Re: [PATCH 1/4] drivers/hwmon/pmbus: Add IBM power supply hwmon driver

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

On Wed, Aug 02, 2017 at 04:17:10PM -0500, Eddie James wrote:
> From: "Edward A. James" <eajames@us.ibm.com>
> 
> Add the driver to monitor power supplies with hwmon over pmbus.
> 
> Signed-off-by: Edward A. James <eajames@us.ibm.com>
> ---
>  drivers/hwmon/pmbus/Kconfig  |  10 +++
>  drivers/hwmon/pmbus/Makefile |   1 +
>  drivers/hwmon/pmbus/ibmps.c  | 164 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 175 insertions(+)
>  create mode 100644 drivers/hwmon/pmbus/ibmps.c
> 
> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> index 68d717a..4eba657 100644
> --- a/drivers/hwmon/pmbus/Kconfig
> +++ b/drivers/hwmon/pmbus/Kconfig
> @@ -37,6 +37,16 @@ config SENSORS_ADM1275
>  	  This driver can also be built as a module. If so, the module will
>  	  be called adm1275.
>  
> +config SENSORS_IBMPS
> +	tristate "IBM Power Supply"

What if IBM ever produces another power supply ?
I think this should be more specific. Similar, ibmps/IBMPS is way
too generic.

> +	default n
> +	help
> +	  If you say yes here you get hardware monitoring support for IBM
> +	  power supply.
> +
> +	  This driver can also be built as a module. If so, the module will
> +	  be called ibmps.
> +
>  config SENSORS_IR35221
>  	tristate "Infineon IR35221"
>  	default n
> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> index 75bb7ca..e37b715 100644
> --- a/drivers/hwmon/pmbus/Makefile
> +++ b/drivers/hwmon/pmbus/Makefile
> @@ -5,6 +5,7 @@
>  obj-$(CONFIG_PMBUS)		+= pmbus_core.o
>  obj-$(CONFIG_SENSORS_PMBUS)	+= pmbus.o
>  obj-$(CONFIG_SENSORS_ADM1275)	+= adm1275.o
> +obj-$(CONFIG_SENSORS_IBMPS)	+= ibmps.o
>  obj-$(CONFIG_SENSORS_IR35221)	+= ir35221.o
>  obj-$(CONFIG_SENSORS_LM25066)	+= lm25066.o
>  obj-$(CONFIG_SENSORS_LTC2978)	+= ltc2978.o
> diff --git a/drivers/hwmon/pmbus/ibmps.c b/drivers/hwmon/pmbus/ibmps.c
> new file mode 100644
> index 0000000..1928dd9
> --- /dev/null
> +++ b/drivers/hwmon/pmbus/ibmps.c
> @@ -0,0 +1,164 @@
> +/*
> + * Copyright 2017 IBM Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/jiffies.h>
> +#include <linux/module.h>
> +
> +#include "pmbus.h"
> +
> +#define IBMPS_MFR_FAN_FAULT			BIT(0)
> +#define IBMPS_MFR_THERMAL_FAULT			BIT(1)
> +#define IBMPS_MFR_OV_FAULT			BIT(2)
> +#define IBMPS_MFR_UV_FAULT			BIT(3)
> +#define IBMPS_MFR_PS_KILL			BIT(4)
> +#define IBMPS_MFR_OC_FAULT			BIT(5)
> +#define IBMPS_MFR_VAUX_FAULT			BIT(6)
> +#define IBMPS_MFR_CURRENT_SHARE_WARNING		BIT(7)
> +
> +static int ibmps_read_word_data(struct i2c_client *client, int page, int reg);
> +
I don't see why this would require a forward declaration.
Why not just move the function ?

> +static int ibmps_read_byte_data(struct i2c_client *client, int page, int reg)
> +{
> +	int rc, mfr;
> +
> +	switch (reg) {
> +	case PMBUS_STATUS_BYTE:

Is the byte part still needed with the upcoming core changes ?

