6.5物聯(lián)網(wǎng)RK3399項(xiàng)目開(kāi)發(fā)實(shí)錄-驅(qū)動(dòng)開(kāi)發(fā)之LCD顯示屏使用（wulianjishu666）

這篇具有很好參考價(jià)值的文章主要介紹了6.5物聯(lián)網(wǎng)RK3399項(xiàng)目開(kāi)發(fā)實(shí)錄-驅(qū)動(dòng)開(kāi)發(fā)之LCD顯示屏使用（wulianjishu666）。希望對(duì)大家有所幫助。如果存在錯(cuò)誤或未考慮完全的地方，請(qǐng)大家不吝賜教，您也可以點(diǎn)擊"舉報(bào)違法"按鈕提交疑問(wèn)。

90款行業(yè)常用傳感器單片機(jī)程序及資料【stm32,stc89c52,arduino適用】

鏈接：https://pan.baidu.com/s/1M3u8lcznKuXfN8NRoLYtTA?pwd=c53f?
========================================================

LCD使用

簡(jiǎn)介

AIO-3399J開(kāi)發(fā)板外置了兩個(gè)LCD屏接口，一個(gè)是EDP，一個(gè)是LVDS，接口對(duì)應(yīng)板子上的位置如下圖：

6.5物聯(lián)網(wǎng)RK3399項(xiàng)目開(kāi)發(fā)實(shí)錄-驅(qū)動(dòng)開(kāi)發(fā)之LCD顯示屏使用（wulianjishu666）,RK3399實(shí)戰(zhàn)開(kāi)發(fā),物聯(lián)網(wǎng),arm開(kāi)發(fā),linux,opencv,人工智能,驅(qū)動(dòng)開(kāi)發(fā)

LVDS屏

DTS配置

引腳配置

AIO-3399J的SDK有LVDS DSI的DTS文件：kernel/arch/arm64/boot/dts/rockchip/rk3399-firefly-aio-lvds.dts，從該文件中我們可以看到以下語(yǔ)句：

/ {
    model = "AIO Board lvds (Android)";
    compatible = "rockchip,android", "rockchip,rk3399-firefly-lvds", "rockchip,rk3399";

    test-power {
        status = "okay";
    };
    ...
    &dsi {
    status = "okay";
    dsi_panel: panel {
        compatible ="simple-panel-dsi";
        reg = <0>;
        //ddc-i2c-bu
        //power-supply = <&vcc_lcd>;
        //pinctrl-0 = <&lcd_panel_reset &lcd_panel_enable>;
        backlight = <&backlight>;
        /*
        enable-gpios = <&gpio1 1 GPIO_ACTIVE_LOW>;
        reset-gpios = <&gpio4 29 GPIO_ACTIVE_LOW>;
        */
        dsi,flags = <(MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST | MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_EOT_PACKET)>;
        dsi,format = <MIPI_DSI_FMT_RGB888>;
        //bus-format = <MEDIA_BUS_FMT_RGB666_1X18>;
        dsi,lanes = <4>;

        dsi,channel = <0>;

        enable-delay-ms = <35>;
        prepare-delay-ms = <6>;

        unprepare-delay-ms = <0>;
        disable-delay-ms = <20>;

        size,width = <120>;
        size,height = <170>;

        status = "okay";
        ...
        power_ctr: power_ctr {
               rockchip,debug = <0>;
               lcd_pwr_en: lcd-pwr-en {
                       gpios = <&gpio3 16 GPIO_ACTIVE_HIGH>;
                       pinctrl-names = "default";
                       pinctrl-0 = <&lcd_panel_pwr_en>;
                       rockchip,delay = <10>;
               };

               lcd_rst: lcd-rst {
                       gpios = <&gpio2 27 GPIO_ACTIVE_HIGH>;
                       pinctrl-names = "default";
                       pinctrl-0 = <&lcd_panel_reset>;
                       rockchip,delay = <6>;
               };
           };
      ...
      &pinctrl {
      lcd-panel {
        lcd_panel_reset: lcd-panel-reset {
            rockchip,pins = <2 27 RK_FUNC_GPIO &pcfg_pull_down>;
        };

        lcd_panel_pwr_en: lcd-panel-pwr-en {
            rockchip,pins = <3 16 RK_FUNC_GPIO &pcfg_pull_down>;
        };

