Re: [PATCH v2 2/3] hwmon: (pmbus): Add POWER system power supply driver

[Guenter Roeck]

On Fri, Aug 11, 2017 at 09:30:59AM -0500, Eddie James wrote:
> 
> 
> On 08/10/2017 08:18 PM, Guenter Roeck wrote:
> >On Thu, Aug 10, 2017 at 05:19:45PM -0500, Eddie James wrote:
> >>From: "Edward A. James" <eajames@xxxxxxxxxx>
> >>
> >>Add the driver to monitor POWER system power supplies with hwmon over
> >>pmbus.
> >>
> >>Signed-off-by: Edward A. James <eajames@xxxxxxxxxx>
> >>---
> >>  drivers/hwmon/pmbus/Kconfig   |  10 +++
> >>  drivers/hwmon/pmbus/Makefile  |   1 +
> >>  drivers/hwmon/pmbus/powerps.c | 144 ++++++++++++++++++++++++++++++++++++++++++
> >>  3 files changed, 155 insertions(+)
> >>  create mode 100644 drivers/hwmon/pmbus/powerps.c
> >>
> >>diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> >>index 68d717a..8925c1a 100644
> >>--- a/drivers/hwmon/pmbus/Kconfig
> >>+++ b/drivers/hwmon/pmbus/Kconfig
> >>@@ -125,6 +125,16 @@ config SENSORS_MAX8688
> >>  	  This driver can also be built as a module. If so, the module will
> >>  	  be called max8688.
> >>+config SENSORS_POWERPS
> >>+	tristate "IBM POWER System Power Supply"
> >>+	default n
> >>+	help
> >>+	  If you say yes here you get hardware monitoring support for the IBM
> >>+	  POWER system power supply.
> >>+
> >>+	  This driver can also be built as a module. If so, the module will
> >>+	  be called powerps.
> >>+
> >>  config SENSORS_TPS40422
> >>  	tristate "TI TPS40422"
> >>  	default n
> >>diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> >>index 75bb7ca..3303af5 100644
> >>--- a/drivers/hwmon/pmbus/Makefile
> >>+++ b/drivers/hwmon/pmbus/Makefile
> >>@@ -13,6 +13,7 @@ obj-$(CONFIG_SENSORS_MAX16064)	+= max16064.o
> >>  obj-$(CONFIG_SENSORS_MAX20751)	+= max20751.o
> >>  obj-$(CONFIG_SENSORS_MAX34440)	+= max34440.o
> >>  obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
> >>+obj-$(CONFIG_SENSORS_POWERPS)	+= powerps.o
> >>  obj-$(CONFIG_SENSORS_TPS40422)	+= tps40422.o
> >>  obj-$(CONFIG_SENSORS_UCD9000)	+= ucd9000.o
> >>  obj-$(CONFIG_SENSORS_UCD9200)	+= ucd9200.o
> >>diff --git a/drivers/hwmon/pmbus/powerps.c b/drivers/hwmon/pmbus/powerps.c
> >>new file mode 100644
> >>index 0000000..21d28f2
> >>--- /dev/null
> >>+++ b/drivers/hwmon/pmbus/powerps.c
> >>@@ -0,0 +1,144 @@
> >>+/*
> >>+ * 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"
> >>+
> >>+/* STATUS_MFR_SPECIFIC bits */
> >>+#define POWERPS_MFR_FAN_FAULT			BIT(0)
> >>+#define POWERPS_MFR_THERMAL_FAULT		BIT(1)
> >>+#define POWERPS_MFR_OV_FAULT			BIT(2)
> >>+#define POWERPS_MFR_UV_FAULT			BIT(3)
> >>+#define POWERPS_MFR_PS_KILL			BIT(4)
> >>+#define POWERPS_MFR_OC_FAULT			BIT(5)
> >>+#define POWERPS_MFR_VAUX_FAULT			BIT(6)
> >>+#define POWERPS_MFR_CURRENT_SHARE_WARNING	BIT(7)
> >>+
> >>+static int powerps_read_byte_data(struct i2c_client *client, int page, int reg)
> >>+{
> >>+	int rc, mfr;
> >>+
> >>+	switch (reg) {
> >>+	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;
> >			return mfr; ?
> 
> Well I returned rc because we read the status register without error, so
> just return the status register contents without the additional mfr bits.
> It's not very clear... I better add a comment.
> 
Ah, yes, that makes sense. Agreed, please add a comment.

