Subject: [PATCH 2/3] nvmem: mediatek: Add Mediatek EFUSE driver

From: [email-masked] (Srinivas Kandagatla)
Date: Mon, 26 Oct 2015 09:56:24 +0000

On 16/10/15 09:39, andrew-ct.chen at mediatek.com wrote:
> From: Andrew-CT Chen <[email-masked]>
>
> Add Mediatek EFUSE driver to access hardware data like
> thermal sensor calibration or HDMI impedance.
>
> Signed-off-by: Andrew-CT Chen <[email-masked]>

Dirver looks pretty simple, below are few minor nits.

Please rebase this patch on top of v4.4-rc1 once its released in few 
weeks, so that I can queue this driver for v4.5.

> ---
>   drivers/nvmem/Kconfig     | 11 ++++++
>   drivers/nvmem/Makefile    |  1 +
>   drivers/nvmem/mtk-efuse.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 101 insertions(+)
>   create mode 100644 drivers/nvmem/mtk-efuse.c
>
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 8db2978..1bd5badc 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -14,6 +14,17 @@ menuconfig NVMEM
>
>   if NVMEM
>
> +config MTK_EFUSE
> +	tristate "Mediatek SoCs EFUSE support"
> +	depends on ARCH_MEDIATEK || COMPILE_TEST
> +	select REGMAP_MMIO
> +	help
> +	  This is a driver to access hardware related data like sensor
> +	  calibration, HDMI impedance etc.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called efuse-mtk.
> +
>   config QCOM_QFPROM
>   	tristate "QCOM QFPROM Support"
>   	depends on ARCH_QCOM || COMPILE_TEST
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index 4328b93..916b727 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_NVMEM)		+= nvmem_core.o
>   nvmem_core-y			:= core.o
>
>   # Devices
> +obj-$(CONFIG_MTK_EFUSE)		+= mtk-efuse.o

For consistency reasons, could you do this similar to other drivers.

>   obj-$(CONFIG_QCOM_QFPROM)	+= nvmem_qfprom.o
>   nvmem_qfprom-y			:= qfprom.o
>   obj-$(CONFIG_NVMEM_SUNXI_SID)	+= nvmem_sunxi_sid.o
> diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
> new file mode 100644
> index 0000000..9021c0b
> --- /dev/null
> +++ b/drivers/nvmem/mtk-efuse.c
> @@ -0,0 +1,89 @@
> +/*
> + * Copyright (c) 2015 MediaTek Inc.
> + * Author: Andrew-CT Chen <[email-masked]>
> + *
> + * 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/device.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-provider.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +static struct regmap_config mtk_regmap_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +};
> +
> +static int mtk_efuse_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	struct nvmem_device *nvmem;
> +	struct nvmem_config *econfig;
> +	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);
> +
> +	econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
> +	if (!econfig)
> +		return -ENOMEM;
Why not use static econfig variable?

> +
> +	mtk_regmap_config.max_register = resource_size(res) - 1;
> +
> +	regmap = devm_regmap_init_mmio(dev, base, &mtk_regmap_config);
> +	if (IS_ERR(regmap)) {
> +		dev_err(dev, "regmap init failed\n");
> +		return PTR_ERR(regmap);
> +	}
> +
> +	econfig->dev = dev;
> +	econfig->owner = THIS_MODULE;
> +	nvmem = nvmem_register(econfig);
> +	if (IS_ERR(nvmem))
> +		return PTR_ERR(nvmem);
> +
> +	platform_set_drvdata(pdev, nvmem);
> +
> +	return 0;
> +}
> +
> +static int mtk_efuse_remove(struct platform_device *pdev)
> +{
> +	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
> +
> +	return nvmem_unregister(nvmem);
> +}
> +
> +static const struct of_device_id mtk_efuse_of_match[] = {
> +	{ .compatible = "mediatek,mt8135-efuse",},
> +	{ .compatible = "mediatek,mt8173-efuse",},
> +	{/* sentinel */},
> +};
> +MODULE_DEVICE_TABLE(of, mtk_efuse_of_match);
> +
> +static struct platform_driver mtk_efuse_driver = {
> +	.probe = mtk_efuse_probe,
> +	.remove = mtk_efuse_remove,
> +	.driver = {
> +		.name = "mediatek,efuse",
> +		.of_match_table = mtk_efuse_of_match,
> +	},
> +};
> +module_platform_driver(mtk_efuse_driver);
> +MODULE_AUTHOR("Andrew-CT Chen <[email-masked]>");
> +MODULE_DESCRIPTION("Mediatek EFUSE driver");
> +MODULE_LICENSE("GPL v2");
>