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Subject[PATCH v2 18/29] nvmem: Add Realtek DHC eFuse driver
Date
Implement enough of a read-only nvmem driver to easily read efuse cells.

Cc: Cheng-Yu Lee <cylee12@realtek.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
---
v2: New

MAINTAINERS | 1 +
drivers/nvmem/Kconfig | 9 ++++
drivers/nvmem/Makefile | 2 +
drivers/nvmem/rtk-dhc-efuse.c | 86 +++++++++++++++++++++++++++++++++++
4 files changed, 98 insertions(+)
create mode 100644 drivers/nvmem/rtk-dhc-efuse.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 1d0d6ab20451..02117fbf0e57 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2312,6 +2312,7 @@ F: Documentation/devicetree/bindings/soc/realtek/
F: arch/arm/boot/dts/rtd*
F: arch/arm/mach-realtek/
F: arch/arm64/boot/dts/realtek/
+F: drivers/nvmem/rtk-dhc-efuse.c
F: drivers/soc/realtek/

ARM/RENESAS ARM64 ARCHITECTURE
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index d7b7f6d688e7..75cf43b16cf9 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -129,6 +129,15 @@ config NVMEM_SPMI_SDAM
Qualcomm Technologies, Inc. PMICs. It provides the clients
an interface to read/write to the SDAM module's shared memory.

+config REALTEK_DHC_EFUSE
+ tristate "Realtek DHC eFuse Support"
+ depends on ARCH_REALTEK || COMPILE_TEST
+ depends on HAS_IOMEM
+ help
+ Say y here to enable read-only access to the Realtek Digital Home
+ This driver can also be built as a module. If so, the module
+ will be called nvmem-rtk-dhc-efuse.
+
config ROCKCHIP_EFUSE
tristate "Rockchip eFuse Support"
depends on ARCH_ROCKCHIP || COMPILE_TEST
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index a7c377218341..67cefdfa44e6 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -33,6 +33,8 @@ obj-$(CONFIG_ROCKCHIP_EFUSE) += nvmem_rockchip_efuse.o
nvmem_rockchip_efuse-y := rockchip-efuse.o
obj-$(CONFIG_ROCKCHIP_OTP) += nvmem-rockchip-otp.o
nvmem-rockchip-otp-y := rockchip-otp.o
+obj-$(CONFIG_REALTEK_DHC_EFUSE) += nvmem-rtk-dhc-efuse.o
+nvmem-rtk-dhc-efuse-y := rtk-dhc-efuse.o
obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem_sunxi_sid.o
nvmem_stm32_romem-y := stm32-romem.o
obj-$(CONFIG_NVMEM_STM32_ROMEM) += nvmem_stm32_romem.o
diff --git a/drivers/nvmem/rtk-dhc-efuse.c b/drivers/nvmem/rtk-dhc-efuse.c
new file mode 100644
index 000000000000..4672db2c2619
--- /dev/null
+++ b/drivers/nvmem/rtk-dhc-efuse.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Realtek Digital Home Center eFuse
+ *
+ * Copyright (c) 2020 Andreas Färber
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+struct dhc_efuse {
+ struct device *dev;
+ void __iomem *base;
+ struct nvmem_device *nvmem;
+};
+
+static int dhc_efuse_reg_read(void *priv, unsigned int offset, void *val,
+ size_t bytes)
+{
+ struct dhc_efuse *efuse = priv;
+ u8 *buf = val;
+
+ while (bytes--)
+ *buf++ = readb_relaxed(efuse->base + offset++);
+
+ return 0;
+}
+
+static int dhc_efuse_probe(struct platform_device *pdev)
+{
+ struct dhc_efuse *efuse;
+ struct nvmem_config config = {};
+ struct resource *res;
+
+ efuse = devm_kzalloc(&pdev->dev, sizeof(*efuse), GFP_KERNEL);
+ if (!efuse)
+ return -ENOMEM;
+
+ efuse->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+ if (IS_ERR(efuse->base))
+ return PTR_ERR(efuse->base);
+
+ efuse->dev = &pdev->dev;
+
+ config.dev = &pdev->dev;
+ config.name = "dhc-efuse";
+ config.owner = THIS_MODULE;
+ config.type = NVMEM_TYPE_OTP;
+ config.read_only = true,
+ config.word_size = 4;
+ config.stride = 1;
+ config.size = resource_size(res);
+ config.reg_read = dhc_efuse_reg_read;
+ config.priv = efuse;
+
+ efuse->nvmem = devm_nvmem_register(&pdev->dev, &config);
+ if (IS_ERR(efuse->nvmem)) {
+ dev_err(&pdev->dev, "failed to register nvmem (%ld)\n",
+ PTR_ERR(efuse->nvmem));
+ return PTR_ERR(efuse->nvmem);
+ }
+
+ return 0;
+}
+
+static const struct of_device_id dhc_efuse_dt_ids[] = {
+ { .compatible = "realtek,rtd1195-efuse" },
+ { }
+};
+
+static struct platform_driver dhc_efuse_driver = {
+ .probe = dhc_efuse_probe,
+ .driver = {
+ .name = "rtk-dhc-efuse",
+ .of_match_table = dhc_efuse_dt_ids,
+ },
+};
+module_platform_driver(dhc_efuse_driver);
+
+MODULE_DESCRIPTION("Realtek DHC eFuse driver");
+MODULE_LICENSE("GPL");
--
2.26.2
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