[PATCH 2/2] power: bq27xxx_battery: allow kernel poll_interval parameter runtime update

[Matt Ranostay]

Fix issue with poll_interval being not updated till the previous
interval expired.

Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
---
 drivers/power/supply/bq27xxx_battery.c | 38 +++++++++++++++++++++++++++++++++-
 include/linux/power/bq27xxx_battery.h  |  1 +
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/bq27xxx_battery.c 
b/drivers/power/supply/bq27xxx_battery.c
index 955424e10ae2..96fd3eec98da 100644
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -39,6 +39,7 @@
 
 #include <linux/device.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/param.h>
 #include <linux/jiffies.h>
 #include <linux/workqueue.h>
@@ -390,8 +391,35 @@ static struct {
        BQ27XXX_PROP(BQ27421, bq27421_battery_props),
 };
 
+static DEFINE_MUTEX(param_lock);
+static LIST_HEAD(bq27xxx_battery_devices);
+
+static int poll_interval_param_set(const char *val, const struct kernel_param 
*kp)
+{
+       struct bq27xxx_device_info *di;
+       int ret;
+
+       ret = param_set_uint(val, kp);
+       if (ret < 0)
+               return ret;
+
+       mutex_lock(&param_lock);
+       list_for_each_entry(di, &bq27xxx_battery_devices, list) {
+               cancel_delayed_work_sync(&di->work);
+               schedule_delayed_work(&di->work, 0);
+       }
+       mutex_unlock(&param_lock);
+
+       return ret;
+}
+
+static const struct kernel_param_ops param_ops_poll_interval = {
+       .get = param_get_ushort,
+       .set = poll_interval_param_set,
+};
+
 static unsigned int poll_interval = 360;
-module_param(poll_interval, uint, 0644);
+module_param_cb(poll_interval, &param_ops_poll_interval, &poll_interval, 0644);
 MODULE_PARM_DESC(poll_interval,
                 "battery poll interval in seconds - 0 disables polling");
 
@@ -1011,6 +1039,10 @@ int bq27xxx_battery_setup(struct bq27xxx_device_info *di)
 
        bq27xxx_battery_update(di);
 
+       mutex_lock(&param_lock);
+       list_add(&di->list, &bq27xxx_battery_devices);
+       mutex_unlock(&param_lock);
+
        return 0;
 
 err_out:
@@ -1036,6 +1068,10 @@ void bq27xxx_battery_teardown(struct bq27xxx_device_info 
*di)
 
        power_supply_unregister(di->bat);
 
+       mutex_lock(&param_lock);
+       list_del(&di->list);
+       mutex_unlock(&param_lock);
+
        mutex_destroy(&di->lock);
 }
 EXPORT_SYMBOL_GPL(bq27xxx_battery_teardown);
diff --git a/include/linux/power/bq27xxx_battery.h 
b/include/linux/power/bq27xxx_battery.h
index b50c0492629d..e30deb046156 100644
--- a/include/linux/power/bq27xxx_battery.h
+++ b/include/linux/power/bq27xxx_battery.h
@@ -58,6 +58,7 @@ struct bq27xxx_device_info {
        unsigned long last_update;
        struct delayed_work work;
        struct power_supply *bat;
+       struct list_head list;
        struct mutex lock;
        u8 *regs;
 };
-- 
2.7.4