Display Driver API

Note

Display driver is currently only available on modules based on RDA8910 and RDA8955.

Application Example

API Reference

Header File

#include <hw/display.h>

Functions

int display_init(const struct lcd_drv_t *lcd)

Initialize onchip display controller and LCD controller.

Parameters:: lcd – LCD driver structure lcd_drv_t
Returns:: 0 for success, negative for error

int display_sleep(uint8_t enable)

Enable or disable sleep.

Note

display flush is needed after wakeup from sleep

Parameters:: enable – TRUE to enable sleep, FALSE to disable
Returns:: 0 for success, negative for error

int display_layer_setup(int layer, const struct layer_cfg_t *cfg)

Setup display layer.

Note

Layer 0 is setup by default during initialization with size of LCD panel

Parameters:

layer – Layer to setup disp_layer_e
cfg – Layer configuration layer_cfg_t

Returns:

0 for success, negative for error

int display_layer_getcfg(int layer, struct layer_cfg_t *cfg)

Get display layer configuration, If layer is not setup cfg will be filled with valid default values and area set to invalid.

Parameters:

layer – Layer number disp_layer_e
cfg – Layer configuration pointer to fill

Returns:

0 for success, negative for error

void *display_layer_getbuffer(int layer)

Get display layer buffer. Image data written on buffer will be sent to display on flush.

Parameters:: layer – Layer number disp_layer_e
Returns:: buffer pointer on success, NULL on error

int display_layer_enable(int layer, uint8_t en)

Enable or disable display layer.

Parameters:

layer – Layer number disp_layer_e
en – TRUE to enable, FALSE to disable layer

Returns:

0 for success, negative for error

int display_layer_delete(int layer)

Delete a display layer.

Note

Base Layer 0 cannot be deleted

Parameters:: layer – Layer number disp_layer_e
Returns:: 0 for success, negative for error

int display_flush(const struct lcd_area_t *area, uint8_t sync)

Flush blended display layers on LCD.

Parameters:

area – area to update, NULL for complete update
sync – TRUE - to wait for operation to complete, FALSE - do not wait

Returns:

0 for success, negative for error

int display_write_cmd(uint16_t cmd)

Send command to LCD controller.

Parameters:: cmd – command to write
Returns:: 0 for success, negative for error

int display_write_data(uint16_t data)

Send data to LCD controller.

Parameters:: data – data to write
Returns:: 0 for success, negative for error

int display_read_data(uint16_t cmd, uint8_t *data, unsigned len)

Read data from LCD controller, e.g. LCD controller ID.

Parameters:

cmd – Read command for LCD controller
data – data buffer to store read data
len – length of data to read (max 4 bytes)

Returns:

0 for success, negative for error

void display_wait_transfer(void): Wait for transfer to complete, this is blocking call.

void display_backlight_enable(uint8_t enabled)

Enable/disable display backlight (if supported by hardware)

Parameters:: enabled – TRUE to enable, FALSE disable

int display_clear(uint8_t sync)

Clear display. This function disable all display layers and set display background to default as in config.

Parameters:: sync – TRUE - to wait for operation to complete, FALSE - do not wait
Returns:: 0 for success, negative for error

Structures

struct lcd_area_t

An area.

Area with (w == 0 || h == 0) is nul or invalid area.

Public Members

uint16_t y: Top left position x coordinate

uint16_t w: Top left position y coordinate

uint16_t h: Width of area

struct lcd_ops_t

LCD driver operations.

Public Members

void (*init)(void): Initialization.

void (*prepare)(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1)

Setup lcd controller area for display data transfer.

Param x0:: top left corner x coordinate
Param y0:: top left corner y coordinate
Param x1:: bottom right corner x coordinate
Param y1:: bottom right corner y coordinate

void (*set_direction)(int dir)

Set LCD controller direction.

Note

This function is currently unused (can be set to NULL), Please set LCD direction

during initialization of LCD controller.

Param dir:: direction transform to set lcd_dir_e

struct lcd_drv_t

LCD Driver structure.