    };
};

這里定義了LCD的電源控制引腳：

lcd_pwr_en:(GPIO3_C0)GPIO_ACTIVE_HIGH
lcd_rst:(GPIO2_D3)GPIO_ACTIVE_HIGH

都是高電平有效，具體的引腳配置請(qǐng)參考《GPIO》一節(jié)。

配置背光

AIO-3399J開(kāi)發(fā)板外置了一個(gè)背光接口用來(lái)控制屏幕背光，如下圖所示：

在DTS文件：kernel/arch/arm64/boot/dts/rockchip/rk3399-firefly-core.dtsi中配置了背光信息，如下：

/ {
    compatible = "rockchip,rk3399-firefly-core", "rockchip,rk3399";

    backlight: backlight {
        status = "disabled";
        compatible = "pwm-backlight";
        pwms = <&pwm0 0 25000 0>;
        brightness-levels = <
              0   1   2   3   4   5   6   7
              8   9  10  11  12  13  14  15
             16  17  18  19  20  21  22  23
             24  25  26  27  28  29  30  31
             32  33  34  35  36  37  38  39
             40  41  42  43  44  45  46  47
             48  49  50  51  52  53  54  55
             56  57  58  59  60  61  62  63
             64  65  66  67  68  69  70  71
             72  73  74  75  76  77  78  79
             80  81  82  83  84  85  86  87
             88  89  90  91  92  93  94  95
             96  97  98  99 100 101 102 103
            104 105 106 107 108 109 110 111
            112 113 114 115 116 117 118 119
            120 121 122 123 124 125 126 127
            128 129 130 131 132 133 134 135
            136 137 138 139 140 141 142 143
            144 145 146 147 148 149 150 151
            152 153 154 155 156 157 158 159
            160 161 162 163 164 165 166 167
            168 169 170 171 172 173 174 175
            176 177 178 179 180 181 182 183
            184 185 186 187 188 189 190 191
            192 193 194 195 196 197 198 199
            200 201 202 203 204 205 206 207
            208 209 210 211 212 213 214 215
            216 217 218 219 220 221 222 223
            224 225 226 227 228 229 230 231
            232 233 234 235 236 237 238 239
            240 241 242 243 244 245 246 247
            248 249 250 251 252 253 254 255>;
        default-brightness-level = <200>;
};

pwms屬性：配置PWM，范例里面默認(rèn)使用pwm0，25000ns是周期(40 KHz)。LVDS需要加背光電源控制腳，在kernel/arch/arm64/boot/dts/rockchip/rk3399-firefly-aio-lvds.dts中可以看到以下語(yǔ)句：

&backlight {
    status = "okay";
    enable-gpios = <&gpio1 1 GPIO_ACTIVE_HIGH>;
    brightness-levels = < 150 151
    152 153 154 155 156 157 158 159
    160 161 162 163 164 165 166 167
    168 169 170 171 172 173 174 175
    176 177 178 179 180 181 182 183
    184 185 186 187 188 189 190 191
    192 193 194 195 196 197 198 199
    200 201 202 203 204 205 206 207
    208 209 210 211 212 213 214 215
    216 217 218 219 220 221 222 223
    224 225 226 227 228 229 230 231
    232 233 234 235 236 237 238 239
    240 241 242 243 244 245 246 247
    248 249 250 251 252 253 254 255>;
};

