[alsa-devel] [PATCH v7 1/2] ASoC: fsl: Add S/PDIF CPU DAI driver
mark.rutland at arm.com
Tue Aug 20 10:47:32 CEST 2013
On Mon, Aug 19, 2013 at 12:34:08PM +0100, Nicolin Chen wrote:
> On Mon, Aug 19, 2013 at 12:13:49PM +0100, Mark Rutland wrote:
> > > > > > > + "rxtx<0-7>" Clock source list for tx and rx clock.
> > > > > > > + This clock list should be identical to
> > > > > > > + the source list connecting to the spdif
> > > > > > > + clock mux in "SPDIF Transceiver Clock
> > > > > > > + Diagram" of SoC reference manual. It
> > > > > > > + can also be referred to TxClk_Source
> > > > > > > + bit of register SPDIF_STC.
> > > Actually there's a clock mux for TxClk and it's connecting with 8 clock
> > > sources. So the TxClk_Source bit show the connection between its value
> > > with the correspond source on the clock mux:
> > >
> > > TxClk_Source 000 XTAL clk input
> > > 001 CCM spdif0_clk_root input
> > > 010 asrc_clk input
> > > 011 spdif_extclk input, from pads
> > > 100 esai_hckt input
> > > 101 frequency divided ipg_clk input
> > > 110 mlb_clk input
> > > 111 mlb phy clk input
> > Ah. So are these the actual input names on the mux, or the names of the
> > outputs that are wired up to the mux? If the former, these may be better
> > clock-names than rxtx<0-7>.
> The clock names are actually different with different SoC. The list above
> is only for i.MX6Q. So we can't specify these names here, because the driver
> then would need to maintain a clock names list for different SoC as well.
Ok. I was working on the assumption there were some logical input names
on the mux that weren't just the names of the actual clocks wired into
> > Is there a similar Rx mux?
> Both Tx and RX clocks can be derived from the Tx mux.
> > Given the "rxtx<0-7>" names you've given these clocks, are there 8 clock
> > inputs that get duplicated within the spdif block and fed into both
> > muxes, or are there 16 external inputs that happen to be two groups of 8
> > identical sets of clocks in systems so far?
> I think you can refer to the RM, since you just got it. The diagram doesn't
> show which one you mentioned is true. But I think we can understand in both
> I'm going to send a v8. So I think I don't need to modify the description
>From the sounds of it, no.
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