Public Members

uint32_t init_delay_us: Reset delay in microseconds

uint16_t io_level_mv: Delay in microseconds before driver init is called

uint16_t width: LCD IO Level in millivolts, 0 for default 1800mV, max 3200mV

uint16_t height: Width of LCD panel

uint16_t bg_color: Height of LCD panel

uint8_t output_format: Default background color

uint8_t in_format: LCD output pixel format lcd_outfmt_e

uint8_t spi_linemode: Input data format for Base layer 0 disp_infmt_e

uint8_t cs_polarity: LCD controller SPI interface lcd_spi_linemode_e

uint8_t te_enable: Chip select line polarity, 0 - active low, 1 - active high

uint8_t te_polarity: Enable tearing effect signal detect (FMARK), - TRUE to enable, FALSE to disable

uint16_t te_delay: TE polarity (unused), positive edge default

uint32_t spi_freq: TE detect delay

struct lcd_ops_t ops: SPI frequency in Hz

struct layer_cfg_t

Display layer configuration.

Public Members

uint8_t alpha: input data format disp_infmt_e

uint8_t key_en: blending alpha, 0 for transparent

uint8_t key_mask: whether to enable color key

uint16_t key_color: key color mask

struct lcd_area_t area: key color in RGB565

Enumerations

enum disp_layer_e

Display Controller Layers.

Values:

enumerator DISPLAY_LAYER0: Base/bottom layer

enumerator DISPLAY_LAYER1: Middle layer

enumerator DISPLAY_LAYER2: Top layer

enumerator DISPLAY_LAYER_VIDEO: Video layer, shown above all graphics layers

enum lcd_outfmt_e

LCD controller supported output format.

Values:

enumerator LCD_OUT_FMT_8BIT_RGB332

enumerator LCD_OUT_FMT_8BIT_RGB444

enumerator LCD_OUT_FMT_8BIT_RGB565

enumerator LCD_OUT_FMT_16BIT_RGB332

enumerator LCD_OUT_FMT_16BIT_RGB444

enumerator LCD_OUT_FMT_16BIT_RGB565

enum lcd_spi_linemode_e

LCD controler SPI interface line mode.

Values:

enumerator LCD_SPI_4WIRE

enumerator LCD_SPI_3WIRE

enumerator LCD_SPI_4WIRE_START_BYTE

enumerator LCD_SPI_3WIRE_2LANE

enum lcd_dir_e

Direction transform.

Values:

enumerator LCD_DIR_NORMAL: normal direction

enumerator LCD_DIR_YINV: Y is inverted

enumerator LCD_DIR_XINV: X is inverted

enumerator LCD_DIR_YINV_XINV: both Y and X are inverted

enumerator LCD_DIR_EXCHG: X-Y are swapped

enumerator LCD_DIR_EXCHG_YINV: X-Y are swapped, Y is inverted

enumerator LCD_DIR_EXCHG_XINV: X-Y are swapped, X is inverted

enumerator LCD_DIR_EXCHG_XINV_YINV: X-Y are swapped, both X and Y are inverted

enumerator LCD_DIR_ROTATE_0: alias for rotate 0 degree

enumerator LCD_DIR_ROTATE_90: alias for rotate 90 degree

enumerator LCD_DIR_ROTATE_180: alias for rotate 180 degree

enumerator LCD_DIR_ROTATE_270: alias for rotate 270 degree

enum disp_infmt_e

Input buffer color format.

RGB565 and ARGB8888 format for layer0, 1 and 2 YUV formats are for video layer

Values:

enumerator LCD_IN_FMT_RGB565: RGB565 in little endian, [15:11] R, [10:5] G, [4:0] B

enumerator LCD_IN_FMT_ARGB8888: ARGB8888 in little endian, [31:24] A, [23:16] R, [15:8] G, [7:0] B

enumerator LCD_IN_FMT_YUV422_UYVY: UYVY pixel-packed format

enumerator LCD_IN_FMT_YUV422_YUYV: YUYV pixel-packed format

enumerator LCD_IN_FMT_YUV420_IYUV: IYUV planar format