lk SPI驱动

1. 初始化时钟

在lk中，我们是从kmain开始执行下来的，而执行顺序则是先初始化时钟，也就是在platform_early_init函数中开始执行的：
在这里我们需要修改这个函数中的platform_clock_init();，我们来这里看这个函数，平台为msm8909：

void platform_clock_init(void)
{
    clk_init(msm_clocks_msm8909, ARRAY_SIZE(msm_clocks_msm8909));
}

msm_clocks_msm8909这个数组增加可以参考链接来增加，之后会提供patch来显示，相关寄存器文档参考80_NU767_1_H_Linux BAM Low-Speed Peripherals Configuration and Debug Guide.pdf；

高通msm8916 LK阶段配置使用i2c5

同样的道理先从aboot_init分析起，进入target_display_init函数中来：

target_display_init(device.display_panel); 这里进行屏幕的初始化。

void target_display_init(const char *panel_name)
{
    uint32_t panel_loop = 0;
    uint32_t ret = 0;

    panel_name += strspn(panel_name, " ");
    if (!strcmp(panel_name, NO_PANEL_CONFIG) || !strcmp(panel_name, SIM_VIDEO_PANEL)
            || !strcmp(panel_name, SIM_CMD_PANEL)) {
        dprintf(INFO, "Selected %s: Skip panel configuration\n", panel_name);
        return;
    }

    dprintf(INFO, "panel_name is %s\n", panel_name);

    do {
            target_force_cont_splash_disable(false);
            ret = gcdb_display_init(panel_name, MDP_REV_305, MIPI_FB_ADDR);
            if (!ret || ret == ERR_NOT_SUPPORTED) {
                break;
            } else {
                target_force_cont_splash_disable(true);
                msm_display_off();
            }
        } while (++panel_loop <= oem_panel_max_auto_detect_panels());
        }

gcdb_display_init调用pan_type = oem_panel_select(panel_name, &panelstruct, &(panel.panel_info), &dsi_video_mode_phy_db)，选择具体的屏幕；

int gcdb_display_init(const char *panel_name, uint32_t rev, void *base)
{
    int ret = NO_ERROR;
    int pan_type;

    pan_type = oem_panel_select(panel_name, &panelstruct, &(panel.panel_info),
    &dsi_video_mode_phy_db);

    if (pan_type == PANEL_TYPE_DSI) {
        init_platform_data();
        if (dsi_panel_init(&(panel.panel_info), &panelstruct)) {
        dprintf(CRITICAL, "DSI panel init failed!\n");
        ret = ERROR;
        goto error_gcdb_display_init;
    }
            panel.panel_info.mipi.mdss_dsi_phy_db = &dsi_video_mode_phy_db;
            panel.pll_clk_func = mdss_dsi_panel_clock;
            panel.power_func = mdss_dsi_panel_power;
            panel.pre_init_func = mdss_dsi_panel_pre_init;
                panel.bl_func = mdss_dsi_bl_enable;
            panel.fb.base = base;
            panel.fb.width = panel.panel_info.xres;
            panel.fb.height = panel.panel_info.yres;
            panel.fb.stride = panel.panel_info.xres;
            panel.fb.bpp = panel.panel_info.bpp;
            panel.fb.format = panel.panel_info.mipi.dst_format;
    } else if (pan_type == PANEL_TYPE_EDP) {
        mdss_edp_panel_init(&(panel.panel_info));
        /* prepare func is set up at edp_panel_init */
        panel.clk_func = mdss_edp_panel_clock;
        panel.power_func = mdss_edp_panel_power;
        panel.bl_func = mdss_edp_bl_enable;
        panel.fb.format = FB_FORMAT_RGB888;
    } else {
        dprintf(CRITICAL, "Target panel init not found!\n");
        ret = ERR_NOT_SUPPORTED;
        goto error_gcdb_display_init;
    }

    panel.fb.base = base;
    panel.mdp_rev = rev;

    ret = msm_display_init(&panel);

    error_gcdb_display_init:
    display_enable = ret ? 0 : 1;
    return ret;
}

根据屏幕的类型，增加panel；如链接所示，可以看到，步骤如下：

2. 在gcdb_display_init()函数中有一个函数oem_panel_select()函数：

（这个函数需要做的工作是：主要是识别不同IC，赋值给参数panel_id，panel_id的使用在同一文件中的 init_panel_data()函数中。）

pan_type = oem_panel_select(panel_name, &panelstruct, &(panel.panel_info), &dsi_video_mode_phy_db);

