[PATCH V2] ASoC: Intel: boards: Use FS as nau8825 sysclk in nau88125_* machine
This single fix address two issues on machines with nau88125: 1) Audio distortion, due to lack of required clock rate on MCLK line 2) Loud audible "pops" on headphones if there is no sysclk during nau8825 playback power up sequence
Explanation for: 1) Due to Skylake HW limitation, MCLK pin can only output 24MHz clk rate (it can be only connected to XTAL parent clk). The BCLK pin can be driven by dividers and therefore FW is able to set it to rate required by chosen audio format. According to nau8825 datasheet, 256*FS sysclk gives the best audio quality and the only way to achieve this (taking into account the above limitations) its to regenerate the MCLK from BCLK on nau8825 side by FFL. Without required clk rate, audio is distorted by added harmonics.
2) Currently Skylake does not output MCLK/FS when the back-end DAI op hw_param is called, so we cannot switch to MCLK/FS in hw_param. This patch reduces pop by letting nau8825 keep using its internal VCO clock during widget power up sequence, until SNDRV_PCM_TRIGGER_START when MCLK/FS is available. Once device resumes, the system will only enable power sequence for playback without doing hardware parameter, audio format, and PLL configure. In the mean time, the jack detecion sequence has changed PLL parameters and switched to internal clock. Thus, the playback signal distorted without correct PLL parameters. That is why we need to configure the PLL again in SNDRV_PCM_TRIGGER_RESUME case.
Signed-off-by: John Hsu KCHSU0@nuvoton.com Signed-off-by: Yong Zhi yong.zhi@intel.com Signed-off-by: Mac Chiang mac.chiang@intel.com Signed-off-by: Ben Zhang benzh@chromium.org Signed-off-by: Radoslaw Biernacki rad@semihalf.com --- .../soc/intel/boards/skl_nau88l25_max98357a.c | 72 +++++++++++++----- sound/soc/intel/boards/skl_nau88l25_ssm4567.c | 73 ++++++++++++++----- 2 files changed, 107 insertions(+), 38 deletions(-)
diff --git a/sound/soc/intel/boards/skl_nau88l25_max98357a.c b/sound/soc/intel/boards/skl_nau88l25_max98357a.c index d7b8154c43a4..0f3cea1342d1 100644 --- a/sound/soc/intel/boards/skl_nau88l25_max98357a.c +++ b/sound/soc/intel/boards/skl_nau88l25_max98357a.c @@ -8,6 +8,7 @@
#include <linux/module.h> #include <linux/platform_device.h> +#include <linux/delay.h> #include <sound/core.h> #include <sound/jack.h> #include <sound/pcm.h> @@ -47,7 +48,7 @@ enum { };
static int platform_clock_control(struct snd_soc_dapm_widget *w, - struct snd_kcontrol *k, int event) + struct snd_kcontrol *k, int event) { struct snd_soc_dapm_context *dapm = w->dapm; struct snd_soc_card *card = dapm->card; @@ -60,14 +61,7 @@ static int platform_clock_control(struct snd_soc_dapm_widget *w, return -EIO; }
- if (SND_SOC_DAPM_EVENT_ON(event)) { - ret = snd_soc_dai_set_sysclk(codec_dai, - NAU8825_CLK_MCLK, 24000000, SND_SOC_CLOCK_IN); - if (ret < 0) { - dev_err(card->dev, "set sysclk err = %d\n", ret); - return -EIO; - } - } else { + if (!SND_SOC_DAPM_EVENT_ON(event)) { ret = snd_soc_dai_set_sysclk(codec_dai, NAU8825_CLK_INTERNAL, 0, SND_SOC_CLOCK_IN); if (ret < 0) { @@ -292,24 +286,40 @@ static const struct snd_soc_ops skylake_nau8825_fe_ops = { .startup = skl_fe_startup, };
-static int skylake_nau8825_hw_params(struct snd_pcm_substream *substream, - struct snd_pcm_hw_params *params) +static int skylake_nau8825_trigger(struct snd_pcm_substream *substream, int cmd) { struct snd_soc_pcm_runtime *rtd = substream->private_data; + struct snd_pcm_runtime *runtime = substream->runtime; struct snd_soc_dai *codec_dai = asoc_rtd_to_codec(rtd, 0); - int ret; - - ret = snd_soc_dai_set_sysclk(codec_dai, - NAU8825_CLK_MCLK, 24000000, SND_SOC_CLOCK_IN); + int ret = 0;
- if (ret < 0) - dev_err(rtd->dev, "snd_soc_dai_set_sysclk err = %d\n", ret); + switch (cmd) { + case SNDRV_PCM_TRIGGER_START: + ret = snd_soc_dai_set_sysclk(codec_dai, NAU8825_CLK_FLL_FS, 0, + SND_SOC_CLOCK_IN); + if (ret < 0) { + dev_err(codec_dai->dev, "can't set FS clock %d\n", ret); + break; + } + ret = snd_soc_dai_set_pll(codec_dai, 0, 0, runtime->rate, + runtime->rate * 256); + if (ret < 0) + dev_err(codec_dai->dev, "can't set FLL: %d\n", ret); + break; + case SNDRV_PCM_TRIGGER_RESUME: + ret = snd_soc_dai_set_pll(codec_dai, 0, 0, runtime->rate, + runtime->rate * 256); + if (ret < 0) + dev_err(codec_dai->dev, "can't set FLL: %d\n", ret); + msleep(20); + break; + }
