power: supply: bq27xxx: fix error return in case of no bq27000 hdq battery

commit 2c334d038466ac509468fbe06905a32d202117db upstream.

Since commit

	commit f16d9fb6cf03 ("power: supply: bq27xxx: Retrieve again when busy")

the console log of some devices with hdq enabled but no bq27000 battery
(like e.g. the Pandaboard) is flooded with messages like:

[   34.247833] power_supply bq27000-battery: driver failed to report 'status' property: -1

as soon as user-space is finding a /sys entry and trying to read the
"status" property.

It turns out that the offending commit changes the logic to now return the
value of cache.flags if it is <0. This is likely under the assumption that
it is an error number. In normal errors from bq27xxx_read() this is indeed
the case.

But there is special code to detect if no bq27000 is installed or accessible
through hdq/1wire and wants to report this. In that case, the cache.flags
are set historically by

	commit 3dd843e1c26a ("bq27000: report missing device better.")

to constant -1 which did make reading properties return -ENODEV. So everything
appeared to be fine before the return value was passed upwards.

Now the -1 is returned as -EPERM instead of -ENODEV, triggering the error
condition in power_supply_format_property() which then floods the console log.

So we change the detection of missing bq27000 battery to simply set

	cache.flags = -ENODEV

instead of -1.

Fixes: f16d9fb6cf03 ("power: supply: bq27xxx: Retrieve again when busy")
Cc: Jerry Lv <Jerry.Lv@axis.com>
Cc: stable@vger.kernel.org
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Link: https://lore.kernel.org/r/692f79eb6fd541adb397038ea6e750d4de2deddf.1755945297.git.hns@goldelico.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
index b8131f823654d27d6d4cd2e7b5be8ded4574ad10..22a928c39fe6e3665c7afb584346634c5a894b65 100644 (file)
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -1829,7 +1829,7 @@ static void bq27xxx_battery_update_unlocked(struct bq27xxx_device_info *di)
 
        cache.flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, has_singe_flag);
        if ((cache.flags & 0xff) == 0xff)
-               cache.flags = -1; /* read error */
+               cache.flags = -ENODEV; /* read error */
        if (cache.flags >= 0) {
                cache.temperature = bq27xxx_battery_read_temperature(di);
                if (di->regs[BQ27XXX_REG_TTE] != INVALID_REG_ADDR)