3. 在oem_panel_select()函数中需要根据你的hw_id来确定使用哪一款的LCD：

panel_override_id = panel_name_to_id(supp_panels, ARRAY_SIZE(supp_panels), panel_name);

supp_panels是struct panel_list，如果要增加一个panel就需要在这里增加一个supp_panels，例如：

static struct panel_list supp_panels[] = {
{"truly_1080p_video", TRULY_1080P_VIDEO_PANEL},
{"truly_1080p_cmd", TRULY_1080P_CMD_PANEL},
{"r69006_1080p_video", R69006_1080P_VIDEO_PANEL},
{"r69006_1080p_cmd", R69006_1080P_CMD_PANEL},
{"truly_wuxga_video", TRULY_WUXGA_VIDEO_PANEL},
{"nt35523_720p_video", NT35523_720P_VIDEO_PANEL},
{"a914_nhd_video", A914_NHD_VIDEO_PANEL}, //这是我们新增的
};

4. 在这个枚举中也需要增加相应的panel：

/*---------------------------------------------------------------------------*/
enum {
TRULY_1080P_VIDEO_PANEL,
TRULY_1080P_CMD_PANEL,
R69006_1080P_VIDEO_PANEL,
R69006_1080P_CMD_PANEL,
TRULY_WUXGA_VIDEO_PANEL,
NT35523_720P_VIDEO_PANEL,
A914_NHD_VIDEO_PANEL, //这是我们新增的
UNKNOWN_PANEL
};

继续向下看：

if (panel_name) {
    panel_override_id = panel_name_to_id(supp_panels,  ARRAY_SIZE(supp_panels), panel_name);

    if (panel_override_id < 0) {
        dprintf(CRITICAL, "Not able to search the panel:%s\n",
        panel_name + strspn(panel_name, " "));
    } else if (panel_override_id < UNKNOWN_PANEL) {
        /* panel override using fastboot oem command */
        panel_id = panel_override_id;

        dprintf(INFO, "OEM panel override:%s\n",
        panel_name + strspn(panel_name, " "));
        goto panel_init;
    }
}
……
panel_init:
/*
* Update all data structures after 'panel_init' label. Only panel
* selection is supposed to happen before that.
*/
pinfo->pipe_type = MDSS_MDP_PIPE_TYPE_RGB;
return init_panel_data(panelstruct, pinfo, phy_db);

确保能直接跳到panel_init函数中来；

5. 来到init_panel_data()函数中来：

在这里也需要增加一个panel：（当然了，要增加相应的头文件）
#include "include/panel_a914_nhd_video.h"，在target/msm8909/oem_panel.c中增加在这个头文件；
（LCM供应商给的上电顺序，一般来说都要自己根据上电初始化代码来参照）