return ret; }
-static const struct snd_soc_ops skylake_nau8825_ops = { - .hw_params = skylake_nau8825_hw_params, +static struct snd_soc_ops skylake_nau8825_ops = { + .trigger = skylake_nau8825_trigger, };
static int skylake_dmic_fixup(struct snd_soc_pcm_runtime *rtd, @@ -630,10 +640,34 @@ static int skylake_card_late_probe(struct snd_soc_card *card) return hdac_hdmi_jack_port_init(component, &card->dapm); }
+static int __maybe_unused skylake_nau8825_resume_post(struct snd_soc_card *card) +{ + struct snd_soc_dai *codec_dai; + + codec_dai = snd_soc_card_get_codec_dai(card, SKL_NUVOTON_CODEC_DAI); + if (!codec_dai) { + dev_err(card->dev, "Codec dai not found\n"); + return -EIO; + } + + dev_dbg(codec_dai->dev, "playback_active:%d playback_widget->active:%d codec_dai->rate:%d\n", + codec_dai->stream_active[SNDRV_PCM_STREAM_PLAYBACK], + codec_dai->playback_widget->active, + codec_dai->rate); + + if (codec_dai->stream_active[SNDRV_PCM_STREAM_PLAYBACK] && + codec_dai->playback_widget->active) + snd_soc_dai_set_sysclk(codec_dai, NAU8825_CLK_FLL_FS, 0, + SND_SOC_CLOCK_IN); + + return 0; +} + /* skylake audio machine driver for SPT + NAU88L25 */ static struct snd_soc_card skylake_audio_card = { .name = "sklnau8825max", .owner = THIS_MODULE, + .resume_post = skylake_nau8825_resume_post, .dai_link = skylake_dais, .num_links = ARRAY_SIZE(skylake_dais), .controls = skylake_controls, diff --git a/sound/soc/intel/boards/skl_nau88l25_ssm4567.c b/sound/soc/intel/boards/skl_nau88l25_ssm4567.c index 4b317bcf6ea0..be44a40067f0 100644 --- a/sound/soc/intel/boards/skl_nau88l25_ssm4567.c +++ b/sound/soc/intel/boards/skl_nau88l25_ssm4567.c @@ -12,6 +12,7 @@
#include <linux/module.h> #include <linux/platform_device.h> +#include <linux/delay.h> #include <sound/core.h> #include <sound/pcm.h> #include <sound/soc.h> @@ -57,7 +58,7 @@ static const struct snd_kcontrol_new skylake_controls[] = { };
static int platform_clock_control(struct snd_soc_dapm_widget *w, - struct snd_kcontrol *k, int event) + struct snd_kcontrol *k, int event) { struct snd_soc_dapm_context *dapm = w->dapm; struct snd_soc_card *card = dapm->card; @@ -70,14 +71,7 @@ static int platform_clock_control(struct snd_soc_dapm_widget *w, return -EIO; }
- if (SND_SOC_DAPM_EVENT_ON(event)) { - ret = snd_soc_dai_set_sysclk(codec_dai, - NAU8825_CLK_MCLK, 24000000, SND_SOC_CLOCK_IN); - if (ret < 0) { - dev_err(card->dev, "set sysclk err = %d\n", ret); - return -EIO; - } - } else { + if (!SND_SOC_DAPM_EVENT_ON(event)) { ret = snd_soc_dai_set_sysclk(codec_dai, NAU8825_CLK_INTERNAL, 0, SND_SOC_CLOCK_IN); if (ret < 0) { @@ -85,6 +79,7 @@ static int platform_clock_control(struct snd_soc_dapm_widget *w, return -EIO; } } + return ret; }
@@ -344,24 +339,40 @@ static int skylake_dmic_fixup(struct snd_soc_pcm_runtime *rtd, return 0; }
-static int skylake_nau8825_hw_params(struct snd_pcm_substream *substream, - struct snd_pcm_hw_params *params) +static int skylake_nau8825_trigger(struct snd_pcm_substream *substream, int cmd) { struct snd_soc_pcm_runtime *rtd = substream->private_data; + struct snd_pcm_runtime *runtime = substream->runtime; struct snd_soc_dai *codec_dai = asoc_rtd_to_codec(rtd, 0); - int ret; - - ret = snd_soc_dai_set_sysclk(codec_dai, - NAU8825_CLK_MCLK, 24000000, SND_SOC_CLOCK_IN); + int ret = 0;
- if (ret < 0) - dev_err(rtd->dev, "snd_soc_dai_set_sysclk err = %d\n", ret); + switch (cmd) { + case SNDRV_PCM_TRIGGER_START: + ret = snd_soc_dai_set_sysclk(codec_dai, NAU8825_CLK_FLL_FS, 0, + SND_SOC_CLOCK_IN); + if (ret < 0) { + dev_err(codec_dai->dev, "can't set FS clock %d\n", ret); + break; + } + ret = snd_soc_dai_set_pll(codec_dai, 0, 0, runtime->rate, + runtime->rate * 256); + if (ret < 0) + dev_err(codec_dai->dev, "can't set FLL: %d\n", ret); + break; + case SNDRV_PCM_TRIGGER_RESUME: + ret = snd_soc_dai_set_pll(codec_dai, 0, 0, runtime->rate, + runtime->rate * 256); + if (ret < 0) + dev_err(codec_dai->dev, "can't set FLL: %d\n", ret); + msleep(20); + break; + }
return ret; }
-static const struct snd_soc_ops skylake_nau8825_ops = { - .hw_params = skylake_nau8825_hw_params, +static struct snd_soc_ops skylake_nau8825_ops = { + .trigger = skylake_nau8825_trigger, };
