[PATCH v4] hwmon: (pmbus): Add debugfs for status registers

[PATCH v4] hwmon: (pmbus): Add debugfs for status registers

[Eddie James]

From: "Edward A. James" <eajames@us.ibm.com>

Export all the available status registers through debugfs. This is
useful for hardware diagnostics, especially on multi-page pmbus devices,
as user-space access of the i2c space could corrupt the pmbus page
accounting.

Signed-off-by: Edward A. James <eajames@us.ibm.com>

Changes since v3:
 * Check for error in debugfs get functions.

Changes since v2:
 * Remove client driver conditional debugfs - add it for all devices.
 * Use scnprintf instead of snprintf.
 * Add module_init and module_exit to create root pmbus debugfs
   directory.
---
 drivers/hwmon/pmbus/pmbus_core.c | 210 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 210 insertions(+)

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index ef135d8..6ac89c9 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 <linux/debugfs.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -101,6 +102,7 @@ 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;
 
@@ -120,6 +122,12 @@ struct pmbus_data {
 	u8 currpage;
 };
 
+struct pmbus_debugfs_entry {
+	struct i2c_client *client;
+	u8 page;
+	u8 reg;
+};
+
 void pmbus_clear_cache(struct i2c_client *client)
 {
 	struct pmbus_data *data = i2c_get_clientdata(client);
@@ -1893,6 +1901,184 @@ static int pmbus_regulator_register(struct pmbus_data *data)
 }
 #endif
 
+static struct dentry *pmbus_debugfs_dir;	/* pmbus debugfs directory */
+
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+static int pmbus_debugfs_get(void *data, u64 *val)
+{
+	int rc;
+	struct pmbus_debugfs_entry *entry = data;
+
+	rc = _pmbus_read_byte_data(entry->client, entry->page, entry->reg);
+	if (rc < 0)
+		return rc;
+
+	*val = rc;
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(pmbus_debugfs_ops, pmbus_debugfs_get, NULL,
+			 "0x%02llx\n");
+
+static int pmbus_debugfs_get_status(void *data, u64 *val)
+{
+	int rc;
+	struct pmbus_debugfs_entry *entry = data;
+	struct pmbus_data *pdata = i2c_get_clientdata(entry->client);
+
+	rc = pdata->read_status(entry->client, entry->page);
+	if (rc < 0)
+		return rc;
+
+	*val = rc;
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(pmbus_debugfs_ops_status, pmbus_debugfs_get_status,
+			 NULL, "0x%04llx\n");
+
+static int pmbus_init_debugfs(struct i2c_client *client,
+			      struct pmbus_data *data)
+{
+	int i, idx = 0;
+	char name[PMBUS_NAME_SIZE];
+	struct pmbus_debugfs_entry *entries;
+
+	if (!pmbus_debugfs_dir)
+		return -ENODEV;
+
+	/*
+	 * 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)) {
+			/* No need to set reg as we have special read op. */
+			entries[idx].client = client;
+			entries[idx].page = i;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops_status);
+		}
+
+		if (data->info->func[i] & PMBUS_HAVE_STATUS_VOUT) {
+			entries[idx].client = client;
+			entries[idx].page = i;
+			entries[idx].reg = PMBUS_STATUS_VOUT;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d_vout", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops);
+		}
+
+		if (data->info->func[i] & PMBUS_HAVE_STATUS_IOUT) {
+			entries[idx].client = client;
+			entries[idx].page = i;
+			entries[idx].reg = PMBUS_STATUS_IOUT;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d_iout", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops);
+		}
+
+		if (data->info->func[i] & PMBUS_HAVE_STATUS_INPUT) {
+			entries[idx].client = client;
+			entries[idx].page = i;
+			entries[idx].reg = PMBUS_STATUS_INPUT;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d_input", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops);
+		}
+
+		if (data->info->func[i] & PMBUS_HAVE_STATUS_TEMP) {
+			entries[idx].client = client;
+			entries[idx].page = i;
+			entries[idx].reg = PMBUS_STATUS_TEMPERATURE;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d_temp", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops);
+		}
+
+		if (pmbus_check_byte_register(client, i, PMBUS_STATUS_CML)) {
+			entries[idx].client = client;
+			entries[idx].page = i;
+			entries[idx].reg = PMBUS_STATUS_CML;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d_cml", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops);
+		}
+
+		if (pmbus_check_byte_register(client, i, PMBUS_STATUS_OTHER)) {
+			entries[idx].client = client;
+			entries[idx].page = i;
+			entries[idx].reg = PMBUS_STATUS_OTHER;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d_other", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops);
+		}
+
+		if (pmbus_check_byte_register(client, i,
+					      PMBUS_STATUS_MFR_SPECIFIC)) {
+			entries[idx].client = client;
+			entries[idx].page = i;
+			entries[idx].reg = PMBUS_STATUS_MFR_SPECIFIC;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d_mfr", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops);
+		}
+
+		if (data->info->func[i] & PMBUS_HAVE_STATUS_FAN12) {
+			entries[idx].client = client;
+			entries[idx].page = i;
+			entries[idx].reg = PMBUS_STATUS_FAN_12;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d_fan12", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops);
+		}
+
+		if (data->info->func[i] & PMBUS_HAVE_STATUS_FAN34) {
+			entries[idx].client = client;
+			entries[idx].page = i;
+			entries[idx].reg = PMBUS_STATUS_FAN_34;
+			scnprintf(name, PMBUS_NAME_SIZE, "status%d_fan34", i);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[idx++],
+					    &pmbus_debugfs_ops);
+		}
+	}
+
+	return 0;
+}
+#else
+static int pmbus_init_debugfs(struct i2c_client *client,
+			      struct pmbus_data *data)
+{
+	return 0;
+}
+#endif	/* IS_ENABLED(CONFIG_DEBUG_FS) */
+
 int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id,
 		   struct pmbus_driver_info *info)
 {
@@ -1952,6 +2138,10 @@ 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");
+
 	return 0;
 
