Hi Eric, Em Ter, 2009-06-09 às 17:39 +0800, Eric Miao escreveu: > frame_width = sample_width * channel ( = LRCLK for I2S ) > > is no longer (and ever) correct. > > E.g. the frame width could be 64fs, meaning a whole frame is > consisting > of 64 bitclks - that's saying, sample width from 1 - 64 are possible, > For typical 16-bit sample width I2S format, the envelope for each > sample > is 32 bitclks, and offseting by 1 bitclk starts the 16-bit sample. I'm working on supporting I2S right now, and I found some issues with this enveloping thing. First, it doesn't work on pxa2xx. DMYSTOP on pxa2xx is only 0-3. Second, is enveloping needed at all? The patch you sent supports 32bits frames for 2*16bits samples or 64bits frames for 2*32bits samples using FSRT. We already use FSRT for DSP_A, and if this works on littleton I2S we should just stick with FSRT (and frame_width = sample_width * channels) to keep the code simple. > And the TDM mode is actually special for PXA-SSP to emulate the I2S > protocol, it's no way generic TDM in a common sense. So talking about > set_tdm_slots(), I'd really like to hide into the format setting code > of I2S/Left_J to avoid further confusion. TDM is needed for frames larger than 32 bits on any dai format. Its not something specific to I2S. -- Daniel Ribeiro
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