Hi Mark,

On 2016年09月19日 22:44, Mark Rutland wrote:

On Mon, Sep 19, 2016 at 10:29:39PM +0800, Xing Zheng wrote:

...

From: Wonjoon Lee woojoo.lee@samsung.com

Pop happens when mclk applied but dmic's own boot-time Specify dmic delay times in dt to make sure clocks are ready earlier than dmic working

Signed-off-by: Wonjoon Lee woojoo.lee@samsung.com Signed-off-by: Xing Zheng zhengxing@rock-chips.com

---

.../bindings/sound/rockchip,rk3399-gru-sound.txt | 6 ++++++ sound/soc/rockchip/rk3399_gru_sound.c | 14 ++++++++++++++ 2 files changed, 20 insertions(+)

diff --git a/Documentation/devicetree/bindings/sound/rockchip,rk3399-gru-sound.txt b/Documentation/devicetree/bindings/sound/rockchip,rk3399-gru-sound.txt index f19b6c8..b7dd3ab 100644 --- a/Documentation/devicetree/bindings/sound/rockchip,rk3399-gru-sound.txt +++ b/Documentation/devicetree/bindings/sound/rockchip,rk3399-gru-sound.txt @@ -6,6 +6,12 @@ Required properties: connected to the codecs

• rockchip,codec: The phandle of the MAX98357A/RT5514/DA7219 codecs

+Optional properties: +- dmic-delay : specify delay time for DMIC ready.

• If this option is specified, which means it's required dmic need
• delay for DMIC to ready so that rt5514 can avoid recording before
• DMIC send valid data

What units is this in? Per the code it looks like ms, so if we follow Documentation/devicetree/bindings/property-units.txt, thous should be named something like dmic-enable-delay-ms.

OK, the "dmic-wakeup-delay-ms" have been done.

That said, do we even need a property for this? Does this vary much in practice?

If it does, can we not derive this delay from other information (e.g. the rates of input clocks and so on)? What exactly determines the necessary delay?

Yeah, the DMIC spec indicates wake-up time as 15ms max, so we need to start recording 15ms after MCLK after testing.

@Woojoo, please correct me if I was wrong.

Thanks.

Thanks, Mark.

...

sound { diff --git a/sound/soc/rockchip/rk3399_gru_sound.c b/sound/soc/rockchip/rk3399_gru_sound.c index 164b6da..6ab838b 100644 --- a/sound/soc/rockchip/rk3399_gru_sound.c +++ b/sound/soc/rockchip/rk3399_gru_sound.c @@ -37,6 +37,8 @@

#define SOUND_FS 256

+unsigned int rt5514_dmic_delay;

• static struct snd_soc_jack rockchip_sound_jack;

  static const struct snd_soc_dapm_widget rockchip_dapm_widgets[] = {

@@ -122,6 +124,9 @@ static int rockchip_sound_rt5514_hw_params(struct snd_pcm_substream *substream, return ret; }

• /* Wait for DMIC stable */
• msleep(rt5514_dmic_delay);
• return 0; }

@@ -334,6 +339,15 @@ static int rockchip_sound_probe(struct platform_device *pdev) return -ENODEV; }

• /* Set DMIC delay */
• ret = device_property_read_u32(&pdev->dev, "dmic-delay",

• 			&rt5514_dmic_delay);
  

• if (ret) {

• rt5514_dmic_delay = 0;
  

• dev_dbg(&pdev->dev,
  

• 	"no optional property 'dmic-delay' found, default: no delay\n");
  

• }
• rockchip_dailinks[DAILINK_RT5514_DSP].cpu_name = kstrdup_const(dev_name(dev), GFP_KERNEL); rockchip_dailinks[DAILINK_RT5514_DSP].cpu_dai_name = kstrdup_const(dev_name(dev), GFP_KERNEL); rockchip_dailinks[DAILINK_RT5514_DSP].platform_name = kstrdup_const(dev_name(dev), GFP_KERNEL);

-- 1.7.9.5