2022-04-22 20:52:44

by Quan Nguyen

[permalink] [raw]
Subject: [PATCH v8 8/9] mfd: smpro-mfd: Adds Ampere's Altra SMpro MFD driver

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 <[email protected]>
---
Changes in v8:
+ None

Changes in v7:
+ Smpro-mfd now significant changes in compare with simple-mfd-i2c
driver, remove the copyright note about simple-mfd-i2c [Quan]
+ Install bus->read/write() to handle multiple types of bus
access. [Quan]
+ Update license to MODULE_LICENSE("GPL") [Quan]
+ Add others minor refactor the code [Quan]

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 | 134 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 147 insertions(+)
create mode 100644 drivers/mfd/smpro-mfd.c

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 3b59456f5545..383d0e6cfb91 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 858cacf659d6..36f8981cc4fd 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -266,6 +266,7 @@ 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..485c4f89ebd9
--- /dev/null
+++ b/drivers/mfd/smpro-mfd.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Ampere Altra Family SMPro MFD - I2C
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ * Author: Quan Nguyen <[email protected]>
+ */
+
+#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 int smpro_mfd_write(void *context, const void *data, size_t count)
+{
+ struct device *dev = context;
+ struct i2c_client *i2c = to_i2c_client(dev);
+ int ret;
+
+ ret = i2c_master_send(i2c, data, count);
+ if (ret == count)
+ return 0;
+ else if (ret < 0)
+ return ret;
+ else
+ return -EIO;
+}
+
+static int smpro_mfd_read(void *context, const void *reg, size_t reg_size,
+ void *val, size_t val_size)
+{
+ struct device *dev = context;
+ struct i2c_client *i2c = to_i2c_client(dev);
+ struct i2c_msg xfer[2];
+ unsigned char buf[2];
+ int ret;
+
+ xfer[0].addr = i2c->addr;
+ xfer[0].flags = 0;
+
+ buf[0] = *(u8 *)reg;
+ buf[1] = val_size;
+ xfer[0].len = 2;
+ xfer[0].buf = buf;
+
+ xfer[1].addr = i2c->addr;
+ xfer[1].flags = I2C_M_RD;
+ xfer[1].len = val_size;
+ xfer[1].buf = val;
+
+ ret = i2c_transfer(i2c->adapter, xfer, 2);
+ if (ret == 2)
+ return 0;
+ else if (ret < 0)
+ return ret;
+ else
+ return -EIO;
+}
+
+static const struct regmap_bus smpro_regmap_bus = {
+ .read = smpro_mfd_read,
+ .write = smpro_mfd_write,
+ .val_format_endian_default = REGMAP_ENDIAN_BIG,
+};
+
+static bool smpro_mfd_readable_noinc_reg(struct device *dev, unsigned int reg)
+{
+ return (reg == 0x82 || reg == 0x85 || reg == 0x92 || reg == 0x95 ||
+ reg == 0xC2 || reg == 0xC5 || reg == 0xD2 || reg == 0xDA);
+}
+
+static const struct regmap_config smpro_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 16,
+ .readable_noinc_reg = smpro_mfd_readable_noinc_reg,
+};
+
+static const struct mfd_cell smpro_devs[] = {
+ MFD_CELL_NAME("smpro-hwmon"),
+ MFD_CELL_NAME("smpro-errmon"),
+ MFD_CELL_NAME("smpro-misc"),
+};
+
+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 = &smpro_regmap_config;
+
+ regmap = devm_regmap_init(&i2c->dev, &smpro_regmap_bus, &i2c->dev, 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 = &smpro_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 <[email protected]>");
+MODULE_DESCRIPTION("SMPRO MFD - I2C driver");
+MODULE_LICENSE("GPL");
--
2.35.1


2022-04-22 23:17:55

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH v8 8/9] mfd: smpro-mfd: Adds Ampere's Altra SMpro MFD driver

Hi Quan,

I love your patch! Perhaps something to improve:

[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on groeck-staging/hwmon-next lee-mfd/for-mfd-next v5.18-rc3 next-20220422]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url: https://github.com/intel-lab-lkp/linux/commits/Quan-Nguyen/Add-Ampere-s-Altra-SMPro-MFD-and-its-child-drivers/20220422-105732
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git c50c29a806113614098efd8da9fd7b48d605ba45
config: arm-randconfig-r004-20220422 (https://download.01.org/0day-ci/archive/20220423/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 5bd87350a5ae429baf8f373cb226a57b62f87280)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm cross compiling tool for clang build
# apt-get install binutils-arm-linux-gnueabi
# https://github.com/intel-lab-lkp/linux/commit/09ec873f0dd4611cb2df0150923d8906b9c5b2d1
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Quan-Nguyen/Add-Ampere-s-Altra-SMPro-MFD-and-its-child-drivers/20220422-105732
git checkout 09ec873f0dd4611cb2df0150923d8906b9c5b2d1
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash arch/arm/mach-at91/ drivers/hwmon/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>

