RE: [PATCH v2 2/4] mfd: intel-m10-bmc: split into core and spi

["Zhang, Tianfei" <tianfei.zhang@intel.com>]

> -----Original Message-----
> From: Xu, Yilun <yilun.xu@intel.com>
> Sent: Monday, June 20, 2022 5:59 PM
> To: Zhang, Tianfei <tianfei.zhang@intel.com>
> Cc: lee.jones@linaro.org; Wu, Hao <hao.wu@intel.com>; trix@redhat.com;
> linux-kernel@vger.kernel.org; linux-fpga@vger.kernel.org; Weight, Russell H
> <russell.h.weight@intel.com>; matthew.gerlach@linux.intel.com
> Subject: Re: [PATCH v2 2/4] mfd: intel-m10-bmc: split into core and spi
> 
> On Thu, Jun 16, 2022 at 10:04:03PM -0400, Tianfei Zhang wrote:
> > Split the common code from intel-m10-bmc driver into intel-m10-bmc-core.
> > intel-m10-bmc-core is the core MFD functions which can support
> > multiple bus interfaces like SPI bus.
> 
> Please specify which else are you going to support, for better understanding.

There are lots of common code for intel-m10-bmc-spi and intel-m10-bmc-pmci driver.
To better support multiple bus interfaces and  reduce  the duplicate code , 
we like to split the common code into a core file.

> 
> >
> > Signed-off-by: Tianfei Zhang <tianfei.zhang@intel.com>
> > ---
> >  drivers/mfd/Kconfig                           |  30 +++---
> >  drivers/mfd/Makefile                          |   5 +-
> >  .../{intel-m10-bmc.c => intel-m10-bmc-core.c} | 101 +++++-------------
> >  drivers/mfd/intel-m10-bmc-spi.c               |  83 ++++++++++++++
> >  include/linux/mfd/intel-m10-bmc.h             |  15 +++
> >  5 files changed, 144 insertions(+), 90 deletions(-)  rename
> > drivers/mfd/{intel-m10-bmc.c => intel-m10-bmc-core.c} (63%)  create
> > mode 100644 drivers/mfd/intel-m10-bmc-spi.c
> >
> > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index
> > 3b59456f5545..ee8398b02321 100644
> > --- a/drivers/mfd/Kconfig
> > +++ b/drivers/mfd/Kconfig
> > @@ -2158,18 +2158,24 @@ config SGI_MFD_IOC3
> >  	  If you have an SGI Origin, Octane, or a PCI IOC3 card,
> >  	  then say Y. Otherwise say N.
> >
> > -config MFD_INTEL_M10_BMC
> > -	tristate "Intel MAX 10 Board Management Controller"
> > -	depends on SPI_MASTER
> > -	select REGMAP_SPI_AVMM
> > -	select MFD_CORE
> > -	help
> > -	  Support for the Intel MAX 10 board management controller using the
> > -	  SPI interface.
> > -
> > -	  This driver provides common support for accessing the device,
> > -	  additional drivers must be enabled in order to use the functionality
> > -	  of the device.
> > +config MFD_INTEL_M10_BMC_CORE
> > +        tristate
> > +        select MFD_CORE
> > +        select REGMAP
> > +        default n
> > +
> > +config MFD_INTEL_M10_BMC_SPI
> > +        tristate "Intel MAX 10 Board Management Controller with SPI"
> > +        depends on SPI_MASTER
> > +        select MFD_INTEL_M10_BMC_CORE
> > +        select REGMAP_SPI_AVMM
> > +        help
> > +          Support for the Intel MAX 10 board management controller using the
> > +          SPI interface.
> > +
> > +          This driver provides common support for accessing the
> > + device,
> 
>                                                                    device by SPI,

