[PATCH v1 3/5] nvmem: rockchip-efuse: implement efuse driver

Shunqian Zheng
2015-08-11T06:19:16Z

There are some SoC specified values store in eFuse,
such as the cpu_leakage and cpu_version,
this driver can expose these values to /sys base on nvmem.

Signed-off-by: Caesar Wang <caesar.wang@rock-chips.com>
Signed-off-by: ZhengShunQian <zhengsq@rock-chips.com>
---
drivers/nvmem/Kconfig | 10 +++
drivers/nvmem/Makefile | 2 +
drivers/nvmem/rockchip-efuse.c | 193 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 205 insertions(+)
create mode 100644 drivers/nvmem/rockchip-efuse.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 8db2978..98f1fac 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -36,4 +36,14 @@ config NVMEM_SUNXI_SID
This driver can also be built as a module. If so, the module
will be called nvmem_sunxi_sid.

+config ROCKCHIP_EFUSE
+ tristate "Rockchip eFuse Support"
+ depends on ARCH_ROCKCHIP || COMPILE_TEST
+ help
+ This is a simple drive to dump specified values of Rockchip SoC
+ from eFuse, such as cpu-leakage.
+
+ This driver can also be built as a module. If so, the module
+ will be called nvmem_rockchip_efuse.
+
endif
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 4328b93..093a528 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -10,3 +10,5 @@ obj-$(CONFIG_QCOM_QFPROM) += nvmem_qfprom.o
nvmem_qfprom-y := qfprom.o
obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem_sunxi_sid.o
nvmem_sunxi_sid-y := sunxi_sid.o
+obj-$(CONFIG_ROCKCHIP_EFUSE) += nvmem_rockchip_efuse.o
+nvmem_rockchip_efuse-y := rockchip-efuse.o
diff --git a/drivers/nvmem/rockchip-efuse.c b/drivers/nvmem/rockchip-efuse.c
new file mode 100644
index 0000000..9d1e2e0
--- /dev/null
+++ b/drivers/nvmem/rockchip-efuse.c
@@ -0,0 +1,193 @@
+/*
+ * Rockchip eFuse Driver
+ *
+ * Copyright (c) 2015 Rockchip Electronics Co. Ltd.
+ * Author: Caesar Wang <wxt@rock-chips.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/nvmem-provider.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/clk.h>
+
+#define EFUSE_A_SHIFT 6
+#define EFUSE_A_MASK 0x3ff
+#define EFUSE_PGENB BIT(3)
+#define EFUSE_LOAD BIT(2)
+#define EFUSE_STROBE BIT(1)
+#define EFUSE_CSB BIT(0)
+
+#define REG_EFUSE_CTRL 0x0000
+#define REG_EFUSE_DOUT 0x0004
+
+struct rockchip_efuse_context {
+ struct device *dev;
+ void __iomem *base;
+ struct clk *efuse_clk;
+};
+
+static int rockchip_efuse_write(void *context, const void *data, size_t count)
+{
+ /* Nothing TBD, Read-Only */
+ return 0;
+}
+
+static int rockchip_efuse_read(void *context,
+ const void *reg, size_t reg_size,
+ void *val, size_t val_size)
+{
+ unsigned int offset = *(u32 *)reg;
+ struct rockchip_efuse_context *_context = context;
+ void __iomem *base = _context->base;
+ struct clk *clk = _context->efuse_clk;
+ u8 *buf = val;
+ int ret;
+
+ ret = clk_prepare(clk);
+ if (ret < 0) {
+ dev_err(_context->dev, "failed to prepare efuse clk\n");
+ return ret;
+ }
+ ret = clk_enable(clk);
+ if (ret < 0) {
