[alsa-devel] [PATCH] ASoC: fsl_ssi: Override bit clock rate based on slot number
The set_sysclk() now is used to override the output bit clock rate. But this is not a common way to implement a set_dai_sysclk(). And this creates a problem when a general machine driver (simple-card for example) tries to do set_dai_sysclk() by passing an input clock rate for the baud clock instead of setting the bit clock rate as fsl_ssi driver expected.
So this patch solves this problem by firstly removing set_sysclk() since the hw_params() can calculate the bit clock rate. Secondly, in order not to break those TDM use cases which previously might have been using set_sysclk() to override the bit clock rate, this patch changes the driver to override it based on the slot number.
The patch also removes an obsolete comment of the dir parameter.
Signed-off-by: Nicolin Chen nicoleotsuka@gmail.com --- sound/soc/fsl/fsl_ssi.c | 26 ++++++++------------------ 1 file changed, 8 insertions(+), 18 deletions(-)
diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c index 64598d1..3657c88 100644 --- a/sound/soc/fsl/fsl_ssi.c +++ b/sound/soc/fsl/fsl_ssi.c @@ -197,12 +197,12 @@ struct fsl_ssi_soc_data { * @use_dma: DMA is used or FIQ with stream filter * @use_dual_fifo: DMA with support for both FIFOs used * @fifo_deph: Depth of the SSI FIFOs + * @slots: number of slots * @rxtx_reg_val: Specific register settings for receive/transmit configuration * * @clk: SSI clock * @baudclk: SSI baud clock for master mode * @baudclk_streams: Active streams that are using baudclk - * @bitclk_freq: bitclock frequency set by .set_dai_sysclk * * @dma_params_tx: DMA transmit parameters * @dma_params_rx: DMA receive parameters @@ -233,12 +233,12 @@ struct fsl_ssi_private { bool use_dual_fifo; bool has_ipg_clk_name; unsigned int fifo_depth; + unsigned int slots; struct fsl_ssi_rxtx_reg_val rxtx_reg_val;
struct clk *clk; struct clk *baudclk; unsigned int baudclk_streams; - unsigned int bitclk_freq;
/* regcache for volatile regs */ u32 regcache_sfcsr; @@ -700,8 +700,7 @@ static void fsl_ssi_shutdown(struct snd_pcm_substream *substream, * Note: This function can be only called when using SSI as DAI master * * Quick instruction for parameters: - * freq: Output BCLK frequency = samplerate * 32 (fixed) * channels - * dir: SND_SOC_CLOCK_OUT -> TxBCLK, SND_SOC_CLOCK_IN -> RxBCLK. + * freq: Output BCLK frequency = samplerate * 32 (fixed) * slots (or channels) */ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream, struct snd_soc_dai *cpu_dai, @@ -716,9 +715,9 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream, unsigned int freq; bool baudclk_is_used;
- /* Prefer the explicitly set bitclock frequency */ - if (ssi_private->bitclk_freq) - freq = ssi_private->bitclk_freq; + /* Generate bit clock based on the slot or channel number */ + if (ssi_private->slots) + freq = ssi_private->slots * 32 * params_rate(hw_params); else freq = params_channels(hw_params) * 32 * params_rate(hw_params);
@@ -805,16 +804,6 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream, return 0; }
-static int fsl_ssi_set_dai_sysclk(struct snd_soc_dai *cpu_dai, - int clk_id, unsigned int freq, int dir) -{ - struct fsl_ssi_private *ssi_private = snd_soc_dai_get_drvdata(cpu_dai); - - ssi_private->bitclk_freq = freq; - - return 0; -} - /** * fsl_ssi_hw_params - program the sample size * @@ -1121,6 +1110,8 @@ static int fsl_ssi_set_dai_tdm_slot(struct snd_soc_dai *cpu_dai, u32 tx_mask,
regmap_update_bits(regs, CCSR_SSI_SCR, CCSR_SSI_SCR_SSIEN, val);
+ ssi_private->slots = slots; + return 0; }
@@ -1191,7 +1182,6 @@ static const struct snd_soc_dai_ops fsl_ssi_dai_ops = { .hw_params = fsl_ssi_hw_params, .hw_free = fsl_ssi_hw_free, .set_fmt = fsl_ssi_set_dai_fmt, - .set_sysclk = fsl_ssi_set_dai_sysclk, .set_tdm_slot = fsl_ssi_set_dai_tdm_slot, .trigger = fsl_ssi_trigger, };
On Thu, Sep 07, 2017 at 10:23:43PM -0700, Nicolin Chen wrote:
The set_sysclk() now is used to override the output bit clock rate. But this is not a common way to implement a set_dai_sysclk(). And this creates a problem when a general machine driver (simple-card for example) tries to do set_dai_sysclk() by passing an input clock rate for the baud clock instead of setting the bit clock rate as fsl_ssi driver expected.