static const unsigned int channels_dmic[] = { @@ -671,10 +682,34 @@ static int skylake_card_late_probe(struct snd_soc_card *card) return hdac_hdmi_jack_port_init(component, &card->dapm); }
+static int __maybe_unused skylake_nau8825_resume_post(struct snd_soc_card *card) +{ + struct snd_soc_dai *codec_dai; + + codec_dai = snd_soc_card_get_codec_dai(card, SKL_NUVOTON_CODEC_DAI); + if (!codec_dai) { + dev_err(card->dev, "Codec dai not found\n"); + return -EIO; + } + + dev_dbg(codec_dai->dev, "playback_active:%d playback_widget->active:%d codec_dai->rate:%d\n", + codec_dai->stream_active[SNDRV_PCM_STREAM_PLAYBACK], + codec_dai->playback_widget->active, + codec_dai->rate); + + if (codec_dai->stream_active[SNDRV_PCM_STREAM_PLAYBACK] && + codec_dai->playback_widget->active) + snd_soc_dai_set_sysclk(codec_dai, NAU8825_CLK_FLL_FS, 0, + SND_SOC_CLOCK_IN); + + return 0; +} + /* skylake audio machine driver for SPT + NAU88L25 */ static struct snd_soc_card skylake_audio_card = { .name = "sklnau8825adi", .owner = THIS_MODULE, + .resume_post = skylake_nau8825_resume_post, .dai_link = skylake_dais, .num_links = ARRAY_SIZE(skylake_dais), .controls = skylake_controls,
On 5/1/20 2:31 PM, Radoslaw Biernacki wrote:
This single fix address two issues on machines with nau88125:
- Audio distortion, due to lack of required clock rate on MCLK line
- Loud audible "pops" on headphones if there is no sysclk during nau8825 playback power up sequence
Explanation for:
- Due to Skylake HW limitation, MCLK pin can only output 24MHz clk rate (it can be only connected to XTAL parent clk). The BCLK pin can be driven by dividers and therefore FW is able to set it to rate required by chosen audio format. According to nau8825 datasheet, 256*FS sysclk gives the best audio quality and the only way to achieve this (taking into account the above limitations) its to regenerate the MCLK from BCLK on nau8825 side by FFL. Without required clk rate, audio is distorted by added harmonics.
The BCLK is going to be a multiple of 50 * Fs due to clocking restrictions. Can the codec regenerate a good-enough sysclk from this?
- Currently Skylake does not output MCLK/FS when the back-end DAI op hw_param is called, so we cannot switch to MCLK/FS in hw_param. This patch reduces pop by letting nau8825 keep using its internal VCO clock during widget power up sequence, until SNDRV_PCM_TRIGGER_START when MCLK/FS is available. Once device resumes, the system will only enable power sequence for playback without doing hardware parameter, audio format, and PLL configure. In the mean time, the jack detecion sequence has changed PLL parameters and switched to internal clock. Thus, the playback signal distorted without correct PLL parameters. That is why we need to configure the PLL again in SNDRV_PCM_TRIGGER_RESUME case.
IIRC the FS can be controlled with the clk_ api with the Skylake driver, as done for some KBL platforms. Or is this not supported by the firmware used by this machine?
-static int skylake_nau8825_hw_params(struct snd_pcm_substream *substream,
- struct snd_pcm_hw_params *params)
+static int skylake_nau8825_trigger(struct snd_pcm_substream *substream, int cmd) { struct snd_soc_pcm_runtime *rtd = substream->private_data;
- struct snd_pcm_runtime *runtime = substream->runtime; struct snd_soc_dai *codec_dai = asoc_rtd_to_codec(rtd, 0);
- int ret;
- ret = snd_soc_dai_set_sysclk(codec_dai,
NAU8825_CLK_MCLK, 24000000, SND_SOC_CLOCK_IN);
- int ret = 0;
- if (ret < 0)
dev_err(rtd->dev, "snd_soc_dai_set_sysclk err = %d\n", ret);
- switch (cmd) {
- case SNDRV_PCM_TRIGGER_START:
ret = snd_soc_dai_set_sysclk(codec_dai, NAU8825_CLK_FLL_FS, 0,SND_SOC_CLOCK_IN);if (ret < 0) {dev_err(codec_dai->dev, "can't set FS clock %d\n", ret);break;}ret = snd_soc_dai_set_pll(codec_dai, 0, 0, runtime->rate,runtime->rate * 256);if (ret < 0)dev_err(codec_dai->dev, "can't set FLL: %d\n", ret);break;- case SNDRV_PCM_TRIGGER_RESUME:
ret = snd_soc_dai_set_pll(codec_dai, 0, 0, runtime->rate,runtime->rate * 256);if (ret < 0)dev_err(codec_dai->dev, "can't set FLL: %d\n", ret);msleep(20);
is there a reason why you'd need a msleep for resume and not for start?