I  will fix it on next version patch.
> 
> > +          additional drivers must be enabled in order to use the functionality
> > +          of the device.
> >
> >  config MFD_RSMU_I2C
> >  	tristate "Renesas Synchronization Management Unit with I2C"
> > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile index
> > 858cacf659d6..b5d3263c1205 100644
> > --- a/drivers/mfd/Makefile
> > +++ b/drivers/mfd/Makefile
> > @@ -266,7 +266,10 @@ 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_INTEL_M10_BMC)   += intel-m10-bmc.o
> > +
> > +intel-m10-bmc-objs             := intel-m10-bmc-core.o
> > +obj-$(CONFIG_MFD_INTEL_M10_BMC_CORE)   += intel-m10-bmc.o
> 
> Why make a intel-m10-bmc obj here? What's the problem of intel-m10-bmc-
> core.o?

This intel-m10-bmc-objs is for CONFIG_MFD_INTEL_M10_BMC_CORE.
So if want to support intel-m10-bmc-spi driver, it should set both CONFIG_MFD_INTEL_M10_BMC_CORE
and CONFIG_MFD_INTEL_M10_BMC_SPI in .config file.

Here is another example in drivers/mfd/Makefile.

intel-soc-pmic-objs             := intel_soc_pmic_core.o intel_soc_pmic_crc.o
obj-$(CONFIG_INTEL_SOC_PMIC)    += intel-soc-pmic.o
obj-$(CONFIG_INTEL_SOC_PMIC_BXTWC)      += intel_soc_pmic_bxtwc.o

> 
> > +obj-$(CONFIG_MFD_INTEL_M10_BMC_SPI)   += intel-m10-bmc-spi.o
> >
> >  obj-$(CONFIG_MFD_ATC260X)	+= atc260x-core.o
> >  obj-$(CONFIG_MFD_ATC260X_I2C)	+= atc260x-i2c.o
> > diff --git a/drivers/mfd/intel-m10-bmc.c
> > b/drivers/mfd/intel-m10-bmc-core.c
> > similarity index 63%
> > rename from drivers/mfd/intel-m10-bmc.c rename to
> > drivers/mfd/intel-m10-bmc-core.c index 7e521df29c72..f6dc549e1bc3
> > 100644
> > --- a/drivers/mfd/intel-m10-bmc.c
> > +++ b/drivers/mfd/intel-m10-bmc-core.c
> > @@ -1,23 +1,14 @@
> >  // SPDX-License-Identifier: GPL-2.0
> >  /*
> > - * Intel MAX 10 Board Management Controller chip
> > + * Intel MAX 10 Board Management Controller chip - common code
> >   *
> > - * Copyright (C) 2018-2020 Intel Corporation. All rights reserved.
> > + * Copyright (C) 2018-2022 Intel Corporation. All rights reserved.
> >   */
> >  #include <linux/bitfield.h>
> >  #include <linux/init.h>
> >  #include <linux/mfd/core.h>
> >  #include <linux/mfd/intel-m10-bmc.h>
> >  #include <linux/module.h>
> > -#include <linux/mutex.h>
> > -#include <linux/regmap.h>
> > -#include <linux/spi/spi.h>
> > -
> > -enum m10bmc_type {
> > -	M10_N3000,
> > -	M10_D5005,
> > -	M10_N5010,
> > -};
> >
> >  static struct mfd_cell m10bmc_d5005_subdevs[] = {
> >  	{ .name = "d5005bmc-hwmon" },
> > @@ -33,26 +24,6 @@ static struct mfd_cell m10bmc_n5010_subdevs[] = {
> >  	{ .name = "n5010bmc-hwmon" },
> >  };
> >
> > -static const struct regmap_range m10bmc_regmap_range[] = {
> > -	regmap_reg_range(M10BMC_LEGACY_BUILD_VER,
> M10BMC_LEGACY_BUILD_VER),
> > -	regmap_reg_range(M10BMC_SYS_BASE, M10BMC_SYS_END),
> > -	regmap_reg_range(M10BMC_FLASH_BASE, M10BMC_FLASH_END),
> > -};
> > -
> > -static const struct regmap_access_table m10bmc_access_table = {
> > -	.yes_ranges	= m10bmc_regmap_range,
> > -	.n_yes_ranges	= ARRAY_SIZE(m10bmc_regmap_range),
> > -};
> > -
> > -static struct regmap_config intel_m10bmc_regmap_config = {
> > -	.reg_bits = 32,
> > -	.val_bits = 32,
> > -	.reg_stride = 4,
> > -	.wr_table = &m10bmc_access_table,
> > -	.rd_table = &m10bmc_access_table,
> > -	.max_register = M10BMC_MEM_END,
> > -};
> 
> Why remove all these configurations, I suppose it is not related to bus type.