So this patch solves this problem by firstly removing set_sysclk() since the hw_params() can calculate the bit clock rate. Secondly, in order not to break those TDM use cases which previously might have been using set_sysclk() to override the bit clock rate, this patch changes the driver to override it based on the slot number.
The patch also removes an obsolete comment of the dir parameter.
Signed-off-by: Nicolin Chen nicoleotsuka@gmail.com
Forgot to mention, I think that it's better to wait for a couple of Tested-by from those who use the TDM mode of SSI before applying it.
Thanks Nicolin
On 08/09/2017 07:42, Nicolin Chen wrote:
On Thu, Sep 07, 2017 at 10:23:43PM -0700, Nicolin Chen wrote:
The set_sysclk() now is used to override the output bit clock rate. But this is not a common way to implement a set_dai_sysclk(). And this creates a problem when a general machine driver (simple-card for example) tries to do set_dai_sysclk() by passing an input clock rate for the baud clock instead of setting the bit clock rate as fsl_ssi driver expected.
So this patch solves this problem by firstly removing set_sysclk() since the hw_params() can calculate the bit clock rate. Secondly, in order not to break those TDM use cases which previously might have been using set_sysclk() to override the bit clock rate, this patch changes the driver to override it based on the slot number.
The patch also removes an obsolete comment of the dir parameter.
Signed-off-by: Nicolin Chen nicoleotsuka@gmail.com
Forgot to mention, I think that it's better to wait for a couple of Tested-by from those who use the TDM mode of SSI before applying it.
I can check next monday or tuesday. Arnaud
Thanks Nicolin
Hi Nicolin,
On Thu, Sep 07, 2017 at 10:23:43PM -0700, Nicolin Chen wrote:
The set_sysclk() now is used to override the output bit clock rate. But this is not a common way to implement a set_dai_sysclk(). And this creates a problem when a general machine driver (simple-card for example) tries to do set_dai_sysclk() by passing an input clock rate for the baud clock instead of setting the bit clock rate as fsl_ssi driver expected.
So this patch solves this problem by firstly removing set_sysclk() since the hw_params() can calculate the bit clock rate. Secondly, in order not to break those TDM use cases which previously might have been using set_sysclk() to override the bit clock rate, this patch changes the driver to override it based on the slot number.
The patch also removes an obsolete comment of the dir parameter.
Signed-off-by: Nicolin Chen nicoleotsuka@gmail.com
Forgot to mention, I think that it's better to wait for a couple of Tested-by from those who use the TDM mode of SSI before applying it.
Although, I'm not the PCM user, I've tested your patch and it works :-)
Tested-by: Łukasz Majewski lukma@denx.de
Test HW: imx6q + tfa9879 codec
Thanks Nicolin
Hello Nicolin
On 08/09/2017 07:23, Nicolin Chen wrote:
The set_sysclk() now is used to override the output bit clock rate. But this is not a common way to implement a set_dai_sysclk(). And this creates a problem when a general machine driver (simple-card for example) tries to do set_dai_sysclk() by passing an input clock rate for the baud clock instead of setting the bit clock rate as fsl_ssi driver expected.
