Display Driver API¶

Note

Display driver is currently only available on 4G platforms

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