diff mbox

ASoC: samsung: Allow setting OP_CLK of the IIS Multi Audio Interface

Message ID 1400520638-6907-1-git-send-email-s.nawrocki@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

This patch adds support for setting source clock of the "Core CLK"
of the IIS Multi Audio Interface.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
---
 sound/soc/samsung/i2s.c |    4 ++++
 sound/soc/samsung/i2s.h |    1 +
 2 files changed, 5 insertions(+)

Comments

Tushar Behera May 20, 2014, 5:14 a.m. UTC | #1
On 05/19/2014 11:00 PM, Sylwester Nawrocki wrote:
> This patch adds support for setting source clock of the "Core CLK"
> of the IIS Multi Audio Interface.
> 
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> ---
>  sound/soc/samsung/i2s.c |    4 ++++
>  sound/soc/samsung/i2s.h |    1 +
>  2 files changed, 5 insertions(+)
> 
> diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
> index 048ead9..ae02811 100644
> --- a/sound/soc/samsung/i2s.c
> +++ b/sound/soc/samsung/i2s.c
> @@ -451,6 +451,10 @@ static int i2s_set_sysclk(struct snd_soc_dai *dai,
>  	u32 mod = readl(i2s->addr + I2SMOD);
>  
>  	switch (clk_id) {
> +	case SAMSUNG_I2S_OPCLK:
> +		mod &= ~MOD_OPCLK_MASK;
> +		mod |= dir;

I am assuming here that dir is one of SND_SOC_CLOCK_IN or
SND_SOC_CLOCK_OUT. In that case, you need to take care of offset (30).

Also the value of this bit-field doesn't match with SND_SOC_CLOCK_XXX
macros.

Bit-field (2'b):
00	Codec Clock out
01	Codec Clock in
10	Bit clock out
11	Audio bus clock

Value of macros:
SND_SOC_CLOCK_IN	0
SND_SOC_CLOCK_OUT	1

In the manual, this field is suggested to be Audio bus clock always. Is
there an use-case where we might need to update this?

The default value for audio playback right now is 00 (2'b), which needs
to be fixed anyways.
On 20/05/14 07:14, Tushar Behera wrote:
> On 05/19/2014 11:00 PM, Sylwester Nawrocki wrote:
>> This patch adds support for setting source clock of the "Core CLK"
>> of the IIS Multi Audio Interface.
>>
>> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>> ---
>>  sound/soc/samsung/i2s.c |    4 ++++
>>  sound/soc/samsung/i2s.h |    1 +
>>  2 files changed, 5 insertions(+)
>>
>> diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
>> index 048ead9..ae02811 100644
>> --- a/sound/soc/samsung/i2s.c
>> +++ b/sound/soc/samsung/i2s.c
>> @@ -451,6 +451,10 @@ static int i2s_set_sysclk(struct snd_soc_dai *dai,
>>  	u32 mod = readl(i2s->addr + I2SMOD);
>>  
>>  	switch (clk_id) {
>> +	case SAMSUNG_I2S_OPCLK:
>> +		mod &= ~MOD_OPCLK_MASK;
>> +		mod |= dir;
> 
> I am assuming here that dir is one of SND_SOC_CLOCK_IN or
> SND_SOC_CLOCK_OUT. In that case, you need to take care of offset (30).

And that's not a correct assumption. I also got similarly confused when 
first seeing this in our downstream kernels. 'dir' is supposed to be one 
of the MOD_OPCLK_* constants, as defined in sound/soc/samsung/i2s-regs.h.

#define MOD_OPCLK_CDCLK_OUT	(0 << 30)
#define MOD_OPCLK_CDCLK_IN	(1 << 30)
#define MOD_OPCLK_BCLK_OUT	(2 << 30)
#define MOD_OPCLK_PCLK		(3 << 30)
#define MOD_OPCLK_MASK		(3 << 30)

So the clock is reconfigured with calls like:
snd_soc_dai_set_sysclk(cpu_dai, SAMSUNG_I2S_OPCLK, 0, MOD_OPCLK_PCLK);

> Also the value of this bit-field doesn't match with SND_SOC_CLOCK_XXX
> macros.
> 
> Bit-field (2'b):
> 00	Codec Clock out
> 01	Codec Clock in
> 10	Bit clock out
> 11	Audio bus clock
> 
> Value of macros:
> SND_SOC_CLOCK_IN	0
> SND_SOC_CLOCK_OUT	1

> In the manual, this field is suggested to be Audio bus clock always. Is
> there an use-case where we might need to update this?

I've checked couple boards and AFAICS we're always setting MOD_OPCLK_PCLK,
however it's still different from the default value after reset - 
MOD_OPCLK_CDCLK_OUT. 
So how do you think this should be addressed ? Isn't it better to give
options to the machine drivers to alter these clock settings, rather than
hard coding it in the I2S driver ? Let's not forget it covers multiple 
Samsung SoC series.

> The default value for audio playback right now is 00 (2'b), which needs
> to be fixed anyways.

