From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753355AbdHJU34 (ORCPT ); Thu, 10 Aug 2017 16:29:56 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:35398 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752882AbdHJU3z (ORCPT ); Thu, 10 Aug 2017 16:29:55 -0400 Date: Thu, 10 Aug 2017 13:29:52 -0700 From: Guenter Roeck To: Eddie James Cc: jdelvare@suse.com, linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, joel@jms.id.au, jk@ozlabs.org, andrew@aj.id.au, cbostic@linux.vnet.ibm.com, "Edward A. James" Subject: Re: [PATCH 4/4] drivers/hwmon/pmbus: Add debugfs for status registers Message-ID: <20170810202952.GA13007@roeck-us.net> References: <1502317157-12648-1-git-send-email-eajames@linux.vnet.ibm.com> <1502317157-12648-5-git-send-email-eajames@linux.vnet.ibm.com> <20170810011524.GB6828@roeck-us.net> <318473de-fa13-2bf7-4f08-95db28c57d49@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <318473de-fa13-2bf7-4f08-95db28c57d49@linux.vnet.ibm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 10, 2017 at 03:15:57PM -0500, Eddie James wrote: > > > On 08/09/2017 08:15 PM, Guenter Roeck wrote: > >On Wed, Aug 09, 2017 at 05:19:17PM -0500, Eddie James wrote: > >>From: "Edward A. James" > >> > >>Export all the available status registers through debugfs, if the client > >>driver wants them. > >> > >>Signed-off-by: Edward A. James > >>--- > >> drivers/hwmon/pmbus/pmbus.c | 24 +++++- > >> drivers/hwmon/pmbus/pmbus.h | 11 +++ > >> drivers/hwmon/pmbus/pmbus_core.c | 175 +++++++++++++++++++++++++++++++++++++++ > >> 3 files changed, 209 insertions(+), 1 deletion(-) > >> > >>diff --git a/drivers/hwmon/pmbus/pmbus.c b/drivers/hwmon/pmbus/pmbus.c > >>index 7718e58..fc27417 100644 > >>--- a/drivers/hwmon/pmbus/pmbus.c > >>+++ b/drivers/hwmon/pmbus/pmbus.c > >That won't work: SENSORS_PMBUS is independent of PMBUS and does not have > >to be enabled even if PMBUS is enabled. This will have to be in pmbus_core.c. > > > >I would suggest to do the same as done with other drivers. Move > >pmbus_debugfs_dir into pmbus_core.c and create the directory on probe > >if it has not already been created. > > Hmm, I'm having trouble with this. Don't I have to call > debugfs_recursive_remove() on the pmbus_debugfs_dir when the pmbus driver is > unloaded? That can't be done from pmbus_core.c, as that is just device > probe/remove. I agree it makes sense to only create it if a device is going > to be using it (and is enabled in the kernel) but I think I need to declare > it here so I can remove it on unload. > So if CONFIG_SENSORS_PMBUS is not enabled, you won't have debugfs. actually, even worse, this effectively mandates that CONFIG_SENSORS_PMBUS must be enabled since it derclares a variable used by the core. That doesn't make sense. What makes even less sense is that it defines the variable in a module, thus _mandating_ that PMBUS_CORE is also built as module if this driver is built as module. Which you can't even express in Kconfig right now without adding a lot of complexity. Guenter > > > >>@@ -18,6 +18,7 @@ > >> * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. > >> */ > >>+#include > >> #include > >> #include > >> #include > >>@@ -230,7 +231,28 @@ static int pmbus_probe(struct i2c_client *client, > >> .id_table = pmbus_id, > >> }; > >>-module_i2c_driver(pmbus_driver); > >>+struct dentry *pmbus_debugfs_dir; > >>+EXPORT_SYMBOL_GPL(pmbus_debugfs_dir); > >>+ > >>+static int __init pmbus_init(void) > >>+{ > >>+ pmbus_debugfs_dir = debugfs_create_dir(pmbus_driver.driver.name, NULL); > >>+ if (IS_ERR(pmbus_debugfs_dir)) > >>+ /* Don't fail out if we don't have debugfs support. */ > >>+ pmbus_debugfs_dir = NULL; > >>+ > >>+ return i2c_add_driver(&pmbus_driver); > >>+} > >>+ > >>+static void __exit pmbus_exit(void) > >>+{ > >>+ debugfs_remove_recursive(pmbus_debugfs_dir); > >>+ > >>+ i2c_del_driver(&pmbus_driver); > >>+} > >>+ > >>+module_init(pmbus_init); > >>+module_exit(pmbus_exit); > >> MODULE_AUTHOR("Guenter Roeck"); > >> MODULE_DESCRIPTION("Generic PMBus driver"); > >>diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h > >>index bfcb13b..c772b83 100644 > >>--- a/drivers/hwmon/pmbus/pmbus.h > >>+++ b/drivers/hwmon/pmbus/pmbus.h > >>@@ -25,6 +25,8 @@ > >> #include > >> #include > >>+struct dentry; > >>+ > >> /* > >> * Registers > >> */ > >>@@ -383,6 +385,12 @@ struct pmbus_driver_info { > >> /* Regulator functionality, if supported by this chip driver. */ > >> int num_regulators; > >> const struct regulator_desc *reg_desc; > >>+ > >>+ /* > >>+ * Controls whether or not to create debugfs entries for this driver's > >>+ * devices. > >>+ */ > >>+ bool debugfs; > >> }; > >> /* Regulator ops */ > >>@@ -401,6 +409,9 @@ struct pmbus_driver_info { > >> .owner = THIS_MODULE, \ > >> } > >>+/* Handle for debugfs directory */ > >>+extern struct dentry *pmbus_debugfs_dir; > >>+ > >> /* Function declarations */ > >> void pmbus_clear_cache(struct i2c_client *client); > >>diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c > >>index 1a51f8f..afbd364 100644 > >>--- a/drivers/hwmon/pmbus/pmbus_core.c > >>+++ b/drivers/hwmon/pmbus/pmbus_core.c > >>@@ -19,6 +19,7 @@ > >> * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. > >> */ > >>+#include > >> #include > >> #include > >> #include > >>@@ -49,6 +50,9 @@ > >> #define PB_STATUS_FAN34_BASE (PB_STATUS_FAN_BASE + PMBUS_PAGES) > >> #define PB_STATUS_TEMP_BASE (PB_STATUS_FAN34_BASE + PMBUS_PAGES) > >> #define PB_STATUS_INPUT_BASE (PB_STATUS_TEMP_BASE + PMBUS_PAGES) > >>+#define PB_STATUS_CML_BASE (PB_STATUS_INPUT_BASE + PMBUS_PAGES) > >>+#define PB_STATUS_OTHER_BASE (PB_STATUS_CML_BASE + PMBUS_PAGES) > >>+#define PB_STATUS_MFR_BASE (PB_STATUS_OTHER_BASE + PMBUS_PAGES) > >We are not actively using those status registers, are we ? > >I am a bit concerned that we'll continuously read those status registers > >but don't do anything with it most of the time. Ultimately I'd prefer > >to get rid of all caching, not more, since it gets quite expensive > >on chips with many pages. > > > >Maybe just display uncached status register values in debugfs ? > > Sounds good. > > > > >> #define PB_STATUS_VMON_BASE (PB_STATUS_INPUT_BASE + 1) > >> #define PB_NUM_STATUS_REG (PB_STATUS_VMON_BASE + 1) > >>@@ -101,6 +105,7 @@ struct pmbus_data { > >> int num_attributes; > >> struct attribute_group group; > >> const struct attribute_group *groups[2]; > >>+ struct dentry *debugfs; /* debugfs device directory */ > >> struct pmbus_sensor *sensors; > >>@@ -119,6 +124,11 @@ struct pmbus_data { > >> u8 currpage; > >> }; > >>+struct pmbus_debugfs_entry { > >>+ struct device *dev; > >>+ int index; > >>+}; > >>+ > >> void pmbus_clear_cache(struct i2c_client *client) > >> { > >> struct pmbus_data *data = i2c_get_clientdata(client); > >>@@ -422,6 +432,19 @@ static struct pmbus_data *pmbus_update_device(struct device *dev) > >> = _pmbus_read_byte_data(client, i, > >> s->reg); > >> } > >>+ > >>+ if (!data->debugfs) > >>+ continue; > >>+ > >>+ data->status[PB_STATUS_CML_BASE + i] > >>+ = _pmbus_read_byte_data(client, i, > >>+ PMBUS_STATUS_CML); > >>+ data->status[PB_STATUS_OTHER_BASE + i] > >>+ = _pmbus_read_byte_data(client, i, > >>+ PMBUS_STATUS_OTHER); > >>+ data->status[PB_STATUS_MFR_BASE + i] > >>+ = _pmbus_read_byte_data(client, i, > >>+ PMBUS_STATUS_MFR_SPECIFIC); > >> } > >> if (info->func[0] & PMBUS_HAVE_STATUS_INPUT) > >>@@ -1891,6 +1914,151 @@ static int pmbus_regulator_register(struct pmbus_data *data) > >> } > >> #endif > >>+static int pmbus_debugfs_get(void *data, u64 *val) > >>+{ > >>+ struct pmbus_debugfs_entry *entry = data; > >>+ struct pmbus_data *pdata = pmbus_update_device(entry->dev); > >>+ > >>+ *val = pdata->status[entry->index]; > >>+ > >>+ return 0; > >>+} > >>+ > >>+DEFINE_DEBUGFS_ATTRIBUTE(pmbus_debugfs_ops8, pmbus_debugfs_get, NULL, > >>+ "0x%02llx\n"); > >>+DEFINE_DEBUGFS_ATTRIBUTE(pmbus_debugfs_ops16, pmbus_debugfs_get, NULL, > >>+ "0x%04llx\n"); > >>+ > >>+static int pmbus_init_debugfs(struct i2c_client *client, > >>+ struct pmbus_data *data) > >>+{ > >>+ int i, idx = 0; > >>+ struct dentry *dbg; > >>+ char name[PMBUS_NAME_SIZE]; > >>+ struct pmbus_debugfs_entry *entries; > >>+ > >>+ /* > >>+ * Either user didn't request debugfs or debugfs is not enabled in > >>+ * kernel. Exit but don't throw an error in these cases. > >>+ */ > >Here might be the place to initialize pmbus_debugfs_dir > >if it is not yet initialized. > > > >>+ if (!data->info->debugfs || !pmbus_debugfs_dir) > >>+ return 0; > >>+ > >>+ /* > >>+ * Create the debugfs directory for this device. Use the hwmon device > >>+ * name to avoid conflicts (hwmon numbers are globally unique). > >>+ */ > >>+ data->debugfs = debugfs_create_dir(dev_name(data->hwmon_dev), > >>+ pmbus_debugfs_dir); > >>+ if (IS_ERR_OR_NULL(data->debugfs)) { > >>+ data->debugfs = NULL; > >>+ return -ENODEV; > >>+ } > >>+ > >>+ /* Allocate the max possible entries we need. */ > >>+ entries = devm_kzalloc(data->dev, > >>+ sizeof(*entries) * (data->info->pages * 10), > >>+ GFP_KERNEL); > >>+ if (!entries) > >>+ return -ENOMEM; > >>+ > >>+ for (i = 0; i < data->info->pages; ++i) { > >>+ /* check accessibility of status register if it's not page 0 */ > >>+ if (!i || pmbus_check_status_register(client, i)) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops16); > >What is the point of the dbg variable ? > > > >>+ } > >>+ > >>+ if (data->info->func[i] & PMBUS_HAVE_STATUS_VOUT) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_VOUT_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d_vout", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops8); > >>+ } > >>+ > >>+ if (data->info->func[i] & PMBUS_HAVE_STATUS_IOUT) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_IOUT_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d_iout", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops8); > >>+ } > >>+ > >>+ if (data->info->func[i] & PMBUS_HAVE_STATUS_INPUT) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_INPUT_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d_input", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops8); > >>+ } > >>+ > >>+ if (data->info->func[i] & PMBUS_HAVE_STATUS_TEMP) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_TEMP_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d_temp", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops8); > >>+ } > >>+ > >>+ if (pmbus_check_byte_register(client, i, PMBUS_STATUS_CML)) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_CML_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d_cml", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops8); > >>+ } > >>+ > >>+ if (pmbus_check_byte_register(client, i, PMBUS_STATUS_OTHER)) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_OTHER_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d_other", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops8); > >>+ } > >>+ > >>+ if (pmbus_check_byte_register(client, i, > >>+ PMBUS_STATUS_MFR_SPECIFIC)) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_MFR_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d_mfr", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops8); > >>+ } > >>+ > >>+ if (data->info->func[i] & PMBUS_HAVE_STATUS_FAN12) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_FAN_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d_fan12", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops8); > >>+ } > >>+ > >>+ if (data->info->func[i] & PMBUS_HAVE_STATUS_FAN34) { > >>+ entries[idx].dev = data->hwmon_dev; > >>+ entries[idx].index = PB_STATUS_FAN34_BASE + i; > >>+ snprintf(name, PMBUS_NAME_SIZE, "status%d_fan34", i); > >>+ dbg = debugfs_create_file(name, 0444, data->debugfs, > >>+ &entries[idx++], > >>+ &pmbus_debugfs_ops8); > >>+ } > >>+ } > >>+ > >>+ return 0; > >>+} > >>+ > >Typically debugfs code is conditional. What happens if DEBUGFS > >is not enabled ? See below. > > > >> int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id, > >> struct pmbus_driver_info *info) > >> { > >>@@ -1950,6 +2118,10 @@ int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id, > >> if (ret) > >> goto out_unregister; > >>+ ret = pmbus_init_debugfs(client, data); > >>+ if (ret) > >>+ dev_warn(dev, "Failed to register debugfs\n"); > >I think this warning will be generated if debugfs is disabled. > >We should not do that. Consider putting the debugfs code into > >#fidef and have a dummy pmbus_init_debugfs() returning 0 if > >it is disabled. > > Yes, good idea. > > > > >>+ > >> return 0; > >> out_unregister: > >>@@ -1963,6 +2135,9 @@ int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id, > >> int pmbus_do_remove(struct i2c_client *client) > >> { > >> struct pmbus_data *data = i2c_get_clientdata(client); > >>+ > >>+ debugfs_remove_recursive(data->debugfs); > >>+ > >> hwmon_device_unregister(data->hwmon_dev); > >> kfree(data->group.attrs); > >> return 0; > >>-- > >>1.8.3.1 > >> > >>-- > >>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 > > -- > 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