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From:   Mario Limonciello <mario.limonciello@amd.com>
To:     Jaroslav Kysela <jkysela@redhat.com>,
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        Mark Brown <broonie@kernel.org>,
        "Jaroslav Kysela" <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
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Subject: [PATCH v2 2/6] ASoC: amd: yc: Add a module parameter to influence pdm_gain
Date:   Mon, 30 Jan 2023 16:07:50 -0600
Message-ID: <20230130220754.8379-3-mario.limonciello@amd.com>
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In case of regressions for any users that the new pdm_gain value is
too high and for additional debugging, introduce a module parameter
that would let them configure it.

This parameter should be removed in the future:
 * If it's determined that the parameter is not needed, just hardcode
   the correct value as before
 * If users do end up using it to debug and report different values
   we should introduce a config knob that can have policy set by ucm.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v1->v2:
 * Add a guard for values > 3 to overflow the FIELD_PREP
 * Clear ACP_WOV_GAIN_CONTROL before setting it
---
 sound/soc/amd/yc/acp6x-pdm-dma.c | 10 +++++++++-
 sound/soc/amd/yc/acp6x.h         |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/sound/soc/amd/yc/acp6x-pdm-dma.c b/sound/soc/amd/yc/acp6x-pdm-dma.c
index acecd6a4ec4b1..2bb3ea14bae9c 100644
--- a/sound/soc/amd/yc/acp6x-pdm-dma.c
+++ b/sound/soc/amd/yc/acp6x-pdm-dma.c
@@ -7,6 +7,7 @@
 
 #include <linux/platform_device.h>
 #include <linux/module.h>
+#include <linux/bitfield.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <sound/pcm_params.h>
@@ -18,6 +19,10 @@
 
 #define DRV_NAME "acp_yc_pdm_dma"
 
+static int pdm_gain = 3;
+module_param(pdm_gain, int, 0644);
+MODULE_PARM_DESC(pdm_gain, "Gain control (0-3)");
+
 static const struct snd_pcm_hardware acp6x_pdm_hardware_capture = {
 	.info = SNDRV_PCM_INFO_INTERLEAVED |
 		SNDRV_PCM_INFO_BLOCK_TRANSFER |
@@ -55,7 +60,10 @@ static void acp6x_enable_pdm_clock(void __iomem *acp_base)
 
 	acp6x_writel(pdm_clk_enable, acp_base + ACP_WOV_CLK_CTRL);
 	pdm_ctrl = acp6x_readl(acp_base + ACP_WOV_MISC_CTRL);
-	pdm_ctrl |= ACP_WOV_MISC_CTRL_MASK;
+	pdm_ctrl &= FIELD_PREP(ACP_WOV_GAIN_CONTROL, 0);
+	if (pdm_gain > 3)
+		pdm_gain = 3;
+	pdm_ctrl |= FIELD_PREP(ACP_WOV_GAIN_CONTROL, pdm_gain);
 	acp6x_writel(pdm_ctrl, acp_base + ACP_WOV_MISC_CTRL);
 }
 
diff --git a/sound/soc/amd/yc/acp6x.h b/sound/soc/amd/yc/acp6x.h
index 846ca10e24d3f..036207568c048 100644
--- a/sound/soc/amd/yc/acp6x.h
+++ b/sound/soc/amd/yc/acp6x.h
@@ -31,7 +31,7 @@
 #define ACP_ERROR_STAT	29
 #define PDM_DECIMATION_FACTOR	2
 #define ACP_PDM_CLK_FREQ_MASK	7
-#define ACP_WOV_MISC_CTRL_MASK	0x18
+#define ACP_WOV_GAIN_CONTROL	GENMASK(4, 3)
 #define ACP_PDM_ENABLE		1
 #define ACP_PDM_DISABLE		0
 #define ACP_PDM_DMA_EN_STATUS	2
-- 
2.34.1