[PATCH 4/4] drivers/hwmon/pmbus: Add debugfs for status registers

[Eddie James <eajames@linux.vnet.ibm.com>]

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.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
@@ -18,6 +18,7 @@
  * 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>
@@ -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 <linux/bitops.h>
 #include <linux/regulator/driver.h>
 
+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 <linux/debugfs.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -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)
 #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.
+	 */
+	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);
+		}
+
+		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;
+}
+
 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");
+
 	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