 out_unregister:
@@ -1965,12 +2155,32 @@ 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;
 }
 EXPORT_SYMBOL_GPL(pmbus_do_remove);
 
+static int __init pmbus_core_init(void)
+{
+	pmbus_debugfs_dir = debugfs_create_dir("pmbus", NULL);
+	if (IS_ERR(pmbus_debugfs_dir))
+		pmbus_debugfs_dir = NULL;
+
+	return 0;
+}
+
+static void __exit pmbus_core_exit(void)
+{
+	debugfs_remove_recursive(pmbus_debugfs_dir);
+}
+
+module_init(pmbus_core_init);
+module_exit(pmbus_core_exit);
+
 MODULE_AUTHOR("Guenter Roeck");
 MODULE_DESCRIPTION("PMBus core driver");
 MODULE_LICENSE("GPL");
-- 
1.8.3.1

Re: [PATCH v4] hwmon: (pmbus): Add debugfs for status registers

[Guenter Roeck]

On Mon, Aug 14, 2017 at 01:55:41PM -0500, Eddie James wrote:
> From: "Edward A. James" <eajames@us.ibm.com>
> 
> Export all the available status registers through debugfs. This is
> useful for hardware diagnostics, especially on multi-page pmbus devices,
> as user-space access of the i2c space could corrupt the pmbus page
> accounting.
> 
> Signed-off-by: Edward A. James <eajames@us.ibm.com>

Applied to hwmon-next.

> 
> Changes since v3:
>  * Check for error in debugfs get functions.
> 
> Changes since v2:
>  * Remove client driver conditional debugfs - add it for all devices.
>  * Use scnprintf instead of snprintf.
>  * Add module_init and module_exit to create root pmbus debugfs
>    directory.

Note that the changelog should be after the '---'; we don't want it in the
commit description.

