| Message ID | 20200716151352.193451-2-arnaud.ferraris@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ASoC: fsl_asrc: improve clock selection and quality | expand |
On Thu, Jul 16, 2020 at 05:13:52PM +0200, Arnaud Ferraris wrote: > The current clock selection algorithm might select the same clock for > both input and output. This can happen when, for instance, the output > sample rate is a multiple of the input rate. What's the issue when selecting the same clock source for both input and output? Please explain it in the commit logs. > This patch makes sure it always selects distinct input and output > clocks. > > Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com> > --- > sound/soc/fsl/fsl_asrc.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c > index 02c81d2e34ad..6d43cab6c885 100644 > --- a/sound/soc/fsl/fsl_asrc.c > +++ b/sound/soc/fsl/fsl_asrc.c > @@ -608,8 +608,8 @@ static void fsl_asrc_select_clk(struct fsl_asrc_priv *asrc_priv, > { > struct fsl_asrc_pair_priv *pair_priv = pair->private; > struct asrc_config *config = pair_priv->config; > - int rate[2], select_clk[2]; /* Array size 2 means IN and OUT */ > - int clk_rate, clk_index; > + int rate[2], select_clk[2], clk_index[2]; /* Array size 2 means IN and OUT */ > + int clk_rate; > int i = 0, j = 0; > > rate[IN] = in_rate; > @@ -618,11 +618,12 @@ static void fsl_asrc_select_clk(struct fsl_asrc_priv *asrc_priv, > /* Select proper clock source for internal ratio mode */ > for (j = 0; j < 2; j++) { > for (i = 0; i < ASRC_CLK_MAP_LEN; i++) { > - clk_index = asrc_priv->clk_map[j][i]; > - clk_rate = clk_get_rate(asrc_priv->asrck_clk[clk_index]); > + clk_index[j] = asrc_priv->clk_map[j][i]; > + clk_rate = clk_get_rate(asrc_priv->asrck_clk[clk_index[j]]); > /* Only match a perfect clock source with no remainder */ Better to update the comments here as there's a new condition. > if (clk_rate != 0 && (clk_rate / rate[j]) <= 1024 && > - (clk_rate % rate[j]) == 0) > + (clk_rate % rate[j]) == 0 && > + (j == 0 || clk_index[j] != clk_index[j-1])) clk_index[j - 1]
diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c index 02c81d2e34ad..6d43cab6c885 100644 --- a/sound/soc/fsl/fsl_asrc.c +++ b/sound/soc/fsl/fsl_asrc.c @@ -608,8 +608,8 @@ static void fsl_asrc_select_clk(struct fsl_asrc_priv *asrc_priv, { struct fsl_asrc_pair_priv *pair_priv = pair->private; struct asrc_config *config = pair_priv->config; - int rate[2], select_clk[2]; /* Array size 2 means IN and OUT */ - int clk_rate, clk_index; + int rate[2], select_clk[2], clk_index[2]; /* Array size 2 means IN and OUT */ + int clk_rate; int i = 0, j = 0; rate[IN] = in_rate; @@ -618,11 +618,12 @@ static void fsl_asrc_select_clk(struct fsl_asrc_priv *asrc_priv, /* Select proper clock source for internal ratio mode */ for (j = 0; j < 2; j++) { for (i = 0; i < ASRC_CLK_MAP_LEN; i++) { - clk_index = asrc_priv->clk_map[j][i]; - clk_rate = clk_get_rate(asrc_priv->asrck_clk[clk_index]); + clk_index[j] = asrc_priv->clk_map[j][i]; + clk_rate = clk_get_rate(asrc_priv->asrck_clk[clk_index[j]]); /* Only match a perfect clock source with no remainder */ if (clk_rate != 0 && (clk_rate / rate[j]) <= 1024 && - (clk_rate % rate[j]) == 0) + (clk_rate % rate[j]) == 0 && + (j == 0 || clk_index[j] != clk_index[j-1])) break; }
The current clock selection algorithm might select the same clock for both input and output. This can happen when, for instance, the output sample rate is a multiple of the input rate. This patch makes sure it always selects distinct input and output clocks. Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com> --- sound/soc/fsl/fsl_asrc.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)