From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-path: Received: from mail-pf0-f194.google.com ([209.85.192.194]:33844 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750911AbdHaELN (ORCPT ); Thu, 31 Aug 2017 00:11:13 -0400 Date: Wed, 30 Aug 2017 21:11:11 -0700 From: Guenter Roeck To: Christopher Bostic Cc: jdelvare@suse.com, corbet@lwn.net, linux-hwmon@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org Subject: Re: [PATCH 2/2] hwmon: (ucd9000) Add sysfs attribute to clear logged faults Message-ID: <20170831041111.GC26660@roeck-us.net> References: <20170830185536.71307-1-cbostic@linux.vnet.ibm.com> <20170830185536.71307-3-cbostic@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170830185536.71307-3-cbostic@linux.vnet.ibm.com> Sender: linux-hwmon-owner@vger.kernel.org List-Id: linux-hwmon@vger.kernel.org On Wed, Aug 30, 2017 at 01:55:36PM -0500, Christopher Bostic wrote: > Add ability to clear logged faults via sysfs. > I am not in favor of such chip specific commands, in this case for several reasons (besides it being a non-standard attribute). The logged faults are not read or used by the driver in the first place. Clearing them doesn't add any benefit for the driver. The command as written only clears non-paged logged faults, but no paged faults. While PMBus "lingo" talks of faults, those are really often just status bits, not "faults" from hwmon perspective. The content of the various fault bits and bites is highly chip specific. On top of that, each chip supported by the driver has different fault bits and bytes. To read the logged faults you have to access the chip directly, not through the driver. I don't see the benefit of providing a sysfs attribute to clear non-paged logged faults, but not doing anything else with it. If you want to do something special with those faults (or status bits/nytes), it might be more appropriate to create debugfs entries. Thanks, Guenter > Signed-off-by: Christopher Bostic > --- > drivers/hwmon/pmbus/ucd9000.c | 45 ++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 44 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c > index b74dbec..8bd8cb1 100644 > --- a/drivers/hwmon/pmbus/ucd9000.c > +++ b/drivers/hwmon/pmbus/ucd9000.c > @@ -27,6 +27,8 @@ > #include > #include > #include > +#include > +#include > #include "pmbus.h" > > enum chips { ucd9000, ucd90120, ucd90124, ucd90160, ucd9090, ucd90910 }; > @@ -35,6 +37,7 @@ > #define UCD9000_NUM_PAGES 0xd6 > #define UCD9000_FAN_CONFIG_INDEX 0xe7 > #define UCD9000_FAN_CONFIG 0xe8 > +#define UCD9000_LOGGED_FAULTS 0xea > #define UCD9000_DEVICE_ID 0xfd > > #define UCD9000_MON_TYPE(x) (((x) >> 5) & 0x07) > @@ -109,6 +112,36 @@ static int ucd9000_read_byte_data(struct i2c_client *client, int page, int reg) > return ret; > } > > +static ssize_t ucd9000_clear_logged_faults(struct device *dev, > + struct device_attribute *attr, const char *buf, > + size_t count) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + int ret; > + > + /* No page set required */ > + ret = i2c_smbus_write_byte_data(client, UCD9000_LOGGED_FAULTS, 0); > + if (ret) { > + dev_err(&client->dev, "Failed to clear logged faults: %d\n", > + ret); > + return ret; > + } > + > + return count; > +} > + > +static DEVICE_ATTR(clear_logged_faults, 0200, NULL, > + ucd9000_clear_logged_faults); > + > +static struct attribute *ucd9000_attributes[] = { > + &dev_attr_clear_logged_faults.attr, > + NULL > +}; > + > +static const struct attribute_group ucd9000_attr_group = { > + .attrs = ucd9000_attributes, > +}; > + > static const struct i2c_device_id ucd9000_id[] = { > {"ucd9000", ucd9000}, > {"ucd90120", ucd90120}, > @@ -263,9 +296,19 @@ static int ucd9000_probe(struct i2c_client *client, > | PMBUS_HAVE_FAN34 | PMBUS_HAVE_STATUS_FAN34; > } > > + ret = sysfs_create_group(&client->dev.kobj, &ucd9000_attr_group); > + if (ret < 0) > + return ret; > + > return pmbus_do_probe(client, mid, info); > } > > +static int ucd9000_remove(struct i2c_client *client) > +{ > + sysfs_remove_group(&client->dev.kobj, &ucd9000_attr_group); > + return pmbus_do_remove(client); > +} > + > /* This is the driver that will be inserted */ > static struct i2c_driver ucd9000_driver = { > .driver = { > @@ -273,7 +316,7 @@ static int ucd9000_probe(struct i2c_client *client, > .of_match_table = of_match_ptr(ucd9000_of_match), > }, > .probe = ucd9000_probe, > - .remove = pmbus_do_remove, > + .remove = ucd9000_remove, > .id_table = ucd9000_id, > }; > > -- > 1.8.2.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html