--
Regards,
Sylwester
Tushar Behera May 20, 2014, 10:01 a.m. UTC | #3
On 05/20/2014 02:40 PM, Sylwester Nawrocki wrote:
> On 20/05/14 07:14, Tushar Behera wrote:
>> On 05/19/2014 11:00 PM, Sylwester Nawrocki wrote:
>>> This patch adds support for setting source clock of the "Core CLK"
>>> of the IIS Multi Audio Interface.
>>>
>>> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>>> ---
>>>  sound/soc/samsung/i2s.c |    4 ++++
>>>  sound/soc/samsung/i2s.h |    1 +
>>>  2 files changed, 5 insertions(+)
>>>
>>> diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
>>> index 048ead9..ae02811 100644
>>> --- a/sound/soc/samsung/i2s.c
>>> +++ b/sound/soc/samsung/i2s.c
>>> @@ -451,6 +451,10 @@ static int i2s_set_sysclk(struct snd_soc_dai *dai,
>>>  	u32 mod = readl(i2s->addr + I2SMOD);
>>>  
>>>  	switch (clk_id) {
>>> +	case SAMSUNG_I2S_OPCLK:
>>> +		mod &= ~MOD_OPCLK_MASK;
>>> +		mod |= dir;
>>
>> I am assuming here that dir is one of SND_SOC_CLOCK_IN or
>> SND_SOC_CLOCK_OUT. In that case, you need to take care of offset (30).
> 
> And that's not a correct assumption. I also got similarly confused when 
> first seeing this in our downstream kernels. 'dir' is supposed to be one 
> of the MOD_OPCLK_* constants, as defined in sound/soc/samsung/i2s-regs.h.
> 
> #define MOD_OPCLK_CDCLK_OUT	(0 << 30)
> #define MOD_OPCLK_CDCLK_IN	(1 << 30)
> #define MOD_OPCLK_BCLK_OUT	(2 << 30)
> #define MOD_OPCLK_PCLK		(3 << 30)
> #define MOD_OPCLK_MASK		(3 << 30)
> 
> So the clock is reconfigured with calls like:
> snd_soc_dai_set_sysclk(cpu_dai, SAMSUNG_I2S_OPCLK, 0, MOD_OPCLK_PCLK);
> 

Ok.

>> Also the value of this bit-field doesn't match with SND_SOC_CLOCK_XXX
>> macros.
>>
>> Bit-field (2'b):
>> 00	Codec Clock out
>> 01	Codec Clock in
>> 10	Bit clock out
>> 11	Audio bus clock
>>
>> Value of macros:
>> SND_SOC_CLOCK_IN	0
>> SND_SOC_CLOCK_OUT	1
> 
>> In the manual, this field is suggested to be Audio bus clock always. Is
>> there an use-case where we might need to update this?
> 
> I've checked couple boards and AFAICS we're always setting MOD_OPCLK_PCLK,
> however it's still different from the default value after reset - 
> MOD_OPCLK_CDCLK_OUT. 
> So how do you think this should be addressed ? Isn't it better to give
> options to the machine drivers to alter these clock settings, rather than
> hard coding it in the I2S driver ? Let's not forget it covers multiple 
> Samsung SoC series.
> 

I don't have any objection to this patch. Just that, I could not find
any use-case where we would not like to set the value as MOD_OPCLK_PCLK.

>> The default value for audio playback right now is 00 (2'b), which needs
>> to be fixed anyways.
> 
> --
> Regards,
> Sylwester
>
Mark Brown May 20, 2014, 10:10 a.m. UTC | #4
On Tue, May 20, 2014 at 11:10:08AM +0200, Sylwester Nawrocki wrote:

> So how do you think this should be addressed ? Isn't it better to give
> options to the machine drivers to alter these clock settings, rather than
> hard coding it in the I2S driver ? Let's not forget it covers multiple 
> Samsung SoC series.

Yes, it's better to make it controllable - ideally this could be moved
into the clock API but for ASoC level stuff set_sysclk() with a sensible
default is how it's supposed to be done.
Mark Brown May 20, 2014, 10:21 p.m. UTC | #5
On Mon, May 19, 2014 at 07:30:38PM +0200, Sylwester Nawrocki wrote:
> This patch adds support for setting source clock of the "Core CLK"
> of the IIS Multi Audio Interface.

Applied, thanks.
diff mbox

Patch

diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index 048ead9..ae02811 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -451,6 +451,10 @@  static int i2s_set_sysclk(struct snd_soc_dai *dai,
 	u32 mod = readl(i2s->addr + I2SMOD);
 
 	switch (clk_id) {
+	case SAMSUNG_I2S_OPCLK:
+		mod &= ~MOD_OPCLK_MASK;
+		mod |= dir;
+		break;
 	case SAMSUNG_I2S_CDCLK:
 		/* Shouldn't matter in GATING(CLOCK_IN) mode */
 		if (dir == SND_SOC_CLOCK_IN)
diff --git a/sound/soc/samsung/i2s.h b/sound/soc/samsung/i2s.h
index 7966afc..21ff24e 100644
--- a/sound/soc/samsung/i2s.h
+++ b/sound/soc/samsung/i2s.h
@@ -18,5 +18,6 @@ 
 #define SAMSUNG_I2S_RCLKSRC_0	0
 #define SAMSUNG_I2S_RCLKSRC_1	1
 #define SAMSUNG_I2S_CDCLK		2
+#define SAMSUNG_I2S_OPCLK		3
 
 #endif /* __SND_SOC_SAMSUNG_I2S_H */