case TRULY_WUXGA_VIDEO_PANEL:
    panelstruct->paneldata = &truly_wuxga_video_panel_data;
    panelstruct->paneldata->panel_with_enable_gpio = 1;
    panelstruct->panelres = &truly_wuxga_video_panel_res;
    panelstruct->color = &truly_wuxga_video_color;
    panelstruct->videopanel = &truly_wuxga_video_video_panel;
    panelstruct->commandpanel = &truly_wuxga_video_command_panel;
    panelstruct->state = &truly_wuxga_video_state;
    panelstruct->laneconfig = &truly_wuxga_video_lane_config;
    panelstruct->paneltiminginfo = &truly_wuxga_video_timing_info;
    panelstruct->panelresetseq = &truly_wuxga_video_panel_reset_seq;
    panelstruct->backlightinfo = &truly_wuxga_video_backlight;
    pinfo->mipi.panel_on_cmds= truly_wuxga_video_on_command;
    pinfo->mipi.num_of_panel_on_cmds= TRULY_WUXGA_VIDEO_ON_COMMAND;
    pinfo->mipi.panel_off_cmds= truly_wuxga_video_off_command;
    pinfo->mipi.num_of_panel_off_cmds= TRULY_WUXGA_VIDEO_OFF_COMMAND;
    memcpy(phy_db->timing, truly_wuxga_14nm_video_timings, MAX_TIMING_CONFIG * sizeof(uint32_t));
    pinfo->dfps.panel_dfps = truly_wuxga_video_dfps;
    pinfo->mipi.signature = TRULY_WUXGA_VIDEO_SIGNATURE;
    break;
/*下面这段代码是我们增加的*/
case A914_NHD_VIDEO_PANEL:
    panelstruct->paneldata = &a914_nhd_video_panel_data;
    panelstruct->panelres = &a914_nhd_video_panel_res;
    panelstruct->color = &a914_nhd_video_color;
    panelstruct->videopanel = &a914_nhd_video_video_panel;
    panelstruct->commandpanel = &a914_nhd_video_command_panel;
    panelstruct->state = &a914_nhd_video_state;
    panelstruct->laneconfig = &a914_nhd_video_lane_config;
    panelstruct->paneltiminginfo = &a914_nhd_video_timing_info;
    panelstruct->panelresetseq = &a914_nhd_video_panel_reset_seq;
    panelstruct->backlightinfo = &a914_nhd_video_backlight;
    pinfo->mipi.panel_on_cmds = a914_nhd_video_on_command;
    pinfo->mipi.num_of_panel_on_cmds = A914_NHD_VIDEO_ON_COMMAND;
    pinfo->mipi.panel_off_cmds = a914_nhd_video_off_command;
    pinfo->mipi.num_of_panel_off_cmds = A914_NHD_VIDEO_OFF_COMMAND;
    memcpy(phy_db->timing,a914_nhd_video_timings, MAX_TIMING_CONFIG * sizeof(uint32_t));
    pinfo->mipi.signature = A914_NHD_VIDEO_SIGNATURE;
    break;

我们上面分析了这个函数里面的内容，并为其增加了一个panel：

pan_type = oem_panel_select(panel_name, &panelstruct, &(panel.panel_info), &dsi_video_mode_phy_db);

6. 为pan_type也增加一个SPI类型：

else if (pan_type == PANEL_TYPE_SPI ) {
    panel.panel_info.xres = panelstruct.panelres->panel_width;
    panel.panel_info.yres = panelstruct.panelres->panel_height;
    panel.panel_info.bpp = panelstruct.color->color_format;
    panel.power_func = mdss_spi_panel_power;
    panel.bl_func = mdss_spi_bl_enable;
    panel.fb.base = base;
    panel.fb.width = panel.panel_info.xres;
    panel.fb.height = panel.panel_info.yres;
    panel.fb.bpp = panel.panel_info.bpp;
    panel.fb.format = FB_FORMAT_RGB888;
    panel.panel_info.type = SPI_PANEL;
}
else {
    dprintf(CRITICAL, "Target panel init not found!\n");
    ret = ERR_NOT_SUPPORTED;
    goto error_gcdb_display_init;
}

我们增加了mdss_spi_panel_power、mdss_spi_bl_enable函数如下所示：

static int mdss_spi_panel_power(uint8_t enable,
struct msm_panel_info *pinfo)
{
    int ret = NO_ERROR;

    if (enable) {
    ret = target_ldo_ctrl(enable, pinfo);
    if (ret) {
    dprintf(CRITICAL, "LDO control enable failed\n");
    return ret;
    }
    /* Panel Reset */
        ret = target_panel_reset(enable, panelstruct.panelresetseq,
        &panel.panel_info);
        if (ret) {
            dprintf(CRITICAL, "panel reset failed\n");
            return ret;
        }
        dprintf(INFO, "Panel power on done\n");
    } else {
        /* Disable panel and ldo */
        ret = target_panel_reset(enable, panelstruct.panelresetseq,
        &panel.panel_info);
        if (ret) {
        dprintf(CRITICAL, "panel reset disable failed\n");
        return ret;
    }

    ret = target_ldo_ctrl(enable, pinfo);
    if (ret) {
        dprintf(CRITICAL, "ldo control disable failed\n");
        return ret;
    }
        dprintf(INFO, "Panel power off done\n");
    }

    return ret;
}

static int mdss_spi_bl_enable(uint8_t enable)
{
    int ret = NO_ERROR;

    mdelay(100);
    ret = panel_backlight_ctrl(enable);
    if (ret)
    dprintf(CRITICAL, "Backlight %s failed\n", enable ? "enable" : "disable");
    return ret;
}

