Re: linux-fsl 5.10 kernels don't appear to have multi-lane in sound/soc/fsl/fsl_sai.c

Andrey Zhizhikin

Hello Brian,

On Wed, Oct 27, 2021 at 2:45 PM Brian Hutchinson <b.hutchman@...> wrote:

On Wed, Oct 27, 2021 at 8:18 AM Fabio Estevam <festevam@...> wrote:

Hi Brian,

On Tue, Oct 26, 2021 at 11:10 AM Brian Hutchinson <b.hutchman@...> wrote:

On Tue, Oct 26, 2021 at 10:07 AM Brian Hutchinson via <> wrote:


First, forgive me for posting a link in an post with no context ... I hit a wrong button and accidentally sent before ready.

Bottom line up front. How can I get a 5.10 kernel with multi-lane support for IMX8MM?

We use linux-fsl 5.4 on a IMXMM based board and have recently stepped up to linux-fsl 5.10 and the sound/fsl/fsl_sai.c has no support for "multi-lane" anymore which breaks our code.

I figure this is simply a case where things in linux-imx are new and just not picked up in linux-fslc yet but wondering if it's possible to get multi-lane support in a 5.10 kernel for the IMX8MM.

I still don't quite fully understand how all the releases work, the linux-imx releases appear to be for newer boards and don't necessarily support the older boards from what I'm seeing.

Thanks for any advice/guidance.



And that link I accidentally posted by itself

... is the reference I mentioned where I see multi-lane support in linux-imx 5.10.
With the mainline SAI driver, it is possible to use several channels.
Not sure what you mean by "multi-lane" in your use-case.

Please check:

I hoped folks would know what I was talking about without getting too far into the weeds. But I guess I need to explain more.

The older 5.4 kernels (and even 4 series kernels) had a imx8mm-evk.dts sai section that looked like this:

&sai1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_sai1>;
assigned-clocks = <&clk IMX8MM_CLK_SAI1>;
assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
assigned-clock-rates = <24576000>;
clocks = <&clk IMX8MM_CLK_SAI1_IPG>, <&clk IMX8MM_CLK_DUMMY>,
clock-names = "bus", "mclk0", "mclk1", "mclk2", "mclk3", "pll8k", "pll11k";
fsl,dataline,dsd = <0 0xff 0xff 2 0xff 0x11>;
dmas = <&sdma2 0 25 0>, <&sdma2 1 25 0>;
#sound-dai-cells = <0>;
status = "okay";

... which has fsl,sai-multi-lane support.

The current linux-fslc 5.10 kernel does not have fsl,sai-multi-lane support.
linux-fslc-imx kernel recipe on the [master] branch on meta-freescale
provides a kernel, which has linux-imx as a base and latest LTS
applied on top.

Assuming you're building now off the [master] branch and do not set
the IMX_DEFAULT_BSP to any value anywhere in your conf files - you
will be building a Mainline BSP (see [1]), which does select
linux-fslc as a preferred provider for your kernel, see [2].

You can try to either switch your BSP to NXP one by setting
IMX_DEFAULT_BSP = "nxp", or switch your kernel provider to
"linux-fslc-imx" one.

As a quick GIT grep in the linux-fslc repo on [5.10-2.1.x-imx] branch:
git grep sai-multi-lane
arch/arm64/boot/dts/freescale/imx8mm-evk-ak4497.dts: fsl,sai-multi-lane;
arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi: fsl,sai-multi-lane;
arch/arm64/boot/dts/freescale/imx8mp-ab2.dts: fsl,sai-multi-lane;
arch/arm64/boot/dts/freescale/imx8mq-evk-ak4497.dts: fsl,sai-multi-lane;
arch/arm64/boot/dts/freescale/imx8mq-evk.dts: fsl,sai-multi-lane;
sound/soc/fsl/fsl_sai.c: if (of_find_property(np,
"fsl,sai-multi-lane", NULL))

Guess this is what you're looking for, right?

If you look at the linux-imx 5.10 link I posted before ... they do have the multi-lane support I'm looking for (in sounds/soc/fsl/fsl_sai.c) but kinda don't want to switch back to linux-imx. So my ask is how can I get linux-fslc 5.10 with multi-lane support?

Apparently the yocto build has changed again. It used to be linux-imx was built by default, now it looks like linux-fslc is built by default even when I check out NXP's latest harpoon release which was supposed to have 5.10 ... and it does have recipes for 5.10 but 5.4 linux-fslc builds by default so I got some catching up to do to figure out how to select between the various kernels but I'm getting into side issues.

My main need is getting fsl,sai-multi-lane back in linux-fslc 5.10 since we moved away from linux-imx over a year ago.

Hopefully that better explains where I'm coming from and what my issue is.



Link: [1]:
Link: [2]:

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