Thread (15 messages) 15 messages, 5 authors, 2020-03-07

Re: [PATCH v4 1/8] ASoC: dt-bindings: fsl_asrc: Change asrc-width to asrc-format

From: Nicolin Chen <nicoleotsuka@gmail.com>
Date: 2020-03-03 07:38:11
Also in: alsa-devel, linux-arm-kernel, linuxppc-dev, lkml

On Tue, Mar 03, 2020 at 11:59:30AM +0800, Shengjiu Wang wrote:
Hi

On Tue, Mar 3, 2020 at 9:43 AM Rob Herring [off-list ref] wrote:
quoted
On Sun, Mar 01, 2020 at 01:24:12PM +0800, Shengjiu Wang wrote:
quoted
asrc_format is more inteligent, which is align with the alsa
definition snd_pcm_format_t, we don't need to convert it to
format in driver, and it can distinguish S24_LE & S24_3LE.

Signed-off-by: Shengjiu Wang <redacted>
---
 Documentation/devicetree/bindings/sound/fsl,asrc.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/sound/fsl,asrc.txt b/Documentation/devicetree/bindings/sound/fsl,asrc.txt
index cb9a25165503..0cbb86c026d5 100644
--- a/Documentation/devicetree/bindings/sound/fsl,asrc.txt
+++ b/Documentation/devicetree/bindings/sound/fsl,asrc.txt
@@ -38,7 +38,9 @@ Required properties:

    - fsl,asrc-rate   : Defines a mutual sample rate used by DPCM Back Ends.

-   - fsl,asrc-width  : Defines a mutual sample width used by DPCM Back Ends.
+   - fsl,asrc-format : Defines a mutual sample format used by DPCM Back
+                       Ends. The value is one of SNDRV_PCM_FORMAT_XX in
+                       "include/uapi/sound/asound.h"
You can't just change properties. They are an ABI.
I have updated all the things related with this ABI in this patch series.
What else should I do?
You probably should add one beside the old one. And all
the existing drivers would have to continue to support
"fsl,asrc-width", even if they start to support the new
"fsl,asrc-format". The ground rule here is that a newer
kernel should be able to work with an old DTB, IIRC.

One more concern here is about the format value. Though
I don't think those values, defined in asound.h, would
be changed, yet I am not sure if it's legit to align DT
bindings to a subsystem header file -- I only know that
usually we keep shared macros under include/dt-bindings
folder. I won't have any problem, if either Rob or Mark
has no objection.
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