How to enable MIPI display(ST7796S) on i.MX6Q sabresd?

jiangshao · ‎11-01-2016

I want to use a MIPI display on our custom board(imx6q sabresd),

and I only got the datasheet of st7796s and a text file from board maker, like this:

//************* Start Initial Sequence **********//
Delay(120);
WriteComm(0x11);
Delay(120);
WriteComm(0xf0);
WriteData(0xc3);

:

Delay(120);
WriteComm(0x29);

I do not know how to use this text file(Start Initial Sequence)。

Do I need to get something else from board maker?

jiangshao · ‎12-22-2016

另外我想问问fae，4.2.2是否支持320*480这个分辨率？如果不支持，需要修改哪里来支持呢？

还有就是fbset出错，不知道是什么原因。。。

busybox fbset –info执行后出错

1|root@android:/ # busybox fbset --info

fbset: can't open '/dev/fb0': No such file or directory

jiangshao · ‎12-22-2016

屏终于亮了（之前可能硬件连接有问题），但是是花屏，如图。

有哪位知道这种情况应该微调哪里吗？

jiangshao · ‎12-13-2016

找到了一份代码很有参考价值：added otm3201a mipi dsi display support · guh/linux-imx6-3.14-tune@8ad29ad · GitHub

参考这个，我做了如下修改：

板文件，修改如下：

static struct mipi_dsi_platform_data mipi_dsi_pdata = {
.ipu_id = 0,
//change by shao, 2016-11-29
//.disp_id = 1,
.disp_id = 0,
//.lcd_panel = "TRULY-WVGA",
.lcd_panel = "ST7796S-HVGA",
.reset = mx6_reset_mipi_dsi,
};

static struct ipuv3_fb_platform_data sabresd_fb_data[] = {
{//change by shao, 2016-11-29
.disp_dev = "mipi_dsi",
.interface_pix_fmt = IPU_PIX_FMT_RGB24,
.mode_str = "ST7796S-HVGA",
.default_bpp = 24,
.int_clk = false,
.late_init = false,
},......

mipi_dsi.c修改如下：

static struct mipi_dsi_match_lcd mipi_dsi_lcd_db[] = {
#ifdef CONFIG_FB_MXC_TRULY_WVGA_SYNC_PANEL
{
"TRULY-WVGA",
{mipid_hx8369_get_lcd_videomode, mipid_hx8369_lcd_setup}
},
#endif
//add by shao, 2016-12-05
#ifdef CONFIG_FB_MXC_ST9976S_HVGA_PANEL
{
"ST7796S-HVGA",
{mipid_st7796s_get_lcd_videomode, mipid_st7796s_lcd_setup}
},
#endif
{
"", {NULL, NULL}
}
};

mipi_dsi.h修改如下：

#ifdef CONFIG_FB_MXC_ST9976S_HVGA_PANEL
void mipid_st7796s_get_lcd_videomode(struct fb_videomode **mode, int *size,
struct mipi_lcd_config **data);
int mipid_st7796s_lcd_setup(struct mipi_dsi_info *);
#endif

#ifndef CONFIG_FB_MXC_ST9976S_HVGA_PANEL
#error "Please configure MIPI LCD panel, we cannot find one!"
#endif

追加一个c文件，名为mxcfb_st7796s_hvga.c

Kconfig和Makefile做相应修改，修改内核配置，选中st7796s

追加的mxcfb_st7796s_hvga.c内容如下：

#define REFRESH 36
#define XRES 320
#define YRES 480
#define LEFT_MARGIN 20
#define RIGHT_MARGIN 20
#define UPPER_MARGIN 50
#define LOWER_MARGIN 20
#define HSYNC_LEN 6
#define VSYNC_LEN 6
#define PIXCLOCK (1e12/((XRES+LEFT_MARGIN+RIGHT_MARGIN+HSYNC_LEN)*(YRES+UPPER_MARGIN+LOWER_MARGIN+VSYNC_LEN)*REFRESH))
#define CHECK_RETCODE(ret) \
do { \
if (ret < 0) { \
dev_err(&mipi_dsi->pdev->dev, \
"%s ERR: ret:%d, line:%d.\n", \
__func__, ret, __LINE__); \
return ret; \
} \
} while (0)

