[PATCH 2/3] nvmem: Add Sophgo SG2044 eFuse driver
Inochi Amaoto
inochiama at gmail.com
Wed Oct 14 00:45:14 PDT 2026
Sophgo SoCs such as SG2044 contain eFuses used to store
factory-programmed data.
As for SG2044, HW automatically loads the eFuse content
into shadow registers which are organized as 32bit values
exposed as MMIO.
Signed-off-by: Inochi Amaoto <inochiama at gmail.com>
---
drivers/nvmem/Kconfig | 12 +++
drivers/nvmem/Makefile | 2 +
drivers/nvmem/sophgo-efuse.c | 176 +++++++++++++++++++++++++++++++++++
3 files changed, 190 insertions(+)
create mode 100644 drivers/nvmem/sophgo-efuse.c
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index c36c2a4c2a0b..a7936dd65bdd 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -465,6 +465,18 @@ config NVMEM_SNVS_LPGPR
This driver can also be built as a module. If so, the module
will be called nvmem-snvs-lpgpr.
+config NVMEM_SOPHGO_EFUSE
+ tristate "Sophgo eFuse support"
+ depends on ARCH_SOPHGO || COMPILE_TEST
+ default ARCH_SOPHGO
+ help
+ Say y here to enable support for reading eFuses on Sophgo SoCs
+ such as the CV1800B. These are e.g. used to store factory programmed
+ calibration data required for the builtin ethernet PHY.
+
+ This driver can also be built as a module. If so, the module will
+ be called nvmem-sophgo-efuse.
+
config NVMEM_SPMI_SDAM
tristate "SPMI SDAM Support"
depends on SPMI
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 2bbfb9ff1885..430ddddf8c3c 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -79,6 +79,8 @@ obj-$(CONFIG_NVMEM_SC27XX_EFUSE) += nvmem-sc27xx-efuse.o
nvmem-sc27xx-efuse-y := sc27xx-efuse.o
obj-$(CONFIG_NVMEM_SNVS_LPGPR) += nvmem_snvs_lpgpr.o
nvmem_snvs_lpgpr-y := snvs_lpgpr.o
+obj-$(CONFIG_NVMEM_SOPHGO_EFUSE) += nvmem-sophgo-efuse.o
+nvmem-sophgo-efuse-y := sophgo-efuse.o
obj-$(CONFIG_NVMEM_SPMI_SDAM) += nvmem_qcom-spmi-sdam.o
nvmem_qcom-spmi-sdam-y += qcom-spmi-sdam.o
obj-$(CONFIG_NVMEM_SPRD_EFUSE) += nvmem_sprd_efuse.o
diff --git a/drivers/nvmem/sophgo-efuse.c b/drivers/nvmem/sophgo-efuse.c
new file mode 100644
index 000000000000..5f90adaf8e4f
--- /dev/null
+++ b/drivers/nvmem/sophgo-efuse.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Sophgo SoC eFuse driver
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/cleanup.h>
+#include <linux/iopoll.h>
+#include <linux/math.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+
+#define SG2044_EFUSE_CONTENT_SIZE 0x400
+
+#define SG2044_EFUSE_MD 0x000
+#define SG2044_EFUSE_ADR 0x004
+#define SG2044_EFUSE_RD_DATA 0x00c
+
+#define SG2044_EFUSE_MODE GENMASK(1, 0)
+#define SG2044_EFUSE_MODE_READ 2
+
+#define SG2044_EFUSE_BOOT_DONE BIT(7)
+#define SG2044_BOOT_TIMEOUT 10000
+
+#define SG2044_EFUSE_ADR_ADDR GENMASK(7, 0)
+
+#define SG2044_EFUSE_ALIGN 4
+
+struct sophgo_efuses {
+ void __iomem *base;
+ struct clk_bulk_data *clks;
+ int num_clks;
+ struct mutex mutex;
+};
+
+static int sg2044_efuse_wait_mode(struct sophgo_efuses *efuse)
+{
+ u32 value;
+
+ return readl_poll_timeout(efuse->base + SG2044_EFUSE_MD, value,
+ FIELD_GET(SG2044_EFUSE_MODE, value) == 0,
+ 1, SG2044_BOOT_TIMEOUT);
+}
+
