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Message-ID: <b635d3b1-8854-443f-ba16-8df1ff8f2019@gmail.com>
Date: Mon, 6 Nov 2023 16:02:56 +0800
From: PeterYin <peteryin.openbmc@...il.com>
To: Guenter Roeck <linux@...ck-us.net>, patrick@...cx.xyz,
Jean Delvare <jdelvare@...e.com>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>,
Jonathan Corbet <corbet@....net>, linux-hwmon@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org
Subject: Re: [PATCH v1 2/2] hwmon: (pmbus) Add support for MPS Multi-phase
mp5990
Guenter Roeck 於 11/3/23 22:35 寫道:
> On 11/3/23 01:01, Peter Yin wrote:
>> Add support for mp5990 device from Monolithic Power Systems, Inc. (MPS)
>> vendor. This is a Hot-Swap Controller.
>>
>> Signed-off-by: Peter Yin <peteryin.openbmc@...il.com>
>> ---
>> Documentation/hwmon/index.rst | 1 +
>> Documentation/hwmon/mp5990.rst | 84 +++++++++++++++++++++++++++++++
>> drivers/hwmon/pmbus/Kconfig | 9 ++++
>> drivers/hwmon/pmbus/Makefile | 1 +
>> drivers/hwmon/pmbus/mp5990.c | 90 ++++++++++++++++++++++++++++++++++
>> 5 files changed, 185 insertions(+)
>> create mode 100644 Documentation/hwmon/mp5990.rst
>> create mode 100644 drivers/hwmon/pmbus/mp5990.c
>>
>> diff --git a/Documentation/hwmon/index.rst
>> b/Documentation/hwmon/index.rst
>> index 042e1cf9501b..8c70e10fc795 100644
>> --- a/Documentation/hwmon/index.rst
>> +++ b/Documentation/hwmon/index.rst
>> @@ -157,6 +157,7 @@ Hardware Monitoring Kernel Drivers
>> mp2888
>> mp2975
>> mp5023
>> + mp5990
>> nct6683
>> nct6775
>> nct7802
>> diff --git a/Documentation/hwmon/mp5990.rst
>> b/Documentation/hwmon/mp5990.rst
>> new file mode 100644
>> index 000000000000..8fc4e388ff7b
>> --- /dev/null
>> +++ b/Documentation/hwmon/mp5990.rst
>> @@ -0,0 +1,84 @@
>> +.. SPDX-License-Identifier: GPL-2.0
>> +
>> +Kernel driver mp5990
>> +====================
>> +
>> +Supported chips:
>> +
>> + * MPS MP5990
>> +
>> + Prefix: 'mp5990'
>> +
>> + * Datasheet
>> +
>> + Publicly available at the MPS website :
>> https://www.monolithicpower.com/en/mp5990.html
>> +
>> +Author:
>> +
>> + Peter Yin <peteryin.openbmc@...il.com>
>> +
>> +Description
>> +-----------
>> +
>> +This driver implements support for Monolithic Power Systems, Inc. (MPS)
>> +MP5990 Hot-Swap Controller.
>> +
>> +Device complaint with:
>
> compliant
>
Thanks, I will fix it.
>> +
>> +- PMBus rev 1.3 interface.
>> +
>> +Device supports direct format for reading input voltage, output voltage,
>> +output current, input power and temperature.
>> +
>> +The driver exports the following attributes via the 'sysfs' files
>> +for input voltage:
>> +
>> +**in1_input**
>> +
>> +**in1_label**
>> +
>> +**in1_max**
>> +
>> +**in1_max_alarm**
>> +
>> +**in1_min**
>> +
>> +**in1_min_alarm**
>> +
>> +The driver provides the following attributes for output voltage:
>> +
>> +**in2_input**
>> +
>> +**in2_label**
>> +
>> +**in2_alarm**
>> +
>> +The driver provides the following attributes for output current:
>> +
>> +**curr1_input**
>> +
>> +**curr1_label**
>> +
>> +**curr1_alarm**
>> +
>> +**curr1_max**
>> +
>> +The driver provides the following attributes for input power:
>> +
>> +**power1_input**
>> +
>> +**power1_label**
>> +
>> +**power1_alarm**
>> +
>> +The driver provides the following attributes for temperature:
>> +
>> +**temp1_input**
>> +
>> +**temp1_max**
>> +
>> +**temp1_max_alarm**
>> +
>> +**temp1_crit**
>> +
>> +**temp1_crit_alarm**
>> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
>> index 270b6336b76d..65a116f7744d 100644
>> --- a/drivers/hwmon/pmbus/Kconfig
>> +++ b/drivers/hwmon/pmbus/Kconfig
>> @@ -326,6 +326,15 @@ config SENSORS_MP5023
>> This driver can also be built as a module. If so, the module will
>> be called mp5023.
>> +config SENSORS_MP5990
>> + tristate "MPS MP5990"
>> + help
>> + If you say yes here you get hardware monitoring support for MPS
>> + MP5990.
>> +
>> + This driver can also be built as a module. If so, the module will
>> + be called mp5990.