static struct fb_videomode st7796s_lcd_modedb[] = {
{
"ST7796S-HVGA", /* name */
REFRESH, /* refresh /frame rate */
XRES, YRES, /* resolution */
PIXCLOCK, /* pixel clock*/
LEFT_MARGIN, RIGHT_MARGIN, /* l/r margin */
UPPER_MARGIN, LOWER_MARGIN, /* u/l margin */
HSYNC_LEN, VSYNC_LEN, /* hsync/vsync length */
FB_SYNC_OE_LOW_ACT, /* sync */
FB_VMODE_NONINTERLACED, /* vmode */
0, /* flag */
},
};

static struct mipi_lcd_config lcd_config = {
.virtual_ch = 0,
.data_lane_num = 1,
.max_phy_clk = 800,
.dpi_fmt = MIPI_RGB565_PACKED,
};

void mipid_st7796s_get_lcd_videomode(struct fb_videomode **mode, int *size,
struct mipi_lcd_config **data)
{
*mode = &st7796s_lcd_modedb[0];
*size = ARRAY_SIZE(st7796s_lcd_modedb);
*data = &lcd_config;
}

int mipid_st7796s_lcd_setup(struct mipi_dsi_info *mipi_dsi)
{
u32 buf[DSI_CMD_BUF_MAXSIZE];
int err;

//printk("MIPI DSI pixelclock = %lu", PIXCLOCK);
dev_info(&mipi_dsi->pdev->dev, "MIPI DSI LCD setup.\n");

msleep(120);

/* Sleep out (R11h) */
buf[0] = 0x11;
err = mipi_dsi_pkt_write(mipi_dsi, MIPI_DSI_GENERIC_LONG_WRITE, buf, 1);
CHECK_RETCODE(err);
printk("err = %i", err);

msleep(120);

/* Command Set Control:C3h enable command 2 part I (RF0h) */
buf[0] = 0xF0C3;
err = mipi_dsi_pkt_write(mipi_dsi, MIPI_DSI_GENERIC_LONG_WRITE, buf, 2);
CHECK_RETCODE(err);

/* Command Set Control:96h enable command 2 part II (RF0h) */
buf[0] = 0xF096;
err = mipi_dsi_pkt_write(mipi_dsi, MIPI_DSI_GENERIC_LONG_WRITE, buf, 2);
CHECK_RETCODE(err);

/* Memory Data Access Control (R36h)*/
buf[0] = 0x3648;
err = mipi_dsi_pkt_write(mipi_dsi, MIPI_DSI_GENERIC_LONG_WRITE, buf, 2);
CHECK_RETCODE(err);

：

《中略》

：

/* wait until sleepout is finished */
msleep(120);

/* Display on (R29h) */
buf[0] = 0x29;
err = mipi_dsi_pkt_write(mipi_dsi, MIPI_DSI_GENERIC_LONG_WRITE, buf, 1);
CHECK_RETCODE(err);
dev_info(&mipi_dsi->pdev->dev, "ST7796S MIPI DSI setup done.\n");

return err;
}

其中，函数mipid_st7796s_lcd_setup的内容是参考屏厂提供的初期化脚本写的：

//************* Start Initial Sequence **********//
Delay(120);
WriteComm(0x11);
Delay(120);
WriteComm(0xf0);
WriteData(0xc3);

WriteComm(0xf0);
WriteData(0x96);

WriteComm(0x36);
WriteData(0x48);

：

《中略》

：

Delay(120);
WriteComm(0x29);

uboot参数如下：

video=mxcfb0:dev=mipi_dsi,ST7796S-HVGA,bpp=RGB24

遗憾的是，烧写后从dmesg看，没有错误输出，但是屏不能点亮。

恳请有经验的fae给些指点，或者指明调查的方向。

jiangshao · ‎12-01-2016

/kernel_imx/drivers/video/mxc/mipi_dsi.中也有个列表：

static struct mipi_dsi_match_lcd mipi_dsi_lcd_db[] = {

#ifdef CONFIG_FB_MXC_TRULY_WVGA_SYNC_PANEL

{

"TRULY-WVGA",

{mipid_hx8369_get_lcd_videomode, mipid_hx8369_lcd_setup}

},

#endif

{

"", {NULL, NULL}

}

};

