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

Srinivas Kandagatla
2015-08-11T08:14:01Z

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;
> +}
> +