7. 来到msm_display_init函数中来：

在上提到的函数中：

int msm_display_init(struct msm_fb_panel_data *pdata)
{
    int ret = NO_ERROR;

    panel = pdata;
    if (!panel) {
        ret = ERR_INVALID_ARGS;
        goto msm_display_init_out;
    }

    /* Turn on panel */
    if (pdata->power_func)
        ret = pdata->power_func(1, &(panel->panel_info)); //执行turn on的函数

    if (ret)
        goto msm_display_init_out;

     /* Enable clock */
    if (pdata->clk_func)
        ret = pdata->clk_func(1); // //执行配置时钟的函数

    /* Only enabled for auto PLL calculation */
    if (pdata->pll_clk_func)
        ret = pdata->pll_clk_func(1, &(panel->panel_info));

    if (ret)
        goto msm_display_init_out;

    /* pinfo prepare */
    if (pdata->panel_info.prepare) {
    /* this is for edp which pinfo derived from edid */
        ret = pdata->panel_info.prepare();
        panel->fb.width = panel->panel_info.xres;
        panel->fb.height = panel->panel_info.yres;
        panel->fb.stride = panel->panel_info.xres;
        panel->fb.bpp = panel->panel_info.bpp;
    }   

    if (ret)
        goto msm_display_init_out;

    ret = msm_fb_alloc(&(panel->fb));
    if (ret)
        goto msm_display_init_out;

    ret = msm_display_config();
    if (ret)
        goto msm_display_init_out;

    fbcon_setup(&(panel->fb));
    display_image_on_screen();
    ret = msm_display_on();
    if (ret)
        goto msm_display_init_out;

    if (pdata->post_power_func)
        ret = pdata->post_power_func(1);
    if (ret)
        goto msm_display_init_out;

    /* Turn on backlight */
    if (pdata->bl_func)
        ret = pdata->bl_func(1);

    if (ret)
        goto msm_display_init_out;

    msm_display_init_out:
        return ret;
}

其中msm_fb_alloc函数是分配framebuffer空间；
下面我们来分析display_image_on_screen();函数：

void display_image_on_screen(void)
{
#if DISPLAY_TYPE_MIPI
    int fetch_image_from_partition();

    if (fetch_image_from_partition() < 0) {
        display_default_image_on_screen();
    } else {
    /* data has been put into the right place */
    fbcon_flush();
    }
#else
    display_default_image_on_screen();
#endif
}

由于我们的已经改为SPI方式传送，不是MIPI；所以会直接进入display_default_image_on_screen();函数；

void display_default_image_on_screen(void)
{
    unsigned i = 0;
    unsigned total_x;
    unsigned total_y;
    unsigned bytes_per_bpp;
    unsigned image_base;

    dprintf("CRITICAL", "linhao display_default_image_on_screen\n");

    if (!config) {
    dprintf(CRITICAL,"NULL configuration, image cannot be displayed\n");
    return;
    }
    fbcon_clear(); // clear screen with Black color

    total_x = config->width;
    total_y = config->height;
    bytes_per_bpp = ((config->bpp) / 8);
    image_base = ((((total_y/2) - (SPLASH_IMAGE_HEIGHT / 2) - 1) *
    (config->width)) + (total_x/2 - (SPLASH_IMAGE_WIDTH / 2)));

    //24 bit bpp
    if (bytes_per_bpp == 3) {
    for (i = 0; i < SPLASH_IMAGE_HEIGHT; i++) {
        memcpy (config->base + ((image_base + (i * (config->width))) * bytes_per_bpp),
        imageBuffer_rgb888 + (i * SPLASH_IMAGE_WIDTH * bytes_per_bpp),
        SPLASH_IMAGE_WIDTH * bytes_per_bpp);
        }
    }
    fbcon_flush();
#if DISPLAY_MIPI_PANEL_NOVATEK_BLUE
    if(is_cmd_mode_enabled())
    mipi_dsi_cmd_mode_trigger();
#endif
//16 bit bpp
if (bytes_per_bpp == 2) {
    for (i = 0; i < SPLASH_IMAGE_HEIGHT; i++) {
        memcpy (config->base + ((image_base + (i * (config->width))) * bytes_per_bpp),
        imageBuffer + (i * SPLASH_IMAGE_WIDTH * bytes_per_bpp),
        SPLASH_IMAGE_WIDTH * bytes_per_bpp);
        }
    }
    fbcon_flush();
}

