imx8mm fsl_sai clock config failing

[Aisheng Dong]

> From: Tim Harvey <tharvey at gateworks.com>
> Sent: Tuesday, May 12, 2020 5:58 AM
> 
> Greetings,
> 
> I'm trying to get imx8mm sai working with a tlv320aic3x codec on a new board
> and am finding that the sai3 bus clock is getting derived from the wrong source
> leading hw_params() to fail with 'fsl-sai
> 30030000.sai: failed to derive required Tx rate: 3072000'
> 
> In comparison to the imx8mm-evk I find it's clock gets configured as desired yet
> I have the same device-tree configuration for sai3.
> 
> Here is my board's dts:
> / {
> ...
>         sound {
>                 compatible = "simple-audio-card";
>                 simple-audio-card,name = "tlv320-audio";
>                 simple-audio-card,format = "i2s";
>                 simple-audio-card,frame-master = <&cpudai>;
>                 simple-audio-card,bitclock-master = <&cpudai>;
>                 simple-audio-card,widgets =
>                         "Line", "Left Line Out Jack",
>                         "Line", "Right Line Out Jack";
>                 simple-audio-card,routing =
>                         "Left Line Out Jack", "LLOUT",
>                         "Right Line Out Jack", "RLOUT";
> 
>                 cpudai: simple-audio-card,cpu {
>                         sound-dai = <&sai3>;
>                         dai-tdm-slot-num = <2>;
>                         dai-tdm-slot-width = <32>;
>                 };
> 
>                 simple-audio-card,codec {
>                         sound-dai = <&tlv320aic3105>;
>                         clocks = <&clk IMX8MM_CLK_SAI3_ROOT>;
>                 };
>         };
> };
> 
> &i2c2 {
> ...
>         tlv320aic3105: codec at 18 {
>                 #sound-dai-cells = <0>;
>                 pinctrl-names = "default";
>                 pinctrl-0 = <&pinctrl_tlv>;
>                 compatible = "ti,tlv320aic3x";
>                 reg = <0x18>;
>                 reset-gpios = <&gpio4 4 GPIO_ACTIVE_LOW>;
>                 ai3x-micbias-vg = <2>; /* MICBIAS_2_5V */
>                 /* Regulators */
>                 DRVDD-supply = <&reg_3p3v>;
>                 AVDD-supply = <&reg_3p3v>;
>                 IOVDD-supply = <&reg_3p3v>;
>                 DVDD-supply = <&reg_1p8v>;
>         };
> }
> 
> &sai3 {
>         pinctrl-names = "default";
>         pinctrl-0 = <&pinctrl_sai3>;
>         assigned-clocks = <&clk IMX8MM_CLK_SAI3>;
>         assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
>         assigned-clock-rates = <24576000>;
>         status = "okay";
> };
> 
> and /sys/kernel/debug/clk/clk_summary from my board:
>  osc_24m                              7       10        0
> 24000000
>         0     0  50000
> ...
>     audio_pll1_ref_sel                0        0        0
> 24000000
>         0     0  50000
>        audio_pll1                     0        0        0
> 650000000
>         0     0  50000
>           audio_pll1_bypass           0        0        0
> 650000000
>         0     0  50000
>              audio_pll1_out           0        0        0
> 650000000
>         0     0  50000
>                 sai3                  0        0        0
> 25000000
>         0     0  50000
>                    sai3_root_clk       0        0        0
> 25000000
>          0     0  50000
> ^^^^ note 25000000 instead of requested 24576000
> 
> And Here is the imx8mm-evk dts:
> / {
> ...
>         wm8524: audio-codec {
>                 #sound-dai-cells = <0>;
>                 compatible = "wlf,wm8524";
>                 pinctrl-names = "default";
>                 pinctrl-0 = <&pinctrl_gpio_wlf>;
>                 wlf,mute-gpios = <&gpio5 21 GPIO_ACTIVE_LOW>;
>         };
> 
>         sound-wm8524 {
>                 compatible = "simple-audio-card";
>                 simple-audio-card,name = "wm8524-audio";
>                 simple-audio-card,format = "i2s";
>                 simple-audio-card,frame-master = <&cpudai>;
>                 simple-audio-card,bitclock-master = <&cpudai>;
>                 simple-audio-card,widgets =
>                         "Line", "Left Line Out Jack",
>                         "Line", "Right Line Out Jack";
>                 simple-audio-card,routing =
>                         "Left Line Out Jack", "LINEVOUTL",
>                         "Right Line Out Jack", "LINEVOUTR";
> 
>                 cpudai: simple-audio-card,cpu {
>                         sound-dai = <&sai3>;
>                         dai-tdm-slot-num = <2>;
>                         dai-tdm-slot-width = <32>;
>                 };
> 
>                 simple-audio-card,codec {
>                         sound-dai = <&wm8524>;
>                         clocks = <&clk IMX8MM_CLK_SAI3_ROOT>;
>                 };
>         };
> };
> 
> &sai3 {
>         pinctrl-names = "default";
>         pinctrl-0 = <&pinctrl_sai3>;
>         assigned-clocks = <&clk IMX8MM_CLK_SAI3>;
>         assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
>         assigned-clock-rates = <24576000>;
>         status = "okay";
> };
> 
> and /sys/kernel/debug/clk/clk_summary from imx8mm_evk:
>  osc_24m                              7       10        0
> 24000000
>         0     0  50000
> ...
>     audio_pll1_ref_sel                0        0        0
> 24000000
>         0     0  50000
>        audio_pll1                     0        0        0
> 393215995
>         0     0  50000
>           audio_pll1_bypass           0        0        0
> 393215995
>         0     0  50000
>              audio_pll1_out           0        0        0
> 393215995
>         0     0  50000
>                 sai3                  0        0        0
> 24576000
>         0     0  50000
>                    sai3_root_clk       0        0        0
> 24576000
>          0     0  50000
> ^^^^ note 24576000 as requested
> 
> Any ideas what I'm doing wrong here?
> 
> Note that even though the imx8mm-evk appears to configure its clock correctly I
> still have not been able to play audio out the wm8524 and the system appears
> to hang during playback as if BCLK/MCLK were not clocking.
> 
> Perhaps there is something not supported yet upstream with regards to
> IMX8MM SAI?
> 

Copy Daniel in case he has some comments.

Regards
Aisheng

> Best Regards,
> 
> Tim