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

Alexander Dahl
2025-02-11T06:53:13Z

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@thorsis.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