[Letux-kernel] omap-abe-twl6040.c setup of backend mcbsp for Panda and OMAP5

[H. Nikolaus Schaller]

Hi Peter,

> Am 19.02.2023 um 22:13 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> 
> Hi Peter,
> I have changed the subject to focus on the next issue.
> 
>> Am 19.02.2023 um 20:06 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>> 
>> I have found more reasons to go that way. One is the setup of e.g.
>> 
>> 	{"omap-mcbsp.1 Playback", NULL, "BT_VX_DL"},
>> 
>>> McBSP also have some funky stuff due to DT naming.
>> 
>> Yes, the "omap-mcbsp.1 Playback" (or "40122000.mcbsp Playback") is currently my main
>> blocking point because it does not appear in the widget list to be matched and the above
>> shown route can not be established.
> 
> So far I have analysed that. The issue is with the BE McBSPs.
> 
> basically they are defined in (my new) code by
> 
> SND_SOC_DAILINK_DEFS(link_be_mcbsp1,
> 	DAILINK_COMP_ARRAY(COMP_CPU("omap-mcbsp.1")),	// NOTE: will be overwritten by OF node
> 	DAILINK_COMP_ARRAY(COMP_DUMMY()),
> 	DAILINK_COMP_ARRAY(COMP_PLATFORM("aess")));
> 
> It does not matter how they are called inside COMP_CPU() because it is nullified by code
> and the OF node is inserted. Since it is named "40122000.mcbsp" by the OF-Node (same on the
> 3.15 kernel) I have modified the snd_soc_dapm_route to
> 
> /* Connections between twl6040 and ABE */
> {"Headset Playback", NULL, "PDM_DL1"},
> {"Handsfree Playback", NULL, "PDM_DL2"},
> {"PDM_UL1", NULL, "Capture"},
> /* Bluetooth <--> ABE*/
> {"40122000.mcbsp Playback", NULL, "BT_VX_DL"},
> {"BT_VX_UL", NULL, "40122000.mcbsp Capture"},
> /* FM <--> ABE */
> {"40124000.mcbsp Playback", NULL, "MM_EXT_DL"},
> {"MM_EXT_UL", NULL, "40124000.mcbsp Capture"},
> 
> Then, at some point it is to be added by snd_soc_dapm_add_route(). This fails
> (here with a lot of private printk):
> 
> [  120.829254] snd_soc_dapm_add_routes: 20: dapm=c1deb17c route=bf21d004
> [  120.836212] snd_soc_dapm_add_route: source = BT_VX_DL sink = 40122000.mcbsp Playback
> [  120.844482] snd_soc_dapm_add_route: try widget Headset Stereophone
> [  120.851104] snd_soc_dapm_add_route: try widget Earphone Spk
> [  120.857116] snd_soc_dapm_add_route: try widget Ext Spk
> [  120.862670] snd_soc_dapm_add_route: try widget Line Out
> 

...

> [  121.545959] snd_soc_dapm_add_route: try widget Handsfree Playback
> [  121.554321] snd_soc_dapm_add_route: try widget Vibra Playback
> [  121.560394] omap-abe-twl6040 sound: ASoC: Failed to add route BT_VX_DL -> 40122000.mcbsp Playback(*)
> [  121.570098] snd_soc_dapm_add_routes: 21: dapm=c1deb17c route=bf21d038
> [  121.576904] snd_soc_dapm_add_route: source = 40122000.mcbsp Capture sink = BT_VX_UL
> 
> So there is no widget to match "40122000.mcbsp Playback". Should there be one?
> Or should there be a different mechanism to identify the route?


I've added similar printk to the 3.15 kernel and there, the missing widgets do exist:

[   29.286834] snd_soc_dapm_add_routes: 11: dapm=bf1050d8 route=ec6096c0
[   29.286834] snd_soc_dapm_add_route: source = BT_VX_DL sink = 40122000.mcbsp Playback
[   29.286834] snd_soc_dapm_add_route: try widget 40124000.mcbsp Capture
[   29.286834] snd_soc_dapm_add_route: try widget 40124000.mcbsp Playback
[   29.286834] snd_soc_dapm_add_route: try widget 40122000.mcbsp Capture
[   29.286865] snd_soc_dapm_add_route: try widget 40122000.mcbsp Playback
[   29.286865] snd_soc_dapm_add_route: try widget Legacy Capture
[   29.286865] snd_soc_dapm_add_route: try widget Legacy Playback
[   29.286865] snd_soc_dapm_add_route: try widget Analog Capture
[   29.286865] snd_soc_dapm_add_route: try widget Headset Playback

...

So something is missing in my 6.2 kernel to create these mcbsp widgets...

Next I searched the 3.15 tree for something with mcbsp + widgets and finally
came across this patch:

$ git show 13a6bf336f13e3
commit 13a6bf336f13e3257de204648587012f38df59c2 (omap-audio/base-bnw/mcbsp)
Author: Peter Ujfalusi <peter.ujfalusi at ti.com>
Date:   Wed May 7 15:53:27 2014 +0300

    ASoC: omap-mcbsp: Register dai widgets to be used by AESS routing
    
    Since McBSP is used with AESS platform driver we need to create the dai
    widgets in order to be able to have complete route.
    
    Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>

diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
index 6c19bba235700..378f143dcc1f8 100644
--- a/sound/soc/omap/omap-mcbsp.c
+++ b/sound/soc/omap/omap-mcbsp.c
@@ -559,6 +559,8 @@ static int omap_mcbsp_probe(struct snd_soc_dai *dai)
 
        pm_runtime_enable(mcbsp->dev);
 
+       snd_soc_dapm_new_dai_widgets(&dai->dapm, dai);
+
        return 0;
 }
 

And indeed, we need this (moved to sound/soc/ti/omap-mcbsp.c) as well.
Plus two additional lines of code to form the individual stream_names
which are needed by snd_soc_dapm_new_dai_widgets().

Unfortunately, all this is just a minor breakthrough...
But I can now focus on other aspects where the 6.2 setup is still incomplete.

BR,
Nikolaus