So this patch solves this problem by firstly removing set_sysclk() since the hw_params() can calculate the bit clock rate. Secondly, in order not to break those TDM use cases which previously might have been using set_sysclk() to override the bit clock rate, this patch changes the driver to override it based on the slot number.
The patch also removes an obsolete comment of the dir parameter.
Signed-off-by: Nicolin Chen nicoleotsuka@gmail.com
sound/soc/fsl/fsl_ssi.c | 26 ++++++++------------------ 1 file changed, 8 insertions(+), 18 deletions(-)
diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c index 64598d1..3657c88 100644 --- a/sound/soc/fsl/fsl_ssi.c +++ b/sound/soc/fsl/fsl_ssi.c @@ -197,12 +197,12 @@ struct fsl_ssi_soc_data {
- @use_dma: DMA is used or FIQ with stream filter
- @use_dual_fifo: DMA with support for both FIFOs used
- @fifo_deph: Depth of the SSI FIFOs
- @slots: number of slots
- @rxtx_reg_val: Specific register settings for receive/transmit configuration
- @clk: SSI clock
- @baudclk: SSI baud clock for master mode
- @baudclk_streams: Active streams that are using baudclk
- @bitclk_freq: bitclock frequency set by .set_dai_sysclk
- @dma_params_tx: DMA transmit parameters
- @dma_params_rx: DMA receive parameters
@@ -233,12 +233,12 @@ struct fsl_ssi_private { bool use_dual_fifo; bool has_ipg_clk_name; unsigned int fifo_depth;
unsigned int slots; struct fsl_ssi_rxtx_reg_val rxtx_reg_val;
struct clk *clk; struct clk *baudclk; unsigned int baudclk_streams;
unsigned int bitclk_freq;
/* regcache for volatile regs */ u32 regcache_sfcsr;
@@ -700,8 +700,7 @@ static void fsl_ssi_shutdown(struct snd_pcm_substream *substream,
- Note: This function can be only called when using SSI as DAI master
- Quick instruction for parameters:
- freq: Output BCLK frequency = samplerate * 32 (fixed) * channels
- dir: SND_SOC_CLOCK_OUT -> TxBCLK, SND_SOC_CLOCK_IN -> RxBCLK.
- freq: Output BCLK frequency = samplerate * 32 (fixed) * slots (or channels)
Slots are not necessarily 32 bits width. Indeed, a simple grep of snd_soc_dai_set_tdm_slot shows 16, 24, 32 and 0 bits usage. (don't know the real meaning of 0 BTW...) So, it should be good to also remember the slots width given in snd_soc_dai_set_tdm_slot() call.
Anyway, there is something wrong in the snd_soc_codec_set_sysclk usage by fsl_ssi Let's get a look again at the description:
/** * snd_soc_dai_set_sysclk - configure DAI system or master clock. * @dai: DAI * @clk_id: DAI specific clock ID * @freq: new clock frequency in Hz * @dir: new clock direction - input/output. * * Configures the DAI master (MCLK) or system (SYSCLK) clocking. */ int snd_soc_dai_set_sysclk(struct snd_soc_dai *dai, int clk_id, unsigned int freq, int dir)
So, it can be used to configure 2 different clocks (and more) with different usages.
Lukasz complains that simple-card is configuring MCLK incorrectly. but simple-card, only want to configure the SYSCLK, whereas fsl_ssi understand "configure the MCLK..." (fsl_ssi doesn't check the clk_id at all)
I think the problem is here. I would propose a new clk_id
#define FSL_SSI_SYSCLK_MCLK 1
And leave fsl_ssi_set_dai_sysclk(xxx, FSL_SSI_SYSCLK_MCLK, ...) override the computed mlck. This will leave a way for obscure TDM users to specify a specific a random mclk frequency for obscure reasons... Unfortunately, such generic clock_id (sysclk, mclk) were never defined widely.
