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

[andrew-ct chen <andrew-ct.chen@mediatek.com>]

On Tue, 2015-10-27 at 13:32 +0800, andrew-ct chen wrote:
> On Mon, 2015-10-26 at 09:56 +0000, Srinivas Kandagatla wrote:
> > On 16/10/15 09:39, andrew-ct.chen@mediatek.com wrote:
> > > From: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
> > >
> > > Add Mediatek EFUSE driver to access hardware data like
> > > thermal sensor calibration or HDMI impedance.
> > >
> > > Signed-off-by: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
> > 
> > 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.
> 
> We will rebase it.
> 
> > 
> > > ---
> > >   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.

We will do this for the consistency.

> > 
> > >   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 <andrew-ct.chen@mediatek.com>
> > > + *
> > > + * 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 <andrew-ct.chen@mediatek.com>");
> > > +MODULE_DESCRIPTION("Mediatek EFUSE driver");
> > > +MODULE_LICENSE("GPL v2");
> > >
>