On Wed, 2009-11-04 at 18:55 +0000, Graeme Gregory wrote:
> On Wed, Nov 04, 2009 at 05:53:55PM +0000, Liam Girdwood wrote:
> > From: Graeme Gregory <gg@xxxxxxxxxxxxxxx>
> >
> > This patch increases the number of supported audio channels from 4
> > to 16 and was sponsored by Shotspotter inc.
> >
> > Signed-off-by: Graeme Gregory <gg@xxxxxxxxxxxxxxx>
> > Signed-off-by: Liam Girdwood <lrg@xxxxxxxxxxxxxxx>
> > + /* Default div to 1 if it wasn't set by machine driver, otherwise
> > + * use set div as the maximum clock value
> > + */
> > + div = mcbsp_data->clk_div ? mcbsp_data->clk_div : 1;
> > +
> > + /* calc best frame size for rate and clock divider */
> > + do {
> > + frame_size = (mcbsp_data->in_freq / div) / params_rate(params);
> > + pr_debug("freq %d, rate %d, frame size %d, div %d\n",
> > + mcbsp_data->in_freq, params_rate(params), frame_size, div);
> > +
> > + if (frame_size > 256)
> > + div++;
> > + } while (frame_size > 256);
> > +
> > + /* Check we can fit the requested number of channels into our
> > + * calculated frame size
> > + */
> > + if ((channels * wlen) > frame_size) {
> > + printk(KERN_ERR
> > + "OMAP-MCBSP: cannot fit channels in frame size\n");
> > + return -EINVAL;
> > + }
> > +
> > + /* Set the actual clkdiv to use for this samplerate */
> > + regs->srgr1 &= ~CLKGDV(0xFF);
> > + regs->srgr1 |= CLKGDV(div - 1);
> > +
>
> This chunk changes the semantics of other devices which I have never tested.
>
> I also dont know how much damage it does if it does to slave mode. In fact
> I think it might break it in cases which are actually allowable as it uses
> the omap as its clock constraint and not the clock source.
>
Btw, this has been reworked to avoid all I2S paths since you last worked
on it.
So it looks like we need a conditional around this block for when the
codec is mastering BCLK/FRM and MCBSP is slave (as you stated above).
This will then use the original SRGR2 values for SND_SOC_DAIFMT_DSP_A/B
in codec master mode.
V2 will follow.
Liam
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