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Subject[PATCH 5.10 294/563] ASoC: fsl_asrc: refine the check of available clock divider
Date
From: Shengjiu Wang <shengjiu.wang@nxp.com>

[ Upstream commit 320386343451ab6a3577e0ee200dac56a6182944 ]

According to RM, the clock divider range is from 1 to 8, clock
prescaling ratio may be any power of 2 from 1 to 128.
So the supported divider is not all the value between
1 and 1024, just limited value in that range.

Create table for the supported divder and add function to
check the clock divider is available by comparing with
the table.

Fixes: d0250cf4f2ab ("ASoC: fsl_asrc: Add an option to select internal ratio mode")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1641380883-20709-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/soc/fsl/fsl_asrc.c | 69 +++++++++++++++++++++++++++++++++-------
1 file changed, 58 insertions(+), 11 deletions(-)

diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c
index 02c81d2e34ad0..5e3c71f025f45 100644
--- a/sound/soc/fsl/fsl_asrc.c
+++ b/sound/soc/fsl/fsl_asrc.c
@@ -19,6 +19,7 @@
#include "fsl_asrc.h"

#define IDEAL_RATIO_DECIMAL_DEPTH 26
+#define DIVIDER_NUM 64

#define pair_err(fmt, ...) \
dev_err(&asrc->pdev->dev, "Pair %c: " fmt, 'A' + index, ##__VA_ARGS__)
@@ -101,6 +102,55 @@ static unsigned char clk_map_imx8qxp[2][ASRC_CLK_MAP_LEN] = {
},
};

+/*
+ * According to RM, the divider range is 1 ~ 8,
+ * prescaler is power of 2 from 1 ~ 128.
+ */
+static int asrc_clk_divider[DIVIDER_NUM] = {
+ 1, 2, 4, 8, 16, 32, 64, 128, /* divider = 1 */
+ 2, 4, 8, 16, 32, 64, 128, 256, /* divider = 2 */
+ 3, 6, 12, 24, 48, 96, 192, 384, /* divider = 3 */
+ 4, 8, 16, 32, 64, 128, 256, 512, /* divider = 4 */
+ 5, 10, 20, 40, 80, 160, 320, 640, /* divider = 5 */
+ 6, 12, 24, 48, 96, 192, 384, 768, /* divider = 6 */
+ 7, 14, 28, 56, 112, 224, 448, 896, /* divider = 7 */
+ 8, 16, 32, 64, 128, 256, 512, 1024, /* divider = 8 */
+};
+
+/*
+ * Check if the divider is available for internal ratio mode
+ */
+static bool fsl_asrc_divider_avail(int clk_rate, int rate, int *div)
+{
+ u32 rem, i;
+ u64 n;
+
+ if (div)
+ *div = 0;
+
+ if (clk_rate == 0 || rate == 0)
+ return false;
+
+ n = clk_rate;
+ rem = do_div(n, rate);
+
+ if (div)
+ *div = n;
+
+ if (rem != 0)
+ return false;
+
+ for (i = 0; i < DIVIDER_NUM; i++) {
+ if (n == asrc_clk_divider[i])
+ break;
+ }
+
+ if (i == DIVIDER_NUM)
+ return false;
+
+ return true;
+}
+
/**
* fsl_asrc_sel_proc - Select the pre-processing and post-processing options
* @inrate: input sample rate
@@ -330,12 +380,12 @@ static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair, bool use_ideal_rate)
enum asrc_word_width input_word_width;
enum asrc_word_width output_word_width;
u32 inrate, outrate, indiv, outdiv;
- u32 clk_index[2], div[2], rem[2];
+ u32 clk_index[2], div[2];
u64 clk_rate;
int in, out, channels;
int pre_proc, post_proc;
struct clk *clk;
- bool ideal;
+ bool ideal, div_avail;

if (!config) {
pair_err("invalid pair config\n");
@@ -415,8 +465,7 @@ static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair, bool use_ideal_rate)
clk = asrc_priv->asrck_clk[clk_index[ideal ? OUT : IN]];

clk_rate = clk_get_rate(clk);
- rem[IN] = do_div(clk_rate, inrate);
- div[IN] = (u32)clk_rate;
+ div_avail = fsl_asrc_divider_avail(clk_rate, inrate, &div[IN]);

/*
* The divider range is [1, 1024], defined by the hardware. For non-
@@ -425,7 +474,7 @@ static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair, bool use_ideal_rate)
* only result in different converting speeds. So remainder does not
* matter, as long as we keep the divider within its valid range.
*/
- if (div[IN] == 0 || (!ideal && (div[IN] > 1024 || rem[IN] != 0))) {
+ if (div[IN] == 0 || (!ideal && !div_avail)) {
pair_err("failed to support input sample rate %dHz by asrck_%x\n",
inrate, clk_index[ideal ? OUT : IN]);
return -EINVAL;
@@ -436,13 +485,12 @@ static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair, bool use_ideal_rate)
clk = asrc_priv->asrck_clk[clk_index[OUT]];
clk_rate = clk_get_rate(clk);
if (ideal && use_ideal_rate)
- rem[OUT] = do_div(clk_rate, IDEAL_RATIO_RATE);
+ div_avail = fsl_asrc_divider_avail(clk_rate, IDEAL_RATIO_RATE, &div[OUT]);
else
- rem[OUT] = do_div(clk_rate, outrate);
- div[OUT] = clk_rate;
+ div_avail = fsl_asrc_divider_avail(clk_rate, outrate, &div[OUT]);

/* Output divider has the same limitation as the input one */
- if (div[OUT] == 0 || (!ideal && (div[OUT] > 1024 || rem[OUT] != 0))) {
+ if (div[OUT] == 0 || (!ideal && !div_avail)) {
pair_err("failed to support output sample rate %dHz by asrck_%x\n",
outrate, clk_index[OUT]);
return -EINVAL;
@@ -621,8 +669,7 @@ static void fsl_asrc_select_clk(struct fsl_asrc_priv *asrc_priv,
clk_index = asrc_priv->clk_map[j][i];
clk_rate = clk_get_rate(asrc_priv->asrck_clk[clk_index]);
/* Only match a perfect clock source with no remainder */
- if (clk_rate != 0 && (clk_rate / rate[j]) <= 1024 &&
- (clk_rate % rate[j]) == 0)
+ if (fsl_asrc_divider_avail(clk_rate, rate[j], NULL))
break;
}

--
2.34.1


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