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ASoC: rockchip: pdm: Allow mclk shift around 1 ppm

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This patch allow mclk shift around +/- 1ppm compared to
requested freq.

we could not always achieve the precise freq as required,
e.g. request: 98304000, but got: 98303999

there is no big deal and any side effect on the above case,
so, we allow a tiny shift for mclk.

Signed-off-by: Sugar Zhang <sugar.zhang@rock-chips.com>
Change-Id: I8da91e467cfc0306fa9069ab30079d5ddf1c0336
This commit is contained in:
Sugar Zhang
2022-10-12 11:42:17 +08:00
committed by Tao Huang
parent a8de4e09e2
commit 10b63561fc
1 changed files with 5 additions and 2 deletions
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7
sound/soc/rockchip/rockchip_pdm.c
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@@ -28,6 +28,7 @@
#define PDM_START_DELAY_MS_MAX (1000)
#define PDM_FILTER_DELAY_MS_MIN (20)
#define PDM_FILTER_DELAY_MS_MAX (1000)
#define PDM_CLK_SHIFT_PPM_MAX (1000000) /* 1 ppm */
enum rk_pdm_version {
RK_PDM_RK3229,
@@ -89,7 +90,7 @@ static unsigned int get_pdm_clk(struct rk_pdm_dev *pdm, unsigned int sr,
unsigned int *clk_src, unsigned int *clk_out,
unsigned int signoff)
{
unsigned int i, count, clk, div, rate;
unsigned int i, count, clk, div, rate, delta;
clk = 0;
if (!sr)
@@ -103,7 +104,9 @@ static unsigned int get_pdm_clk(struct rk_pdm_dev *pdm, unsigned int sr,
if ((div & (div - 1)) == 0) {
*clk_out = clkref[i].clk_out;
rate = clk_round_rate(pdm->clk, clkref[i].clk);
if (rate != clkref[i].clk)
delta = clkref[i].clk / PDM_CLK_SHIFT_PPM_MAX;
if (rate < clkref[i].clk - delta ||
rate > clkref[i].clk + delta)
continue;
clk = clkref[i].clk;
*clk_src = clkref[i].clk;