> +	case PMBUS_STATUS_WORD:
> +		rc = ibmps_read_word_data(client, page, PMBUS_STATUS_WORD);
> +		break;
> +	case PMBUS_STATUS_VOUT:
> +	case PMBUS_STATUS_IOUT:
> +	case PMBUS_STATUS_TEMPERATURE:
> +	case PMBUS_STATUS_FAN_12:
> +		rc = pmbus_read_byte_data(client, page, reg);
> +		if (rc < 0)
> +			return rc;
> +
> +		mfr = pmbus_read_byte_data(client, page,
> +					   PMBUS_STATUS_MFR_SPECIFIC);
> +		if (mfr < 0)
> +			return rc;
> +
> +		if (reg == PMBUS_STATUS_FAN_12) {
> +			if (mfr & IBMPS_MFR_FAN_FAULT)
> +				rc |= PB_FAN_FAN1_FAULT;
> +		} else if (reg == PMBUS_STATUS_TEMPERATURE) {
> +			if (mfr & IBMPS_MFR_THERMAL_FAULT)
> +				rc |= PB_TEMP_OT_FAULT;
> +		} else if (reg == PMBUS_STATUS_VOUT) {
> +			if (mfr & (IBMPS_MFR_OV_FAULT | IBMPS_MFR_VAUX_FAULT))
> +				rc |= PB_VOLTAGE_OV_FAULT;
> +			if (mfr & IBMPS_MFR_UV_FAULT)
> +				rc |= PB_VOLTAGE_UV_FAULT;
> +		} else if (reg == PMBUS_STATUS_IOUT) {
> +			if (mfr & IBMPS_MFR_OC_FAULT)
> +				rc |= PB_IOUT_OC_FAULT;
> +			if (mfr & IBMPS_MFR_CURRENT_SHARE_WARNING)
> +				rc |= PB_CURRENT_SHARE_FAULT;

Is changing a warning to a fault a good idea ?

> +		}
> +		break;
> +	default:
> +		if (reg >= PMBUS_VIRT_BASE)
> +			return -ENXIO;
> +
> +		rc = pmbus_read_byte_data(client, page, reg);
> +		break;

The idea here is to return -ENODATA to let the core handle it.
Please see similar drivers.

> +	}
> +
> +	return rc;
> +}
> +
> +static int ibmps_read_word_data(struct i2c_client *client, int page, int reg)
> +{
> +	int rc, mfr;
> +
> +	switch (reg) {
> +	case PMBUS_STATUS_BYTE:
> +	case PMBUS_STATUS_WORD:
> +		rc = pmbus_read_word_data(client, page, PMBUS_STATUS_WORD);
> +		if (rc < 0)
> +			return rc;
> +
> +		mfr = pmbus_read_byte_data(client, page,
> +					   PMBUS_STATUS_MFR_SPECIFIC);
> +		if (mfr < 0)
> +			return rc;
> +
> +		if (mfr & IBMPS_MFR_PS_KILL)
> +			rc |= PB_STATUS_OFF;
> +
> +		if (mfr)
> +			rc |= PB_STATUS_WORD_MFR;
> +		break;
> +	default:
> +		if (reg >= PMBUS_VIRT_BASE)
> +			return -ENXIO;

-ENODATA

> +
> +		rc = pmbus_read_word_data(client, page, reg);
> +		if (rc < 0)
> +			rc = ibmps_read_byte_data(client, page, reg);

I am a bit at loss here. Why ?

> +		break;
> +	}
> +
> +	return rc;
> +}
> +
> +static struct pmbus_driver_info ibmps_info = {
> +	.pages = 1,
> +	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
> +		PMBUS_HAVE_PIN | PMBUS_HAVE_FAN12 | PMBUS_HAVE_TEMP |
> +		PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3 | PMBUS_HAVE_STATUS_VOUT |
> +		PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_INPUT |
> +		PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_STATUS_FAN12,
> +	.read_byte_data = ibmps_read_byte_data,
> +	.read_word_data = ibmps_read_word_data,
> +};
> +
> +static int ibmps_probe(struct i2c_client *client,
> +		       const struct i2c_device_id *id)
> +{
> +	return pmbus_do_probe(client, id, &ibmps_info);
> +}
> +
> +static int ibmps_remove(struct i2c_client *client)
> +{
> +	return pmbus_do_remove(client);
> +}
> +
> +enum chips { witherspoon };
> +
> +static const struct i2c_device_id ibmps_id[] = {
> +	{ "witherspoon", witherspoon },

This is confusing. ibmps everywhere but witherspoon here ?

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, ibmps_id);
> +
> +static const struct of_device_id ibmps_of_match[] = {
> +	{ .compatible = "ibm,ibmps" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, p8_i2c_occ_of_match);
> +
> +static struct i2c_driver ibmps_driver = {
> +	.driver = {
> +		.name = "ibmps",
> +		.of_match_table = ibmps_of_match,
> +	},
> +	.probe = ibmps_probe,
> +	.remove = ibmps_remove,
> +	.id_table = ibmps_id,
> +};
> +
> +module_i2c_driver(ibmps_driver);
> +
> +MODULE_AUTHOR("Eddie James");
> +MODULE_DESCRIPTION("PMBus driver for IBM power supply");
> +MODULE_LICENSE("GPL");
> -- 
> 1.8.3.1
> 
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