[PATCH 2/3] nvmem: rockchip-efuse: implement eFuse driver

[Srinivas Kandagatla]

Hi Shunqian,


On 10/08/15 04:22, Shunqian Zheng wrote:
> From: ZhengShunQian <zhengsq at rock-chips.com>
>
> 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.
>
> Also add the docs of efuse bindings and the rk3288's efuse config.
>
> Signed-off-by: Caesar Wang <caesar.wang at rock-chips.com>
> Signed-off-by: ZhengShunQian <zhengsq at rock-chips.com>
> ---
>   .../devicetree/bindings/nvmem/rockchip-efuse.txt   |  36 +++++
>   arch/arm/boot/dts/rk3288.dtsi                      |  13 ++
>   drivers/nvmem/Kconfig                              |  10 ++
>   drivers/nvmem/Makefile                             |   2 +
>   drivers/nvmem/rockchip-efuse.c                     | 155 +++++++++++++++++++++
>   5 files changed, 216 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/nvmem/rockchip-efuse.txt
>   create mode 100644 drivers/nvmem/rockchip-efuse.c
>

Please split this patch into alteast 3 parts, one for dts, one for 
documentation, one for driver.

> diff --git a/Documentation/devicetree/bindings/nvmem/rockchip-efuse.txt b/Documentation/devicetree/bindings/nvmem/rockchip-efuse.txt
> new file mode 100644
> index 0000000..bb487ec
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/nvmem/rockchip-efuse.txt
> @@ -0,0 +1,36 @@
> += Rockchip eFuse device tree bindings =
> +
> +Required properties:
> +- compatible: Should be "rockchip,rockchip-efuse"
> +- reg: Should contain the registers location and exact eFuse size

Why did you not mention the clocks property here?

> +
> += Data cells =
> +Are child nodes of eFuse, bindings of which as described in
> +bindings/nvmem/nvmem.txt
> +
> +Example:
> +
> +	efuse: efuse at ffb40000 {
> +		compatible = "rockchip,rockchip-efuse";
> +		reg = <0xffb40000 0x20>;
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		clocks = <&cru PCLK_EFUSE256>;
> +		clock-names = "pclk_efuse_256";
> +
> +		/* Data cells */
> +		cpu_leakage: cpu_leakage {
> +			reg = <0x17 0x1>;
> +		};
> +	};
> +
> += Data consumers =
> +Are device nodes which consume nvmem data cells.
> +
> +Example:
> +
> +	cpu_leakage {
> +		...
> +		nvmem-cells = <&cpu_leakage>;
> +		nvmem-cell-names = "cpu_leakage";
> +	};
> diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi
> index 2db91c9..272c0b5 100644
> --- a/arch/arm/boot/dts/rk3288.dtsi
> +++ b/arch/arm/boot/dts/rk3288.dtsi
> @@ -749,6 +749,19 @@
>   		interrupts = <GIC_PPI 9 0xf04>;
>   	};
>
> +	efuse: efuse at ffb40000 {
> +		compatible = "rockchip,rockchip-efuse";
> +		reg = <0xffb40000 0x20>;
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		clocks = <&cru PCLK_EFUSE256>;
> +		clock-names = "pclk_efuse_256";
> +
> +		cpu_leakage: cpu_leakage {
> +			reg = <0x17 0x1>;
> +		};
> +	};
> +
>   	usbphy: phy {
>   		compatible = "rockchip,rk3288-usb-phy";
>   		rockchip,grf = <&grf>;
> 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..30ee772
> --- /dev/null
> +++ b/drivers/nvmem/rockchip-efuse.c
> @@ -0,0 +1,155 @@
> +/*
> + * Rockchip eFuse Driver
> + *
> + * Copyright (c) 2015 Rockchip Electronics Co. Ltd.
> + * Author: Caesar Wang <wxt at 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
> +
> +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;
> +	void __iomem *base = context;
> +	u8 *buf = val;

As discussed in the "clk: rockchip: do not gate the efuse256 clock" 
patch, please get hold of the clock via context and enable/disable as 
required.

Other than this the patch is looking good.

Pleas Add Greg KH into the loop so that we can request him to take this 
for this merge window.


> +
> +	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);
> +
> +	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;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	base = devm_ioremap_resource(dev, res);
> +
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	rockchip_efuse_regmap_config.max_register = resource_size(res) - 1;
> +
> +	regmap = devm_regmap_init(dev, &rockchip_efuse_bus,
> +				  base, &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");
>