[Linux Audio Driver] 高通平台MI2S总线配置

0. 背景

hardware platform：骁龙865

android version：android10

Linux kernel version：msm-4.19

思维导图如下：

1. 遇到的一点坑

由于我没有拿到这个平台的MI2S高通配置文档，所以遇到了一点坑，同步也分享。

这个平台目前还没有具体codec器件的调试需求，但是我想验证下接口，于是找硬件，告诉我可以配置MI2S1，对应上面几个GPIO，然后我寻思，默认pri_mi2s应该是MI2S0，这个MI2S1不就应该是配置sec_mi2s嘛。

（我可真是大聪明，逃…)

/vendor/qcom/proprietary/devicetree-4.19/qcom/kona-pinctrl.dtsi

sec_mi2s_sck {sec_mi2s_sck_sleep: sec_mi2s_sck_sleep {mux {-pins = "gpio142";+pins = "gpio152";function = "gpio";};config {-pins = "gpio142";+pins = "gpio152";drive-strength = <2>; /* 2 mA */bias-pull-down; /* PULL DOWN */input-enable;@@ -1871,12 +1871,12 @@sec_mi2s_sck_active: sec_mi2s_sck_active {mux {-pins = "gpio142";+pins = "gpio152";function = "mi2s1_sck";};config {-pins = "gpio142";+pins = "gpio152";drive-strength = <8>; /* 8 mA */bias-disable; /* NO PULL */};@@ -1886,12 +1886,12 @@sec_mi2s_ws {sec_mi2s_ws_sleep: sec_mi2s_ws_sleep {mux {-pins = "gpio145";+pins = "gpio153";function = "gpio";};config {-pins = "gpio145";+pins = "gpio153";drive-strength = <2>; /* 2 mA */bias-pull-down; /* PULL DOWN */input-enable;@@ -1900,12 +1900,12 @@sec_mi2s_ws_active: sec_mi2s_ws_active {mux {-pins = "gpio145";+pins = "gpio153";function = "mi2s1_ws";};config {-pins = "gpio145";+pins = "gpio153";drive-strength = <8>; /* 8 mA */bias-disable; /* NO PULL */};@@ -1915,12 +1915,12 @@sec_mi2s_sd0 {sec_mi2s_sd0_sleep: sec_mi2s_sd0_sleep {mux {-pins = "gpio143";+pins = "gpio154";function = "gpio";};config {-pins = "gpio143";+pins = "gpio154";drive-strength = <2>; /* 2 mA */bias-pull-down; /* PULL DOWN */input-enable;@@ -1929,12 +1929,12 @@sec_mi2s_sd0_active: sec_mi2s_sd0_active {mux {-pins = "gpio143";+pins = "gpio154";function = "mi2s1_data0";};config {-pins = "gpio143";+pins = "gpio154";drive-strength = <8>; /* 8 mA */bias-disable; /* NO PULL */};@@ -1944,12 +1944,12 @@sec_mi2s_sd1 {sec_mi2s_sd1_sleep: sec_mi2s_sd1_sleep {mux {-pins = "gpio144";+pins = "gpio155";function = "gpio";};config {-pins = "gpio144";+pins = "gpio155";drive-strength = <2>; /* 2 mA */bias-pull-down; /* PULL DOWN */input-enable;@@ -1958,12 +1958,12 @@sec_mi2s_sd1_active: sec_mi2s_sd1_active {mux {-pins = "gpio144";+pins = "gpio155";function = "mi2s1_data1";};config {-pins = "gpio144";+pins = "gpio155";drive-strength = <8>; /* 8 mA */bias-disable; /* NO PULL */};