This intel_m10bmc_regmap_config has removed to intel-m10-bmc-spi driver, it is related to SPI bus.

> 
> > -
> >  static ssize_t bmc_version_show(struct device *dev,
> >  				struct device_attribute *attr, char *buf)  { @@
> -131,7 +102,16 @@
> > static struct attribute *m10bmc_attrs[] = {
> >  	&dev_attr_mac_count.attr,
> >  	NULL,
> >  };
> > -ATTRIBUTE_GROUPS(m10bmc);
> > +
> > +static const struct attribute_group m10bmc_group = {
> > +	.attrs = m10bmc_attrs,
> > +};
> > +
> > +const struct attribute_group *m10bmc_dev_groups[] = {
> > +	&m10bmc_group,
> > +	NULL,
> > +};
> > +EXPORT_SYMBOL_GPL(m10bmc_dev_groups);
> >
> >  static int check_m10bmc_version(struct intel_m10bmc *ddata)  { @@
> > -158,37 +138,21 @@ static int check_m10bmc_version(struct intel_m10bmc
> *ddata)
> >  	return 0;
> >  }
> >
> > -static int intel_m10_bmc_spi_probe(struct spi_device *spi)
> > +int m10bmc_dev_init(struct intel_m10bmc *m10bmc)
> >  {
> > -	const struct spi_device_id *id = spi_get_device_id(spi);
> > -	struct device *dev = &spi->dev;
> > +	enum m10bmc_type type = m10bmc->type;
> >  	struct mfd_cell *cells;
> > -	struct intel_m10bmc *ddata;
> >  	int ret, n_cell;
> >
> > -	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
> > -	if (!ddata)
> > -		return -ENOMEM;
> > -
> > -	ddata->dev = dev;
> > -
> > -	ddata->regmap =
> > -		devm_regmap_init_spi_avmm(spi,
> &intel_m10bmc_regmap_config);
> > -	if (IS_ERR(ddata->regmap)) {
> > -		ret = PTR_ERR(ddata->regmap);
> > -		dev_err(dev, "Failed to allocate regmap: %d\n", ret);
> > -		return ret;
> > -	}
> > -
> > -	spi_set_drvdata(spi, ddata);
> > +	dev_set_drvdata(m10bmc->dev, m10bmc);
> 
> The naming is not consistent here, some are ddata, some are m10bmc, please
> keep a unified name acress all the patches.

I agree, I will fix it.

> 
> >
> > -	ret = check_m10bmc_version(ddata);
> > +	ret = check_m10bmc_version(m10bmc);
> >  	if (ret) {
> > -		dev_err(dev, "Failed to identify m10bmc hardware\n");
> > +		dev_err(m10bmc->dev, "Failed to identify m10bmc
> hardware\n");
> 
> Keep the dev local variable so that we don't have to change every related lines.

I agree, I will fix it.