Is it really needed ? It is true that, up to now, we are using fsl_ssi_set_dai_sysclk() in addition to snd_soc_dai_set_tdm_slot() only because this was the only way to deal with correct mclk setting. And if now, snd_soc_dai_set_tdm_slot() do its job correctly, fsl_ssi_set_dai_sysclk() will become useless (except for obscure TDM users of course)
Will it break TDM users ? I will say yes, surely, but TDM users (at least myself) may consider something will break in TDM audio area every-time we jump to a new linux release...
Arnaud
*/ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream, struct snd_soc_dai *cpu_dai, @@ -716,9 +715,9 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream, unsigned int freq; bool baudclk_is_used;
- /* Prefer the explicitly set bitclock frequency */
- if (ssi_private->bitclk_freq)
freq = ssi_private->bitclk_freq;
- /* Generate bit clock based on the slot or channel number */
- if (ssi_private->slots)
freq = ssi_private->slots * 32 * params_rate(hw_params);@@ -805,16 +804,6 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream, return 0; }
-static int fsl_ssi_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
int clk_id, unsigned int freq, int dir)-{
- struct fsl_ssi_private *ssi_private = snd_soc_dai_get_drvdata(cpu_dai);
- ssi_private->bitclk_freq = freq;
- return 0;
-}
- /**
- fsl_ssi_hw_params - program the sample size
@@ -1121,6 +1110,8 @@ static int fsl_ssi_set_dai_tdm_slot(struct snd_soc_dai *cpu_dai, u32 tx_mask,
regmap_update_bits(regs, CCSR_SSI_SCR, CCSR_SSI_SCR_SSIEN, val);
- ssi_private->slots = slots;
- return 0; }
@@ -1191,7 +1182,6 @@ static const struct snd_soc_dai_ops fsl_ssi_dai_ops = { .hw_params = fsl_ssi_hw_params, .hw_free = fsl_ssi_hw_free, .set_fmt = fsl_ssi_set_dai_fmt,
- .set_sysclk = fsl_ssi_set_dai_sysclk, .set_tdm_slot = fsl_ssi_set_dai_tdm_slot, .trigger = fsl_ssi_trigger, };
On Tue, Sep 12, 2017 at 04:35:13PM +0200, Arnaud Mouiche wrote:
- freq: Output BCLK frequency = samplerate * 32 (fixed) * channels
- dir: SND_SOC_CLOCK_OUT -> TxBCLK, SND_SOC_CLOCK_IN -> RxBCLK.
- freq: Output BCLK frequency = samplerate * 32 (fixed) * slots (or channels)
Slots are not necessarily 32 bits width. Indeed, a simple grep of snd_soc_dai_set_tdm_slot shows 16, 24, 32 and 0 bits usage. (don't know the real meaning of 0 BTW...) So, it should be good to also remember the slots width given in snd_soc_dai_set_tdm_slot() call.
RM says that the word length is fixed to 32 in I2S Master mode. So I used it here. But I think using it with the slots could be wrong here as you stated. What kind of clock rates (bit and lr) does a TDM case have?
The problem of slot width here is handled in the set_tdm_slot() at all. So I tried to ignored that. But we probably do need it when calculating things with the slot number.
Could you please give me a few set of examples of how you set set_sysclk(), set_tdm_slot() with the current driver? The idea here is to figure out a way to calculate the bclk in hw_params without getting set_sysclk() involved any more.
Anyway, there is something wrong in the snd_soc_codec_set_sysclk usage by fsl_ssi Let's get a look again at the description:
/** * snd_soc_dai_set_sysclk - configure DAI system or master clock. * @dai: DAI * @clk_id: DAI specific clock ID * @freq: new clock frequency in Hz * @dir: new clock direction - input/output. * * Configures the DAI master (MCLK) or system (SYSCLK) clocking. */ int snd_soc_dai_set_sysclk(struct snd_soc_dai *dai, int clk_id, unsigned int freq, int dir)
So, it can be used to configure 2 different clocks (and more) with different usages.
