linux-kernel - [PATCH 01/11] ASoC: cs35l56: Read silicon ID during initialization and save it

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Message-ID: <20251016104242.157325-2-rf@opensource.cirrus.com>
Date: Thu, 16 Oct 2025 11:42:32 +0100
From: Richard Fitzgerald <rf@...nsource.cirrus.com>
To: broonie@...nel.org, tiwai@...e.com
Cc: linux-sound@...r.kernel.org, linux-kernel@...r.kernel.org,
        patches@...nsource.cirrus.com
Subject: [PATCH 01/11] ASoC: cs35l56: Read silicon ID during initialization and save it

Read the silicon ID from the amp during one-time cs35l56_hw_init()
and store it in struct cs35l56_base, instead of reading it from
registers every time it is needed.

Note that marking it non-volatile without a default in regmap isn't
a suitable alternative because this causes regcache_sync() to always
write the cached value out to the registers. This could trigger a bus
fault interrupt inside the amp, which we want to avoid.

Signed-off-by: Richard Fitzgerald <rf@...nsource.cirrus.com>
---
 include/sound/cs35l56.h           |  1 +
 sound/soc/codecs/cs35l56-shared.c | 53 +++++++++++++++----------------
 2 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/include/sound/cs35l56.h b/include/sound/cs35l56.h
index ab044ce2aa8b..ec9b1072d6be 100644
--- a/include/sound/cs35l56.h
+++ b/include/sound/cs35l56.h
@@ -309,6 +309,7 @@ struct cs35l56_base {
 	struct cs35l56_spi_payload *spi_payload_buf;
 	const struct cs35l56_fw_reg *fw_reg;
 	const struct cirrus_amp_cal_controls *calibration_controls;
+	u64 silicon_uid;
 };
 
 static inline bool cs35l56_is_otp_register(unsigned int reg)
diff --git a/sound/soc/codecs/cs35l56-shared.c b/sound/soc/codecs/cs35l56-shared.c
index 9e6b9ca2f354..1ecfc38d8eb4 100644
--- a/sound/soc/codecs/cs35l56-shared.c
+++ b/sound/soc/codecs/cs35l56-shared.c
@@ -853,7 +853,7 @@ struct cs35l56_pte {
 } __packed;
 static_assert((sizeof(struct cs35l56_pte) % sizeof(u32)) == 0);
 
-static int cs35l56_read_silicon_uid(struct cs35l56_base *cs35l56_base, u64 *uid)
+static int cs35l56_read_silicon_uid(struct cs35l56_base *cs35l56_base)
 {
 	struct cs35l56_pte pte;
 	u64 unique_id;
@@ -870,14 +870,15 @@ static int cs35l56_read_silicon_uid(struct cs35l56_base *cs35l56_base, u64 *uid)
 	unique_id |= (u32)pte.x | ((u32)pte.y << 8) | ((u32)pte.wafer_id << 16) |
 		     ((u32)pte.dvs << 24);
 
-	*uid = unique_id;
+	cs35l56_base->silicon_uid = unique_id;
 
 	return 0;
 }
 
-static int cs35l63_read_silicon_uid(struct cs35l56_base *cs35l56_base, u64 *uid)
+static int cs35l63_read_silicon_uid(struct cs35l56_base *cs35l56_base)
 {
 	u32 tmp[2];
+	u64 unique_id;
 	int ret;
 
 	ret = regmap_bulk_read(cs35l56_base->regmap, CS35L56_DIE_STS1, tmp, ARRAY_SIZE(tmp));
@@ -886,9 +887,11 @@ static int cs35l63_read_silicon_uid(struct cs35l56_base *cs35l56_base, u64 *uid)
 		return ret;
 	}
 
-	*uid = tmp[1];
-	*uid <<= 32;
-	*uid |= tmp[0];
+	unique_id = tmp[1];
+	unique_id <<= 32;
+	unique_id |= tmp[0];
+
+	cs35l56_base->silicon_uid = unique_id;
 
 	return 0;
 }
@@ -915,33 +918,14 @@ static const struct cirrus_amp_cal_controls cs35l63_calibration_controls = {
 
 int cs35l56_get_calibration(struct cs35l56_base *cs35l56_base)
 {
-	u64 silicon_uid = 0;
 	int ret;
 
 	/* Driver can't apply calibration to a secured part, so skip */
 	if (cs35l56_base->secured)
 		return 0;
 
-	switch (cs35l56_base->type) {
-	case 0x54:
-	case 0x56:
-	case 0x57:
-		ret = cs35l56_read_silicon_uid(cs35l56_base, &silicon_uid);
-		break;
-	case 0x63:
-		ret = cs35l63_read_silicon_uid(cs35l56_base, &silicon_uid);
-		break;
-	default:
-		ret = -ENODEV;
-		break;
-	}
-
-	if (ret < 0)
-		return ret;
-
-	dev_dbg(cs35l56_base->dev, "UniqueID = %#llx\n", silicon_uid);
-
-	ret = cs_amp_get_efi_calibration_data(cs35l56_base->dev, silicon_uid,
+	ret = cs_amp_get_efi_calibration_data(cs35l56_base->dev,
+					      cs35l56_base->silicon_uid,
 					      cs35l56_base->cal_index,
 					      &cs35l56_base->cal_data);
 
@@ -1111,6 +1095,21 @@ int cs35l56_hw_init(struct cs35l56_base *cs35l56_base)
 			   CS35L56_TEMP_ERR_EINT1_MASK,
 			   0);
 
+	switch (cs35l56_base->type) {
+	case 0x54:
+	case 0x56:
+	case 0x57:
+		ret = cs35l56_read_silicon_uid(cs35l56_base);
+		break;
+	default:
+		ret = cs35l63_read_silicon_uid(cs35l56_base);
+		break;
+	}
+	if (ret)
+		return ret;
+
+	dev_dbg(cs35l56_base->dev, "SiliconID = %#llx\n", cs35l56_base->silicon_uid);
+
 	return 0;
 }
 EXPORT_SYMBOL_NS_GPL(cs35l56_hw_init, "SND_SOC_CS35L56_SHARED");
-- 
2.47.3