Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754163AbaJUByi (ORCPT ); Mon, 20 Oct 2014 21:54:38 -0400 Received: from eusmtp01.atmel.com ([212.144.249.243]:42414 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752610AbaJUByh (ORCPT ); Mon, 20 Oct 2014 21:54:37 -0400 Message-ID: <5445BCBF.5090002@atmel.com> Date: Tue, 21 Oct 2014 09:54:07 +0800 From: Bo Shen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.2 MIME-Version: 1.0 To: Peter Rosin CC: Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , "'alsa-devel@alsa-project.org'" , "linux-kernel@vger.kernel.org" Subject: Re: [alsa-devel] [PATCH] ASoC: atmel_ssc_dai: Track playback and capture CMR dividers separately. References: In-Reply-To: Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.168.5.13] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, On 10/20/2014 09:45 PM, Peter Rosin wrote: > From 1e5621d7b9887c648d1a66238dc82d715c1e2cad Mon Sep 17 00:00:00 2001 > From: Peter Rosin > Date: Mon, 20 Oct 2014 14:38:04 +0200 > Subject: [PATCH] ASoC: atmel_ssc_dai: Track playback and capture CMR dividers > separately. > > The CMR divider register is shared by playback and capture. The SSC driver > therefore tries to enforce rules so that the needed register content do > not conflict during simultaneous playback/capture. However, the > implementation also prevents changing the register content in a > half-duplex scenario, which is needed when changing sample rates. I am not fully get what you mean here, do you mean: - when playback, first playback 48kHz, and then playback 8Khz, the 8Khz still playback in 48kHz mode? or other things? > Thus, keep track of the desired playback and capture clock dividers > separately, and allow changing rates without closing the stream. > > Signed-off-by: Peter Rosin > --- > sound/soc/atmel/atmel_ssc_dai.c | 31 ++++++++++++++++++++++--------- > sound/soc/atmel/atmel_ssc_dai.h | 10 ++++++---- > 2 files changed, 28 insertions(+), 13 deletions(-) > > diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c > index f403f39..fec14fb 100644 > --- a/sound/soc/atmel/atmel_ssc_dai.c > +++ b/sound/soc/atmel/atmel_ssc_dai.c > @@ -277,7 +277,8 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream, > /* Reset the SSC */ > ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_SWRST)); > /* Clear the SSC dividers */ > - ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0; > + ssc_p->tcmr_div = ssc_p->rcmr_div = 0; > + ssc_p->tcmr_period = ssc_p->rcmr_period = 0; > } > spin_unlock_irq(&ssc_p->lock); > } > @@ -304,17 +305,27 @@ static int atmel_ssc_set_dai_clkdiv(struct snd_soc_dai *cpu_dai, > struct atmel_ssc_info *ssc_p = &ssc_info[cpu_dai->id]; > > switch (div_id) { > - case ATMEL_SSC_CMR_DIV: > + case ATMEL_SSC_TCMR_DIV: > /* > * The same master clock divider is used for both > * transmit and receive, so if a value has already > - * been set, it must match this value. > + * been set for the other direction, it must match > + * this value. > */ > - if (ssc_p->cmr_div == 0) > - ssc_p->cmr_div = div; > - else > - if (div != ssc_p->cmr_div) > - return -EBUSY; > + if (ssc_p->rcmr_div == 0) > + ssc_p->tcmr_div = div; > + else if (div != ssc_p->rcmr_div) > + return -EBUSY; > + break; > + > + case ATMEL_SSC_RCMR_DIV: > + /* > + * See ATMEL_SSC_TCMR_DIV. > + */ > + if (ssc_p->tcmr_div == 0) > + ssc_p->rcmr_div = div; > + else if (div != ssc_p->tcmr_div) > + return -EBUSY; > break; > > case ATMEL_SSC_TCMR_PERIOD: > @@ -345,6 +356,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream, > struct atmel_pcm_dma_params *dma_params; > int dir, channels, bits; > u32 tfmr, rfmr, tcmr, rcmr; > + u16 cmr; should be u32. > int start_event; > int ret; > int fslen, fslen_ext; > @@ -626,7 +638,8 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream, > } > > /* set SSC clock mode register */ > - ssc_writel(ssc_p->ssc->regs, CMR, ssc_p->cmr_div); > + cmr = ssc_p->tcmr_div ? ssc_p->tcmr_div : ssc_p->rcmr_div; > + ssc_writel(ssc_p->ssc->regs, CMR, cmr); > > /* set receive clock mode and format */ > ssc_writel(ssc_p->ssc->regs, RCMR, rcmr); > diff --git a/sound/soc/atmel/atmel_ssc_dai.h b/sound/soc/atmel/atmel_ssc_dai.h > index b1f08d5..a25df7a 100644 > --- a/sound/soc/atmel/atmel_ssc_dai.h > +++ b/sound/soc/atmel/atmel_ssc_dai.h > @@ -39,9 +39,10 @@ > #define ATMEL_SYSCLK_MCK 0 /* SSC uses AT91 MCK as system clock */ > > /* SSC divider ids */ > -#define ATMEL_SSC_CMR_DIV 0 /* MCK divider for BCLK */ > -#define ATMEL_SSC_TCMR_PERIOD 1 /* BCLK divider for transmit FS */ > -#define ATMEL_SSC_RCMR_PERIOD 2 /* BCLK divider for receive FS */ > +#define ATMEL_SSC_TCMR_DIV 0 /* MCK divider for transmit BCLK */ > +#define ATMEL_SSC_RCMR_DIV 1 /* MCK divider for receive BCLK */ > +#define ATMEL_SSC_TCMR_PERIOD 2 /* BCLK divider for transmit FS */ > +#define ATMEL_SSC_RCMR_PERIOD 3 /* BCLK divider for receive FS */ > /* > * SSC direction masks > */ > @@ -110,7 +111,8 @@ struct atmel_ssc_info { > unsigned short dir_mask; /* 0=unused, 1=playback, 2=capture */ > unsigned short initialized; /* true if SSC has been initialized */ > unsigned short daifmt; > - unsigned short cmr_div; > + unsigned short tcmr_div; > + unsigned short rcmr_div; > unsigned short tcmr_period; > unsigned short rcmr_period; > struct atmel_pcm_dma_params *dma_params[2]; > Best Regards, Bo Shen -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/