[PATCH] ASoC: fsl_asrc: refine the check of available clock divider

[PATCH] ASoC: fsl_asrc: refine the check of available clock divider

[Shengjiu Wang]

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>
---
 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 24b41881a68f..d7d1536a4f37 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;
 		}
 
-- 
2.17.1

Re: [PATCH] ASoC: fsl_asrc: refine the check of available clock divider

[Mark Brown]

On Wed, 5 Jan 2022 19:08:03 +0800, Shengjiu Wang wrote:
> 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.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: fsl_asrc: refine the check of available clock divider
      commit: 320386343451ab6a3577e0ee200dac56a6182944

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

Re: [PATCH] ASoC: fsl_asrc: refine the check of available clock divider

[Mark Brown]

On Wed, 5 Jan 2022 19:08:03 +0800, Shengjiu Wang wrote:
> 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.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: fsl_asrc: refine the check of available clock divider
      commit: 320386343451ab6a3577e0ee200dac56a6182944

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark