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Subject[PATCH v3] hwmon: (pmbus): Add debugfs for status registers
Date
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 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 | 200 +++++++++++++++++++++++++++++++++++++++
1 file changed, 200 insertions(+)

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index ef135d8..677bea1 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 +1901,174 @@ 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;
+
+ 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 +2128,10 @@ 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 +2145,32 @@ 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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