在这里由于没有mipi，所以去掉了#if DISPLAY_TYPE_MIPI宏定义，然后根据24bit真彩色和16bit颜色深度进行相应处理；
最后使用fbcon_flush刷新framebuffer缓冲区；
这样就可以显示默认图片了~~;

display_image_on_screen函数分析完毕之后，继续回到我们的函数msm_display_init函数当中来：
下一步分析msm_display_config函数中来：

int msm_display_config()
{
    int ret = NO_ERROR;
    int mdp_rev;
    struct msm_panel_info *pinfo;

    if (!panel)
        return ERR_INVALID_ARGS;

    pinfo = &(panel->panel_info);

    /* Set MDP revision */
    mdp_set_revision(panel->mdp_rev);

    switch (pinfo->type) {
        case LVDS_PANEL:
            dprintf(INFO, "Config LVDS_PANEL.\n");
            ret = mdp_lcdc_config(pinfo, &(panel->fb));
        if (ret)
            goto msm_display_config_out;
        break;
    case MIPI_VIDEO_PANEL:
        dprintf(INFO, "Config MIPI_VIDEO_PANEL.\n");

        mdp_rev = mdp_get_revision();
        if (mdp_rev == MDP_REV_50 || mdp_rev == MDP_REV_304 ||
            mdp_rev == MDP_REV_305)
            ret = mdss_dsi_config(panel);
        else
            ret = mipi_config(panel);

        if (ret)
            goto msm_display_config_out;

        if (pinfo->early_config)
            ret = pinfo->early_config((void *)pinfo);

        ret = mdp_dsi_video_config(pinfo, &(panel->fb));
        if (ret)
            goto msm_display_config_out;
        break;
    case MIPI_CMD_PANEL:
        dprintf(INFO, "Config MIPI_CMD_PANEL.\n");
        mdp_rev = mdp_get_revision();
        if (mdp_rev == MDP_REV_50 || mdp_rev == MDP_REV_304 ||
            mdp_rev == MDP_REV_305)
            ret = mdss_dsi_config(panel);
        else
            ret = mipi_config(panel);
        if (ret)
            goto msm_display_config_out;

        ret = mdp_dsi_cmd_config(pinfo, &(panel->fb));
        if (ret)
            goto msm_display_config_out;
        break;
    case LCDC_PANEL:
        dprintf(INFO, "Config LCDC PANEL.\n");
        ret = mdp_lcdc_config(pinfo, &(panel->fb));
    if (ret)
        goto msm_display_config_out;
    break;
    //added by linhao
    case SPI_PANEL:
        dprintf(INFO, "Config SPI PANEL.\n");
        ret = mdss_spi_panel_init(pinfo);
    if (ret)
        goto msm_display_config_out;
    break;
    case HDMI_PANEL:
        dprintf(INFO, "Config HDMI PANEL.\n");
        ret = mdss_hdmi_config(pinfo, &(panel->fb));
    if (ret)
        goto msm_display_config_out;
    break;
    case EDP_PANEL:
        dprintf(INFO, "Config EDP PANEL.\n");
        ret = mdp_edp_config(pinfo, &(panel->fb));
        if (ret)
            goto msm_display_config_out;
            break;
            default:
            return ERR_INVALID_ARGS;
        };

    if (pinfo->config)
        ret = pinfo->config((void *)pinfo);

    msm_display_config_out:
        return ret;
}

在SPI_PANEL中进入了mdss_spi_panel_init函数中来：

int mdss_spi_panel_init(struct msm_panel_info *pinfo)
{
    int cmd_count = 0;
    int ret = 0;