Thank you Pierre for the review! answers inline
pt., 1 maj 2020 o 22:16 Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com wrote:
On 5/1/20 2:31 PM, Radoslaw Biernacki wrote:
This single fix address two issues on machines with nau88125:
- Audio distortion, due to lack of required clock rate on MCLK line
- Loud audible "pops" on headphones if there is no sysclk during nau8825 playback power up sequence
Explanation for:
- Due to Skylake HW limitation, MCLK pin can only output 24MHz clk rate (it can be only connected to XTAL parent clk). The BCLK pin can be driven by dividers and therefore FW is able to set it to rate required by chosen audio format. According to nau8825 datasheet, 256*FS sysclk gives the best audio quality and the only way to achieve this (taking into account the above limitations) its to regenerate the MCLK from BCLK on nau8825 side by FFL. Without required clk rate, audio is distorted by added harmonics.
The BCLK is going to be a multiple of 50 * Fs due to clocking restrictions. Can the codec regenerate a good-enough sysclk from this?
According to Intel, silicon has a limitation, on SKL/KBL only clk_id = SKL_XTAL, .name = "xtal" is available for IO domain. As mentioned in the commit: MCLK is generated by using 24MHz Xtal directly or applying a divider (so no way of achieving the rate required by audio format). BCLK/FS is generated from 24MHz and uses dividers and additional padding bits are used to match the clock source. Next gen silicon has the possibility of using additional clock sources.
Summing up, using MCLK from SKL to NAU88L25 is not an option. The only option we found is to use BCLK and regen the required clock rate by FLL on the NAU88l25 side.
- Currently Skylake does not output MCLK/FS when the back-end DAI op hw_param is called, so we cannot switch to MCLK/FS in hw_param. This patch reduces pop by letting nau8825 keep using its internal VCO clock during widget power up sequence, until SNDRV_PCM_TRIGGER_START when MCLK/FS is available. Once device resumes, the system will only enable power sequence for playback without doing hardware parameter, audio format, and PLL configure. In the mean time, the jack detecion sequence has changed PLL parameters and switched to internal clock. Thus, the playback signal distorted without correct PLL parameters. That is why we need to configure the PLL again in SNDRV_PCM_TRIGGER_RESUME case.
IIRC the FS can be controlled with the clk_ api with the Skylake driver, as done for some KBL platforms. Or is this not supported by the firmware used by this machine?
According to Ben, SKL had limitations in FW for managing the clk's back in the days. Can you point to the other driver you mention so we can cross check?
-static int skylake_nau8825_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)+static int skylake_nau8825_trigger(struct snd_pcm_substream *substream, int cmd) { struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct snd_pcm_runtime *runtime = substream->runtime; struct snd_soc_dai *codec_dai = asoc_rtd_to_codec(rtd, 0);
int ret;ret = snd_soc_dai_set_sysclk(codec_dai,NAU8825_CLK_MCLK, 24000000, SND_SOC_CLOCK_IN);
int ret = 0;
if (ret < 0)dev_err(rtd->dev, "snd_soc_dai_set_sysclk err = %d\n", ret);
switch (cmd) {case SNDRV_PCM_TRIGGER_START:ret = snd_soc_dai_set_sysclk(codec_dai, NAU8825_CLK_FLL_FS, 0,SND_SOC_CLOCK_IN);if (ret < 0) {dev_err(codec_dai->dev, "can't set FS clock %d\n", ret);break;}ret = snd_soc_dai_set_pll(codec_dai, 0, 0, runtime->rate,runtime->rate * 256);if (ret < 0)dev_err(codec_dai->dev, "can't set FLL: %d\n", ret);break;case SNDRV_PCM_TRIGGER_RESUME:ret = snd_soc_dai_set_pll(codec_dai, 0, 0, runtime->rate,runtime->rate * 256);if (ret < 0)dev_err(codec_dai->dev, "can't set FLL: %d\n", ret);msleep(20);is there a reason why you'd need a msleep for resume and not for start?
No. I think we missed this. msleep() is needed to stabilize FLL. Will fix in next rev.
