Freescale Semiconductor i.MX 6DualLite, Справочное руководство

Страница: 59 / 329

• Configurable RGB 16, 24 or 32 bits per pixel frame buffer
• Configurable panel interface signal timings and polarities
• Palette/color conversion management
• Power management
• LCD power off/on
User applications use the generic video API (the standard Linux frame buffer driver API)
to perform functions with the frame buffer. These include the following:
• Obtaining screen information, such as the resolution or scan length
• Allocating user space memory by using mmap for performing direct blitting
operations
A second frame buffer driver supports a second video/graphics plane.
6.3.2 IPU Backlight Driver
The IPU backlight driver implements IPU PWM backlight control for panels. It exports a
system control file under /sys/class/backlight/pwm-backlight.0/brightness to user space.
The default backlight intensity value is 128.
6.3.3 IPU Device Driver
IPU (processing) device driver provide image processing features, including resizing,
rotation, CSC, combination, and deinterlacing based on IC/IRT modules in IPUv3.
The IPU device driver is task based. Users only need to prepare for task setting, queue
task, and then the block waits for the task to finish. The driver now supports the blocking
method only, and the non-block method will be added in the future. The task structures
are as follows:
struct ipu_task {
struct ipu_input input;
struct ipu_output output;
bool overlay_en;
struct ipu_overlay overlay;
#define IPU_TASK_PRIORITY_NORMAL 0
#define IPU_TASK_PRIORITY_HIGH 1
u8 priority;
#define IPU_TASK_ID_ANY 0
#define IPU_TASK_ID_VF 1
#define IPU_TASK_ID_PP 2
#define IPU_TASK_ID_MAX 3
u8 task_id;
Chapter 6 Image Processing Unit (IPU) Drivers
i.MX 6Solo/6DualLite Linux Reference Manual, Rev. L3.0.35_4.1.0, 09/2013
Freescale Semiconductor, Inc. 59