[net-next PATCH v14 12/16] nvmem: an8855: Add support for Airoha AN8855 Switch EFUSE

Christian Marangi
2025-04-08T09:52:31Z

Add support for Airoha AN8855 Switch EFUSE. These EFUSE might be used
for calibration data for the internal switch PHYs.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
drivers/nvmem/Kconfig | 11 +++++++
drivers/nvmem/Makefile | 2 ++
drivers/nvmem/an8855-efuse.c | 63 ++++++++++++++++++++++++++++++++++++
3 files changed, 76 insertions(+)
create mode 100644 drivers/nvmem/an8855-efuse.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 8671b7c974b9..ca96c6ea685a 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -28,6 +28,17 @@ source "drivers/nvmem/layouts/Kconfig"

# Devices

+config NVMEM_AN8855_EFUSE
+ tristate "Airoha AN8855 eFuse support"
+ depends on MFD_AIROHA_AN8855 || COMPILE_TEST
+ help
+ Say y here to enable support for reading eFuses on Airoha AN8855
+ Switch. These are e.g. used to store factory programmed
+ calibration data required for the PHY.
+
+ This driver can also be built as a module. If so, the module will
+ be called nvmem-an8855-efuse.
+
config NVMEM_APPLE_EFUSES
tristate "Apple eFuse support"
depends on ARCH_APPLE || COMPILE_TEST
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 5b77bbb6488b..c732132c0e45 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -10,6 +10,8 @@ nvmem_layouts-y := layouts.o
obj-y += layouts/

# Devices
+obj-$(CONFIG_NVMEM_AN8855_EFUSE) += nvmem-an8855-efuse.o
+nvmem-an8855-efuse-y := an8855-efuse.o
obj-$(CONFIG_NVMEM_APPLE_EFUSES) += nvmem-apple-efuses.o
nvmem-apple-efuses-y := apple-efuses.o
obj-$(CONFIG_NVMEM_BCM_OCOTP) += nvmem-bcm-ocotp.o
diff --git a/drivers/nvmem/an8855-efuse.c b/drivers/nvmem/an8855-efuse.c
new file mode 100644
index 000000000000..cd1564379098
--- /dev/null
+++ b/drivers/nvmem/an8855-efuse.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Airoha AN8855 Switch EFUSE Driver
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define AN8855_EFUSE_CELL 50
+
+#define AN8855_EFUSE_DATA0 0x1000a500
+#define AN8855_EFUSE_R50O GENMASK(30, 24)
+
+static int an8855_efuse_read(void *context, unsigned int offset,
+ void *val, size_t bytes)
+{
+ struct regmap *regmap = context;
+
+ return regmap_bulk_read(regmap, AN8855_EFUSE_DATA0 + offset,
+ val, bytes / sizeof(u32));
+}
+
+static int an8855_efuse_probe(struct platform_device *pdev)
+{
+ struct nvmem_config an8855_nvmem_config = {
+ .name = "an8855-efuse",
+ .size = AN8855_EFUSE_CELL * sizeof(u32),
+ .stride = sizeof(u32),
+ .word_size = sizeof(u32),
+ .reg_read = an8855_efuse_read,
+ };
+ struct device *dev = &pdev->dev;
+ struct nvmem_device *nvmem;
+
+ /* Assign NVMEM priv to MFD regmap */
+ an8855_nvmem_config.priv = dev_get_regmap(dev->parent, "switch");
+ an8855_nvmem_config.dev = dev;
+ nvmem = devm_nvmem_register(dev, &an8855_nvmem_config);
+
+ return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static const struct of_device_id an8855_efuse_of_match[] = {
+ { .compatible = "airoha,an8855-efuse", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, an8855_efuse_of_match);
+
+static struct platform_driver an8855_efuse_driver = {
+ .probe = an8855_efuse_probe,
+ .driver = {
+ .name = "an8855-efuse",
+ .of_match_table = an8855_efuse_of_match,
+ },
+};
+module_platform_driver(an8855_efuse_driver);
+
+MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>");
+MODULE_DESCRIPTION("Driver for AN8855 Switch EFUSE");
+MODULE_LICENSE("GPL");
--
2.48.1