This single fix address two issues on machines with nau88125:
- Audio distortion, due to lack of required clock rate on MCLK line
- Loud audible "pops" on headphones if there is no sysclk during nau8825 playback power up sequence
Explanation for:
- Due to Skylake HW limitation, MCLK pin can only output 24MHz clk rate (it can be only connected to XTAL parent clk). The BCLK pin can be driven by dividers and therefore FW is able to set it to rate required by chosen audio format. According to nau8825 datasheet, 256*FS sysclk gives the best audio quality and the only way to achieve this (taking into account the above limitations) its to regenerate the MCLK from BCLK on nau8825 side by FFL. Without required clk rate, audio is distorted by added harmonics.
The BCLK is going to be a multiple of 50 * Fs due to clocking restrictions. Can the codec regenerate a good-enough sysclk from this?
According to Intel, silicon has a limitation, on SKL/KBL only clk_id = SKL_XTAL, .name = "xtal" is available for IO domain. As mentioned in the commit: MCLK is generated by using 24MHz Xtal directly or applying a divider (so no way of achieving the rate required by audio format). BCLK/FS is generated from 24MHz and uses dividers and additional padding bits are used to match the clock source. Next gen silicon has the possibility of using additional clock sources.
Summing up, using MCLK from SKL to NAU88L25 is not an option. The only option we found is to use BCLK and regen the required clock rate by FLL on the NAU88l25 side.
Right, this 24 MHz is a recurring problem. But what I was asking was if the NAU8825 is fine working with e.g. a 2.4MHz bit clock. i.e. with 25 bit slots or padding at the end of the frame?
- Currently Skylake does not output MCLK/FS when the back-end DAI op hw_param is called, so we cannot switch to MCLK/FS in hw_param. This patch reduces pop by letting nau8825 keep using its internal VCO clock during widget power up sequence, until SNDRV_PCM_TRIGGER_START when MCLK/FS is available. Once device resumes, the system will only enable power sequence for playback without doing hardware parameter, audio format, and PLL configure. In the mean time, the jack detecion sequence has changed PLL parameters and switched to internal clock. Thus, the playback signal distorted without correct PLL parameters. That is why we need to configure the PLL again in SNDRV_PCM_TRIGGER_RESUME case.
IIRC the FS can be controlled with the clk_ api with the Skylake driver, as done for some KBL platforms. Or is this not supported by the firmware used by this machine?
According to Ben, SKL had limitations in FW for managing the clk's back in the days. Can you point to the other driver you mention so we can cross check?
There are two KBL drivers that control the SSP clocks from the machine driver, but indeed I don't know if this would work on Firmware, it'd be a question for Lech/Cezary.
kbl_rt5663_max98927.c: ret = clk_prepare_enable(priv->mclk); kbl_rt5663_max98927.c: ret = clk_prepare_enable(priv->sclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->mclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->sclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->mclk);
Sorry for missing the response for so long. Somehow lost this thread in my mailbox.
śr., 6 maj 2020 o 00:04 Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com napisał(a):
This single fix address two issues on machines with nau88125:
- Audio distortion, due to lack of required clock rate on MCLK line
- Loud audible "pops" on headphones if there is no sysclk during nau8825 playback power up sequence
Explanation for:
- Due to Skylake HW limitation, MCLK pin can only output 24MHz clk rate (it can be only connected to XTAL parent clk). The BCLK pin can be driven by dividers and therefore FW is able to set it to rate required by chosen audio format. According to nau8825 datasheet, 256*FS sysclk gives the best audio quality and the only way to achieve this (taking into account the above limitations) its to regenerate the MCLK from BCLK on nau8825 side by FFL. Without required clk rate, audio is distorted by added harmonics.
The BCLK is going to be a multiple of 50 * Fs due to clocking restrictions. Can the codec regenerate a good-enough sysclk from this?
According to Intel, silicon has a limitation, on SKL/KBL only clk_id = SKL_XTAL, .name = "xtal" is available for IO domain. As mentioned in the commit: MCLK is generated by using 24MHz Xtal directly or applying a divider (so no way of achieving the rate required by audio format). BCLK/FS is generated from 24MHz and uses dividers and additional padding bits are used to match the clock source. Next gen silicon has the possibility of using additional clock sources.
Summing up, using MCLK from SKL to NAU88L25 is not an option. The only option we found is to use BCLK and regen the required clock rate by FLL on the NAU88l25 side.
Right, this 24 MHz is a recurring problem. But what I was asking was if the NAU8825 is fine working with e.g. a 2.4MHz bit clock. i.e. with 25 bit slots or padding at the end of the frame?
From our tests NAU8825 is working fine with these parameters.
Also the output audio signal looks fine on the scope and FFT and there are no audible glitches.
- Currently Skylake does not output MCLK/FS when the back-end DAI op hw_param is called, so we cannot switch to MCLK/FS in hw_param. This patch reduces pop by letting nau8825 keep using its internal VCO clock during widget power up sequence, until SNDRV_PCM_TRIGGER_START when MCLK/FS is available. Once device resumes, the system will only enable power sequence for playback without doing hardware parameter, audio format, and PLL configure. In the mean time, the jack detecion sequence has changed PLL parameters and switched to internal clock. Thus, the playback signal distorted without correct PLL parameters. That is why we need to configure the PLL again in SNDRV_PCM_TRIGGER_RESUME case.
