Re: [PATCH 4/6] nvmem: amlogic: Add Amlogic Meson EFUSE driver

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

Hi Carlo,

On 19/06/16 13:39, Carlo Caione wrote:
> From: Carlo Caione <carlo@endlessm.com>
>
> Add Amlogic EFUSE driver to access hardware data like ethernet address,
> serial number or IDs.
>
> Signed-off-by: Carlo Caione <carlo@endlessm.com>
> ---
>   drivers/nvmem/Kconfig       |  11 ++++
>   drivers/nvmem/Makefile      |   2 +
>   drivers/nvmem/meson-efuse.c | 130 ++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 143 insertions(+)
>   create mode 100644 drivers/nvmem/meson-efuse.c
>
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index ca52952..ef17bc9 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -102,4 +102,15 @@ config NVMEM_VF610_OCOTP
>   	  This driver can also be build as a module. If so, the module will
>   	  be called nvmem-vf610-ocotp.
>
> +config MESON_EFUSE
> +	tristate "Amlogic eFuse Support"
> +	depends on ARCH_MESON || COMPILE_TEST
> +	select REGMAP_MMIO

NVMEM recently moved out of using regmap, as regmap did not provide 
better abstraction, could you rebase your patch on top of mainline.

Thanks,
srini

> +	help
> +	  This is a driver to retrieve specific values from the eFuse found on
> +	  the Amlogic Meson SoCs.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called nvmem_meson_efuse.
> +
>   endif
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index 45ab1ae..8f942a0 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -22,3 +22,5 @@ obj-$(CONFIG_NVMEM_SUNXI_SID)	+= nvmem_sunxi_sid.o
>   nvmem_sunxi_sid-y		:= sunxi_sid.o
>   obj-$(CONFIG_NVMEM_VF610_OCOTP)	+= nvmem-vf610-ocotp.o
>   nvmem-vf610-ocotp-y		:= vf610-ocotp.o
> +obj-$(CONFIG_MESON_EFUSE)	+= nvmem_meson_efuse.o
> +nvmem_meson_efuse-y		:= meson-efuse.o
> diff --git a/drivers/nvmem/meson-efuse.c b/drivers/nvmem/meson-efuse.c
> new file mode 100644
> index 0000000..7c80e1c
> --- /dev/null
> +++ b/drivers/nvmem/meson-efuse.c
> @@ -0,0 +1,130 @@
> +/*
> + * Amlogic eFuse Driver
> + *
> + * Copyright (c) 2016 Endless Computers, Inc.
> + * Author: Carlo Caione <carlo@endlessm.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/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-provider.h>
> +#include <linux/slab.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#include <linux/firmware/meson/meson_sm.h>
> +
> +static struct meson_sm_firmware *fw;
> +
> +static int meson_efuse_write(void *context, const void *data, size_t count)
> +{
> +	/* Nothing TBD, Read-Only */
> +	return 0;
> +}
> +
> +static int meson_efuse_read(void *context,
> +			    const void *reg, size_t reg_size,
> +			    void *val, size_t val_size)
> +{
> +	unsigned int offset = *(u32 *)reg;
> +	u8 *buf = val;
> +	int ret;
> +
> +	ret = meson_sm_call_read(fw, buf, SM_EFUSE_READ, offset,
> +				 val_size, 0, 0, 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static struct nvmem_config econfig = {
> +	.name = "meson-efuse",
> +	.owner = THIS_MODULE,
> +	.read_only = true,
> +};
> +
> +static struct regmap_bus meson_efuse_bus = {
> +	.read = meson_efuse_read,
> +	.write = meson_efuse_write,
> +	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +};
> +
> +static struct regmap_config meson_efuse_regmap_config = {
> +	.reg_bits = 32,
> +	.reg_stride = 1,
> +	.val_bits = 8,
> +};
> +
> +static const struct of_device_id meson_efuse_match[] = {
> +	{ .compatible = "amlogic,meson-gxbb-efuse", },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, meson_efuse_match);
> +
> +static int meson_efuse_probe(struct platform_device *pdev)
> +{
> +	struct nvmem_device *nvmem;
> +	struct regmap *regmap;
> +	unsigned int size;
> +
> +	fw = meson_sm_get_fw();
> +	if (!fw)
> +		return -EPROBE_DEFER;
> +
> +	if (meson_sm_call(fw, SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0)
> +		return -EINVAL;
> +	meson_efuse_regmap_config.max_register = size - 1;
> +
> +	regmap = devm_regmap_init(&pdev->dev, &meson_efuse_bus,
> +				  NULL, &meson_efuse_regmap_config);
> +	if (IS_ERR(regmap)) {
> +		dev_err(&pdev->dev, "regmap init failed\n");
> +		return PTR_ERR(regmap);
> +	}
> +
> +	econfig.dev = &pdev->dev;
> +	nvmem = nvmem_register(&econfig);
> +	if (IS_ERR(nvmem))
> +		return PTR_ERR(nvmem);
> +
> +	platform_set_drvdata(pdev, nvmem);
> +
> +	return 0;
> +}
> +
> +static int meson_efuse_remove(struct platform_device *pdev)
> +{
> +	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
> +
> +	return nvmem_unregister(nvmem);
> +}
> +
> +static struct platform_driver meson_efuse_driver = {
> +	.probe = meson_efuse_probe,
> +	.remove = meson_efuse_remove,
> +	.driver = {
> +		.name = "meson-efuse",
> +		.of_match_table = meson_efuse_match,
> +	},
> +};
> +
> +module_platform_driver(meson_efuse_driver);
> +
> +MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
> +MODULE_DESCRIPTION("Amlogic Meson NVMEM driver");
> +MODULE_LICENSE("GPL v2");
>