Re: [PATCH v3 2/2] hwmon: add MP5920 driver

[Guenter Roeck <linux@roeck-us.net>]

On 7/1/24 13:19, Thomas Weißschuh wrote:
> On 2024-07-01 17:56:01+0000, Alex Vdovydchenko wrote:
>> Add support for MPS Hot-Swap controller mp5920. This driver exposes
>> telemetry and limit value readings and writings.
>>
>> Signed-off-by: Alex Vdovydchenko <xzeol@yahoo.com>
>> ---
>>   Documentation/hwmon/index.rst  |  1 +
>>   Documentation/hwmon/mp5920.rst | 91 +++++++++++++++++++++++++++++++++
>>   drivers/hwmon/pmbus/Kconfig    |  9 ++++
>>   drivers/hwmon/pmbus/Makefile   |  1 +
>>   drivers/hwmon/pmbus/mp5920.c   | 93 ++++++++++++++++++++++++++++++++++
>>   5 files changed, 195 insertions(+)
>>   create mode 100644 Documentation/hwmon/mp5920.rst
>>   create mode 100644 drivers/hwmon/pmbus/mp5920.c
>>
>> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
>> index e92a3d5c7..9eba7e402 100644
>> --- a/Documentation/hwmon/index.rst
>> +++ b/Documentation/hwmon/index.rst
>> @@ -168,6 +168,7 @@ Hardware Monitoring Kernel Drivers
>>      mp2975
>>      mp2993
>>      mp5023
>> +   mp5920
>>      mp5990
>>      mp9941
>>      mpq8785
>> --- /dev/null
>> +++ b/Documentation/hwmon/mp5920.rst
>> @@ -0,0 +1,91 @@
>> +.. SPDX-License-Identifier: GPL-2.0
>> +
>> +Kernel driver mp5920
>> +====================
>> +
>> +Supported chips:
>> +
>> +  * MPS MP5920
>> +
>> +    Prefix: 'mp5920'
>> +
>> +  * Datasheet
>> +
>> +    Publicly available at the MPS website : https://www.monolithicpower.com/en/mp5920.html
>> +
>> +Authors:
>> +
>> +	Tony Ao <tony_ao@wiwynn.com>
>> +	Alex Vdovydchenko <xzeol@yahoo.com>
>> +
>> +Description
>> +-----------
>> +
>> +This driver implements support for Monolithic Power Systems, Inc. (MPS)
>> +MP5920 Hot-Swap Controller.
>> +
>> +Device compliant with:
>> +
>> +- PMBus rev 1.3 interface.
>> +
>> +Device supports direct and linear 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_rated_max**
>> +
>> +**in1_rated_min**
>> +
>> +**in1_crit**
>> +
>> +**in1_alarm**
>> +
>> +The driver provides the following attributes for output voltage:
>> +
>> +**in2_input**
>> +
>> +**in2_label**
>> +
>> +**in2_rated_max**
>> +
>> +**in2_rated_min**
>> +
>> +**in2_alarm**
>> +
>> +The driver provides the following attributes for output current:
>> +
>> +**curr1_input**
>> +
>> +**curr1_label**
>> +
>> +**curr1_crit**
>> +
>> +**curr1_alarm**
>> +
>> +**curr1_rated_max**
>> +
>> +The driver provides the following attributes for input power:
>> +
>> +**power1_input**
>> +
>> +**power1_label**
>> +
>> +**power1_max**
>> +
>> +**power1_rated_max**
>> +
>> +The driver provides the following attributes for temperature:
>> +
>> +**temp1_input**
>> +
>> +**temp1_max**
>> +
>> +**temp1_crit**
>> +
>> +**temp1_alarm**
>> --- a/drivers/hwmon/pmbus/Kconfig
>> +++ b/drivers/hwmon/pmbus/Kconfig
>> @@ -371,6 +371,15 @@ config SENSORS_MP5023
>>   	  This driver can also be built as a module. If so, the module will
>>   	  be called mp5023.
>>   
>> +config SENSORS_MP5920
>> +	tristate "MPS MP5920"
>> +	help
>> +	  If you say yes here you get hardware monitoring support for Monolithic
>> +	  MP5920.
