/* Only used for Ideal Ratio mode */
static int asrc_set_clock_ratio(enum asrc_pair_index index,
int inrate, int outrate)
{
unsigned long val = 0;
int integ, i;
if (outrate == 0) {
dev_err(asrc->dev, "wrong output sample rate: %d\n", outrate);
return -EINVAL;
}
/* Formula: r = (1 << ASRC_RATIO_DECIMAL_DEPTH) / outrate * inrate; */
for (integ = 0; inrate >= outrate; integ++)
inrate -= outrate;
val |= (integ << ASRC_RATIO_DECIMAL_DEPTH);
for (i = 1; i <= ASRC_RATIO_DECIMAL_DEPTH; i++) {
if ((inrate * 2) >= outrate) {
val |= (1 << (ASRC_RATIO_DECIMAL_DEPTH - i));
inrate = inrate * 2 - outrate;
} else
inrate = inrate << 1;
if (inrate == 0)
break;
}
regmap_write(asrc->regmap, REG_ASRIDRL(index), val);
regmap_write(asrc->regmap, REG_ASRIDRH(index), (val >> 24));
return 0;
}
/**
* Calculate and set the ratio for Ideal Ratio mode only
*
* The ratio is a 32-bit fixed point value with 26 fractional bits.
*/
static int fsl_asrc_set_ideal_ratio(struct fsl_asrc_pair *pair,
int inrate, int outrate)
{
struct fsl_asrc *asrc_priv = pair->asrc_priv;
enum asrc_pair_index index = pair->index;
unsigned long ratio;
int i;
if (!outrate) {
pair_err("output rate should not be zero\n");
return -EINVAL;
}
/* Calculate the intergal part of the ratio */
ratio = (inrate / outrate) << IDEAL_RATIO_DECIMAL_DEPTH;
/* ... and then the 26 depth decimal part */
inrate %= outrate;
for (i = 1; i <= IDEAL_RATIO_DECIMAL_DEPTH; i++) {
inrate <<= 1;
if (inrate < outrate)
continue;
ratio |= 1 << (IDEAL_RATIO_DECIMAL_DEPTH - i);
inrate -= outrate;
if (!inrate)
break;
}
regmap_write(asrc_priv->regmap, REG_ASRIDRL(index), ratio);
regmap_write(asrc_priv->regmap, REG_ASRIDRH(index), ratio >> 24);
return 0;
}