Lukasz complains that simple-card is configuring MCLK incorrectly. but simple-card, only want to configure the SYSCLK, whereas fsl_ssi understand "configure the MCLK..." (fsl_ssi doesn't check the clk_id at all)
It's more than a clock_id in my opinion. The driver now sets the bit clock rate via set_sysclk() other than the MCLK rate actually.
I think the problem is here. I would propose a new clk_id
#define FSL_SSI_SYSCLK_MCLK 1And leave fsl_ssi_set_dai_sysclk(xxx, FSL_SSI_SYSCLK_MCLK, ...) override the computed mlck. This will leave a way for obscure TDM users to specify a specific a random mclk frequency for obscure reasons... Unfortunately, such generic clock_id (sysclk, mclk) were never defined widely.
Unfortunately, it looks like a work around to me. I understand the idea of leaving set_sysclk() out there to override the bit clock is convenient, but it is not a standard ALSA design and may eventually introduce new problems like today.
Is it really needed ? It is true that, up to now, we are using fsl_ssi_set_dai_sysclk() in addition to snd_soc_dai_set_tdm_slot() only because this was the only way to deal with correct mclk setting. And if now, snd_soc_dai_set_tdm_slot() do its job correctly, fsl_ssi_set_dai_sysclk() will become useless (except for obscure TDM users of course)
The idea here is to drop the set_sysclk() for all user cases including TDM cases. So we need a solid patch to calculate the bit clock rate in hw_params() for TDM user cases..
On 12/09/2017 23:32, Nicolin Chen wrote:
On Tue, Sep 12, 2017 at 04:35:13PM +0200, Arnaud Mouiche wrote:
- freq: Output BCLK frequency = samplerate * 32 (fixed) * channels
- dir: SND_SOC_CLOCK_OUT -> TxBCLK, SND_SOC_CLOCK_IN -> RxBCLK.
- freq: Output BCLK frequency = samplerate * 32 (fixed) * slots (or channels)
Slots are not necessarily 32 bits width. Indeed, a simple grep of snd_soc_dai_set_tdm_slot shows 16, 24, 32 and 0 bits usage. (don't know the real meaning of 0 BTW...) So, it should be good to also remember the slots width given in snd_soc_dai_set_tdm_slot() call.
RM says that the word length is fixed to 32 in I2S Master mode. So I used it here. But I think using it with the slots could be wrong here as you stated. What kind of clock rates (bit and lr) does a TDM case have?
The problem of slot width here is handled in the set_tdm_slot() at all. So I tried to ignored that. But we probably do need it when calculating things with the slot number.
Could you please give me a few set of examples of how you set set_sysclk(), set_tdm_slot() with the current driver? The idea here is to figure out a way to calculate the bclk in hw_params without getting set_sysclk() involved any more.
Here is one, where a bclk = 4*16*fs is expected
static int imx_hifi_hw_params(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params) { struct snd_soc_pcm_runtime *rtd = substream->private_data; struct imx_priv *priv = &card_priv; struct device *dev = &priv->pdev->dev;
int ret = 0; struct snd_soc_dai *cpu_dai = rtd->cpu_dai; unsigned int freq; int ch;
/* configuring cpu_dai * - bitclk (fclk is computed automatically) * 16bit * 4 (max) channels * sampling rate * - tdm maskto select the active channels */
freq = 4 * 16 * params_rate(params); if (freq != priv->current_freq) { /* clk_id and direction are not taken in count by fsl_ssi driver */ ret = snd_soc_dai_set_sysclk( cpu_dai, 0, freq, 0 ); if (ret) { dev_err(dev, "failed to set cpu dai bitclk: %u\n", freq); return ret; } priv->current_freq = freq; } ch = params_channels(params); if (ch != priv->current_ch) { ret = snd_soc_dai_set_tdm_slot( cpu_dai, (1 << ch)-1, (1 << ch)-1, 4, 16 ); if (ret) { dev_err(dev, "failed to set cpu dai tdm slots: ch=%d\n", ch); return ret; } priv->current_ch = ch; } return 0; }
In another setup, there are 8 x 16 bits slots, whatever the number of active channels is. In this case bclk = 128 * fs The number of slots is completely arbitrary. Some slots can even be reserved for communication between codecs that don't communicate with linux.
