On Fri, Jul 26, 2019 at 10:33:29AM +0000, Codrin.Ciubotariu@xxxxxxxxxxxxx wrote:
> On 25.07.2019 21:24, mirq-linux@xxxxxxxxxxxx wrote:
> > On Thu, Jul 25, 2019 at 03:02:34PM +0000, Codrin.Ciubotariu@xxxxxxxxxxxxx wrote:
> >> On 22.07.2019 21:27, Michał Mirosław wrote:
> >>> SSC driver allows only synchronous TX and RX. In slave mode for BCLK
> >>> it uses only one of TK or RK pin, but for LRCLK it configured separate
> >>> inputs from TF and RF pins. Allow configuration with common FS signal.
> > [...]
> >>> @@ -613,10 +607,30 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
> >>> return -EINVAL;
> >>> }
> >>>
> >>> - if (!atmel_ssc_cfs(ssc_p)) {
> >>> + if (atmel_ssc_cfs(ssc_p)) {
> >>> + /*
> >>> + * SSC provides LRCLK
> >>> + *
> >>> + * Both TF and RF are generated, so use them directly.
> >>> + */
> >>> + rcmr |= SSC_BF(RCMR_START, fs_edge);
> >>> + tcmr |= SSC_BF(TCMR_START, fs_edge);
> >>> + } else {
> >>> fslen = fslen_ext = 0;
> >>> rcmr_period = tcmr_period = 0;
> >>> fs_osync = SSC_FSOS_NONE;
> >>> + if (!ssc->shared_fs_pin) {
> >>> + rcmr |= SSC_BF(RCMR_START, fs_edge);
> >>> + tcmr |= SSC_BF(TCMR_START, fs_edge);
> >>> + } else if (ssc->clk_from_rk_pin) {
> >>> + /* assume RF is to be used when RK is used as BCLK input */
> >>> + /* Note: won't work correctly on SAMA5D2 due to errata */
> >>> + rcmr |= SSC_BF(RCMR_START, fs_edge);
> >>> + tcmr |= SSC_BF(TCMR_START, SSC_START_RECEIVE);
> >>
> >> Did you find a platform in which this mode works?
> >
> > To be exact: according to the errata, TX is delayed improperly. So if you
> > use only RX (SSC side receives) direction, you're fine.
>
> I know, but there are other platforms with SSC, which don't have this
> errata, like sam9x35 or sama5d3. Have you tested this mode, RK input, RF
> input, RD starts on edge detect, TF input, TD starts synchronously with
> receiver?
No, I have only SAMA5D2 available to test.
Best Regards,
Michał Mirosław
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