>> +
>> config SENSORS_MPQ7932_REGULATOR
>> bool "Regulator support for MPQ7932"
>> depends on SENSORS_MPQ7932 && REGULATOR
>> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
>> index 84ee960a6c2d..212d9ca0acc9 100644
>> --- a/drivers/hwmon/pmbus/Makefile
>> +++ b/drivers/hwmon/pmbus/Makefile
>> @@ -35,6 +35,7 @@ obj-$(CONFIG_SENSORS_MAX8688) += max8688.o
>> obj-$(CONFIG_SENSORS_MP2888) += mp2888.o
>> obj-$(CONFIG_SENSORS_MP2975) += mp2975.o
>> obj-$(CONFIG_SENSORS_MP5023) += mp5023.o
>> +obj-$(CONFIG_SENSORS_MP5990) += mp5990.o
>> obj-$(CONFIG_SENSORS_MPQ7932) += mpq7932.o
>> obj-$(CONFIG_SENSORS_PLI1209BC) += pli1209bc.o
>> obj-$(CONFIG_SENSORS_PM6764TR) += pm6764tr.o
>> diff --git a/drivers/hwmon/pmbus/mp5990.c b/drivers/hwmon/pmbus/mp5990.c
>> new file mode 100644
>> index 000000000000..c3b31af9f750
>> --- /dev/null
>> +++ b/drivers/hwmon/pmbus/mp5990.c
>> @@ -0,0 +1,90 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Driver for MPS MP5990 Hot-Swap Controller
>> + */
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +#include <linux/pmbus.h>
>> +#include "pmbus.h"
>> +
>> +static int mp5990_read_byte_data(struct i2c_client *client, int page,
>> int reg)
>> +{
>> + switch (reg) {
>> + case PMBUS_VOUT_MODE:
>> + /*
>> + Enforce VOUT direct format, C4h reg BIT9
>> + default val is not match vout format
>> + */
>
> /*
> * Please use proper multi-line comments. Also, the problem here is
> that the
> * chip does not support the VOUT_MODE command, which should be mentioned.
> *
> * On top of that, overwriting PMBUS_VOUT_MODE result from the chip is
> only
> * necessary if the chip does not return an error when reading the value.
> * If that is the case, it should be mentioned in the comment. The above
> * does not explain why this would be needed, even if the command is not
> * (officially) supported by the chip. What does it return that requires
> * an overwrite ?
> */
>
The datasheet does not support the VOUT command, but the device responds
with a default value of 0x17. In the standard, 0x17 represents linear mode.
>> + return PB_VOUT_MODE_DIRECT;
>> + default:
>> + return -ENODATA;
>> + }
>> +}
>> +
>> +static struct pmbus_driver_info mp5990_info = {
>> + .pages = 1,
>> + .format[PSC_VOLTAGE_IN] = direct,
>> + .format[PSC_VOLTAGE_OUT] = direct,
>> + .format[PSC_CURRENT_OUT] = direct,
>> + .format[PSC_POWER] = direct,
>> + .format[PSC_TEMPERATURE] = direct,
>> + .m[PSC_VOLTAGE_IN] = 32,
>> + .b[PSC_VOLTAGE_IN] = 0,
>> + .R[PSC_VOLTAGE_IN] = 0,
>> + .m[PSC_VOLTAGE_OUT] = 32,
>> + .b[PSC_VOLTAGE_OUT] = 0,
>> + .R[PSC_VOLTAGE_OUT] = 0,
>> + .m[PSC_CURRENT_OUT] = 16,
>> + .b[PSC_CURRENT_OUT] = 0,
>> + .R[PSC_CURRENT_OUT] = 0,
>> + .m[PSC_POWER] = 1,
>> + .b[PSC_POWER] = 0,
>> + .R[PSC_POWER] = 0,
>> + .m[PSC_TEMPERATURE] = 1,
>> + .b[PSC_TEMPERATURE] = 0,
>> + .R[PSC_TEMPERATURE] = 0,
>> + .func[0] =
>> + PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_PIN |
>> + PMBUS_HAVE_TEMP | PMBUS_HAVE_IOUT |
>> + PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP,
>> + .read_byte_data = mp5990_read_byte_data,
>> +};
>> +
>> +static int mp5990_probe(struct i2c_client *client)
>> +{
>> + int ret;
>> +
>> + ret = i2c_smbus_write_byte_data(client, PMBUS_VOUT_MODE,
>> + PB_VOUT_MODE_DIRECT);
>
> According to the datasheet, the chip does not support the VOUT_MODE
> command. Supposedly, direct vs. linear mode is selected with bit 9
> of EFUSE_CFG. Even if the chip happens to "silently" support the command,
> the official command should be used to select the chip mode.
>
> Next question: Why use direct mode ? Linear mode is supported and would
> be much more flexible.
>
The MP5990, the VOUT linear mode is linear11, not linear16. Therefore,
we should enforce the VOUT in the direct format.
>> + if (ret < 0)
>> + return ret;
>> + return pmbus_do_probe(client, &mp5990_info);
>> +}
>> +
>> +static const struct of_device_id mp5990_of_match[] = {
>> + { .compatible = "mps,mp5990" },
>> + {}
>> +};
>> +
>> +static const struct i2c_device_id mp5990_id[] = {
>> + {"mp5990", 0},
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, mp5990_id);
>> +
>> +static struct i2c_driver mp5990_driver = {
>> + .driver = {
>> + .name = "mp5990",
>> + .of_match_table = of_match_ptr(mp5990_of_match),
>
> Using of_match_ptr() will result in a build failure if CONFIG_OF=n.
>
Should I use .of_match_table = mp5990_of_match, ?
>> + },
>> + .probe = mp5990_probe,
>> + .id_table = mp5990_id,
>> +};
>> +module_i2c_driver(mp5990_driver);
>> +
>> +MODULE_AUTHOR("Peter Yin <peter.yin@...ntatw.com>");
>> +MODULE_DESCRIPTION("PMBus driver for MP5990 HSC");
>> +MODULE_LICENSE("GPL");
>> +MODULE_IMPORT_NS(PMBUS);
>
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