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