改为：

static struct mipi_dsi_match_lcd mipi_dsi_lcd_db[] = {

#ifdef CONFIG_FB_MXC_TRULY_WVGA_SYNC_PANEL

{

//change by shao, 2016-12-01

//"TRULY-WVGA",

"HALF-VGA",

{mipid_hx8369_get_lcd_videomode, mipid_hx8369_lcd_setup}

},

#endif

{

"", {NULL, NULL}

}

};

错误变为：

<6>mxc_mipi_dsi mxc_mipi_dsi: i.MX MIPI DSI driver probed

<6>MIPI DSI driver module loaded

<6>mxc_sdc_fb mxc_sdc_fb.0: register mxc display driver mipi_dsi

<3>mxc_mipi_dsi mxc_mipi_dsi: mipi_dsi_pkt_read err:-5, data:0x0.

<6>mxc_mipi_dsi mxc_mipi_dsi: MIPI DSI LCD not detected!

<3>mxc_mipi_dsi mxc_mipi_dsi: failed to init mipi lcd.

<3>mxc_sdc_fb mxc_sdc_fb.0: enable error, dispdrv:mipi_dsi.

<4>detected fb_set_par error, error code: -22

<3>mxc_sdc_fb mxc_sdc_fb.0: Error fb_set_var ret:-22

<4>mxc_sdc_fb: probe of mxc_sdc_fb.0 failed with error -22

<3>mxc_sdc_fb mxc_sdc_fb.1: Can't get fb option for mxcfb1!

感觉hx8369的源码是不能用了，可是Initial Sequence里的command和data怎么写入呢？

有人做过类似mipi屏的porting吗？希望能给些帮助。

jiangshao · ‎11-29-2016

板文件修改导致的编译错误解决了，请参考：undefined reference to `imx_add_mipi_dsi' `imx6q_mipi_dsi_data'

但是现在有了新的疑问。

我根据手册（附件）修改板文件如下：

static struct mipi_dsi_platform_data mipi_dsi_pdata = {

.ipu_id = 0,

//change by shao, 2016-11-29

//.disp_id = 1,

.disp_id = 0,

//.lcd_panel = "TRULY-WVGA",

.lcd_panel = "HALF-VGA",

.reset = mx6_reset_mipi_dsi,

};

static struct ipuv3_fb_platform_data sabresd_fb_data[] = {

{//change by shao, 2016-11-29

.disp_dev = "mipi_dsi",

.interface_pix_fmt = IPU_PIX_FMT_RGB24,

.mode_str = "HALF-VGA",

.default_bpp = 24,

.int_clk = false,

.late_init = false,

},

mxcfb_hx8369_wvga.c修改如下

static struct fb_videomode truly_lcd_modedb[] = {

{

//change by shao, 2016-11-29

//"TRULY-WVGA", 64, 480, 800, 37880,

//8, 8,

//6, 6,

//8, 6,

"HALF-VGA", //name

60, //refresh

320, //xres

480, //yres

37880, //pixclock

4, //left_margin, HBP (Horizontal Back Porch)

38, //right_margin, HFP (Horizontal Front Porch)

4, //upper_margin, VBP (Vertical Back Porch)

8, //lower_margin, VFP (Vertical Front Porch)

2, //hsync_len, HPW (HSYNC plus width), HWH(HSYNC width)

4, //vsync_len, VPW (VSYNC width), VWH(VSYNC width)

FB_SYNC_OE_LOW_ACT, //sync

FB_VMODE_NONINTERLACED,//vmode

0, // flag

},

};

uboot参数：video=mxcfb0:dev=mipi_dsi,HALF-VGA,bpp=RGB24

烧写后，查看dmesg

mxc_mipi_dsi mxc_mipi_dsi: i.MX MIPI DSI driver probed

MIPI DSI driver module loaded

mxc_sdc_fb mxc_sdc_fb.0: register mxc display driver mipi_dsi

mxc_mipi_dsi mxc_mipi_dsi: failed to find supported lcd panel.

mxc_mipi_dsi mxc_mipi_dsi: failed to init mipi dsi lcd

Trying to free nonexistent resource <00000000020e0000-00000000020e0fff>

mxc_sdc_fb mxc_sdc_fb.0: NO mxc display driver found!

mxc_sdc_fb mxc_sdc_fb.1: Can't get fb option for mxcfb1!

