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Subject[PATCH] ASoC: fsl_ssi: Fix the incorrect limitation of the bit clock rate
Date
According to i.MX Reference Manual, the bit-clock frequency generated
by SSI must be never greater than 1/5 of the peripheral clock frequency.

This peripheral clock, however, is not baudclk but the IPG clock (i.e.
ssi_private->clk in the fsl_ssi driver).

So this patch just simply fixes the incorrect limitation applied to
the bit clock (baudclk) rate.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
sound/soc/fsl/fsl_ssi.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index 059496e..d7365c5 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -603,10 +603,6 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream,
factor = (div2 + 1) * (7 * psr + 1) * 2;

for (i = 0; i < 255; i++) {
- /* The bclk rate must be smaller than 1/5 sysclk rate */
- if (factor * (i + 1) < 5)
- continue;
-
tmprate = freq * factor * (i + 2);

if (baudclk_is_used)
@@ -614,6 +610,13 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream,
else
clkrate = clk_round_rate(ssi_private->baudclk, tmprate);

+ /*
+ * Hardware limitation: The bclk rate must be
+ * never greater than 1/5 IPG clock rate
+ */
+ if (clkrate * 5 > clk_get_rate(ssi_private->clk))
+ continue;
+
clkrate /= factor;
afreq = clkrate / (i + 1);

--
1.9.1


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