Re: [PATCH v1 2/3] nvmem: uniphier: add UniPhier eFuse driver

[Masahiro Yamada]

2017-09-01 8:20 GMT+09:00 Keiji Hayashibara <hayashibara.keiji@xxxxxxxxxxxxx>:
> Add eFuse driver for Socionext UniPhier series SoC.
> Note that eFuse device is under soc-glue and this register
> implements as read only.
>
> Signed-off-by: Keiji Hayashibara <hayashibara.keiji@xxxxxxxxxxxxx>
> ---
>  arch/arm64/configs/defconfig   |  1 +
>  drivers/nvmem/Kconfig          | 11 +++++
>  drivers/nvmem/Makefile         |  2 +
>  drivers/nvmem/uniphier-efuse.c | 98 ++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 112 insertions(+)
>  create mode 100644 drivers/nvmem/uniphier-efuse.c
>
> diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
> index 6c7d147..5c38b4a 100644
> --- a/arch/arm64/configs/defconfig
> +++ b/arch/arm64/configs/defconfig
> @@ -514,6 +514,7 @@ CONFIG_PHY_XGENE=y
>  CONFIG_PHY_TEGRA_XUSB=y
>  CONFIG_QCOM_L2_PMU=y
>  CONFIG_QCOM_L3_PMU=y
> +CONFIG_UNIPHIER_EFUSE=y
>  CONFIG_ARM_SCPI_PROTOCOL=y
>  CONFIG_RASPBERRYPI_FIRMWARE=y
>  CONFIG_EFI_CAPSULE_LOADER=y


You need to send this separately
(after this driver is accepted)



> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 101ced4..aaeaebe 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -123,6 +123,17 @@ config NVMEM_SUNXI_SID
>           This driver can also be built as a module. If so, the module
>           will be called nvmem_sunxi_sid.
>
> +config UNIPHIER_EFUSE
> +       tristate "UniPhier SoCs eFuse support"
> +       depends on ARCH_UNIPHIER || COMPILE_TEST
> +       depends on OF && MFD_SYSCON
> +       help
> +         This is a simple drive to dump specified values of UniPhier SoC
> +         from eFuse.


s/drive/driver/


I see the same typo in ROCKCHIP_EFUSE.

You copied it verbatim.




> +         This driver can also be built as a module. If so, the module
> +         will be called nvmem_uniphier-efuse.


I do not like a mixture of '_' and '-' though...





>  config NVMEM_VF610_OCOTP
>         tristate "VF610 SoC OCOTP support"
>         depends on SOC_VF610 || COMPILE_TEST
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index 1731406..f5277c3 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -26,6 +26,8 @@ obj-$(CONFIG_ROCKCHIP_EFUSE)  += nvmem_rockchip_efuse.o
>  nvmem_rockchip_efuse-y         := rockchip-efuse.o
>  obj-$(CONFIG_NVMEM_SUNXI_SID)  += nvmem_sunxi_sid.o
>  nvmem_sunxi_sid-y              := sunxi_sid.o
> +obj-$(CONFIG_UNIPHIER_EFUSE)   += nvmem_uniphier-efuse.o
> +nvmem_uniphier-efuse-y         := uniphier-efuse.o
>  obj-$(CONFIG_NVMEM_VF610_OCOTP)        += nvmem-vf610-ocotp.o
>  nvmem-vf610-ocotp-y            := vf610-ocotp.o
>  obj-$(CONFIG_MESON_EFUSE)      += nvmem_meson_efuse.o
> diff --git a/drivers/nvmem/uniphier-efuse.c b/drivers/nvmem/uniphier-efuse.c
> new file mode 100644
> index 0000000..d553fa3
> --- /dev/null
> +++ b/drivers/nvmem/uniphier-efuse.c
> @@ -0,0 +1,98 @@
> +/*
> + * UniPhier eFuse driver
> + *
> + * Copyright (C) 2017 Socionext Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 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/mfd/syscon.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/regmap.h>
> +
> +#define UNIPHIER_EFUSE_WORD_SIZE       4
> +#define UNIPHIER_EFUSE_STRIDE          4
> +
> +static int uniphier_reg_read(void *context,
> +                            unsigned int offset, void *val, size_t bytes)
> +{
> +       int words = bytes / UNIPHIER_EFUSE_WORD_SIZE;
> +
> +       return regmap_bulk_read(context, offset, val, words);
> +}
> +
> +static struct nvmem_config econfig = {
> +       .name = "uniphier-efuse",
> +       .owner = THIS_MODULE,
> +       .read_only = true,
> +       .reg_read = uniphier_reg_read,
> +       .word_size = UNIPHIER_EFUSE_WORD_SIZE,
> +       .stride = UNIPHIER_EFUSE_STRIDE,
> +};



"struct nvmem_config" exists for the purpose of containing
driver-specific parameters.
Do you still want to use
UNIPHIER_EFUSE_WORD_SIZE / UNIPHIER_EFUSE_STRIDE macros here?




static struct nvmem_config econfig = {
       .name = "uniphier-efuse",
       .owner = THIS_MODULE,
       .read_only = true,
       .reg_read = uniphier_reg_read,
       .word_size = 4,
       .stride = 4,
};

looks nicer in my taste.



BTW, is there really no possibility
where the unphier_efuse_probe() is run concurrently?

Many other drivers pass statically allocated memory
to nvmem_register() like this...




> +static int uniphier_efuse_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct nvmem_device *nvmem;
> +       struct regmap *regmap;
> +       struct resource res;
> +       int ret;
> +
> +       ret = of_address_to_resource(dev->of_node, 0, &res);
> +       if (ret)
> +               return ret;
> +
> +       regmap = syscon_node_to_regmap(dev->of_node);
> +       if (IS_ERR(regmap))
> +               return PTR_ERR(regmap);


In my understanding,
syscon_node_to_regmap() is generally useful
to get regmap of another node,
i.e. it is often used together with of_get_parent / of_parse_phandle etc.

You can use devm_regmap_init_mmio()
to init regmap for itself.


BTW, what is your motivation of using regmap?


I think what you want to do is
the same as mtk-efuse.c, right?
(and qfprom.c is similar, the difference is just register width)






> +       econfig.size = resource_size(&res);
> +       econfig.priv = regmap;
> +       econfig.dev = dev;
> +
> +       nvmem = nvmem_register(&econfig);
> +       if (IS_ERR(nvmem))
> +               return PTR_ERR(nvmem);
> +
> +       platform_set_drvdata(pdev, nvmem);
> +
> +       return 0;
> +}
> +
> +static int uniphier_efuse_remove(struct platform_device *pdev)
> +{
> +       struct nvmem_device *nvmem = platform_get_drvdata(pdev);
> +
> +       return nvmem_unregister(nvmem);
> +}
> +
> +static const struct of_device_id uniphier_efuse_of_match[] = {
> +       { .compatible = "socionext,uniphier-efuse",},
> +       {/* sentinel */},
> +};
> +MODULE_DEVICE_TABLE(of, uniphier_efuse_of_match);
> +
> +static struct platform_driver uniphier_efuse_driver = {
> +       .probe = uniphier_efuse_probe,
> +       .remove = uniphier_efuse_remove,
> +       .driver = {
> +               .name = "uniphier-efuse",
> +               .of_match_table = uniphier_efuse_of_match,
> +       },
> +};
> +module_platform_driver(uniphier_efuse_driver);
> +
> +MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("UniPhier eFuse driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>



-- 
Best Regards
Masahiro Yamada