./vendor/qcom/proprietary/devicetree-4.19/qcom/kona-audio-overlay.dtsi

qcom,codec-aux-devs = <&wcd938x_codec>;+qcom,sec-mi2s-gpios = <&cdc_sec_mi2s_gpios>;qcom,msm_audio_ssr_devs = <&audio_apr>, <&q6core>, <&lpi_tlmm>,<&bolero>;};@@ -377,6 +378,17 @@qcom,lpi-gpios;qcom,tlmm-gpio = <147>;};+cdc_sec_mi2s_gpios: cdc_sec_mi2s_clk_data_pinctrl {+compatible = "qcom,msm-cdc-pinctrl";+pinctrl-names = "aud_active", "aud_sleep";+pinctrl-0 = <&sec_mi2s_sck_active &sec_mi2s_ws_active &sec_mi2s_sd0_active+ &sec_mi2s_sd1_active>;+pinctrl-1 = <&sec_mi2s_sck_sleep &sec_mi2s_ws_sleep &sec_mi2s_sd0_sleep+ &sec_mi2s_sd1_sleep>;+qcom,lpi-gpios;+qcom,tlmm-gpio = <152 153 154 155>;+};};

然后编译，烧录，adb shell执行tinyalsa命令录音：

tinymix "MultiMedia1 Mixer SEC_MI2S_TX" 1tinycap /sdcard/rec.wav

发现终端录制不了：

kona:/ # tinymix "MultiMedia1 Mixer SEC_MI2S_TX" 1p /sdcard/rec.wavkona:/ # tinycap /sdcard/rec.wavUnable to open PCM device (cannot set hw params: Invalid argument)Captured 0 frames

然后串口报错log如下：

[ 410.635747] bt_ioctl: BT_CMD_PWR_CTRL pwr_cntrl:1[ 410.641033] bt_vreg_enable: vreg_en successful for : qca,bt-vdd-aon[ 410.647820] bt_vreg_init: regulator_get(qca,bt-vdd-dig) failed. rc=-517[ 410.655571] bluetooth_power: bt_power vdddig config failed[ 410.661381] bt_vreg_disable: vreg_disable successful for : qca,bt-vdd-aon[ 412.117603] msm_dai_q6_mi2s_hw_params: dai_data->channels = 1 channel_mode = 0[ 412.125138] msm-dai-q6-mi2s soc:qcom,msm-dai-mi2s:qcom,msm-dai-q6-mi2s-sec:ASoC: can't set Secondary MI2S hw params: -22[ 412.137315] SEC_MI2S_TX: ASoC: hw_params BE failed -22[ 412.142744] KONA Media1: ASoC: hw_params BE failed -22[ 412.148442] q6asm_callback: cmd = 0x10bcd returned error = 0x1[ 412.155280] __q6asm_cmd: DSP returned error[ADSP_EFAILED] opcode 68557

这个报错看起来是平台info里面xml backend配置异常，但是我们当前是用tinyalsa命令抓数据，无须考虑那个info的配置，这里我怀疑是硬件搞错了MI2S GPIO(其实是我搞错了=_=)。

在我的再三请求下，硬件老哥帮我又检查了一遍，说gpio没有问题，我当时感觉自己麻了，没个文档都不知道gpio配的对不对，然后我问他有没有这个平台的PING定义啊，GPIO的那种表格。

（一番沟通之后，俺拿到了表格）

从表格里面拿到了两个重要的信息：这组MI2S是和数字麦克冲突的，gpio152对应LPI GPIO6。

这里说明下，类比已知的高通外部MI2S总线，按顺序依次是：Primary MI2S、Secondary MI2S、Tertiary MI2S、Quaternary MI2S、Quinary MI2S、 Senary MI2S。

