Re: [PATCH v6 2/9] mfd: smpro-mfd: Adds Ampere's Altra SMpro MFD driver

[Lee Jones <lee.jones@linaro.org>]

On Fri, 24 Dec 2021, Quan Nguyen wrote:

> Adds Multi-function devices driver for SMpro co-processor found on the
> Mt.Jade hardware reference platform with Ampere's Altra processor family.
> 
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> Changes in v6:
>   + Update license part to reflect that this driver is clone from
>   simple-mfd-i2c driver [Quan]
> 
> Changes in v5:
>   + Dropped the use of simple-mfd-i2c driver [Quan]
>   + Introduced drivers/mfd/smpro-mfd.c driver to instantiate
>   sub-devices. This is to avoid DT nodes without resource issue [Quan]
>   + Revised commit message [Quan]
> 
> Changes in v4:
>   + Add "depends on I2C" to fix build issue found by kernel test
>   robot [Guenter]
> 
> Changes in v3:
>   + None
> 
> Changes in v2:
>   + Used 'struct of_device_id's .data attribute [Lee Jones]
> 
>  drivers/mfd/Kconfig     | 12 +++++++
>  drivers/mfd/Makefile    |  1 +
>  drivers/mfd/smpro-mfd.c | 76 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 89 insertions(+)
>  create mode 100644 drivers/mfd/smpro-mfd.c
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index a21cbdf89477..a886da5018b1 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -77,6 +77,18 @@ config MFD_AS3711
>  	help
>  	  Support for the AS3711 PMIC from AMS
>  
> +config MFD_SMPRO
> +	tristate "Ampere Computing MFD SMpro core driver"
> +	depends on I2C
> +	select MFD_CORE
> +	select REGMAP_I2C
> +	help
> +	  Say yes here to enable SMpro driver support for Ampere's Altra
> +	  processor family.
> +
> +	  Ampere's Altra SMpro exposes an I2C regmap interface that can
> +	  be accessed by child devices.
> +
>  config MFD_AS3722
>  	tristate "ams AS3722 Power Management IC"
>  	select MFD_CORE
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 4d53e951a92d..fbcd09dce5ce 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -267,6 +267,7 @@ obj-$(CONFIG_MFD_QCOM_PM8008)	+= qcom-pm8008.o
>  
>  obj-$(CONFIG_SGI_MFD_IOC3)	+= ioc3.o
>  obj-$(CONFIG_MFD_SIMPLE_MFD_I2C)	+= simple-mfd-i2c.o
> +obj-$(CONFIG_MFD_SMPRO)		+= smpro-mfd.o
>  obj-$(CONFIG_MFD_INTEL_M10_BMC)   += intel-m10-bmc.o
>  
>  obj-$(CONFIG_MFD_ATC260X)	+= atc260x-core.o
> diff --git a/drivers/mfd/smpro-mfd.c b/drivers/mfd/smpro-mfd.c
> new file mode 100644
> index 000000000000..132d4e2dde12
> --- /dev/null
> +++ b/drivers/mfd/smpro-mfd.c
> @@ -0,0 +1,76 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Ampere Altra Family SMPro MFD - I2C
> + *
> + * Copyright (c) 2021, Ampere Computing LLC
> + * Author: Quan Nguyen <quan@os.amperecomputing..com>
> + *
> + * Based on simple-mfd-i2c.c:

Why aren't you just using this?

> + * Copyright (c) by Michael Walle <michael@walle.cc>
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_platform.h>
> +#include <linux/mfd/core.h>
> +#include <linux/regmap.h>
> +
> +/* Identification Registers */
> +#define MANUFACTURER_ID_REG     0x02
> +#define AMPERE_MANUFACTURER_ID  0xCD3A
> +
> +static const struct regmap_config simple_word_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 16,
> +};
> +
> +static const struct mfd_cell smpro_devs[] = {
> +	MFD_CELL_NAME("smpro-hwmon"),
> +};

What are the other devices?

> +static int smpro_mfd_probe(struct i2c_client *i2c)
> +{
> +	const struct regmap_config *config;
> +	struct regmap *regmap;
> +	unsigned int val;
> +	int ret;
> +
> +	config = device_get_match_data(&i2c->dev);
> +	if (!config)
> +		config = &simple_word_regmap_config;
> +
> +	regmap = devm_regmap_init_i2c(i2c, config);
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	/* Check for valid ID */
> +	ret = regmap_read(regmap, MANUFACTURER_ID_REG, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val != AMPERE_MANUFACTURER_ID)
> +		return -ENODEV;
> +
> +	return devm_mfd_add_devices(&i2c->dev, PLATFORM_DEVID_AUTO,
> +				    smpro_devs, ARRAY_SIZE(smpro_devs), NULL, 0, NULL);
> +}
> +
> +static const struct of_device_id smpro_mfd_of_match[] = {
> +	{ .compatible = "ampere,smpro", .data = &simple_word_regmap_config },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, smpro_mfd_of_match);
> +
> +static struct i2c_driver smpro_mfd_driver = {
> +	.probe_new = smpro_mfd_probe,
> +	.driver = {
> +		.name = "smpro-mfd-i2c",
> +		.of_match_table = smpro_mfd_of_match,
> +	},
> +};
> +module_i2c_driver(smpro_mfd_driver);
> +
> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
> +MODULE_DESCRIPTION("SMPRO MFD - I2C driver");
> +MODULE_LICENSE("GPL v2");

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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