Re: [alsa-devel] [PATCH 1/1] ASoC: mxs-saif: clear clk gate first before register setting

On 21/08/11 16:45, Dong Aisheng wrote:

Saif needs clear clk gate first before writing registers or the write will not success.

The original xx_get_mclk function clear clk gate after mclk setting that may cause the former mclk setting unwork, then the real output mclk maybe inaccurate. Placing the clear before setting mclk to avoid such an issue.

We also have to clear clk gate in startup instead of in prepare function.

Signed-off-by: Dong Aisheng b29396@freescale.com Cc: Mark Brown broonie@opensource.wolfsonmicro.com Cc: Liam Girdwood lrg@ti.com Cc: Sascha Hauer s.hauer@pengutronix.de Cc: Wolfram Sang w.sang@pengutronix.de

---

sound/soc/mxs/mxs-saif.c | 22 ++++++++++++---------- 1 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/sound/soc/mxs/mxs-saif.c b/sound/soc/mxs/mxs-saif.c index 0b3adae..530017f 100644 --- a/sound/soc/mxs/mxs-saif.c +++ b/sound/soc/mxs/mxs-saif.c @@ -187,16 +187,20 @@ int mxs_saif_get_mclk(unsigned int saif_id, unsigned int mclk, if (!saif) return -EINVAL;

• /* Clear Reset */
• __raw_writel(BM_SAIF_CTRL_SFTRST,

• saif->base + SAIF_CTRL + MXS_CLR_ADDR);
  

• /* FIXME: need clear clk gate for register r/w */
• __raw_writel(BM_SAIF_CTRL_CLKGATE,

• saif->base + SAIF_CTRL + MXS_CLR_ADDR);
  

• stat = __raw_readl(saif->base + SAIF_STAT); if (stat & BM_SAIF_STAT_BUSY) { dev_err(saif->dev, "error: busy\n"); return -EBUSY; }

• /* Clear Reset */
• __raw_writel(BM_SAIF_CTRL_SFTRST,

• saif->base + SAIF_CTRL + MXS_CLR_ADDR);
  

• saif->mclk_in_use = 1; ret = mxs_saif_set_clk(saif, mclk, rate); if (ret)

@@ -207,8 +211,6 @@ int mxs_saif_get_mclk(unsigned int saif_id, unsigned int mclk, return ret;

/* enable MCLK output */

• __raw_writel(BM_SAIF_CTRL_CLKGATE,

• saif->base + SAIF_CTRL + MXS_CLR_ADDR);
  

  __raw_writel(BM_SAIF_CTRL_RUN, saif->base + SAIF_CTRL + MXS_SET_ADDR);

@@ -303,6 +305,10 @@ static int mxs_saif_startup(struct snd_pcm_substream *substream, __raw_writel(BM_SAIF_CTRL_SFTRST, saif->base + SAIF_CTRL + MXS_CLR_ADDR);

• /* clear clock gate */
• __raw_writel(BM_SAIF_CTRL_CLKGATE,

• saif->base + SAIF_CTRL + MXS_CLR_ADDR);
  

• return 0;

}

@@ -379,10 +385,6 @@ static int mxs_saif_prepare(struct snd_pcm_substream *substream, { struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);

• /* clear clock gate */
• __raw_writel(BM_SAIF_CTRL_CLKGATE,

• saif->base + SAIF_CTRL + MXS_CLR_ADDR);
  

• /* enable FIFO error irqs */ __raw_writel(BM_SAIF_CTRL_FIFO_ERROR_IRQ_EN, saif->base + SAIF_CTRL + MXS_SET_ADDR);

Acked-by: Liam Girdwood lrg@ti.com