其中，和DMIC1以及DMIC2冲突的总线应该是，quin_mi2s。

总之，之前是白捣鼓了，我们可以再看看lpi设备树来佐证想法：当前应该配置quin_mi2s。

./vendor/qcom/proprietary/devicetree-4.19/qcom/kona-lpi.dtsi

如我们所料，这个LPI GPIO6是QUAT总线的下一组MI2S的SCLK，即 QUIN总线的SCLK。

2. 按照上面的思维导图再进行一遍

●获取到正确信息，明确要配置的MI2S。（已完成，明确是quin总线）

●对应平台pinctrl dtsi里面添加MI2S相关的GPIO配置。

./vendor/qcom/proprietary/devicetree-4.19/qcom/kona-pinctrl.dtsi

+//add for test QUIN MI2S start++quin_mi2s_sck {+ quin_mi2s_sck_sleep: quin_mi2s_sck_sleep {+ mux {+ pins = "gpio152";+ function = "gpio";+ };++ config {+ pins = "gpio152";+ drive-strength = <2>; /* 2 mA */+ bias-pull-down; /* PULL DOWN */+ input-enable;+ };+ };++ quin_mi2s_sck_active: quin_mi2s_sck_active {+ mux {+ pins = "gpio152";+ function = "mi2s4_sck";+ };++ config {+ pins = "gpio152";+ drive-strength = <8>; /* 8 mA */+ bias-disable; /* NO PULL */+ };+ };+};++quin_mi2s_ws {+ quin_mi2s_ws_sleep: quin_mi2s_ws_sleep {+ mux {+ pins = "gpio153";+ function = "gpio";+ };++ config {+ pins = "gpio153";+ drive-strength = <2>; /* 2 mA */+ bias-pull-down; /* PULL DOWN */+ input-enable;+ };+ };++ quin_mi2s_ws_active: quin_mi2s_ws_active {+ mux {+ pins = "gpio153";+ function = "mi2s4_ws";+ };++ config {+ pins = "gpio153";+ drive-strength = <8>; /* 8 mA */+ bias-disable; /* NO PULL */+ };+ };+};++quin_mi2s_sd0 {+ quin_mi2s_sd0_sleep: quin_mi2s_sd0_sleep {+ mux {+ pins = "gpio154";+ function = "gpio";+ };++ config {+ pins = "gpio154";+ drive-strength = <2>; /* 2 mA */+ bias-pull-down; /* PULL DOWN */+ input-enable;+ };+ };++ quin_mi2s_sd0_active: quin_mi2s_sd0_active {+ mux {+ pins = "gpio154";+ function = "mi2s4_data0";+ };++ config {+ pins = "gpio154";+ drive-strength = <8>; /* 8 mA */+ bias-disable; /* NO PULL */+ };+ };+};++quin_mi2s_sd1 {+ quin_mi2s_sd1_sleep: quin_mi2s_sd1_sleep {+ mux {+ pins = "gpio155";+ function = "gpio";+ };++ config {+ pins = "gpio155";+ drive-strength = <2>; /* 2 mA */+ bias-pull-down; /* PULL DOWN */+ input-enable;+ };+ };++ quin_mi2s_sd1_active: quin_mi2s_sd1_active {+ mux {+ pins = "gpio155";+ function = "mi2s4_data1";+ };++ config {+ pins = "gpio155";+ drive-strength = <8>; /* 8 mA */+ bias-disable; /* NO PULL */+ };+ };+};++//add for test QUIN MI2S end

●对应平台主要的audio dtsi 里面添加调用MI2S。

./vendor/qcom/proprietary/devicetree-4.19/qcom/kona-audio-overlay.dtsi

+qcom,codec-max-aux-devs = <0>;+qcom,quin-mi2s-gpios = <&cdc_quin_mi2s_gpios>;qcom,codec-aux-devs = <&wcd938x_codec>;qcom,msm_audio_ssr_devs = <&audio_apr>, <&q6core>, <&lpi_tlmm>,<&bolero>;};&q6core {+++cdc_quin_mi2s_gpios: cdc_quin_mi2s_clk_data_pinctrl {+compatible = "qcom,msm-cdc-pinctrl";+pinctrl-names = "aud_active", "aud_sleep";+pinctrl-0 = <&quin_mi2s_sck_active &quin_mi2s_ws_active &quin_mi2s_sd0_active+ &quin_mi2s_sd1_active>;+pinctrl-1 = <&quin_mi2s_sck_sleep &quin_mi2s_ws_sleep &quin_mi2s_sd0_sleep+ &quin_mi2s_sd1_sleep>;+qcom,lpi-gpios;+qcom,tlmm-gpio = <152 153 154 155>;+};