> 
> >  		return ret;
> >  	}
> >
> > -	switch (id->driver_data) {
> > +	switch (type) {
> >  	case M10_N3000:
> >  		cells = m10bmc_pacn3000_subdevs;
> >  		n_cell = ARRAY_SIZE(m10bmc_pacn3000_subdevs);
> > @@ -205,33 +169,16 @@ static int intel_m10_bmc_spi_probe(struct
> spi_device *spi)
> >  		return -ENODEV;
> >  	}
> >
> > -	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO, cells,
> n_cell,
> > -				   NULL, 0, NULL);
> > +	ret = devm_mfd_add_devices(m10bmc->dev, PLATFORM_DEVID_AUTO,
> > +				   cells, n_cell, NULL, 0, NULL);
> 
> ditto
> 
> >  	if (ret)
> > -		dev_err(dev, "Failed to register sub-devices: %d\n", ret);
> > +		dev_err(m10bmc->dev, "Failed to register sub-devices: %d\n",
> > +			ret);
> 
> ditto
> 
> >
> >  	return ret;
> >  }
> > +EXPORT_SYMBOL_GPL(m10bmc_dev_init);
> >
> > -static const struct spi_device_id m10bmc_spi_id[] = {
> > -	{ "m10-n3000", M10_N3000 },
> > -	{ "m10-d5005", M10_D5005 },
> > -	{ "m10-n5010", M10_N5010 },
> > -	{ }
> > -};
> > -MODULE_DEVICE_TABLE(spi, m10bmc_spi_id);
> > -
> > -static struct spi_driver intel_m10bmc_spi_driver = {
> > -	.driver = {
> > -		.name = "intel-m10-bmc",
> > -		.dev_groups = m10bmc_groups,
> > -	},
> > -	.probe = intel_m10_bmc_spi_probe,
> > -	.id_table = m10bmc_spi_id,
> > -};
> > -module_spi_driver(intel_m10bmc_spi_driver);
> > -
> > -MODULE_DESCRIPTION("Intel MAX 10 BMC Device Driver");
> > +MODULE_DESCRIPTION("Intel MAX 10 BMC core MFD driver");
> >  MODULE_AUTHOR("Intel Corporation");
> >  MODULE_LICENSE("GPL v2");
> > -MODULE_ALIAS("spi:intel-m10-bmc");
> > diff --git a/drivers/mfd/intel-m10-bmc-spi.c
> > b/drivers/mfd/intel-m10-bmc-spi.c new file mode 100644 index
> > 000000000000..9cafbc0f89f0
> > --- /dev/null
> > +++ b/drivers/mfd/intel-m10-bmc-spi.c
> > @@ -0,0 +1,83 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Intel MAX 10 Board Management Controller chip
> 
> SPI driver for Intel MAX 10 ...

This is good for me.

> 
> > + *
> > + * Copyright (C) 2018-2021 Intel Corporation. All rights reserved.
> > + */
> > +#include <linux/bitfield.h>
> > +#include <linux/init.h>
> > +#include <linux/mfd/core.h>
> > +#include <linux/mfd/intel-m10-bmc.h>
> > +#include <linux/module.h>
> > +#include <linux/regmap.h>
> > +#include <linux/spi/spi.h>
> > +
> > +static const struct regmap_range m10bmc_regmap_range[] = {
> > +	regmap_reg_range(M10BMC_LEGACY_BUILD_VER,
> M10BMC_LEGACY_BUILD_VER),
> > +	regmap_reg_range(M10BMC_SYS_BASE, M10BMC_SYS_END),
> > +	regmap_reg_range(M10BMC_FLASH_BASE, M10BMC_FLASH_END), };
> > +
> > +static const struct regmap_access_table m10bmc_access_table = {
> > +	.yes_ranges	= m10bmc_regmap_range,
> > +	.n_yes_ranges	= ARRAY_SIZE(m10bmc_regmap_range),
> > +};
> > +
> > +static struct regmap_config intel_m10bmc_regmap_config = {
> > +	.reg_bits = 32,
> > +	.val_bits = 32,
> > +	.reg_stride = 4,
> > +	.wr_table = &m10bmc_access_table,
> > +	.rd_table = &m10bmc_access_table,
> > +	.max_register = M10BMC_MEM_END,
> > +};
> > +
> > +static int intel_m10_bmc_spi_probe(struct spi_device *spi) {
> > +	const struct spi_device_id *id = spi_get_device_id(spi);
> > +	struct device *dev = &spi->dev;
> > +	struct intel_m10bmc *ddata;
> > +	int ret;
> > +
> > +	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
> > +	if (!ddata)
> > +		return -ENOMEM;
> > +
> > +	ddata->dev = dev;
> > +	ddata->type = (enum m10bmc_type)(id->driver_data);
> > +
> > +	ddata->regmap =
> > +		devm_regmap_init_spi_avmm(spi,
> &intel_m10bmc_regmap_config);
> > +	if (IS_ERR(ddata->regmap)) {
> > +		ret = PTR_ERR(ddata->regmap);
> > +		dev_err(dev, "Failed to allocate regmap: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	spi_set_drvdata(spi, ddata);
> 
> Why we need this? I saw the dev.drvdata is set in core driver.