+static int sg2044_efuse_set_mode(struct sophgo_efuses *efuse, int mode)
+{
+ u32 val = readl(efuse->base + SG2044_EFUSE_MD);
+
+ val &= ~SG2044_EFUSE_MODE;
+ val |= FIELD_PREP(SG2044_EFUSE_MODE, mode);
+
+ writel(val, efuse->base + SG2044_EFUSE_MD);
+
+ return sg2044_efuse_wait_mode(efuse);
+}
+
+static u32 sg2044_efuses_read_strip(struct sophgo_efuses *efuse,
+ unsigned int offset, u32 *strip)
+{
+ u32 val = FIELD_PREP(SG2044_EFUSE_ADR_ADDR, offset);
+ int ret;
+
+ guard(mutex)(&efuse->mutex);
+
+ writel(val, efuse->base + SG2044_EFUSE_ADR);
+
+ ret = sg2044_efuse_set_mode(efuse, SG2044_EFUSE_MODE_READ);
+ if (ret < 0)
+ return ret;
+
+ *strip = readl(efuse->base + SG2044_EFUSE_RD_DATA);
+
+ return 0;
+}
+
+static int sg2044_efuses_read(void *context, unsigned int offset, void *val,
+ size_t bytes)
+{
+ struct sophgo_efuses *efuse = context;
+ unsigned int start, start_offset, end, i;
+ u32 value;
+ u8 *buf;
+ int ret;
+
+ start = rounddown(offset, SG2044_EFUSE_ALIGN);
+ end = roundup(offset + bytes, SG2044_EFUSE_ALIGN);
+ start_offset = offset - start;
+
+ start /= SG2044_EFUSE_ALIGN;
+ end /= SG2044_EFUSE_ALIGN;
+
+ ret = readl_poll_timeout(efuse->base + SG2044_EFUSE_MD, value,
+ (value & SG2044_EFUSE_BOOT_DONE),
+ 1, SG2044_BOOT_TIMEOUT);
+ if (ret < 0)
+ return ret;
+
+ buf = kzalloc(end - start, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ for (i = start; i < end; i++) {
+ ret = sg2044_efuses_read_strip(efuse, i, &value);
+ if (ret)
+ goto failed;
+
+ memcpy(&buf[(i - start) * 4], &value, SG2044_EFUSE_ALIGN);
+ }
+
+ memcpy(val, buf + start_offset, bytes);
+
+failed:
+ kfree(buf);
+
+ return ret;
+}
+
+static int sophgo_efuses_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct sophgo_efuses *efuse;
+ struct nvmem_config config = {
+ .dev = &pdev->dev,
+ .add_legacy_fixed_of_cells = true,
+ .read_only = true,
+ .reg_read = sg2044_efuses_read,
+ .stride = 1,
+ .word_size = 1,
+ .name = "sophgo-efuse",
+ .id = NVMEM_DEVID_AUTO,
+ .root_only = true,
+ };
+
+ efuse = devm_kzalloc(dev, sizeof(*efuse), GFP_KERNEL);
+ if (!efuse)
+ return -ENOMEM;
+
+ efuse->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(efuse->base))
+ return PTR_ERR(efuse->base);
+
+ efuse->num_clks = devm_clk_bulk_get_all_enabled(&pdev->dev, &efuse->clks);
+ if (efuse->num_clks < 0)
+ return dev_err_probe(dev, efuse->num_clks, "failed to get clocks\n");
+
+ config.priv = efuse;
+ config.size = SG2044_EFUSE_CONTENT_SIZE;
+
+ return PTR_ERR_OR_ZERO(devm_nvmem_register(config.dev, &config));
+}
+
+static const struct of_device_id sophgo_efuses_of_match[] = {
+ { .compatible = "sophgo,sg2044-efuse", },
+ {}
+};
+
+MODULE_DEVICE_TABLE(of, sophgo_efuses_of_match);
+
+static struct platform_driver sophgo_efuses_driver = {
+ .driver = {
+ .name = "sophgo_efuse",
+ .of_match_table = sophgo_efuses_of_match,
+ },
+ .probe = sophgo_efuses_probe,
+};
+
+module_platform_driver(sophgo_efuses_driver);
+
+MODULE_AUTHOR("Inochi Amaoto <inochiama at gmail.com>");
+MODULE_DESCRIPTION("Sophgo efuse driver");
+MODULE_LICENSE("GPL");
--
2.56.0
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