Re: [PATCH] ASoC: fsl_sai: Use physical format width

On 3/31/23 04:55, Shengjiu Wang wrote:

On Thu, Mar 30, 2023 at 4:30 PM Emil Abildgaard Svendsen <
EMAS@bang-olufsen.dk> wrote:

quoted

Slot width should follow the physical width of the format instead of the
data width.

This is needed for formats like SNDRV_PCM_FMTBIT_S24_LE where physical
width is 32 and data width is 24. By using the physical width, data
won't get misaligned.

There are different requirements for this slot width. Some need physical
width,
Some need format width. We need to be careful about change here.

I might be wrong but shouldn't physical width always correspond to what
can be physically measured. If you need the slot width, the same as
format width you use a format with matching widths like
SNDRV_PCM_FORMAT_S24_3LE?

Actually there is .set_tdm_slot API for slot specific setting, please use
this API.

But if you're using the generic sound cards. You need to add it to the
DTS. Thus, if you want a static TDM slot width, all is fine. But if you
want to change slot width runtime then it isn't enough.
Unless I missed something.

Kind regards,
Emil Svendsen 

best regards
wang shengjiu

quoted

Signed-off-by: Emil Svendsen <redacted>
---
 sound/soc/fsl/fsl_sai.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index 939c6bdd22c4..213e2d462076 100644
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c

@@ -519,13 +519,13 @@ static int fsl_sai_hw_params(struct

snd_pcm_substream *substream,
        unsigned int channels = params_channels(params);
        struct snd_dmaengine_dai_dma_data *dma_params;
        struct fsl_sai_dl_cfg *dl_cfg = sai->dl_cfg;
+       u32 slot_width = params_physical_width(params);
        u32 word_width = params_width(params);
        int trce_mask = 0, dl_cfg_idx = 0;
        int dl_cfg_cnt = sai->dl_cfg_cnt;
        u32 dl_type = FSL_SAI_DL_I2S;
        u32 val_cr4 = 0, val_cr5 = 0;
        u32 slots = (channels == 1) ? 2 : channels;
-       u32 slot_width = word_width;
        int adir = tx ? RX : TX;
        u32 pins, bclk;
        u32 watermark;
--
2.34.1