Anyway, there is something wrong in the snd_soc_codec_set_sysclk usage by fsl_ssi Let's get a look again at the description:
/** * snd_soc_dai_set_sysclk - configure DAI system or master clock. * @dai: DAI * @clk_id: DAI specific clock ID * @freq: new clock frequency in Hz * @dir: new clock direction - input/output. * * Configures the DAI master (MCLK) or system (SYSCLK) clocking. */ int snd_soc_dai_set_sysclk(struct snd_soc_dai *dai, int clk_id, unsigned int freq, int dir)So, it can be used to configure 2 different clocks (and more) with different usages.
Lukasz complains that simple-card is configuring MCLK incorrectly. but simple-card, only want to configure the SYSCLK, whereas fsl_ssi understand "configure the MCLK..." (fsl_ssi doesn't check the clk_id at all)
It's more than a clock_id in my opinion. The driver now sets the bit clock rate via set_sysclk() other than the MCLK rate actually.
I think the problem is here. I would propose a new clk_id
#define FSL_SSI_SYSCLK_MCLK 1And leave fsl_ssi_set_dai_sysclk(xxx, FSL_SSI_SYSCLK_MCLK, ...) override the computed mlck. This will leave a way for obscure TDM users to specify a specific a random mclk frequency for obscure reasons... Unfortunately, such generic clock_id (sysclk, mclk) were never defined widely.
Unfortunately, it looks like a work around to me. I understand the idea of leaving set_sysclk() out there to override the bit clock is convenient, but it is not a standard ALSA design and may eventually introduce new problems like today.
I agree. I'm not conservative at all concerning this question. I don't see a way to remove set_sysclk without breaking current TDM users anyway, at least for those who don't have their code upstreamed.
All information provided through snd_soc_dai_set_tdm_slot( cpu_dai, mask, mask, slots, width ) should be enough In this case, for TDM users
bclk = slots * width * fs (where slots is != channels)
will manage 99 % of the cases. And the remaining 1% will concern people who need to hack the kernel so widely they don't care about the set_sysclk removal.
Now, looking at the code currently in linus/master:sound/soc/fsl concerning TDM - imx-mc13783.c : the codec is master => OK - fsl-asoc-card.c : *something will break since snd_soc_dai_set_sysclk returned code is checked* - eukrea-tlv320.c : based on imx-ssi.c, so not affected by changes in fsl_ssi.c. Use set_sysclk() only to setup the clock direction - wm1133-ev1.c : bclk generated by the codec. set_sysclk() not called for cpu_dai
Consequently, we can say that few things is broken in linux upstream if set_sysclk is removed, and this can be fixed easily for fsl-asoc-card.c
Arnaud
On Wed, Sep 13, 2017 at 10:02:20AM +0200, Arnaud Mouiche wrote:
Could you please give me a few set of examples of how you set set_sysclk(), set_tdm_slot() with the current driver? The idea here is to figure out a way to calculate the bclk in hw_params without getting set_sysclk() involved any more.
Here is one, where a bclk = 4*16*fs is expected
In another setup, there are 8 x 16 bits slots, whatever the number of active channels is. In this case bclk = 128 * fs The number of slots is completely arbitrary. Some slots can even be reserved for communication between codecs that don't communicate with linux.
In summary, bclk = sample rate * slots * slot_width;
I will update my patch soon.
