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

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 11/08/15 07:15, Shunqian Zheng wrote:
> From: ZhengShunQian <zhengsq@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.
>
> 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;
> +
--snip--
> +	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;
> +	}
--snip--
can be replaced with

  clk_prepare_enable(clk);


> +
> +	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);
same replace it with

clk_disable_unprepare(clk);


Other than that the patch looks good to me.

with above fixed, you can add my Ack to this patch.

--srini

> +
> +	return 0;
> +}
> +