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[PATCH v2 4/4] hwmon: (pmbus): Add debugfs for status registers

Started byEddie James <eajames@linux.vnet.ibm.com>
First post2017-08-11 00:00 +0200
Last post2017-08-14 17:00 +0200
Articles 3 — 2 participants

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  [PATCH v2 4/4] hwmon: (pmbus): Add debugfs for status registers Eddie James <eajames@linux.vnet.ibm.com> - 2017-08-11 00:00 +0200
    Re: [PATCH v2 4/4] hwmon: (pmbus): Add debugfs for status registers Guenter Roeck <linux@roeck-us.net> - 2017-08-11 16:00 +0200
      Re: [PATCH v2 4/4] hwmon: (pmbus): Add debugfs for status registers Eddie James <eajames@linux.vnet.ibm.com> - 2017-08-14 17:00 +0200

#1709052 — [PATCH v2 4/4] hwmon: (pmbus): Add debugfs for status registers

FromEddie James <eajames@linux.vnet.ibm.com>
Date2017-08-11 00:00 +0200
Subject[PATCH v2 4/4] hwmon: (pmbus): Add debugfs for status registers
Message-ID<ud3EJ-384-17@gated-at.bofh.it>
From: "Edward A. James" <eajames@us.ibm.com>

Export all the available status registers through debugfs, if the client
driver wants them.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
---
 drivers/hwmon/pmbus/pmbus.h      |   6 ++
 drivers/hwmon/pmbus/pmbus_core.c | 201 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 207 insertions(+)

diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index bfcb13b..5f91a19 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -383,6 +383,12 @@ 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 */
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index ef135d8..b11ebec 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)
+{
+	struct pmbus_debugfs_entry *entry = data;
+
+	*val = _pmbus_read_byte_data(entry->client, entry->page, entry->reg);
+
+	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)
+{
+	struct pmbus_debugfs_entry *entry = data;
+	struct pmbus_data *pdata = i2c_get_clientdata(entry->client);
+
+	*val = pdata->read_status(entry->client, entry->page);
+
+	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;
+
+	/* Check if client driver requested debugfs support. */
+	if (!data->info->debugfs)
+		return 0;
+
+	/* Create the root pmbus debugfs directory if it's not created yet. */
+	if (!pmbus_debugfs_dir) {
+		pmbus_debugfs_dir = debugfs_create_dir("pmbus", NULL);
+		if (IS_ERR_OR_NULL(pmbus_debugfs_dir)) {
+			pmbus_debugfs_dir = NULL;
+			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;
+			snprintf(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;
+			snprintf(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;
+			snprintf(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;
+			snprintf(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;
+			snprintf(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;
+			snprintf(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;
+			snprintf(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;
+			snprintf(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;
+			snprintf(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;
+			snprintf(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:
@@ -1965,6 +2155,17 @@ 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);
+	if (pmbus_debugfs_dir && simple_empty(pmbus_debugfs_dir)) {
+		/*
+		 * Remove the root pmbus debugfs directory if we've removed
+		 * all the device directories underneath already.
+		 */
+		debugfs_remove(pmbus_debugfs_dir);
+		pmbus_debugfs_dir = NULL;
+	}
+
 	hwmon_device_unregister(data->hwmon_dev);
 	kfree(data->group.attrs);
 	return 0;
-- 
1.8.3.1

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#1709648

FromGuenter Roeck <linux@roeck-us.net>
Date2017-08-11 16:00 +0200
Message-ID<udiDM-4ef-11@gated-at.bofh.it>
In reply to#1709052
On 08/10/2017 02:57 PM, Eddie James wrote:
> From: "Edward A. James" <eajames@us.ibm.com>
> 
> Export all the available status registers through debugfs, if the client
> driver wants them.
> 
> Signed-off-by: Edward A. James <eajames@us.ibm.com>
> ---
>   drivers/hwmon/pmbus/pmbus.h      |   6 ++
>   drivers/hwmon/pmbus/pmbus_core.c | 201 +++++++++++++++++++++++++++++++++++++++
>   2 files changed, 207 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
> index bfcb13b..5f91a19 100644
> --- a/drivers/hwmon/pmbus/pmbus.h
> +++ b/drivers/hwmon/pmbus/pmbus.h
> @@ -383,6 +383,12 @@ 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 */
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index ef135d8..b11ebec 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)
> +{
> +	struct pmbus_debugfs_entry *entry = data;
> +
> +	*val = _pmbus_read_byte_data(entry->client, entry->page, entry->reg);
> +
> +	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)
> +{
> +	struct pmbus_debugfs_entry *entry = data;
> +	struct pmbus_data *pdata = i2c_get_clientdata(entry->client);
> +
> +	*val = pdata->read_status(entry->client, entry->page);
> +
> +	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;
> +
> +	/* Check if client driver requested debugfs support. */
> +	if (!data->info->debugfs)
> +		return 0;
> +

Let's just make this unconditional and drop the flag. I don't see the value
in enabling it per driver. The code is there anyway, might as well support it.