> >
> >>+
> >>+		/* Add MFR_SPECIFIC bits to the standard pmbus status regs. */
> >>+		if (reg == PMBUS_STATUS_FAN_12) {
> >>+			if (mfr & POWERPS_MFR_FAN_FAULT)
> >>+				rc |= PB_FAN_FAN1_FAULT;
> >>+		} else if (reg == PMBUS_STATUS_TEMPERATURE) {
> >>+			if (mfr & POWERPS_MFR_THERMAL_FAULT)
> >>+				rc |= PB_TEMP_OT_FAULT;
> >>+		} else if (reg == PMBUS_STATUS_VOUT) {
> >>+			if (mfr &
> >>+			    (POWERPS_MFR_OV_FAULT | POWERPS_MFR_VAUX_FAULT))
> >Wondering - this suggests that there is a VAUX. Would it make sense
> >to map it to PMBUS_VIRT_READ_VMON ?
> 
> There is no VAUX for this device. The power supply spec calls it "12Vaux
> Fault" but I don't know why.
> 
power supply designers having some fun ;-)

Guenter

> Thanks for the quick review!
> Eddie
> 
> >
> >>+				rc |= PB_VOLTAGE_OV_FAULT;
> >>+			if (mfr & POWERPS_MFR_UV_FAULT)
> >>+				rc |= PB_VOLTAGE_UV_FAULT;
> >>+		} else if (reg == PMBUS_STATUS_IOUT) {
> >>+			if (mfr & POWERPS_MFR_OC_FAULT)
> >>+				rc |= PB_IOUT_OC_FAULT;
> >>+			if (mfr & POWERPS_MFR_CURRENT_SHARE_WARNING)
> >>+				rc |= PB_CURRENT_SHARE_FAULT;
> >>+		}
> >>+		break;
> >>+	default:
> >>+		rc = -ENODATA;
> >>+		break;
> >>+	}
> >>+
> >>+	return rc;
> >>+}
> >>+
> >>+static int powerps_read_word_data(struct i2c_client *client, int page, int reg)
> >>+{
> >>+	int rc, mfr;
> >>+
> >>+	switch (reg) {
> >>+	case PMBUS_STATUS_WORD:
> >>+		rc = pmbus_read_word_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;
> >			return mfr; ?
> >
> >>+
> >>+		if (mfr & POWERPS_MFR_PS_KILL)
> >>+			rc |= PB_STATUS_OFF;
> >>+		break;
> >>+	default:
> >>+		rc = -ENODATA;
> >>+		break;
> >>+	}
> >>+
> >>+	return rc;
> >>+}
> >>+
> >>+static struct pmbus_driver_info powerps_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 = powerps_read_byte_data,
> >>+	.read_word_data = powerps_read_word_data,
> >>+	.debugfs = true,
> >>+};
> >>+
> >>+static int powerps_probe(struct i2c_client *client,
> >>+			 const struct i2c_device_id *id)
> >>+{
> >>+	return pmbus_do_probe(client, id, &powerps_info);
> >>+}
> >>+
> >>+static const struct i2c_device_id powerps_id[] = {
> >>+	{ "power_ps", 1 },
> >>+	{}
> >>+};
> >>+MODULE_DEVICE_TABLE(i2c, powerps_id);
> >>+
> >>+/* IBM provides many compatible power supplies; use a generic name. */
> >>+static const struct of_device_id powerps_of_match[] = {
> >>+	{ .compatible = "ibm,power-ps" },
> >>+	{}
> >>+};
> >>+MODULE_DEVICE_TABLE(of, powerps_of_match);
> >>+
> >>+static struct i2c_driver powerps_driver = {
> >>+	.driver = {
> >>+		.name = "powerps",
> >>+		.of_match_table = powerps_of_match,
> >>+	},
> >>+	.probe = powerps_probe,
> >>+	.remove = pmbus_do_remove,
> >>+	.id_table = powerps_id,
> >>+};
> >>+
> >>+module_i2c_driver(powerps_driver);
> >>+
> >>+MODULE_AUTHOR("Eddie James");
> >>+MODULE_DESCRIPTION("PMBus driver for POWER system power supplies");
> >>+MODULE_LICENSE("GPL");
> >>-- 
> >>1.8.3.1
> >>
>