power_supply_get_property() should ideally return -EAGAIN if it is
called while the power_supply is being registered. There was no way
previously to determine if use_cnt == 0 meant that the power_supply
wasn't fully registered yet, or if it had already been unregistered.

Add a new boolean to the power_supply struct to simply show if
registration is completed. Lastly, modify the check in
power_supply_show_property() to also ignore -EAGAIN when so it
doesn't complain about not returning the property.

Signed-off-by: Rhyland Klein <rkl...@nvidia.com>
---
v2:
 - Modify power_supply_show_property() to not complain if it
   sees a return value of -EAGAIN after calling
   power_supply_get_property().

 drivers/power/power_supply_core.c  | 6 +++++-
 drivers/power/power_supply_sysfs.c | 2 +-
 include/linux/power_supply.h       | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/power/power_supply_core.c 
b/drivers/power/power_supply_core.c
index b13cd074c52a..a39a47672979 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -491,8 +491,11 @@ int power_supply_get_property(struct power_supply *psy,
                            enum power_supply_property psp,
                            union power_supply_propval *val)
 {
-       if (atomic_read(&psy->use_cnt) <= 0)
+       if (atomic_read(&psy->use_cnt) <= 0) {
+               if (!psy->initialized)
+                       return -EAGAIN;
                return -ENODEV;
+       }
 
        return psy->desc->get_property(psy, psp, val);
 }
@@ -775,6 +778,7 @@ __power_supply_register(struct device *parent,
        if (rc)
                goto create_triggers_failed;
 
+       psy->initialized = true;
        /*
         * Update use_cnt after any uevents (most notably from device_add()).
         * We are here still during driver's probe but
diff --git a/drivers/power/power_supply_sysfs.c 
b/drivers/power/power_supply_sysfs.c
index 80fed98832f9..bcde8d13476a 100644
--- a/drivers/power/power_supply_sysfs.c
+++ b/drivers/power/power_supply_sysfs.c
@@ -83,7 +83,7 @@ static ssize_t power_supply_show_property(struct device *dev,
                        if (ret == -ENODATA)
                                dev_dbg(dev, "driver has no data for `%s' 
property\n",
                                        attr->attr.name);
-                       else if (ret != -ENODEV)
+                       else if (ret != -ENODEV && ret != -EAGAIN)
                                dev_err(dev, "driver failed to report `%s' 
property: %zd\n",
                                        attr->attr.name, ret);
                        return ret;
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 751061790626..3965503315ef 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -248,6 +248,7 @@ struct power_supply {
        struct delayed_work deferred_register_work;
        spinlock_t changed_lock;
        bool changed;
+       bool initialized;
        atomic_t use_cnt;
 #ifdef CONFIG_THERMAL
        struct thermal_zone_device *tzd;
-- 
1.9.1

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