> +	/* Create the root pmbus debugfs directory if it's not created yet. */
> +	if (!pmbus_debugfs_dir) {
> +		pmbus_debugfs_dir = debugfs_create_dir("pmbus", NULL);
> +		if (IS_ERR_OR_NULL(pmbus_debugfs_dir)) {
> +			pmbus_debugfs_dir = NULL;
> +			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;
> +			snprintf(name, PMBUS_NAME_SIZE, "status%d", i);

scnprintf might be better.

> +			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;
> +			snprintf(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;
> +			snprintf(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;
> +			snprintf(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;
> +			snprintf(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;
> +			snprintf(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;
> +			snprintf(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;
> +			snprintf(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;
> +			snprintf(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;
> +			snprintf(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:
> @@ -1965,6 +2155,17 @@ 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);
> +	if (pmbus_debugfs_dir && simple_empty(pmbus_debugfs_dir)) {

Almost. Problem is that it is racy against insertions.
We would need a mutex to protect write accesses to pmbus_debugfs_dir.
Wonder if we can just add module_init/module_exit to pmbus_core.c
and initialize/remove the directory from there.

Guenter

> +		/*
> +		 * Remove the root pmbus debugfs directory if we've removed
> +		 * all the device directories underneath already.
> +		 */
> +		debugfs_remove(pmbus_debugfs_dir);
> +		pmbus_debugfs_dir = NULL;
> +	}
> +
>   	hwmon_device_unregister(data->hwmon_dev);
>   	kfree(data->group.attrs);
>   	return 0;
> 

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#1710994

FromEddie James <eajames@linux.vnet.ibm.com>
Date2017-08-14 17:00 +0200
Message-ID<uep0u-5p7-21@gated-at.bofh.it>
In reply to#1709648

On 08/11/2017 08:52 AM, Guenter Roeck wrote:
> On 08/10/2017 02:57 PM, Eddie James wrote:
>> From: "Edward A. James" <eajames@us.ibm.com>
>>
>> Export all the available status registers through debugfs, if the client
>> driver wants them.
>>
>> Signed-off-by: Edward A. James <eajames@us.ibm.com>
>> ---
>>   drivers/hwmon/pmbus/pmbus.h      |   6 ++
>>   drivers/hwmon/pmbus/pmbus_core.c | 201 
>> +++++++++++++++++++++++++++++++++++++++
>>   2 files changed, 207 insertions(+)
>>
>> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
>> index bfcb13b..5f91a19 100644
>> --- a/drivers/hwmon/pmbus/pmbus.h
>> +++ b/drivers/hwmon/pmbus/pmbus.h
>> @@ -383,6 +383,12 @@ 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 */
>> diff --git a/drivers/hwmon/pmbus/pmbus_core.c 
>> b/drivers/hwmon/pmbus/pmbus_core.c
>> index ef135d8..b11ebec 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)
>> +{
>> +    struct pmbus_debugfs_entry *entry = data;
>> +
>> +    *val = _pmbus_read_byte_data(entry->client, entry->page, 
>> entry->reg);
>> +
>> +    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)
>> +{
>> +    struct pmbus_debugfs_entry *entry = data;
>> +    struct pmbus_data *pdata = i2c_get_clientdata(entry->client);
>> +
>> +    *val = pdata->read_status(entry->client, entry->page);
>> +
>> +    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;
>> +
>> +    /* Check if client driver requested debugfs support. */
>> +    if (!data->info->debugfs)
>> +        return 0;
>> +
>
> Let's just make this unconditional and drop the flag. I don't see the 
> value
> in enabling it per driver. The code is there anyway, might as well 
> support it.
>
>> +    /* Create the root pmbus debugfs directory if it's not created 
>> yet. */
>> +    if (!pmbus_debugfs_dir) {
>> +        pmbus_debugfs_dir = debugfs_create_dir("pmbus", NULL);
>> +        if (IS_ERR_OR_NULL(pmbus_debugfs_dir)) {
>> +            pmbus_debugfs_dir = NULL;
>> +            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;
>> +            snprintf(name, PMBUS_NAME_SIZE, "status%d", i);
>
> scnprintf might be better.
>
>> +            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;
>> +            snprintf(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;
>> +            snprintf(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;
>> +            snprintf(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;
>> +            snprintf(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;
>> +            snprintf(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;
>> +            snprintf(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;
>> +            snprintf(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;
>> +            snprintf(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;
>> +            snprintf(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:
>> @@ -1965,6 +2155,17 @@ 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);
>> +    if (pmbus_debugfs_dir && simple_empty(pmbus_debugfs_dir)) {
>
> Almost. Problem is that it is racy against insertions.
> We would need a mutex to protect write accesses to pmbus_debugfs_dir.
> Wonder if we can just add module_init/module_exit to pmbus_core.c
> and initialize/remove the directory from there.

Got it, this worked well. Will send up v3 for this patch. Thanks for 
merging the others!

Eddie

>
> Guenter
>
>> +        /*
>> +         * Remove the root pmbus debugfs directory if we've removed
>> +         * all the device directories underneath already.
>> +         */
>> +        debugfs_remove(pmbus_debugfs_dir);
>> +        pmbus_debugfs_dir = NULL;
>> +    }
>> +
>>       hwmon_device_unregister(data->hwmon_dev);
>>       kfree(data->group.attrs);
>>       return 0;
>>
>

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