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

From: Eddie James
Date: Mon Aug 14 2017 - 10:58:25 EST

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Next in thread: Eddie James: "[PATCH v2 2/4] hwmon: (pmbus): Access word data for STATUS_WORD"
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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@xxxxxxxxxx>

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

Signed-off-by: Edward A. James <eajames@xxxxxxxxxx>
---
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;

Next message: James Simmons: "Re: [PATCH] staging: lustre: lnet: fix incorrect arguments order calling lstcon_session_new"
Previous message: tip-bot for Waiman Long: "[tip:core/debugobjects] debugobjects: Make kmemleak ignore debug objects"
In reply to: Guenter Roeck: "Re: [PATCH v2 4/4] hwmon: (pmbus): Add debugfs for status registers"
Next in thread: Eddie James: "[PATCH v2 2/4] hwmon: (pmbus): Access word data for STATUS_WORD"
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