All warnings (new ones prefixed by >>):

>> drivers/hwmon/smpro-hwmon.c:376:3: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
default:
^
drivers/hwmon/smpro-hwmon.c:376:3: note: insert 'break;' to avoid fall-through
default:
^
break;
1 warning generated.


vim +376 drivers/hwmon/smpro-hwmon.c

e1354080fc83378 Quan Nguyen 2022-04-22 359
e1354080fc83378 Quan Nguyen 2022-04-22 360 static umode_t smpro_is_visible(const void *data, enum hwmon_sensor_types type,
e1354080fc83378 Quan Nguyen 2022-04-22 361 u32 attr, int channel)
e1354080fc83378 Quan Nguyen 2022-04-22 362 {
e1354080fc83378 Quan Nguyen 2022-04-22 363 const struct smpro_hwmon *hwmon = data;
e1354080fc83378 Quan Nguyen 2022-04-22 364 unsigned int value;
e1354080fc83378 Quan Nguyen 2022-04-22 365 int ret;
e1354080fc83378 Quan Nguyen 2022-04-22 366
e1354080fc83378 Quan Nguyen 2022-04-22 367 switch (type) {
e1354080fc83378 Quan Nguyen 2022-04-22 368 case hwmon_temp:
e1354080fc83378 Quan Nguyen 2022-04-22 369 switch (attr) {
e1354080fc83378 Quan Nguyen 2022-04-22 370 case hwmon_temp_input:
e1354080fc83378 Quan Nguyen 2022-04-22 371 case hwmon_temp_label:
e1354080fc83378 Quan Nguyen 2022-04-22 372 case hwmon_temp_crit:
e1354080fc83378 Quan Nguyen 2022-04-22 373 ret = regmap_read(hwmon->regmap, temperature[channel].reg, &value);
e1354080fc83378 Quan Nguyen 2022-04-22 374 if (ret || value == 0xFFFF)
e1354080fc83378 Quan Nguyen 2022-04-22 375 return 0;
e1354080fc83378 Quan Nguyen 2022-04-22 @376 default:
e1354080fc83378 Quan Nguyen 2022-04-22 377 break;
e1354080fc83378 Quan Nguyen 2022-04-22 378 }
e1354080fc83378 Quan Nguyen 2022-04-22 379 break;
e1354080fc83378 Quan Nguyen 2022-04-22 380 default:
e1354080fc83378 Quan Nguyen 2022-04-22 381 break;
e1354080fc83378 Quan Nguyen 2022-04-22 382 }
e1354080fc83378 Quan Nguyen 2022-04-22 383
e1354080fc83378 Quan Nguyen 2022-04-22 384 return 0444;
e1354080fc83378 Quan Nguyen 2022-04-22 385 }
e1354080fc83378 Quan Nguyen 2022-04-22 386

--
0-DAY CI Kernel Test Service
https://01.org/lkp

2022-06-15 22:33:49

by Lee Jones

[permalink] [raw]
Subject: Re: [PATCH v8 8/9] mfd: smpro-mfd: Adds Ampere's Altra SMpro MFD driver

On Fri, 22 Apr 2022, Quan Nguyen wrote:

> Adds Multi-function devices driver for SMpro co-processor found on the

Please drop the term MFD and describe the device instead.

> Mt.Jade hardware reference platform with Ampere's Altra processor family.
>
> Signed-off-by: Quan Nguyen <[email protected]>
> ---
> Changes in v8:
> + None
>
> Changes in v7:
> + Smpro-mfd now significant changes in compare with simple-mfd-i2c
> driver, remove the copyright note about simple-mfd-i2c [Quan]
> + Install bus->read/write() to handle multiple types of bus
> access. [Quan]
> + Update license to MODULE_LICENSE("GPL") [Quan]
> + Add others minor refactor the code [Quan]
>
> 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 | 134 ++++++++++++++++++++++++++++++++++++++++

Please drop the 'mfd' part. Does 'core' work instead?

> 3 files changed, 147 insertions(+)
> create mode 100644 drivers/mfd/smpro-mfd.c
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 3b59456f5545..383d0e6cfb91 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"

Drop 'MFD'.

> + 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 858cacf659d6..36f8981cc4fd 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -266,6 +266,7 @@ 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..485c4f89ebd9
> --- /dev/null
> +++ b/drivers/mfd/smpro-mfd.c
> @@ -0,0 +1,134 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Ampere Altra Family SMPro MFD - I2C

Drop 'MFD' throughout.

> + * Copyright (c) 2022, Ampere Computing LLC
> + * Author: Quan Nguyen <[email protected]>
> + */
> +
> +#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>

Alphabetical.