因此使用時(shí)需修改DTS文件。

brightness-levels屬性：配置背光亮度數(shù)組，最大值為255，配置暗區(qū)和亮區(qū)，并把亮區(qū)數(shù)組做255的比例調(diào)節(jié)。比如范例中暗區(qū)是255-221，亮區(qū)是220-0。 default-brightness-level屬性：開(kāi)機(jī)時(shí)默認(rèn)背光亮度，范圍為0-255。具體請(qǐng)參考kernel中的說(shuō)明文檔：kernel/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt

配置顯示時(shí)序

與EDP屏不同，LVDS屏的 Timing 寫(xiě)在DTS文件中，在kernel/arch/arm64/boot/dts/rockchip/rk3399-firefly-aio-lvds.dts中可以看到以下語(yǔ)句：

disp_timings: display-timings {
    native-mode = <&timing0>;
    timing0: timing0 {
         clock-frequency = <80000000>;
         hactive = <768>;
         vactive = <1024>;
         hsync-len = <20>;   //20, 50
         hback-porch = <130>; //50, 56
         hfront-porch = <150>;//50, 30
         vsync-len = <40>;
         vback-porch = <130>;
         vfront-porch = <136>;
         hsync-active = <0>;
         vsync-active = <0>;
         de-active = <0>;
         pixelclk-active = <0>;
           };
    }
}

時(shí)序?qū)傩詤⒖枷聢D：

Init Code

lvds屏上完電后需要發(fā)送初始化指令才能使之工作。初始化指令需要以下工具文檔生成，下載TC358764_5_774_5XBG_DSI-LVDS_Tv11p_nm_1280x800.xls

如何配置LVDS panel-init-sequence

以1280x800單lvds為例: 首先打開(kāi)TC358764_5_774_5XBG_DSI-LVDS_Tv11p_nm_1280x800.xls?

?選擇頁(yè)面”Timing Parameters_SYNC_EVENT”，按照LVDS屏的時(shí)序填入LVDS timing黃色單元,一般只需填入以下單元即可。

HPW / HBPR / HDISPR / HFPR 分別對(duì)應(yīng) hsync-len / hback-porch / hactive / hfront-porch
VPW / VBPR / VDISPR / VFPR 分別對(duì)應(yīng) vhsync-len / vback-porch / vactive / vfront-porch

LVDS timing填入完成后還需配置常規(guī)參數(shù)?

1.根據(jù)LVDS屏規(guī)格書(shū)確認(rèn)LVDS Link和LVDS output format并選擇屏的參數(shù)。
2.計(jì)算LVDS clock(藍(lán)色單元無(wú)法寫(xiě)入，需要黃色單元自動(dòng)計(jì)算得出)，需要填入DSI Clock(HOST), Pixel Clock Source, Pixel Clock Divider。計(jì)算公式如下:DSI Clock/Pixel Clock Source/Pixel Clock Divider=LVDS Clock

填入上述黃色單元基本上完成配置，接下來(lái)選擇頁(yè)面”Source”即可看到轉(zhuǎn)換后的Comment?

?以上面為例”013C 00030005”，mipi command就應(yīng)該是”29 02 06 3C 01 05 00 03 00”

29 : packet ID
02 : 2ms delay
06 : 6 bytes
3C 01 : address = 0x013C
00 03 00 05 : data=0x05000300

將頁(yè)面source所有地址寫(xiě)入數(shù)據(jù)，即可完成初始化指令panel-init-sequence。

dts在kernel/arch/arm64/boot/dts/rockchip/rk3399-firefly-aio-lvds.dts中可以看到lvds的初始化指令列表：

