each word */ + flags |= SPI_XFER_ONCE; + + buf[0] = (is_data ? 0x80 : 0x00) | (data >> 1); + buf[1] = ((data & 0x1) << 7); + + return spi_xfer(spi, 9, &buf, NULL, flags); +} + +int mipi_dbi_command_buf(struct mipi_dbi *dbi, u8 cmd, const u8 *data, size_t len) +{ + struct spi_slave *spi = dbi->spi; + int wordlen; + int retval = -1; + + if (spi_claim_bus(spi)) + return -1; + + wordlen = spi_set_wordlen(spi, 9); + if (wordlen == -1) + goto done; + + if (mipi_dbi_xfer(dbi, cmd, 0, len) != 0) + goto done; + + for (int i = 1; i <= len; ++i) { + u8 dat = data[i - 1]; + + if (mipi_dbi_xfer(dbi, dat, i, len) != 0) + goto done; + } + + retval = 0; + +done: + if (wordlen != -1) + spi_set_wordlen(spi, wordlen); + + spi_release_bus(spi); + + return retval; +} diff --git a/include/mipi_dbi.h b/include/mipi_dbi.h new file mode 100644 index 0000000000..1c0c21ba81 --- /dev/null +++ b/include/mipi_dbi.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * MIPI DBI Bus support + * + * Copyright 2024 John Watts contact@jookia.org + */ +#ifndef MIPI_DBI_H +#define MIPI_DBI_H + +#include <asm/gpio.h> +#include <mipi_display.h> +#include <spi.h> + +/** + * struct mipi_dbi - MIPI DBI bus info + * + * This contains information about a MIPI DBI bus. + * Use mipi_dbi_spi_init to create and initialize this structure. + * + * @spi: SPI slave this bus operates on. + */ +struct mipi_dbi { + struct spi_slave *spi; +}; + +/** + * mipi_dbi_spi_init - Creates a new MIPI DBI bus + * + * Creates and sets up a 'struct mipi_dbi' using the provided SPI slave + * and optional D/C GPIO. + * + * @slave: SPI slave the bus is on + * @dbi: Destination mipi_dbi structure to initialize + * @dc: D/C GPIO (NULL if unused) + * + * Returns: 0 on success, -1 on failure. + */ +int mipi_dbi_spi_init(struct spi_slave *slave, struct mipi_dbi *dbi, + struct gpio_desc *dc); + +/** + * mipi_dbi_command_buf - Sends a command and data over the bus + * + * Sends a command and any optional data over a bus. + * + * @dbi: MIPI DBI bus to use + * @cmd: MIPI DBI command + * @data: Command data (NULL if len is 0) + * @len: Length of data in bytes + * + * Returns: 0 on success, -1 on failure. + */ +int mipi_dbi_command_buf(struct mipi_dbi *dbi, u8 cmd, const u8 *data, size_t len); + +/** + * mipi_dbi_command - Sends a command and data sequence over the bus + * + * Sends a command and any optional data over a bus. + * The data is a variadic sequence. + * + * @dbi: MIPI DBI bus to use + * @cmd: MIPI DBI command + * @seq: Command data bytes + * + * Returns: 0 on success, -1 on failure. + */ +#define mipi_dbi_command(dbi, cmd, seq...) \ +({ \ + const u8 data[] = { seq }; \ + mipi_dbi_command_buf(dbi, cmd, data, ARRAY_SIZE(data)); \ +}) + +#endif /* MIPI_DBI_H */