Re: [alsa-devel] [PATCH v4 3/7] ASoC: tegra: i2s: Add support for more than 2 channels

[Jon Hunter <jonathanh@nvidia.com>]

On 17/10/2019 18:38, Dmitry Osipenko wrote:
> 17.10.2019 19:23, Ben Dooks пишет:
>> On 08/10/2019 16:29, Dmitry Osipenko wrote:
>>> Hello Ben,
>>>
>>> 07.10.2019 18:31, Ben Dooks пишет:
>>>> From: Edward Cragg <edward.cragg@codethink.co.uk>
>>>>
>>>> The CIF configuration and clock setting is currently hard coded for 2
>>>> channels. Since the hardware is capable of supporting 1-8 channels add
>>>> support for reading the channel count from the supplied parameters to
>>>> allow for better TDM support. It seems the original implementation of
>>>> this
>>>> driver was fixed at 2 channels for simplicity, and not implementing TDM.
>>>>
>>>> Signed-off-by: Edward Cragg <edward.cragg@codethink.co.uk>
>>>> [ben.dooks@codethink.co.uk: added is_tdm and channel nr check]
>>>> [ben.dooks@codethink.co.uk: merge edge control into set-format]
>>>> [ben.dooks@codethink.co.uk: removed is_tdm and moved edge to hw_params]
>>>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
>>>> ---
>>>>   sound/soc/tegra/tegra30_i2s.c | 21 +++++++++++++--------
>>>>   1 file changed, 13 insertions(+), 8 deletions(-)
>>>>
>>>> diff --git a/sound/soc/tegra/tegra30_i2s.c
>>>> b/sound/soc/tegra/tegra30_i2s.c
>>>> index 063f34c882af..7382f7949bf4 100644
>>>> --- a/sound/soc/tegra/tegra30_i2s.c
>>>> +++ b/sound/soc/tegra/tegra30_i2s.c
>>>> @@ -67,6 +67,7 @@ static int tegra30_i2s_set_fmt(struct snd_soc_dai
>>>> *dai,
>>>>   {
>>>>       struct tegra30_i2s *i2s = snd_soc_dai_get_drvdata(dai);
>>>>       unsigned int mask = 0, val = 0;
>>>> +    unsigned int ch_mask, ch_val = 0;
>>>>         switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
>>>>       case SND_SOC_DAIFMT_NB_NF:
>>>> @@ -75,6 +76,7 @@ static int tegra30_i2s_set_fmt(struct snd_soc_dai
>>>> *dai,
>>>>           return -EINVAL;
>>>>       }
>>>>   +    ch_mask = TEGRA30_I2S_CH_CTRL_EGDE_CTRL_MASK;
>>>>       mask |= TEGRA30_I2S_CTRL_MASTER_ENABLE;
>>>>       switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
>>>>       case SND_SOC_DAIFMT_CBS_CFS:
>>>> @@ -90,10 +92,12 @@ static int tegra30_i2s_set_fmt(struct snd_soc_dai
>>>> *dai,
>>>>           TEGRA30_I2S_CTRL_LRCK_MASK;
>>>>       switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
>>>>       case SND_SOC_DAIFMT_DSP_A:
>>>> +        ch_val = TEGRA30_I2S_CH_CTRL_EGDE_CTRL_NEG_EDGE;
>>>>           val |= TEGRA30_I2S_CTRL_FRAME_FORMAT_FSYNC;
>>>>           val |= TEGRA30_I2S_CTRL_LRCK_L_LOW;
>>>>           break;
>>>>       case SND_SOC_DAIFMT_DSP_B:
>>>> +        ch_val = TEGRA30_I2S_CH_CTRL_EGDE_CTRL_NEG_EDGE;
>>>
>>> Downstream code sets DSP_B to POS_EDGE, looks like you have a typo here.
>>> Or does DSP_B happen to work with the NEG_EDGE?
>>
>> ok, will change, we've only been using SND_SOC_DAIFMT_DSP_A
>>
>> For reference, is there a git repo with this version of tegra tdm support?
> 
> Looks like all downstream kernels that supported T30 are doing the same
> thing.
> 
> Take a look here for example:
> 
> https://nv-tegra.nvidia.com/gitweb/?p=linux-3.10.git;a=commit;h=49834eef9d51a6eff950e0f52ddc5343d960652e

That version of the driver is known to be buggy/incorrect. I don't think
we want to do that. We want to set the polarity based upon the format
passed and not the mode ...

https://nv-tegra.nvidia.com/gitweb/?p=linux-nvidia.git;a=blob;f=sound/soc/tegra-alt/tegra210_i2s_alt.c;h=24cf3b55326f687aded22b91182df41c5ae188ac;hb=703aa948d2c92b87fd84f367f43a07778ed098b5#l333

Jon

-- 
nvpublic
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