&dsi {
   status = "okay";
        ...
    panel-init-sequence = [
    29 00 06 3C 01 09 00 07 00
    29 00 06 14 01 06 00 00 00
    29 00 06 64 01 0B 00 00 00
    29 00 06 68 01 0B 00 00 00
    29 00 06 6C 01 0B 00 00 00
    29 00 06 70 01 0B 00 00 00
    29 00 06 34 01 1F 00 00 00
    29 00 06 10 02 1F 00 00 00
    29 00 06 04 01 01 00 00 00
    29 00 06 04 02 01 00 00 00
    29 00 06 50 04 20 01 F0 03
    29 00 06 54 04 32 00 B4 00
    29 00 06 58 04 80 07 48 00
    29 00 06 5C 04 0A 00 19 00
    29 00 06 60 04 38 04 0A 00
    29 00 06 64 04 01 00 00 00
    29 01 06 A0 04 06 80 44 00
    29 00 06 A0 04 06 80 04 00
    29 00 06 04 05 04 00 00 00
    29 00 06 80 04 00 01 02 03
    29 00 06 84 04 04 07 05 08
    29 00 06 88 04 09 0A 0E 0F
    29 00 06 8C 04 0B 0C 0D 10
    29 00 06 90 04 16 17 11 12
    29 00 06 94 04 13 14 15 1B
    29 00 06 98 04 18 19 1A 06
    29 02 06 9C 04 33 04 00 00
        ];
 panel-exit-sequence = [
            05 05 01 28
            05 78 01 10
            ];
        ...
};

命令格式以及說(shuō)明可參考以下附件：?Rockchip DRM Panel Porting Guide.pdf

kernel 發(fā)送指令可以看到在kernel/drivers/gpu/drm/panel/panel-simple.c文件中的操作：

static int panel_simple_enable(struct drm_panel *panel)
{
    struct panel_simple *p = to_panel_simple(panel);
    int err;
    if (p->enabled)
        return 0;
    DBG("enter\n");
    if (p->on_cmds) {
        err = panel_simple_dsi_send_cmds(p, p->on_cmds);
        if (err)
            dev_err(p->dev, "failed to send on cmds\n");
    }
    if (p->desc && p->desc->delay.enable) {
        DBG("p->desc->delay.enable=%d\n", p->desc->delay.enable);
        msleep(p->desc->delay.enable);
    }
    if (p->backlight) {
        DBG("open backlight\n");
        p->backlight->props.power = FB_BLANK_UNBLANK;
        backlight_update_status(p->backlight);
    }
    p->enabled = true;
    return 0;
}

u-boot

發(fā)送指令可以看到在u-boot/drivers/video/rockchip-dw-mipi-dsi.c文件中的操作：

static int rockchip_dw_mipi_dsi_enable(struct display_state *state)
{
    struct connector_state *conn_state = &state->conn_state;
    struct crtc_state *crtc_state = &state->crtc_state;
    const struct rockchip_connector *connector = conn_state->connector;
    const struct dw_mipi_dsi_plat_data *pdata = connector->data;
    struct dw_mipi_dsi *dsi = conn_state->private;
    u32 val;
    DBG("enter\n");
    dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
    dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
    dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
    if (!pdata->has_vop_sel)
        return 0;
    if (pdata->grf_switch_reg) {
        if (crtc_state->crtc_id)
            val = pdata->dsi0_en_bit | (pdata->dsi0_en_bit << 16);
        else
            val = pdata->dsi0_en_bit << 16;
        writel(val, RKIO_GRF_PHYS + pdata->grf_switch_reg);
    }
    debug("vop %s output to dsi0\n", (crtc_state->crtc_id) ? "LIT" : "BIG");
    //rockchip_dw_mipi_dsi_read_allregs(dsi);
    return 0;
}

常見(jiàn)問(wèn)題

1. 畫(huà)面抖動(dòng)閃屏

排查屏參數(shù)是否超出屏規(guī)格書(shū)限定周期，排查屏?xí)r鐘大小?！盩iming Parameters_SYNC_EVENT”所有參數(shù)變動(dòng)必須和comment同步調(diào)整。

2. 顏色顯示異常

嘗試同步調(diào)整color mapping或者lvds timing。

NOTE: 頁(yè)面”How to use”有詳細(xì)步驟，其他參數(shù)說(shuō)明可以參考文檔”頁(yè)面”菜單。文章來(lái)源地址http://www.zghlxwxcb.cn/news/detail-845909.html

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