Thanks,
Guenter

> ---
>  drivers/hwmon/pmbus/pmbus_core.c | 210 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 210 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index ef135d8..6ac89c9 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 <linux/debugfs.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/init.h>
> @@ -101,6 +102,7 @@ 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;
>  
> @@ -120,6 +122,12 @@ struct pmbus_data {
>  	u8 currpage;
>  };
>  
> +struct pmbus_debugfs_entry {
> +	struct i2c_client *client;
> +	u8 page;
> +	u8 reg;
> +};
> +
>  void pmbus_clear_cache(struct i2c_client *client)
>  {
>  	struct pmbus_data *data = i2c_get_clientdata(client);
> @@ -1893,6 +1901,184 @@ static int pmbus_regulator_register(struct pmbus_data *data)
>  }
>  #endif
>  
> +static struct dentry *pmbus_debugfs_dir;	/* pmbus debugfs directory */
> +
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +static int pmbus_debugfs_get(void *data, u64 *val)
> +{
> +	int rc;
> +	struct pmbus_debugfs_entry *entry = data;
> +
> +	rc = _pmbus_read_byte_data(entry->client, entry->page, entry->reg);
> +	if (rc < 0)
> +		return rc;
> +
> +	*val = rc;
> +
> +	return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(pmbus_debugfs_ops, pmbus_debugfs_get, NULL,
> +			 "0x%02llx\n");
> +
> +static int pmbus_debugfs_get_status(void *data, u64 *val)
> +{
> +	int rc;
> +	struct pmbus_debugfs_entry *entry = data;
> +	struct pmbus_data *pdata = i2c_get_clientdata(entry->client);
> +
> +	rc = pdata->read_status(entry->client, entry->page);
> +	if (rc < 0)
> +		return rc;
> +
> +	*val = rc;
> +
> +	return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(pmbus_debugfs_ops_status, pmbus_debugfs_get_status,
> +			 NULL, "0x%04llx\n");
> +
> +static int pmbus_init_debugfs(struct i2c_client *client,
> +			      struct pmbus_data *data)
> +{
> +	int i, idx = 0;
> +	char name[PMBUS_NAME_SIZE];
> +	struct pmbus_debugfs_entry *entries;
> +
> +	if (!pmbus_debugfs_dir)
> +		return -ENODEV;
> +
> +	/*
> +	 * 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)) {
> +			/* No need to set reg as we have special read op. */
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops_status);
> +		}
> +
> +		if (data->info->func[i] & PMBUS_HAVE_STATUS_VOUT) {
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			entries[idx].reg = PMBUS_STATUS_VOUT;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d_vout", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops);
> +		}
> +
> +		if (data->info->func[i] & PMBUS_HAVE_STATUS_IOUT) {
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			entries[idx].reg = PMBUS_STATUS_IOUT;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d_iout", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops);
> +		}
> +
> +		if (data->info->func[i] & PMBUS_HAVE_STATUS_INPUT) {
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			entries[idx].reg = PMBUS_STATUS_INPUT;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d_input", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops);
> +		}
> +
> +		if (data->info->func[i] & PMBUS_HAVE_STATUS_TEMP) {
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			entries[idx].reg = PMBUS_STATUS_TEMPERATURE;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d_temp", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops);
> +		}
> +
> +		if (pmbus_check_byte_register(client, i, PMBUS_STATUS_CML)) {
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			entries[idx].reg = PMBUS_STATUS_CML;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d_cml", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops);
> +		}
> +
> +		if (pmbus_check_byte_register(client, i, PMBUS_STATUS_OTHER)) {
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			entries[idx].reg = PMBUS_STATUS_OTHER;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d_other", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops);
> +		}
> +
> +		if (pmbus_check_byte_register(client, i,
> +					      PMBUS_STATUS_MFR_SPECIFIC)) {
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			entries[idx].reg = PMBUS_STATUS_MFR_SPECIFIC;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d_mfr", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops);
> +		}
> +
> +		if (data->info->func[i] & PMBUS_HAVE_STATUS_FAN12) {
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			entries[idx].reg = PMBUS_STATUS_FAN_12;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d_fan12", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops);
> +		}
> +
> +		if (data->info->func[i] & PMBUS_HAVE_STATUS_FAN34) {
> +			entries[idx].client = client;
> +			entries[idx].page = i;
> +			entries[idx].reg = PMBUS_STATUS_FAN_34;
> +			scnprintf(name, PMBUS_NAME_SIZE, "status%d_fan34", i);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[idx++],
> +					    &pmbus_debugfs_ops);
> +		}
> +	}
> +
> +	return 0;
> +}
> +#else
> +static int pmbus_init_debugfs(struct i2c_client *client,
> +			      struct pmbus_data *data)
> +{
> +	return 0;
> +}
> +#endif	/* IS_ENABLED(CONFIG_DEBUG_FS) */
> +
>  int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id,
>  		   struct pmbus_driver_info *info)
>  {
> @@ -1952,6 +2138,10 @@ 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");
> +
>  	return 0;
>  
>  out_unregister:
> @@ -1965,12 +2155,32 @@ 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;
>  }
>  EXPORT_SYMBOL_GPL(pmbus_do_remove);
>  
> +static int __init pmbus_core_init(void)
> +{
> +	pmbus_debugfs_dir = debugfs_create_dir("pmbus", NULL);
> +	if (IS_ERR(pmbus_debugfs_dir))
> +		pmbus_debugfs_dir = NULL;
> +
> +	return 0;
> +}
> +
> +static void __exit pmbus_core_exit(void)
> +{
> +	debugfs_remove_recursive(pmbus_debugfs_dir);
> +}
> +
> +module_init(pmbus_core_init);
> +module_exit(pmbus_core_exit);
> +
>  MODULE_AUTHOR("Guenter Roeck");
>  MODULE_DESCRIPTION("PMBus core driver");
>  MODULE_LICENSE("GPL");
> -- 
> 1.8.3.1
> 
> --
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