IIRC the FS can be controlled with the clk_ api with the Skylake driver, as done for some KBL platforms. Or is this not supported by the firmware used by this machine?
According to Ben, SKL had limitations in FW for managing the clk's back in the days. Can you point to the other driver you mention so we can cross check?
There are two KBL drivers that control the SSP clocks from the machine driver, but indeed I don't know if this would work on Firmware, it'd be a question for Lech/Cezary.
kbl_rt5663_max98927.c: ret = clk_prepare_enable(priv->mclk); kbl_rt5663_max98927.c: ret = clk_prepare_enable(priv->sclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->mclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->sclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->mclk);
Czarek answered this and we got the same response from other Intel devs while consulting this change: FW cannot request a chosen rate (48k) for MCLK pin as it does not "align with what's present on SKL hw".
The only way we found out for NAU8825 to cooperate at chosen rate with SKL HW is to regen the MCLK from BCLK by FLL as mentioned above. NHTL is used to set SSP0 (48k, 24/25 bit on 24MHz crystal). If I get all of this right, use of NHTL and HW "abilities" would explain why there is no call to change SSP from a machine driver.
If all of this is ok I will send V3 with msleep() removed.
On 9/8/20 12:42 PM, Radosław Biernacki wrote:
Sorry for missing the response for so long. Somehow lost this thread in my mailbox.
That happens to all of us!
śr., 6 maj 2020 o 00:04 Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com napisał(a):
This single fix address two issues on machines with nau88125:
- Audio distortion, due to lack of required clock rate on MCLK line
- Loud audible "pops" on headphones if there is no sysclk during nau8825 playback power up sequence
Explanation for:
- Due to Skylake HW limitation, MCLK pin can only output 24MHz clk rate (it can be only connected to XTAL parent clk). The BCLK pin can be driven by dividers and therefore FW is able to set it to rate required by chosen audio format. According to nau8825 datasheet, 256*FS sysclk gives the best audio quality and the only way to achieve this (taking into account the above limitations) its to regenerate the MCLK from BCLK on nau8825 side by FFL. Without required clk rate, audio is distorted by added harmonics.
The BCLK is going to be a multiple of 50 * Fs due to clocking restrictions. Can the codec regenerate a good-enough sysclk from this?
According to Intel, silicon has a limitation, on SKL/KBL only clk_id = SKL_XTAL, .name = "xtal" is available for IO domain. As mentioned in the commit: MCLK is generated by using 24MHz Xtal directly or applying a divider (so no way of achieving the rate required by audio format). BCLK/FS is generated from 24MHz and uses dividers and additional padding bits are used to match the clock source. Next gen silicon has the possibility of using additional clock sources.
Summing up, using MCLK from SKL to NAU88L25 is not an option. The only option we found is to use BCLK and regen the required clock rate by FLL on the NAU88l25 side.
Right, this 24 MHz is a recurring problem. But what I was asking was if the NAU8825 is fine working with e.g. a 2.4MHz bit clock. i.e. with 25 bit slots or padding at the end of the frame?
From our tests NAU8825 is working fine with these parameters. Also the output audio signal looks fine on the scope and FFT and there are no audible glitches.
- Currently Skylake does not output MCLK/FS when the back-end DAI op hw_param is called, so we cannot switch to MCLK/FS in hw_param. This patch reduces pop by letting nau8825 keep using its internal VCO clock during widget power up sequence, until SNDRV_PCM_TRIGGER_START when MCLK/FS is available. Once device resumes, the system will only enable power sequence for playback without doing hardware parameter, audio format, and PLL configure. In the mean time, the jack detecion sequence has changed PLL parameters and switched to internal clock. Thus, the playback signal distorted without correct PLL parameters. That is why we need to configure the PLL again in SNDRV_PCM_TRIGGER_RESUME case.
IIRC the FS can be controlled with the clk_ api with the Skylake driver, as done for some KBL platforms. Or is this not supported by the firmware used by this machine?
According to Ben, SKL had limitations in FW for managing the clk's back in the days. Can you point to the other driver you mention so we can cross check?
There are two KBL drivers that control the SSP clocks from the machine driver, but indeed I don't know if this would work on Firmware, it'd be a question for Lech/Cezary.
kbl_rt5663_max98927.c: ret = clk_prepare_enable(priv->mclk); kbl_rt5663_max98927.c: ret = clk_prepare_enable(priv->sclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->mclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->sclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->mclk);
Czarek answered this and we got the same response from other Intel devs while consulting this change: FW cannot request a chosen rate (48k) for MCLK pin as it does not "align with what's present on SKL hw".
The only way we found out for NAU8825 to cooperate at chosen rate with SKL HW is to regen the MCLK from BCLK by FLL as mentioned above. NHTL is used to set SSP0 (48k, 24/25 bit on 24MHz crystal). If I get all of this right, use of NHTL and HW "abilities" would explain why there is no call to change SSP from a machine driver.
If all of this is ok I will send V3 with msleep() removed.
Sounds good.