>> +
>> +	  This driver can also be built as a module. If so, the module will
>> +	  be called mp5920.
>> +
>>   config SENSORS_MP5990
>>   	tristate "MPS MP5990"
>>   	help
>> --- a/drivers/hwmon/pmbus/Makefile
>> +++ b/drivers/hwmon/pmbus/Makefile
>> @@ -39,6 +39,7 @@ obj-$(CONFIG_SENSORS_MP2888)	+= mp2888.o
>>   obj-$(CONFIG_SENSORS_MP2975)	+= mp2975.o
>>   obj-$(CONFIG_SENSORS_MP2993)	+= mp2993.o
>>   obj-$(CONFIG_SENSORS_MP5023)	+= mp5023.o
>> +obj-$(CONFIG_SENSORS_MP5920)	+= mp5920.o
>>   obj-$(CONFIG_SENSORS_MP5990)	+= mp5990.o
>>   obj-$(CONFIG_SENSORS_MP9941)	+= mp9941.o
>>   obj-$(CONFIG_SENSORS_MPQ7932)	+= mpq7932.o
>> --- /dev/null
>> +++ b/drivers/hwmon/pmbus/mp5920.c
>> @@ -0,0 +1,82 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +#include "pmbus.h"
>> +
>> +static struct pmbus_driver_info mp5920_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] = 2266,
>> +	.b[PSC_VOLTAGE_IN] = 0,
>> +	.R[PSC_VOLTAGE_IN] = -1,
>> +	.m[PSC_VOLTAGE_OUT] = 2266,
>> +	.b[PSC_VOLTAGE_OUT] = 0,
>> +	.R[PSC_VOLTAGE_OUT] = -1,
>> +	.m[PSC_CURRENT_OUT] = 546,
>> +	.b[PSC_CURRENT_OUT] = 0,
>> +	.R[PSC_CURRENT_OUT] = -2,
>> +	.m[PSC_POWER] = 5840,
>> +	.b[PSC_POWER] = 0,
>> +	.R[PSC_POWER] = -3,
>> +	.m[PSC_TEMPERATURE] = 1067,
>> +	.b[PSC_TEMPERATURE] = 20500,
>> +	.R[PSC_TEMPERATURE] = -2,
>> +	.func[0] = PMBUS_HAVE_VIN  | PMBUS_HAVE_VOUT |
>> +		PMBUS_HAVE_IOUT | PMBUS_HAVE_POUT |
>> +		PMBUS_HAVE_TEMP,
>> +};
>> +
>> +static int mp5920_probe(struct i2c_client *client)
>> +{
>> +	struct device *dev =  &client->dev;
>> +	int ret;
>> +	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
>> +
>> +	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
> 
> If you do keep a custom call to i2c_smbus_read_block_data(),
> then you probably should also keep the call to i2c_check_functionality().
> 
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to read PMBUS_MFR_MODEL\n");
>> +		return ret;
>> +	}
> 
> If you use dev_err_probe() that would be shorter:
> 
> if (ret < 0)
> 	return dev_err_probe(dev, ret, "Failed to read PMBUS_MFR_MODEL\n");
> 
>> +	if (ret != 6 || strncmp(buf, "MP5920", 6)) {
>> +		buf[ret] = '\0';
>> +		dev_err(dev, "Model '%s' not supported\n", buf);
> 
> The manual 0-byte termination and the size + 1 can be avoided by using
> 
> dev_err_probe(dev, -ENODEV, "Model '%.*s' not supported\n", sizeof(buf), buf);
> 
>> +		return -ENODEV;
>> +	}
>> +
>> +	return pmbus_do_probe(client, &mp5920_info);
>> +}
>> +
>> +static const struct of_device_id mp5920_of_match[] = {
>> +	{ .compatible = "mps,mp5920" },
>> +	{ }
>> +};
>> +
>> +MODULE_DEVICE_TABLE(of, mp5920_of_match);
>> +
>> +static const struct i2c_device_id mp5920_id[] = {
>> +	{ "mp5920" },
>> +	{ }
>> +};
>> +
>> +MODULE_DEVICE_TABLE(i2c, mp5920_id);
>> +
>> +static struct i2c_driver mp5920_driver = {
>> +	.driver = {
>> +			.name = "mp5920",
>> +			},
> 
> Borked indentation.
> You can also use the shorter variant:
> 	.driver.name = "mp5920",
> 
> Where did the .driver.of_match_table go?
> 

I personally prefer the longer version, but, yes,
.driver.of_match_table disappeared. Good catch.

Thanks,
Guenter