+ dev_err(_context->dev, "failed to enable efuse clk\n");
+ clk_unprepare(clk);
+ return ret;
+ }
+
+ writel(EFUSE_LOAD | EFUSE_PGENB, base + REG_EFUSE_CTRL);
+ udelay(1);
+ while (val_size) {
+ writel(readl(base + REG_EFUSE_CTRL) &
+ (~(EFUSE_A_MASK << EFUSE_A_SHIFT)),
+ base + REG_EFUSE_CTRL);
+ writel(readl(base + REG_EFUSE_CTRL) |
+ ((offset & EFUSE_A_MASK) << EFUSE_A_SHIFT),
+ base + REG_EFUSE_CTRL);
+ udelay(1);
+ writel(readl(base + REG_EFUSE_CTRL) |
+ EFUSE_STROBE, base + REG_EFUSE_CTRL);
+ udelay(1);
+ *buf++ = readb(base + REG_EFUSE_DOUT);
+ writel(readl(base + REG_EFUSE_CTRL) &
+ (~EFUSE_STROBE), base + REG_EFUSE_CTRL);
+ udelay(1);
+
+ val_size -= 1;
+ offset += 1;
+ }
+
+ /* Switch to standby mode */
+ writel(EFUSE_PGENB | EFUSE_CSB, base + REG_EFUSE_CTRL);
+
+ clk_disable(clk);
+ clk_unprepare(clk);
+
+ return 0;
+}
+
+static struct regmap_bus rockchip_efuse_bus = {
+ .read = rockchip_efuse_read,
+ .write = rockchip_efuse_write,
+ .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
+ .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
+};
+
+struct regmap_config rockchip_efuse_regmap_config = {
+ .reg_bits = 32,
+ .reg_stride = 1,
+ .val_bits = 8,
+};
+
+static struct nvmem_config econfig = {
+ .name = "rockchip-efuse",
+ .owner = THIS_MODULE,
+ .read_only = true,
+};
+
+static const struct of_device_id rockchip_efuse_match[] = {
+ { .compatible = "rockchip,rockchip-efuse",},
+ { /* sentinel */},
+};
+MODULE_DEVICE_TABLE(of, rockchip_efuse_match);
+
+int rockchip_efuse_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+ struct nvmem_device *nvmem;
+ struct regmap *regmap;
+ void __iomem *base;
+ struct clk *clk;
+ struct rockchip_efuse_context *context;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ context = devm_kzalloc(dev, sizeof(struct rockchip_efuse_context),
+ GFP_KERNEL);
+ if (IS_ERR(context))
+ return PTR_ERR(context);
+
+ clk = devm_clk_get(dev, "pclk_efuse");
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ context->dev = dev;
+ context->base = base;
+ context->efuse_clk = clk;
+
+ rockchip_efuse_regmap_config.max_register = resource_size(res) - 1;
+
+ regmap = devm_regmap_init(dev, &rockchip_efuse_bus,
+ context, &rockchip_efuse_regmap_config);
+ if (IS_ERR(regmap)) {
+ dev_err(dev, "regmap init failed\n");
+ return PTR_ERR(regmap);
+ }
+ econfig.dev = dev;
+ nvmem = nvmem_register(&econfig);
+ if (IS_ERR(nvmem))
+ return PTR_ERR(nvmem);
+
+ platform_set_drvdata(pdev, nvmem);
+
+ return 0;
+}
+
+int rockchip_efuse_remove(struct platform_device *pdev)
+{
+ struct nvmem_device *nvmem = platform_get_drvdata(pdev);
+
+ return nvmem_unregister(nvmem);
+}
+
+static struct platform_driver rockchip_efuse_driver = {
+ .probe = rockchip_efuse_probe,
+ .remove = rockchip_efuse_remove,
+ .driver = {
+ .name = "rockchip-efuse",
+ .of_match_table = rockchip_efuse_match,
+ },
+};
+
+module_platform_driver(rockchip_efuse_driver);
+MODULE_DESCRIPTION("rockchip_efuse driver");
+MODULE_LICENSE("GPL v2");
--
1.9.1