You may want to simplify your commit message and just state what you described, e.g.
"Since 64xfs clocks cannot be generated, the NAU8825 is configured to re-generate its system clock from the BCLK using the FLL. The link is configured to use a 48kHz frame rate, and 24 bits in 25-bit slot. The SSP configuration is extracted from NHLT settings and not dynamically changed. Listening tests and measurements do not show any distortion or issues".
Thanks for the tip! Let me reformat the patch.
wt., 8 wrz 2020 o 20:06 Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com napisał(a):
On 9/8/20 12:42 PM, Radosław Biernacki wrote:
Sorry for missing the response for so long. Somehow lost this thread in my mailbox.
That happens to all of us!
śr., 6 maj 2020 o 00:04 Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com napisał(a):
This single fix address two issues on machines with nau88125:
- Audio distortion, due to lack of required clock rate on MCLK line
- Loud audible "pops" on headphones if there is no sysclk during nau8825 playback power up sequence
Explanation for:
- Due to Skylake HW limitation, MCLK pin can only output 24MHz clk rate (it can be only connected to XTAL parent clk). The BCLK pin can be driven by dividers and therefore FW is able to set it to rate required by chosen audio format. According to nau8825 datasheet, 256*FS sysclk gives the best audio quality and the only way to achieve this (taking into account the above limitations) its to regenerate the MCLK from BCLK on nau8825 side by FFL. Without required clk rate, audio is distorted by added harmonics.
The BCLK is going to be a multiple of 50 * Fs due to clocking restrictions. Can the codec regenerate a good-enough sysclk from this?
According to Intel, silicon has a limitation, on SKL/KBL only clk_id = SKL_XTAL, .name = "xtal" is available for IO domain. As mentioned in the commit: MCLK is generated by using 24MHz Xtal directly or applying a divider (so no way of achieving the rate required by audio format). BCLK/FS is generated from 24MHz and uses dividers and additional padding bits are used to match the clock source. Next gen silicon has the possibility of using additional clock sources.
Summing up, using MCLK from SKL to NAU88L25 is not an option. The only option we found is to use BCLK and regen the required clock rate by FLL on the NAU88l25 side.
Right, this 24 MHz is a recurring problem. But what I was asking was if the NAU8825 is fine working with e.g. a 2.4MHz bit clock. i.e. with 25 bit slots or padding at the end of the frame?
From our tests NAU8825 is working fine with these parameters. Also the output audio signal looks fine on the scope and FFT and there are no audible glitches.
- Currently Skylake does not output MCLK/FS when the back-end DAI op hw_param is called, so we cannot switch to MCLK/FS in hw_param. This patch reduces pop by letting nau8825 keep using its internal VCO clock during widget power up sequence, until SNDRV_PCM_TRIGGER_START when MCLK/FS is available. Once device resumes, the system will only enable power sequence for playback without doing hardware parameter, audio format, and PLL configure. In the mean time, the jack detecion sequence has changed PLL parameters and switched to internal clock. Thus, the playback signal distorted without correct PLL parameters. That is why we need to configure the PLL again in SNDRV_PCM_TRIGGER_RESUME case.
IIRC the FS can be controlled with the clk_ api with the Skylake driver, as done for some KBL platforms. Or is this not supported by the firmware used by this machine?
According to Ben, SKL had limitations in FW for managing the clk's back in the days. Can you point to the other driver you mention so we can cross check?
There are two KBL drivers that control the SSP clocks from the machine driver, but indeed I don't know if this would work on Firmware, it'd be a question for Lech/Cezary.
kbl_rt5663_max98927.c: ret = clk_prepare_enable(priv->mclk); kbl_rt5663_max98927.c: ret = clk_prepare_enable(priv->sclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->mclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->sclk); kbl_rt5663_rt5514_max98927.c: ret = clk_prepare_enable(priv->mclk);
Czarek answered this and we got the same response from other Intel devs while consulting this change: FW cannot request a chosen rate (48k) for MCLK pin as it does not "align with what's present on SKL hw".
The only way we found out for NAU8825 to cooperate at chosen rate with SKL HW is to regen the MCLK from BCLK by FLL as mentioned above. NHTL is used to set SSP0 (48k, 24/25 bit on 24MHz crystal). If I get all of this right, use of NHTL and HW "abilities" would explain why there is no call to change SSP from a machine driver.
If all of this is ok I will send V3 with msleep() removed.
Sounds good.
You may want to simplify your commit message and just state what you described, e.g.
"Since 64xfs clocks cannot be generated, the NAU8825 is configured to re-generate its system clock from the BCLK using the FLL. The link is configured to use a 48kHz frame rate, and 24 bits in 25-bit slot. The SSP configuration is extracted from NHLT settings and not dynamically changed. Listening tests and measurements do not show any distortion or issues".