    if(!dev) {
        //传入参数为SPI_BLSP_ID_1，SPI_QUP_ID_5
        dev = qup_blsp_spi_init(SPI_BLSP_ID_1, SPI_QUP_ID_5);
        if (!dev) {
        dprintf(CRITICAL, "Failed initializing SPI\n");
        return -ENODEV;
        }
    }

    gpio_tlmm_config(dc_gpio.pin_id, 0,
    dc_gpio.pin_direction, dc_gpio.pin_pull,
    dc_gpio.pin_strength, dc_gpio.pin_state);


    while (cmd_count < pinfo->spi.num_of_panel_cmds) {

        mdss_spi_write_cmd(pinfo->spi.panel_cmds[cmd_count].payload);

        if (pinfo->spi.panel_cmds[cmd_count].size > 1)
        mdss_spi_write_data(pinfo->spi.panel_cmds[cmd_count].payload + 1,
        pinfo->spi.panel_cmds[cmd_count].size - 1);

        if (pinfo->spi.panel_cmds[cmd_count].wait)
        mdelay(pinfo->spi.panel_cmds[cmd_count].wait);

        cmd_count ++;
    }

    return 0;
}

这个函数在lk/platform/msm_shared/mdss_spi.c中，如有需要，则添加这个文件即可；（Android7.0中没有这个文件，之后需要的话，使用patch来补充）
首先增加qup_blsp_spi_init函数，这个函数的作用是配置高通的blsp，高通msm8909的有12个blsp，每一个BLSP含有两个QUP, 每一个QUP可以被配置为I2C， SPI, UART, UIM接口， BLSP是高通对于低速接口的一种管理方式。参考文档为80_NU767_1_H_Linux BAM Low-Speed Peripherals Configuration and Debug Guide.pdf，该文档适用类型为MSM8996, MSM8994,
MSM8992, MSM8952, MSM8916, MSM8936/ MSM8939, MSM8909, MDM9x35, and
MDM9x40/MDM9x45 chipsets.：

struct qup_spi_dev *qup_blsp_spi_init(uint8_t blsp_id, uint8_t qup_id)
{
struct qup_spi_dev *dev;

dev = malloc(sizeof(struct qup_spi_dev));
if (!dev) {
return NULL;
}
dev = memset(dev, 0, sizeof(struct qup_spi_dev));

/* Platform uses BLSP */
dev->qup_irq = BLSP_QUP_IRQ(blsp_id, qup_id);
dev->qup_base = BLSP_QUP_BASE(blsp_id, qup_id);

/* Initialize the GPIO for BLSP spi */
gpio_config_blsp_spi(blsp_id, qup_id);

clock_config_blsp_spi(blsp_id, qup_id);

qup_spi_sec_init(dev);

return dev;
}

对着文档中的表来看：

因为我们选择的是BLSP1（一般为BLSP1），所以QUP_BASE_ADDRESS为0x78B5000；我们选择的是qup5，所以根据下面公式来计算：
QUP_BASE_ADDRESS的计算公式为:

#define PERIPH_SS_BASE              0x07800000
#define BLSP_QUP_BASE(blsp_id, qup_id) (PERIPH_SS_BASE + 0xB5000 + 0x1000 * qup_id)

根据硬件，进入QUP_ID_5，配置spi的管脚：

void gpio_config_blsp_spi(uint8_t blsp_id, uint8_t qup_id)
{
    if(blsp_id == BLSP_ID_1) {
        switch (qup_id) {

            case QUP_ID_4:
                /* configure SPI MOSI gpio */
                gpio_tlmm_config(16, 1, GPIO_OUTPUT, GPIO_NO_PULL,
                    GPIO_16MA, GPIO_DISABLE);

                    /* configure SPI MISO gpio */
                gpio_tlmm_config(17, 1, GPIO_OUTPUT, GPIO_NO_PULL,
                    GPIO_16MA, GPIO_DISABLE);

                /* configure SPI CS_N gpio */
                gpio_tlmm_config(18, 1, GPIO_OUTPUT, GPIO_NO_PULL,
                    GPIO_16MA, GPIO_DISABLE);