●关闭设备树里面可能引起冲突的dtsi配置，正确启用MI2S总线，而不是其他总线，比如TDM总线。

./vendor/qcom/proprietary/devicetree-4.19/qcom/kona-audio-overlay.dtsi

cdc_dmic01_gpios: cdc_dmic01_pinctrl {+status = "disabled";compatible = "qcom,msm-cdc-pinctrl";pinctrl-names = "aud_active", "aud_sleep";pinctrl-0 = <&cdc_dmic01_clk_active &cdc_dmic01_data_active>;@@ -333,6 +349,7 @@};cdc_dmic23_gpios: cdc_dmic23_pinctrl {+status = "disabled";compatible = "qcom,msm-cdc-pinctrl";pinctrl-names = "aud_active", "aud_sleep";pinctrl-0 = <&cdc_dmic23_clk_active &cdc_dmic23_data_active>;@@ -341,6 +358,7 @@};cdc_dmic45_gpios: cdc_dmic45_pinctrl {+status = "disabled";compatible = "qcom,msm-cdc-pinctrl";pinctrl-names = "aud_active", "aud_sleep";pinctrl-0 = <&cdc_dmic45_clk_active &cdc_dmic45_data_active>;@@ -350,6 +368,7 @@};

./vendor/qcom/proprietary/devicetree-4.19/qcom/kona-audio.dtsi

qcom,mi2s-audio-intf = <1>;-qcom,auxpcm-audio-intf = <1>;-qcom,tdm-audio-intf = <1>;+qcom,auxpcm-audio-intf = <0>;+qcom,tdm-audio-intf = <0>;

●tinyalsa命令起进程，抓波形。

编译烧录之后，adb root，adb shell，执行以下命令录音：

tinymix "MultiMedia1 Mixer QUIN_MI2S_TX" 1tinycap /sdcard/rec.wav

波形一动不动=_=。

3. 终章

因为配置个总线就这几个步骤，没啥说的，到这步心里一点不慌（逃…)，估计是哪里犯了个小错误。经过排查，发现是

gpio的引用方式不对，原因是检索dmic的配置:

./vendor/qcom/proprietary/devicetree-4.19/qcom/kona-audio-overlay.dtsi

cdc_dmic01_gpios: cdc_dmic01_pinctrl {status = "disabled";compatible = "qcom,msm-cdc-pinctrl";pinctrl-names = "aud_active", "aud_sleep";pinctrl-0 = <&cdc_dmic01_clk_active &cdc_dmic01_data_active>;pinctrl-1 = <&cdc_dmic01_clk_sleep &cdc_dmic01_data_sleep>;qcom,lpi-gpios;};

grep -nrR “cdc_dmic01_clk_active” ./vendor/qcom/proprietary/devicetree-4.19/qcom/

发现dmic直接引用的平台lpi设备树的节点：kona-lpi.dtsi，那么依次类推，我们准备也直接引用lpi的节点即可。

补充以下修改：

./vendor/qcom/proprietary/devicetree-4.19/qcom/kona-audio-overlay.dtsi

+//cdc_quin_mi2s_gpios: cdc_quin_mi2s_clk_data_pinctrl {+//compatible = "qcom,msm-cdc-pinctrl";+//pinctrl-names = "aud_active", "aud_sleep";+//pinctrl-0 = <&quin_mi2s_sck_active &quin_mi2s_ws_active &quin_mi2s_sd0_active+// &quin_mi2s_sd1_active>;+//pinctrl-1 = <&quin_mi2s_sck_sleep &quin_mi2s_ws_sleep &quin_mi2s_sd0_sleep+// &quin_mi2s_sd1_sleep>;+//qcom,lpi-gpios;+//qcom,tlmm-gpio = <152 153 154 155>;+//};++cdc_quin_mi2s_gpios: cdc_quin_mi2s_clk_data_pinctrl {+compatible = "qcom,msm-cdc-pinctrl";+pinctrl-names = "aud_active", "aud_sleep";+pinctrl-0 = <&lpi_i2s1_sck_active &lpi_i2s1_ws_active &lpi_i2s1_sd0_active+ &lpi_i2s1_sd1_active>;+pinctrl-1 = <&lpi_i2s1_sck_sleep &lpi_i2s1_ws_sleep &lpi_i2s1_sd0_sleep+ &lpi_i2s1_sd1_sleep>;+qcom,lpi-gpios;+//qcom,tlmm-gpio = <152 153 154 155>;+};

（小细节，SCLK为1.536MHz，那么周期应该为1us左右可以抓到 稳定波形）

这两个图片表明正确获取到了SCLK以及WS的波形，WS是48KHz，由于我没有在machine driver修改sclk，此时sclk应该为默认值1.536MHz ：

总线至此配置OK，本文到此结束，篇幅过长，感谢阅读！