* [PATCH] power: supply: ip5xxx: Fix integer overflow in current_now calculation
@ 2022-10-28 22:40 Ondrej Jirman
2022-10-28 23:06 ` Samuel Holland
0 siblings, 1 reply; 3+ messages in thread
From: Ondrej Jirman @ 2022-10-28 22:40 UTC (permalink / raw)
To: linux-rockchip
Cc: Ondrej Jirman, Samuel Holland, Sebastian Reichel,
open list:POWER SUPPLY CLASS/SUBSYSTEM and DRIVERS, open list
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>
---
drivers/power/supply/ip5xxx_power.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/power/supply/ip5xxx_power.c b/drivers/power/supply/ip5xxx_power.c
index 02ee4d252a3e..f39cb2f7aa11 100644
--- a/drivers/power/supply/ip5xxx_power.c
+++ b/drivers/power/supply/ip5xxx_power.c
@@ -398,7 +398,7 @@ 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 * 261095, 350);
return 0;
case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
--
2.38.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] power: supply: ip5xxx: Fix integer overflow in current_now calculation
2022-10-28 22:40 [PATCH] power: supply: ip5xxx: Fix integer overflow in current_now calculation Ondrej Jirman
@ 2022-10-28 23:06 ` Samuel Holland
2022-11-01 0:08 ` Sebastian Reichel
0 siblings, 1 reply; 3+ messages in thread
From: Samuel Holland @ 2022-10-28 23:06 UTC (permalink / raw)
To: Ondrej Jirman, Sebastian Reichel
Cc: open list:POWER SUPPLY CLASS/SUBSYSTEM and DRIVERS, open list,
linux-rockchip
On 10/28/22 17:40, Ondrej Jirman wrote:
> 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>
> ---
> drivers/power/supply/ip5xxx_power.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/power/supply/ip5xxx_power.c b/drivers/power/supply/ip5xxx_power.c
> index 02ee4d252a3e..f39cb2f7aa11 100644
> --- a/drivers/power/supply/ip5xxx_power.c
> +++ b/drivers/power/supply/ip5xxx_power.c
> @@ -398,7 +398,7 @@ 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 * 261095, 350);
DIV_ROUND_CLOSEST(raw * 149197, 200) would be marginally more accurate,
but it doesn't matter in practice.
> return 0;
>
> case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] power: supply: ip5xxx: Fix integer overflow in current_now calculation
2022-10-28 23:06 ` Samuel Holland
@ 2022-11-01 0:08 ` Sebastian Reichel
0 siblings, 0 replies; 3+ messages in thread
From: Sebastian Reichel @ 2022-11-01 0:08 UTC (permalink / raw)
To: Samuel Holland
Cc: Ondrej Jirman,
open list:POWER SUPPLY CLASS/SUBSYSTEM and DRIVERS, open list,
linux-rockchip
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Hi,
On Fri, Oct 28, 2022 at 06:06:07PM -0500, Samuel Holland wrote:
> On 10/28/22 17:40, Ondrej Jirman wrote:
> > 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>
>
> > ---
> > drivers/power/supply/ip5xxx_power.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/power/supply/ip5xxx_power.c b/drivers/power/supply/ip5xxx_power.c
> > index 02ee4d252a3e..f39cb2f7aa11 100644
> > --- a/drivers/power/supply/ip5xxx_power.c
> > +++ b/drivers/power/supply/ip5xxx_power.c
> > @@ -398,7 +398,7 @@ 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 * 261095, 350);
>
> DIV_ROUND_CLOSEST(raw * 149197, 200) would be marginally more accurate,
> but it doesn't matter in practice.
Thanks, I queued it with that change included.
-- Sebastian
>
> > return 0;
> >
> > case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
>
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2022-10-28 22:40 [PATCH] power: supply: ip5xxx: Fix integer overflow in current_now calculation Ondrej Jirman
2022-10-28 23:06 ` Samuel Holland
2022-11-01 0:08 ` Sebastian Reichel
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