> +/* Identification Registers */
> +#define MANUFACTURER_ID_REG 0x02
> +#define AMPERE_MANUFACTURER_ID 0xCD3A
> +
> +static int smpro_mfd_write(void *context, const void *data, size_t count)
> +{
> + struct device *dev = context;
> + struct i2c_client *i2c = to_i2c_client(dev);
> + int ret;
> +
> + ret = i2c_master_send(i2c, data, count);
> + if (ret == count)
> + return 0;
> + else if (ret < 0)
> + return ret;
> + else
> + return -EIO;
> +}
> +
> +static int smpro_mfd_read(void *context, const void *reg, size_t reg_size,
> + void *val, size_t val_size)
> +{
> + struct device *dev = context;
> + struct i2c_client *i2c = to_i2c_client(dev);
> + struct i2c_msg xfer[2];
> + unsigned char buf[2];
> + int ret;
> +
> + xfer[0].addr = i2c->addr;
> + xfer[0].flags = 0;
> +
> + buf[0] = *(u8 *)reg;
> + buf[1] = val_size;
> + xfer[0].len = 2;
> + xfer[0].buf = buf;
> +
> + xfer[1].addr = i2c->addr;
> + xfer[1].flags = I2C_M_RD;
> + xfer[1].len = val_size;
> + xfer[1].buf = val;
> +
> + ret = i2c_transfer(i2c->adapter, xfer, 2);
> + if (ret == 2)
> + return 0;
> + else if (ret < 0)
> + return ret;
> + else
> + return -EIO;
> +}

This looks all too familiar.

I wonder how generic these i2c call-backs actually are.

> +static const struct regmap_bus smpro_regmap_bus = {
> + .read = smpro_mfd_read,
> + .write = smpro_mfd_write,
> + .val_format_endian_default = REGMAP_ENDIAN_BIG,
> +};
> +
> +static bool smpro_mfd_readable_noinc_reg(struct device *dev, unsigned int reg)
> +{
> + return (reg == 0x82 || reg == 0x85 || reg == 0x92 || reg == 0x95 ||
> + reg == 0xC2 || reg == 0xC5 || reg == 0xD2 || reg == 0xDA);

No magic numbers. Please define these registers.

> +}
> +
> +static const struct regmap_config smpro_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 16,
> + .readable_noinc_reg = smpro_mfd_readable_noinc_reg,
> +};
> +
> +static const struct mfd_cell smpro_devs[] = {
> + MFD_CELL_NAME("smpro-hwmon"),
> + MFD_CELL_NAME("smpro-errmon"),
> + MFD_CELL_NAME("smpro-misc"),
> +};
> +
> +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 = &smpro_regmap_config;

This use-case is not currently supported.

Please return an error instead.

> + regmap = devm_regmap_init(&i2c->dev, &smpro_regmap_bus, &i2c->dev, config);
> + if (IS_ERR(regmap))
> + return PTR_ERR(regmap);
> +
> + /* Check for valid ID */

Decent #define nomenclature should render this comment superfluous.

> + 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 = &smpro_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",

"smpro-core"

> + .of_match_table = smpro_mfd_of_match,
> + },
> +};
> +module_i2c_driver(smpro_mfd_driver);
> +
> +MODULE_AUTHOR("Quan Nguyen <[email protected]>");
> +MODULE_DESCRIPTION("SMPRO MFD - I2C driver");
> +MODULE_LICENSE("GPL");

--
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

2022-06-29 10:04:13

by Quan Nguyen

[permalink] [raw]
Subject: Re: [PATCH v8 8/9] mfd: smpro-mfd: Adds Ampere's Altra SMpro MFD driver

Dear Lee Jones,

Thank you for the comment as on the link:
https://lore.kernel.org/lkml/[email protected]/T/#m476dce286d806bb3713f689663fa631f5a1f0909

I'm not sure what happen (maybe due to my bad junk filter) but I could
only see your email when checking the link mentioned above.

I will try to response on each of your comment inline.

Thank you very much for the comment.
- Quan

On 22/04/2022 09:46, Quan Nguyen wrote:
> Adds Multi-function devices driver for SMpro co-processor found on the
[Lee] Please drop the term MFD and describe the device instead.

[Quan] Will replace MFD with "core" as your suggestion.

> Mt.Jade hardware reference platform with Ampere's Altra processor family.
>
> Signed-off-by: Quan Nguyen <[email protected]>
> ---
> Changes in v8:
> + None
>
> Changes in v7:
> + Smpro-mfd now significant changes in compare with simple-mfd-i2c
> driver, remove the copyright note about simple-mfd-i2c [Quan]
> + Install bus->read/write() to handle multiple types of bus
> access. [Quan]
> + Update license to MODULE_LICENSE("GPL") [Quan]
> + Add others minor refactor the code [Quan]
>
> 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 | 134 ++++++++++++++++++++++++++++++++++++++++
[Lee] Please drop the 'mfd' part. Does 'core' work instead?

[Quan] Will drop the MFD thoroughly in next version.

> 3 files changed, 147 insertions(+)
> create mode 100644 drivers/mfd/smpro-mfd.c
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 3b59456f5545..383d0e6cfb91 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 858cacf659d6..36f8981cc4fd 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -266,6 +266,7 @@ 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..485c4f89ebd9
> --- /dev/null
> +++ b/drivers/mfd/smpro-mfd.c
> @@ -0,0 +1,134 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Ampere Altra Family SMPro MFD - I2C
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + * Author: Quan Nguyen <[email protected]>
> + */
> +
> +#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>
> +
[Lee] Alphabetical.

[Quan] Will sort the included files follow alphbetical order in next
version.

> +/* Identification Registers */
> +#define MANUFACTURER_ID_REG 0x02
> +#define AMPERE_MANUFACTURER_ID 0xCD3A
> +
> +static int smpro_mfd_write(void *context, const void *data, size_t count)
> +{
> + struct device *dev = context;
> + struct i2c_client *i2c = to_i2c_client(dev);
> + int ret;
> +
> + ret = i2c_master_send(i2c, data, count);
> + if (ret == count)
> + return 0;
> + else if (ret < 0)
> + return ret;
> + else
> + return -EIO;
> +}
> +
> +static int smpro_mfd_read(void *context, const void *reg, size_t reg_size,
> + void *val, size_t val_size)
> +{
> + struct device *dev = context;
> + struct i2c_client *i2c = to_i2c_client(dev);
> + struct i2c_msg xfer[2];
> + unsigned char buf[2];
> + int ret;
> +
> + xfer[0].addr = i2c->addr;
> + xfer[0].flags = 0;
> +
> + buf[0] = *(u8 *)reg;
> + buf[1] = val_size;
> + xfer[0].len = 2;
> + xfer[0].buf = buf;
> +
> + xfer[1].addr = i2c->addr;
> + xfer[1].flags = I2C_M_RD;
> + xfer[1].len = val_size;
> + xfer[1].buf = val;
> +
> + ret = i2c_transfer(i2c->adapter, xfer, 2);
> + if (ret == 2)
> + return 0;
> + else if (ret < 0)
> + return ret;
> + else
> + return -EIO;
> +}
> +
[Lee] This looks all too familiar.

I wonder how generic these i2c call-backs actually are.

[Quan] yes, this is similar with regmap_i2c_read() but with reg_size is
force to 2.
We can reuse regmap_i2c_read() but it needs to be exported from
drivers/base/regmap/regmap-i2c.c

> +static const struct regmap_bus smpro_regmap_bus = {
> + .read = smpro_mfd_read,
> + .write = smpro_mfd_write,
> + .val_format_endian_default = REGMAP_ENDIAN_BIG,
> +};
> +
> +static bool smpro_mfd_readable_noinc_reg(struct device *dev, unsigned int reg)
> +{
> + return (reg == 0x82 || reg == 0x85 || reg == 0x92 || reg == 0x95 ||
> + reg == 0xC2 || reg == 0xC5 || reg == 0xD2 || reg == 0xDA);
> +}
[Lee] No magic numbers. Please define these registers.

[Quan] Will fix this in next version.

> +
> +static const struct regmap_config smpro_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 16,
> + .readable_noinc_reg = smpro_mfd_readable_noinc_reg,
> +};
> +
> +static const struct mfd_cell smpro_devs[] = {
> + MFD_CELL_NAME("smpro-hwmon"),
> + MFD_CELL_NAME("smpro-errmon"),
> + MFD_CELL_NAME("smpro-misc"),
> +};
> +
> +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 = &smpro_regmap_config;
> +
[Lee] This use-case is not currently supported.

Please return an error instead.

[Quan] Will update in next version.

> + regmap = devm_regmap_init(&i2c->dev, &smpro_regmap_bus, &i2c->dev, config);
> + if (IS_ERR(regmap))
> + return PTR_ERR(regmap);
> +
> + /* Check for valid ID */
[Lee] Decent #define nomenclature should render this comment superfluous.

[Quan] Thanks, will remove in next version.

> + 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 = &smpro_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",
[Lee] "smpro-core"

[Quan] Will change mfd to "core" thoroughly.
Thanks for the review.

> + .of_match_table = smpro_mfd_of_match,
> + },
> +};
> +module_i2c_driver(smpro_mfd_driver);
> +
> +MODULE_AUTHOR("Quan Nguyen <[email protected]>");
> +MODULE_DESCRIPTION("SMPRO MFD - I2C driver");
> +MODULE_LICENSE("GPL");