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

[Dmitry Osipenko]

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 at 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 at codethink.co.uk>
>>> [ben.dooks at codethink.co.uk: added is_tdm and channel nr check]
>>> [ben.dooks at codethink.co.uk: merge edge control into set-format]
>>> [ben.dooks at codethink.co.uk: removed is_tdm and moved edge to hw_params]
>>> Signed-off-by: Ben Dooks <ben.dooks at 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