[PATCH 1/2] power: bq27xxx_battery: add configurable poll_interval by sysfs

[Matt Ranostay]

Allow the poll_interval to be runtime configurable via an sysfs entry.
This is needed for udev control of the poll interval.

Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
---
 drivers/power/supply/bq27xxx_battery.c | 48 +++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/bq27xxx_battery.c 
b/drivers/power/supply/bq27xxx_battery.c
index 3f57dd54803a..955424e10ae2 100644
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -395,6 +395,36 @@ module_param(poll_interval, uint, 0644);
 MODULE_PARM_DESC(poll_interval,
                 "battery poll interval in seconds - 0 disables polling");
 
+
+static ssize_t show_poll_interval(struct device *dev,
+                                 struct device_attribute *attr, char *buf)
+{
+       return sprintf(buf, "%d\n", poll_interval);
+}
+
+static ssize_t store_poll_interval(struct device *dev,
+                                  struct device_attribute *attr,
+                                  const char *buf, size_t size)
+{
+       struct bq27xxx_device_info *di = dev_get_drvdata(dev);
+       int tmp = poll_interval;
+
+       if (sscanf(buf, "%d\n", &poll_interval) != 1)
+               return -EINVAL;
+
+       if (poll_interval < 0)
+               return -EINVAL;
+
+       if (tmp != poll_interval) {
+               cancel_delayed_work_sync(&di->work);
+               schedule_delayed_work(&di->work, 0);
+       }
+
+       return size;
+}
+
+static DEVICE_ATTR(poll_interval, 0644, show_poll_interval, 
store_poll_interval);
+
 /*
  * Common code for BQ27xxx devices
  */
@@ -946,6 +976,7 @@ int bq27xxx_battery_setup(struct bq27xxx_device_info *di)
 {
        struct power_supply_desc *psy_desc;
        struct power_supply_config psy_cfg = { .drv_data = di, };
+       int ret;
 
        INIT_DELAYED_WORK(&di->work, bq27xxx_battery_poll);
        mutex_init(&di->lock);
@@ -961,11 +992,19 @@ int bq27xxx_battery_setup(struct bq27xxx_device_info *di)
        psy_desc->num_properties = bq27xxx_battery_props[di->chip].size;
        psy_desc->get_property = bq27xxx_battery_get_property;
        psy_desc->external_power_changed = bq27xxx_external_power_changed;
+       dev_set_drvdata(di->dev, di);
+
+       ret = sysfs_create_file(&di->dev->kobj, &dev_attr_poll_interval.attr);
+       if (ret) {
+               dev_err(di->dev, "failed to register poll_interval sysfs 
entry");
+               return ret;
+       }
 
        di->bat = power_supply_register_no_ws(di->dev, psy_desc, &psy_cfg);
        if (IS_ERR(di->bat)) {
                dev_err(di->dev, "failed to register battery\n");
-               return PTR_ERR(di->bat);
+               ret = PTR_ERR(di->bat);
+               goto err_out;
        }
 
        dev_info(di->dev, "support ver. %s enabled\n", DRIVER_VERSION);
@@ -973,6 +1012,11 @@ int bq27xxx_battery_setup(struct bq27xxx_device_info *di)
        bq27xxx_battery_update(di);
 
        return 0;
+
+err_out:
+       sysfs_remove_file(&di->dev->kobj, &dev_attr_poll_interval.attr);
+
+       return ret;
 }
 EXPORT_SYMBOL_GPL(bq27xxx_battery_setup);
 
@@ -988,6 +1032,8 @@ void bq27xxx_battery_teardown(struct bq27xxx_device_info 
*di)
 
        cancel_delayed_work_sync(&di->work);
 
+       sysfs_remove_file(&di->dev->kobj, &dev_attr_poll_interval.attr);
+
        power_supply_unregister(di->bat);
 
        mutex_destroy(&di->lock);
-- 
2.7.4