[PATCH 1/3] pmbus: support for custom sysfs attributes

[Adamski, Krzysztof (Nokia - PL/Wroclaw)]

This patch makes it possible to pass custom struct attribute_group array
via the pmbus_driver_info struct so that those can be added to the
attribute groups passed to hwmon_device_register_with_groups().

This makes it possible to register custom sysfs attributes by PMBUS
drivers similar to how you can do this with most other busses/classes.

Signed-off-by: Krzysztof Adamski <krzysztof.adam...@nokia.com>
---
 drivers/hwmon/pmbus/pmbus.h      |  3 +++
 drivers/hwmon/pmbus/pmbus_core.c | 13 ++++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index 1d24397d36ec..fb267ec11623 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -417,6 +417,9 @@ struct pmbus_driver_info {
        /* Regulator functionality, if supported by this chip driver. */
        int num_regulators;
        const struct regulator_desc *reg_desc;
+
+       /* custom attributes */
+       const struct attribute_group **groups;
 };
 
 /* Regulator ops */
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 2e2b5851139c..7a7dcdc8acc9 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -103,7 +103,7 @@ struct pmbus_data {
        int max_attributes;
        int num_attributes;
        struct attribute_group group;
-       const struct attribute_group *groups[2];
+       const struct attribute_group **groups;
        struct dentry *debugfs;         /* debugfs device directory */
 
        struct pmbus_sensor *sensors;
@@ -2305,6 +2305,7 @@ int pmbus_do_probe(struct i2c_client *client, const 
struct i2c_device_id *id,
        struct device *dev = &client->dev;
        const struct pmbus_platform_data *pdata = dev_get_platdata(dev);
        struct pmbus_data *data;
+       size_t groups_num = 0;
        int ret;
 
        if (!info)
@@ -2319,6 +2320,15 @@ int pmbus_do_probe(struct i2c_client *client, const 
struct i2c_device_id *id,
        if (!data)
                return -ENOMEM;
 
+       if (info->groups)
+               while (info->groups[groups_num])
+                       groups_num++;
+
+       data->groups = devm_kcalloc(dev, groups_num + 2, sizeof(void *),
+                                   GFP_KERNEL);
+       if (!data->groups)
+               return -ENOMEM;
+
        i2c_set_clientdata(client, data);
        mutex_init(&data->update_lock);
        data->dev = dev;
@@ -2346,6 +2356,7 @@ int pmbus_do_probe(struct i2c_client *client, const 
struct i2c_device_id *id,
        }
 
        data->groups[0] = &data->group;
+       memcpy(data->groups + 1, info->groups, sizeof(void *) * groups_num);
        data->hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
                                                            data, data->groups);
        if (IS_ERR(data->hwmon_dev)) {
-- 
2.20.1