Unfortunately, it looks like a work around to me. I understand the idea of leaving set_sysclk() out there to override the bit clock is convenient, but it is not a standard ALSA design and may eventually introduce new problems like today.
I agree. I'm not conservative at all concerning this question. I don't see a way to remove set_sysclk without breaking current TDM users anyway, at least for those who don't have their code upstreamed.
Which TDM case would be broken by this removal? The only impact that I can see is that the ASoC core returns an ENOTSUPP for a set_sysclk() call now, which is something that a dai-link driver should have taken care of anyway.
All information provided through snd_soc_dai_set_tdm_slot( cpu_dai, mask, mask, slots, width ) should be enough In this case, for TDM users
bclk = slots * width * fs (where slots is != channels)
will manage 99 % of the cases. And the remaining 1% will concern people who need to hack the kernel so widely they don't care about the set_sysclk removal.
A patch from those people will be always welcome.
- fsl-asoc-card.c : *something will break since
snd_soc_dai_set_sysclk returned code is checked*
I've already submitted a patch to ignore all ENOTSUPP.
Hi Nicolin,
On Wed, Sep 13, 2017 at 10:02:20AM +0200, Arnaud Mouiche wrote:
Could you please give me a few set of examples of how you set set_sysclk(), set_tdm_slot() with the current driver? The idea here is to figure out a way to calculate the bclk in hw_params without getting set_sysclk() involved any more.
Here is one, where a bclk = 4*16*fs is expected
In another setup, there are 8 x 16 bits slots, whatever the number of active channels is. In this case bclk = 128 * fs The number of slots is completely arbitrary. Some slots can even be reserved for communication between codecs that don't communicate with linux.
In summary, bclk = sample rate * slots * slot_width;
I will update my patch soon.
Unfortunately, it looks like a work around to me. I understand the idea of leaving set_sysclk() out there to override the bit clock is convenient, but it is not a standard ALSA design and may eventually introduce new problems like today.
I agree. I'm not conservative at all concerning this question. I don't see a way to remove set_sysclk without breaking current TDM users anyway, at least for those who don't have their code upstreamed.
Which TDM case would be broken by this removal? The only impact that I can see is that the ASoC core returns an ENOTSUPP for a set_sysclk() call now, which is something that a dai-link driver should have taken care of anyway.
All information provided through snd_soc_dai_set_tdm_slot( cpu_dai, mask, mask, slots, width ) should be enough In this case, for TDM users
bclk = slots * width * fs (where slots is != channels)
will manage 99 % of the cases. And the remaining 1% will concern people who need to hack the kernel so widely they don't care about the set_sysclk removal.
A patch from those people will be always welcome.
- fsl-asoc-card.c : *something will break since
snd_soc_dai_set_sysclk returned code is checked*
I've already submitted a patch to ignore all ENOTSUPP.
Nicolin, do you know what happened with this patch? I couldn't find it in current linux/master.
Has it been applied to any asoc tree for being upstreamed?
Best regards,
Lukasz Majewski
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On Sat, Nov 25, 2017 at 11:29:48PM +0100, Lukasz Majewski wrote:
Nicolin, do you know what happened with this patch? I couldn't find it in current linux/master.
Has it been applied to any asoc tree for being upstreamed?
A similar patch with an updated subject got applied: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?...
Hi Nicolin,
On Sat, Nov 25, 2017 at 11:29:48PM +0100, Lukasz Majewski wrote:
Nicolin, do you know what happened with this patch? I couldn't find it in current linux/master.
Has it been applied to any asoc tree for being upstreamed?
A similar patch with an updated subject got applied: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?...
Thanks for update - I was not aware of it.
Tested-by: Lukasz Majewski lukma@denx.de
HW: iMX6Q.
Best regards,
Lukasz Majewski
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participants (4)
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Arnaud Mouiche -
Lukasz Majewski -
Nicolin Chen -
Łukasz Majewski