linux-kernel - [PATCH v2 16/16] nvmem: microchip-otpc: Expose UID registers as 2nd nvmem device

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Message-Id: <20250211065304.5019-4-ada@thorsis.com>
Date: Tue, 11 Feb 2025 07:53:04 +0100
From: Alexander Dahl <ada@...rsis.com>
To: Claudiu Beznea <claudiu.beznea@...on.dev>
Cc: Nicolas Ferre <nicolas.ferre@...rochip.com>,
	Ryan Wanner <ryan.wanner@...rochip.com>,
	linux-arm-kernel@...ts.infradead.org,
	devicetree@...r.kernel.org,
	linux-clk@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: [PATCH v2 16/16] nvmem: microchip-otpc: Expose UID registers as 2nd nvmem device

For SAM9X60 the Product UID x Register containing the Unique Product ID
is part of the OTPC registers.  We have everything at hand here to just
create a trivial nvmem device for those.

Signed-off-by: Alexander Dahl <ada@...rsis.com>
---

Notes:
    v2:
    - Use dev_err_probe() for error reporting (thanks Claudiu)
    - Move required register definition over here from removed patch

 drivers/nvmem/microchip-otpc.c | 38 +++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/nvmem/microchip-otpc.c b/drivers/nvmem/microchip-otpc.c
index 2c524c163b7e2..8353a117769a8 100644
--- a/drivers/nvmem/microchip-otpc.c
+++ b/drivers/nvmem/microchip-otpc.c
@@ -25,10 +25,14 @@
 #define MCHP_OTPC_HR			(0x20)
 #define MCHP_OTPC_HR_SIZE		GENMASK(15, 8)
 #define MCHP_OTPC_DR			(0x24)
+#define MCHP_OTPC_UID0R			(0x60)
 
 #define MCHP_OTPC_NAME			"mchp-otpc"
 #define MCHP_OTPC_SIZE			(11 * 1024)
 
+#define MCHP_OTPC_UID_NAME		"mchp-uid"
+#define MCHP_OTPC_UID_SIZE		16
+
 /**
  * struct mchp_otpc - OTPC private data structure
  * @base: base address
@@ -230,6 +234,16 @@ static int mchp_otpc_init_packets_list(struct mchp_otpc *otpc, u32 *size)
 	return 0;
 }
 
+static int mchp_otpc_uid_read(void *priv, unsigned int offset,
+			      void *val, size_t bytes)
+{
+	struct mchp_otpc *otpc = priv;
+
+	memcpy_fromio(val, otpc->base + MCHP_OTPC_UID0R + offset, bytes);
+
+	return 0;
+}
+
 static struct nvmem_config mchp_nvmem_config = {
 	.name = MCHP_OTPC_NAME,
 	.type = NVMEM_TYPE_OTP,
@@ -239,6 +253,15 @@ static struct nvmem_config mchp_nvmem_config = {
 	.reg_read = mchp_otpc_read,
 };
 
+static struct nvmem_config mchp_otpc_uid_nvmem_config = {
+	.name = MCHP_OTPC_UID_NAME,
+	.read_only = true,
+	.word_size = 4,
+	.stride = 4,
+	.size = MCHP_OTPC_UID_SIZE,
+	.reg_read = mchp_otpc_uid_read,
+};
+
 static int mchp_otpc_probe(struct platform_device *pdev)
 {
 	struct nvmem_device *nvmem;
@@ -270,8 +293,21 @@ static int mchp_otpc_probe(struct platform_device *pdev)
 	mchp_nvmem_config.size = size;
 	mchp_nvmem_config.priv = otpc;
 	nvmem = devm_nvmem_register(&pdev->dev, &mchp_nvmem_config);
+	if (IS_ERR(nvmem)) {
+		return dev_err_probe(&pdev->dev, PTR_ERR(nvmem),
+				     "Error registering OTP as nvmem device\n");
+	}
 
-	return PTR_ERR_OR_ZERO(nvmem);
+	mchp_otpc_uid_nvmem_config.dev = otpc->dev;
+	mchp_otpc_uid_nvmem_config.priv = otpc;
+
+	nvmem = devm_nvmem_register(&pdev->dev, &mchp_otpc_uid_nvmem_config);
+	if (IS_ERR(nvmem)) {
+		return dev_err_probe(&pdev->dev, PTR_ERR(nvmem),
+				     "Error registering UIDxR as nvmem device\n");
+	}
+
+	return 0;
 }
 
 static const struct of_device_id __maybe_unused mchp_otpc_ids[] = {
-- 
2.39.5