Messages in this thread | | | Date | Thu, 04 Dec 2014 09:13:01 +0000 | From | Andrew Jackson <> | Subject | Re: [PATCH 3/5] ASoC: dwc: Iterate over all channels |
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On 12/04/14 06:55, rajeev kumar wrote: > On Wed, Dec 3, 2014 at 10:59 PM, Mark Brown <broonie@kernel.org> wrote: >> On Wed, Dec 03, 2014 at 04:39:01PM +0000, Andrew Jackson wrote: >> >>> + /* Iterate over set of channels - independently controlled. >>> + */ >>> + do { >>> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { >>> + i2s_write_reg(dev->i2s_base, TCR(ch_reg), >>> + xfer_resolution); >>> + i2s_write_reg(dev->i2s_base, TFCR(ch_reg), 0x02); >>> + irq = i2s_read_reg(dev->i2s_base, IMR(ch_reg)); >>> + i2s_write_reg(dev->i2s_base, IMR(ch_reg), irq & ~0x30); >>> + i2s_write_reg(dev->i2s_base, TER(ch_reg), 1); >>> + } else { >>> + i2s_write_reg(dev->i2s_base, RCR(ch_reg), >>> + xfer_resolution); >>> + i2s_write_reg(dev->i2s_base, RFCR(ch_reg), 0x07); >>> + irq = i2s_read_reg(dev->i2s_base, IMR(ch_reg)); >>> + i2s_write_reg(dev->i2s_base, IMR(ch_reg), irq & ~0x03); >>> + i2s_write_reg(dev->i2s_base, RER(ch_reg), 1); >>> + } >>> + } while (ch_reg-- > 0); >> >> The normal way to write an iteration would be with a for loop - why are >> we not doing that? >> >> Also I see that you've not sent these as a single thread - please use >> --thread. > > designware i2s has individual register for channel support. It is like > TCR(0), TCR(1) and so on.. So a macro is defined to capture these > please check below #define > > #define TCR(x) (0x40 * x + 0x034) > > and the same is true for capture also. So there is no need for > iteration. Only writing to the particular register will do the work.
However params_channels returns the number of channels that the device needs to configure. So, for example, when there are four channels two sets of channel registers need to be programmed.
Andrew > > ~Rajeev >
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