I agree, it is duplicate, we can remove it.

> 
> > +
> > +	return m10bmc_dev_init(ddata);
> > +}
> > +
> > +static const struct spi_device_id m10bmc_spi_id[] = {
> > +	{ "m10-n3000", M10_N3000 },
> > +	{ "m10-d5005", M10_D5005 },
> > +	{ "m10-n5010", M10_N5010 },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(spi, m10bmc_spi_id);
> > +
> > +static struct spi_driver intel_m10bmc_spi_driver = {
> > +	.driver = {
> > +		.name = "intel-m10-bmc",
> 
> Need renaming?

How about "intel-m10-bmc-spi"?

> 
> > +		.dev_groups = m10bmc_dev_groups,
> > +	},
> > +	.probe = intel_m10_bmc_spi_probe,
> > +	.id_table = m10bmc_spi_id,
> > +};
> > +module_spi_driver(intel_m10bmc_spi_driver);
> > +
> > +MODULE_DESCRIPTION("Intel MAX 10 BMC SPI bus interface");
> > +MODULE_AUTHOR("Intel Corporation"); MODULE_LICENSE("GPL");
> > +MODULE_ALIAS("spi:intel-m10-bmc");
> > diff --git a/include/linux/mfd/intel-m10-bmc.h
> > b/include/linux/mfd/intel-m10-bmc.h
> > index f0044b14136e..dd81ffdcf168 100644
> > --- a/include/linux/mfd/intel-m10-bmc.h
> > +++ b/include/linux/mfd/intel-m10-bmc.h
> > @@ -118,14 +118,23 @@
> >  /* Address of 4KB inverted bit vector containing staging area FLASH count */
> >  #define STAGING_FLASH_COUNT	0x17ffb000
> >
> > +/* Supported MAX10 BMC types */
> 
> Please use correct format for kernel doc comments

I will fix it on next version patch.

> 
> > +enum m10bmc_type {
> > +	M10_N3000,
> > +	M10_D5005,
> > +	M10_N5010,
> > +};
> > +
> >  /**
> >   * struct intel_m10bmc - Intel MAX 10 BMC parent driver data structure
> >   * @dev: this device
> >   * @regmap: the regmap used to access registers by m10bmc itself
> > + * @type: the type of MAX10 BMC
> >   */
> >  struct intel_m10bmc {
> >  	struct device *dev;
> >  	struct regmap *regmap;
> > +	enum m10bmc_type type;
> >  };
> >
> >  /*
> > @@ -159,4 +168,10 @@ m10bmc_raw_read(struct intel_m10bmc *m10bmc,
> > unsigned int addr,  #define m10bmc_sys_read(m10bmc, offset, val) \
> >  	m10bmc_raw_read(m10bmc, M10BMC_SYS_BASE + (offset), val)
> >
> > +/*
> > + * MAX10 BMC Core support
> > + */
> > +int m10bmc_dev_init(struct intel_m10bmc *m10bmc); extern const struct
> > +attribute_group *m10bmc_dev_groups[];
> > +
> >  #endif /* __MFD_INTEL_M10_BMC_H */
> > --
> > 2.26.2