power: supply: ip5xxx: Fix integer overflow in current_now calculation

When current is larger than ~2A, the multiplication in current_now
property overflows and the kernel reports invalid negative current
value. Change the numerator and denominator while preserving their
ratio to allow up to +-6A before the overflow.

Fixes: 75853406fa27 ("power: supply: Add a driver for Injoinic power bank ICs")
Signed-off-by: Ondrej Jirman <megi@xff.cz>
Reviewed-by: Samuel Holland <samuel@sholland.org>
[use 149197/200 instead of 261095/350 as suggested by Samuel]
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

diff --git a/drivers/power/supply/ip5xxx_power.c b/drivers/power/supply/ip5xxx_power.c
index 218e8e6..00221e9 100644 (file)
--- a/drivers/power/supply/ip5xxx_power.c
+++ b/drivers/power/supply/ip5xxx_power.c
@@ -352,7 +352,7 @@ static int ip5xxx_battery_get_property(struct power_supply *psy,
                ret = ip5xxx_battery_read_adc(ip5xxx, IP5XXX_BATIADC_DAT0,
                                              IP5XXX_BATIADC_DAT1, &raw);
 
-               val->intval = DIV_ROUND_CLOSEST(raw * 745985, 1000);
+               val->intval = DIV_ROUND_CLOSEST(raw * 149197, 200);
                return 0;
 
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT: