topic IMX8M Mini SAI5 Status Query in i.MX Processors

IMX8M Mini SAI5 Status Query

sreedhar_appala — Wed, 11 Mar 2020 10:16:48 GMT

Hi,

We are working with IMX8M Mini based EVK HW and NXP Audio Board.

I am working with 4.14.98.2_0_0 sumo version.

For recording/capture we used SAI5 interface. In the dts file: fsl-imx8mm-evk.dts

&sai5 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_sai5>;
assigned-clocks = <&clk IMX8MM_CLK_SAI5_SRC>,
<&clk IMX8MM_CLK_SAI5_DIV>;
assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
assigned-clock-rates = <0>, <49152000>;
clocks = <&clk IMX8MM_CLK_SAI5_IPG>, <&clk IMX8MM_CLK_DUMMY>,
<&clk IMX8MM_CLK_SAI5_ROOT>, <&clk IMX8MM_CLK_DUMMY>,
<&clk IMX8MM_CLK_DUMMY>, <&clk IMX8MM_AUDIO_PLL1_OUT>,
<&clk IMX8MM_AUDIO_PLL2_OUT>;
clock-names = "bus", "mclk0", "mclk1", "mclk2", "mclk3", "pll8k", "pll11k";
fsl,sai-asynchronous;
status = "disabled";
};

For making use of SAI5, I changed the status to okay.

status = "okay";

Recording is working fine , tested using arecord utility.

But for me recording is working for status = disabled also.

Could you please clarify me why recording is working for status = disabled.

Thank you,

Sreedhar

Re: IMX8M Mini SAI5 Status Query

weidong_sun — Mon, 16 Mar 2020 03:58:32 GMT

Hi Sreedhar,

See below, please!

1. Question on status="okay" and "disabled"
For a device, even though you set it in device tree, and you don't handle it in probe function of the device drier, the driver will still be loaded.
so open sound/soc/fsl/fsl_sai.c, you will find it not be handled.

2. suggest you do a test
(1) Power off the board
(2) remove audio board.
(3) power on and boot the board
(4) check if the device exists
/proc/device-tree/

Hope above information is helpful for you.

Have a nice day!

B.R,

weidong

Re: IMX8M Mini SAI5 Status Query

sreedhar_appala — Wed, 25 Mar 2020 08:50:08 GMT

Thank you weidong