这是屏的厂家给的Initial Sequence，根据手册分析如下：

//************* Start Initial Sequence **********//

Delay(120);

WriteComm(0x11); Sleep Out

Delay(120);

WriteComm(0xf0); Command Set Control

WriteData(0xc3); C3h enable command 2 part I

WriteComm(0xf0); Command Set Control

WriteData(0x96); 96h enable command 2 part II

WriteComm(0x36); Memory Data Access Control

WriteData(0x48);

WriteComm(0xe8); Display Output Ctrl Adjust

WriteData(0x40); 第一参数

WriteData(0x82);

WriteData(0x07);

WriteData(0x18);

WriteData(0x27);

WriteData(0x0a);

WriteData(0xb6);

WriteData(0x33); 第八参数

WriteComm(0xc2); Power Control 3

WriteData(0xa7);

WriteComm(0xc5); VCOM Control

WriteData(0x25);//13

WriteComm(0xb7); Entry Mode Set

WriteData(0x46);//13 06

WriteComm(0xe0); Positive Gamma Control

WriteData(0xf0); 第一参数

WriteData(0x07);

WriteData(0x11);

WriteData(0x10);

WriteData(0x11);

WriteData(0x0b);

WriteData(0x3c);

WriteData(0x43);

WriteData(0x4b);

WriteData(0x0b);

WriteData(0x17);

WriteData(0x16);

WriteData(0x1b);

WriteData(0x1d); 第十四参数

WriteComm(0xe1); Negative Gamma Control

WriteData(0xf0);

WriteData(0x07);

WriteData(0x11);

WriteData(0x0f);

WriteData(0x10);

WriteData(0x1a);

WriteData(0x39);

WriteData(0x55);

WriteData(0x4a);

WriteData(0x0b);

WriteData(0x16);

WriteData(0x15);

WriteData(0x1a);

WriteData(0x1d);

WriteComm(0xf0); Command Set Control

WriteData(0x3c); 3Ch disable command 2 part I

WriteComm(0xf0); Command Set Control

WriteData(0x69); 69h disable command 2 part II

WriteComm(0x3A); Interface Pixel Format

WriteData(0x55);

Delay(120);

WriteComm(0x29); Display On

1，通过查看上述command，发现和hx8369一致的非常少。这是不是意味着不能使用mxcfb_hx8369_wvga.c而必须自己写一个驱动？

2，Initial Sequence里的command和data怎么写入呢？

jiangshao · ‎11-16-2016

最近参考了i.MX_Linux_Reference_Manual.pdf和

Integating mipi lcd display over i.mx6.

动手做了一些修改，但是在板文件中打开如下注释：

// change by shao, 2016-11-16
// imx6q_add_mipi_dsi(&mipi_dsi_pdata);
imx6q_add_mipi_dsi(&mipi_dsi_pdata);

编译出现了错误：

arch/arm/mach-mx6/built-in.o: In function `mx6_sabresd_board_init':
/media/myandroid/work/20161018newB/kernel_imx/arch/arm/mach-mx6/board-mx6q_sabresd.c:2272: undefined reference to `imx_add_mipi_dsi'
/media/myandroid/work/20161018newB/kernel_imx/arch/arm/mach-mx6/board-mx6q_sabresd.c:2474: undefined reference to `imx6q_mipi_dsi_data'
make: *** [.tmp_vmlinux1] 错误 1

而确认板文件包含的头文件devices-imx6q.h中，明明有如下定义

extern const struct imx_mipi_dsi_data imx6q_mipi_dsi_data __initconst;
#define imx6q_add_mipi_dsi(pdata) \
imx_add_mipi_dsi(&imx6q_mipi_dsi_data, pdata)

make distclean也都试过了，错误依旧，

有哪位知道为什么吗？

igorpadykov · ‎11-02-2016

Hi jiang

for new lcd its timings parameters should be entered in struct fb_videomode,

please check example in linux/drivers/video/fbdev/mxc/ mxcfb_hx8369_wvga.c

Chapter 7 MIPI DSI Driver attached Linux Manual.

Best regards
igor
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jiangshao · ‎11-02-2016

Thank you for your reply.

I will read the DOC, but the OS of the board is Android4.2.2

How to enable MIPI display(ST7796S) on i.MX6Q sabresd?

How to enable MIPI display(ST7796S) on i.MX6Q sabresd?

Android

i.MX6DL

i.MX6Quad