malhuda/msm-4.14
1
0
Fork 0
mirror of https://github.com/rd-stuffs/msm-4.14.git synced 2025-02-20 11:45:48 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

hwmon: (adt7475) Make volt2reg return same reg as reg2volt input

Browse Source 
commit cf3ca1877574a306c0207cbf7fdf25419d9229df upstream.

reg2volt returns the voltage that matches a given register value.
Converting this back the other way with volt2reg didn't return the same
register value because it used truncation instead of rounding.

This meant that values read from sysfs could not be written back to sysfs
to set back the same register value.

With this change, volt2reg will return the same value for every voltage
previously returned by reg2volt (for the set of possible input values)

Signed-off-by: Luuk Paulussen <luuk.paulussen@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20191205231659.1301-1-luuk.paulussen@alliedtelesis.co.nz
cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Luuk Paulussen 2019-12-06 12:16:59 +13:00 committed by Greg Kroah-Hartman
parent e841252840
commit 6090ac18fc
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/hwmon/adt7475.c
View File

@ -297,9 +297,10 @@ static inline u16 volt2reg(int channel, long volt, u8 bypass_attn)
long reg;
if (bypass_attn & (1 << channel))
reg = (volt * 1024) / 2250;
reg = DIV_ROUND_CLOSEST(volt * 1024, 2250);
else
reg = (volt * r[1] * 1024) / ((r[0] + r[1]) * 2250);
reg = DIV_ROUND_CLOSEST(volt * r[1] * 1024,
(r[0] + r[1]) * 2250);
return clamp_val(reg, 0, 1023) & (0xff << 2);
}