                /* configure SPI CLK gpio */
                gpio_tlmm_config(19, 1, GPIO_OUTPUT, GPIO_NO_PULL,
                    GPIO_16MA, GPIO_DISABLE);
                break;
            case QUP_ID_0:
                break;
            case QUP_ID_1:
                break;
            case QUP_ID_2:
                break;
            case QUP_ID_3:
                break;
            case QUP_ID_5:
                /* configure SPI MOSI gpio */
                gpio_tlmm_config(8, 1, GPIO_OUTPUT, GPIO_NO_PULL,
                    GPIO_16MA, GPIO_DISABLE);

                    /* configure SPI MISO gpio */
                gpio_tlmm_config(9, 1, GPIO_OUTPUT, GPIO_NO_PULL,
                    GPIO_16MA, GPIO_DISABLE);

                /* configure SPI CS_N gpio */
                gpio_tlmm_config(10, 1, GPIO_OUTPUT, GPIO_NO_PULL,
                    GPIO_16MA, GPIO_DISABLE);

                /* configure SPI CLK gpio */
                gpio_tlmm_config(11, 1, GPIO_OUTPUT, GPIO_NO_PULL,
                    GPIO_16MA, GPIO_DISABLE);
                break;
            default:
                dprintf(CRITICAL, "Incorrect QUP id %d\n",qup_id);
                ASSERT(0);
        };
    } else {
        dprintf(CRITICAL, "Incorrect BLSP id %d\n",blsp_id);
        ASSERT(0);
    }
}

继续向下看，配置spi时钟：

/* Configure spi clock */
void clock_config_blsp_spi(uint8_t blsp_id, uint8_t qup_id)
{
    uint8_t ret = 0;
    char clk_name[64];

    struct clk *qup_clk;

    if((blsp_id != BLSP_ID_1)) {
        dprintf(CRITICAL, "Incorrect BLSP-%d configuration\n", blsp_id);
        ASSERT(0);
    }

    snprintf(clk_name, sizeof(clk_name), "blsp1_ahb_iface_clk");

    ret = clk_get_set_enable(clk_name, 0 , 1);

    if (ret) {
        dprintf(CRITICAL, "%s: Failed to enable %s clock\n", __func__, clk_name);
        return;
    }

    snprintf(clk_name, sizeof(clk_name), "gcc_blsp1_qup%u_spi_apps_clk", qup_id + 1);

    /* Set the highest clk frequency by default for good performance. */
    ret = clk_get_set_enable(clk_name, 50000000, 1);

    if (ret) {
        dprintf(CRITICAL, "%s: Failed to enable %s\n", __func__, clk_name);
        return;
    }
}

接下来看qup_spi_sec_init(dev);
这里都是寄存器配置的东西，直接看patch就行了；
至此：msm_display_config()函数分析完毕；
我们接下来分析msm_display_on函数：

int msm_display_on()
{
    int ret = NO_ERROR;
    int mdp_rev;
    struct msm_panel_info *pinfo;

    if (!panel)
        return ERR_INVALID_ARGS;

    bs_set_timestamp(BS_SPLASH_SCREEN_DISPLAY);

    pinfo = &(panel->panel_info);

    if (pinfo->pre_on) {
        ret = pinfo->pre_on();
        if (ret)
            goto msm_display_on_out;
    }

    switch (pinfo->type) {
    case LVDS_PANEL:
        dprintf(INFO, "Turn on LVDS PANEL.\n");
        ret = mdp_lcdc_on(panel);
        if (ret)
            goto msm_display_on_out;
        ret = lvds_on(panel);
        if (ret)
            goto msm_display_on_out;
        break;
    case MIPI_VIDEO_PANEL:
        dprintf(INFO, "Turn on MIPI_VIDEO_PANEL.\n");
        ret = mdp_dsi_video_on(pinfo);
        if (ret)
            goto msm_display_on_out;

        ret = mdss_dsi_post_on(panel);
        if (ret)
            goto msm_display_on_out;

        ret = mipi_dsi_on();
        if (ret)
            goto msm_display_on_out;
        break;
    case MIPI_CMD_PANEL:
        dprintf(INFO, "Turn on MIPI_CMD_PANEL.\n");
        ret = mdp_dma_on(pinfo);
        if (ret)
            goto msm_display_on_out;
        mdp_rev = mdp_get_revision();
        if (mdp_rev != MDP_REV_50 && mdp_rev != MDP_REV_304 &&
                        mdp_rev != MDP_REV_305) {
            ret = mipi_cmd_trigger();
            if (ret)
                goto msm_display_on_out;
        }

