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authorLuuk Paulussen <luuk.paulussen@alliedtelesis.co.nz>2019-12-06 12:16:59 +1300
committerGuenter Roeck <linux@roeck-us.net>2020-01-17 07:56:48 -0800
commitcf3ca1877574a306c0207cbf7fdf25419d9229df (patch)
tree9a0c1dff0f2b07324774ab6f010256e3bd6e87cb /drivers/hwmon
parente51a7dda299815e92f43960d620cdfc8dfc144f2 (diff)
hwmon: (adt7475) Make volt2reg return same reg as reg2volt input
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>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/adt7475.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index 6c64d50c9aae..01c2eeb02aa9 100644
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -294,9 +294,10 @@ 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);
}