On Thu, Jan 22, 2015 at 03:50:20PM -0800, Nicolin Chen wrote: > On Thu, Jan 22, 2015 at 02:20:06PM +0800, Zidan Wang wrote: > > > > > > @@ -369,10 +380,25 @@ static int fsl_sai_hw_params(struct > > > > > > snd_pcm_substream *substream, > > > > > > u32 word_width = snd_pcm_format_width(params_format(params)); > > > > > > u32 val_cr4 = 0, val_cr5 = 0; > > > > > > int ret; > > > > > > + u32 bclk; > > > > > > + > > > > > > + if (channels == 1) > > > > > > + channels = 2; > > > > > > + > > > > > > + if (!sai->slots || sai->slots % channels) > > > > > > + sai->slots = channels; > > > > > > + > > > > > > + sai->slots = sai->slots / channels; > > > > > > + > > > > > > + if (sai->slot_width < word_width || sai->is_dsp_mode) > > > > > > + sai->slot_width = word_width; > > > > > > > > > > Could you pls explain a bit what's this overriding for? > > > > > Or it might be better to put into a comment. > > > > > > > > > In machine driver, we should use snd_soc_dai_set_tdm_slot to set slots > > > > and slot width. In my opinion, slots in machine driver means the slot > > > > number of all channels. But in sai driver, the slots means the slot > > > > number > > > > of one channel. So snd_soc_calc_bclk use > > > > fs*sample_size*channels*tdm_slots > > > > to caculate bclk. > > > > > > Could you pls use the standard way as you described for slot number > > > in machine driver instead of defining some other meanings? That one > > > is really confusing, not to mention a code without any comment. > > > > > > You can add some extra local variables with extinguished names and > > > calculate the slot number and channels you want without changing > > > the original sai->slots and channels in the hw_params(). As you said, > > > you only need that new slot number and channels for snd_soc_calc_bclk > > > call. So you may also put this code right before the call -- a normal > > > routine doesn't need to recalculate the special slots and channels, > > > right? > > > Actually i don't kown which meaning is the standard way. Because i found > > in wm8993 and wm8904 codec driver, they also use slots/channels to set > > tdm_slots in set_tdm_slot function. > > The slots via machine driver should be total slot number per frame. > For I2S, we're passing 2 for slots parameter in our machine drivers. > > So why not just following that pattern. You code for calculating slot > per channel is used to calculate bclk. But keeping slot per frame will > also allow you to do that, meanwhile you can drop some code to do the > extra calculation so as to keep it neat. > > I suggest you to take a look at fsl_esai.c and to follow that way: > Override slots and slot_width if specified from machine driver. > I will follow slot per frame pattern like fsl_esai.c, thanks very mush.
I have another question. Can a channel have several slots? Or channel just means slot. > And another problem of your patch is the configurations for FRSZ and > xMR fields. For monaural case, the channels == 1, the current code > passes it directly to set them while your code overrides it to 2. > > I'm not sure if you've tested the monaural case and confirmed it works. > But, apparently, the configurations look pretty different. > I have tested the mono case, it works well. Best Regards, Zidan _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