        ret = mdss_dsi_post_on(panel);
        if (ret)
            goto msm_display_on_out;

        break;
    case LCDC_PANEL:
        dprintf(INFO, "Turn on LCDC PANEL.\n");
        ret = mdp_lcdc_on(panel);
        if (ret)
            goto msm_display_on_out;
        break;
    case HDMI_PANEL:
        dprintf(INFO, "Turn on HDMI PANEL.\n");
        ret = mdss_hdmi_init();
        if (ret)
            goto msm_display_on_out;

        ret = mdss_hdmi_on();
        if (ret)
            goto msm_display_on_out;
        break;
    case EDP_PANEL:
        dprintf(INFO, "Turn on EDP PANEL.\n");
        ret = mdp_edp_on(pinfo);
        if (ret)
            goto msm_display_on_out;
        break;
    //added by linhao,support spi
    case SPI_PANEL:
        dprintf(INFO, "Turn on SPI PANEL.\n");
        ret = mdss_spi_on(pinfo, &(panel->fb));
        if (ret)
            goto msm_display_on_out;
        break;
    default:
        return ERR_INVALID_ARGS;
    };

    if (pinfo->on)
        ret = pinfo->on();

msm_display_on_out:
    return ret;
}

接下来就继续执行这两个函数了：

if (pdata->post_power_func)
    ret = pdata->post_power_func(1);
if (ret)
    goto msm_display_init_out;

/* Turn on backlight */
if (pdata->bl_func)
    ret = pdata->bl_func(1);

看它们的函数指针内容：
第一个函数mdss_spi_panel_power，这个函数实现了:

static int mdss_spi_panel_power(uint8_t enable,
                struct msm_panel_info *pinfo)
{
    int ret = NO_ERROR;

    if (enable) {
        ret = target_ldo_ctrl(enable, pinfo);
        if (ret) {
            dprintf(CRITICAL, "LDO control enable failed\n");
            return ret;
        }

        /* Panel Reset */
        ret = target_panel_reset(enable, panelstruct.panelresetseq,
                        &panel.panel_info);
        if (ret) {
            dprintf(CRITICAL, "panel reset failed\n");
            return ret;
        }
        dprintf(INFO, "Panel power on done\n");
    } else {
        /* Disable panel and ldo */
        ret = target_panel_reset(enable, panelstruct.panelresetseq,
                        &panel.panel_info);
        if (ret) {
            dprintf(CRITICAL, "panel reset disable failed\n");
            return ret;
        }

        ret = target_ldo_ctrl(enable, pinfo);
        if (ret) {
            dprintf(CRITICAL, "ldo control disable failed\n");
            return ret;
        }
        dprintf(INFO, "Panel power off done\n");
    }

    return ret;
}

看其中的target_ldo_ctrl函数，这个函数是控制电源的：

int target_ldo_ctrl(uint8_t enable, struct msm_panel_info *pinfo)
{
    if (enable){
        if (pinfo->type == SPI_PANEL)
            spi_panel_regulator_enable();    /* L6, and L17 */      
        else            
            regulator_enable();     /* L2, L6, and L17 */   
    }   
    return NO_ERROR;
}

由于pinfo->type == SPI_PANEL进入了spi_panel_regulator_enable函数中来，根据电路图，需要使能L6、L17：

void spi_panel_regulator_enable()
{   
    rpm_send_data(&ldo17[GENERIC_ENABLE][0], 36, RPM_REQUEST_TYPE); 
    rpm_send_data(&ldo6[GENERIC_ENABLE][0], 36, RPM_REQUEST_TYPE);
}

然后使用target_panel_reset函数对面板进行重置；
至此电源已经完成；
背光函数mdss_spi_bl_enable->panel_backlight_ctrl->target_backlight_ctrl函数中：
通过pwm或者WLED方式控制背光，不支持BL_DCS：

if (bl->bl_interface_type == BL_DCS)
        return 0;

终于，msm_display_init函数已经分析完毕，随之gcdb_display_init也分析完毕；target_display_init也分析完了；

8. patch地址

patch地址