- Currently Skylake does not output MCLK/FS when the back-end DAI op hw_param is called, so we cannot switch to MCLK/FS in hw_param. This patch reduces pop by letting nau8825 keep using its internal VCO clock during widget power up sequence, until SNDRV_PCM_TRIGGER_START when MCLK/FS is available. Once device resumes, the system will only enable power sequence for playback without doing hardware parameter, audio format, and PLL configure. In the mean time, the jack detecion sequence has changed PLL parameters and switched to internal clock. Thus, the playback signal distorted without correct PLL parameters. That is why we need to configure the PLL again in SNDRV_PCM_TRIGGER_RESUME case.
IIRC the FS can be controlled with the clk_ api with the Skylake driver, as done for some KBL platforms. Or is this not supported by the firmware used by this machine?
According to Ben, SKL had limitations in FW for managing the clk's back in the days. Can you point to the other driver you mention so we can cross check?
Skylake driver is found within: /sound/soc/intel/skylake directory.
"SKL had limitations in FW" - that's misleading. This is neither FW issue nor HW 'limitation'. SKL is an older platform and its goals and design was different than say APL+. Basically, your needs do not align with what's present on SKL hw.
Czarek
Hi Radoslaw,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on asoc/for-next] [also build test WARNING on sound/for-next v5.7-rc3 next-20200501] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Radoslaw-Biernacki/ASoC-Intel-board... base: https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next config: i386-allyesconfig (attached as .config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce: # save the attached .config to linux build tree make ARCH=i386
If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot lkp@intel.com
Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
All warnings (new ones prefixed by >>):
sound/soc/intel/boards/skl_nau88l25_max98357a.c: In function 'platform_clock_control':
sound/soc/intel/boards/skl_nau88l25_max98357a.c:56:6: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
int ret; ^~~
vim +/ret +56 sound/soc/intel/boards/skl_nau88l25_max98357a.c
0ab338ff33762d Sathyanarayana Nujella 2016-02-24 49 8eaf2b31dd316f Rohit Ainapure 2015-12-11 50 static int platform_clock_control(struct snd_soc_dapm_widget *w, 8eaf2b31dd316f Rohit Ainapure 2015-12-11 51 struct snd_kcontrol *k, int event) 8eaf2b31dd316f Rohit Ainapure 2015-12-11 52 { 8eaf2b31dd316f Rohit Ainapure 2015-12-11 53 struct snd_soc_dapm_context *dapm = w->dapm; 8eaf2b31dd316f Rohit Ainapure 2015-12-11 54 struct snd_soc_card *card = dapm->card; 8eaf2b31dd316f Rohit Ainapure 2015-12-11 55 struct snd_soc_dai *codec_dai; 8eaf2b31dd316f Rohit Ainapure 2015-12-11 @56 int ret; 8eaf2b31dd316f Rohit Ainapure 2015-12-11 57 dfb6ec7ae57d33 Pierre-Louis Bossart 2017-10-12 58 codec_dai = snd_soc_card_get_codec_dai(card, SKL_NUVOTON_CODEC_DAI); 8eaf2b31dd316f Rohit Ainapure 2015-12-11 59 if (!codec_dai) { 8eaf2b31dd316f Rohit Ainapure 2015-12-11 60 dev_err(card->dev, "Codec dai not found; Unable to set platform clock\n"); 8eaf2b31dd316f Rohit Ainapure 2015-12-11 61 return -EIO; 8eaf2b31dd316f Rohit Ainapure 2015-12-11 62 } 8eaf2b31dd316f Rohit Ainapure 2015-12-11 63 4adaffea05f2fa Radoslaw Biernacki 2020-05-01 64 if (!SND_SOC_DAPM_EVENT_ON(event)) { 8eaf2b31dd316f Rohit Ainapure 2015-12-11 65 ret = snd_soc_dai_set_sysclk(codec_dai, 8eaf2b31dd316f Rohit Ainapure 2015-12-11 66 NAU8825_CLK_INTERNAL, 0, SND_SOC_CLOCK_IN); 8eaf2b31dd316f Rohit Ainapure 2015-12-11 67 if (ret < 0) { 8eaf2b31dd316f Rohit Ainapure 2015-12-11 68 dev_err(card->dev, "set sysclk err = %d\n", ret); 8eaf2b31dd316f Rohit Ainapure 2015-12-11 69 return -EIO; 8eaf2b31dd316f Rohit Ainapure 2015-12-11 70 } 8eaf2b31dd316f Rohit Ainapure 2015-12-11 71 } 8eaf2b31dd316f Rohit Ainapure 2015-12-11 72 8eaf2b31dd316f Rohit Ainapure 2015-12-11 73 return ret; 8eaf2b31dd316f Rohit Ainapure 2015-12-11 74 } 8eaf2b31dd316f Rohit Ainapure 2015-12-11 75
:::::: The code at line 56 was first introduced by commit :::::: 8eaf2b31dd316ff5ffbdad14853d2bf8779bab13 ASoC: Intel: Skylake: Add Nuvoton Maxim machine driver
:::::: TO: Rohit Ainapure rohit.m.ainapure@intel.com :::::: CC: Mark Brown broonie@kernel.org
--- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
participants (5)
-
Cezary Rojewski -
kbuild test robot -
Pierre-Louis Bossart -
Radoslaw Biernacki -
Radosław Biernacki