https://github.com/torvalds/linux
Revision 227a3a2fc31d8e4bb9c88d4804e19530af245b1b authored by Eliav Farber on 08 September 2022, 15:24:32 UTC, committed by Guenter Roeck on 08 September 2022, 18:55:24 UTC
According to Moortec Embedded Voltage Monitor (MEVM) series 3 data sheet, the minimum input signal is -100mv and maximum input signal is +1000mv. The equation used to convert the digital word to voltage uses mixed types (*val signed and n unsigned), and on 64 bit machines also has different size, since sizeof(u32) = 4 and sizeof(long) = 8. So when measuring a negative input, n will be small enough, such that PVT_N_CONST * n < PVT_R_CONST, and the result of (PVT_N_CONST * n - PVT_R_CONST) will overflow to a very big positive 32 bit number. Then when storing the result in *val it will be the same value just in 64 bit (instead of it representing a negative number which will what happen when sizeof(long) = 4). When -1023 <= (PVT_N_CONST * n - PVT_R_CONST) <= -1 dividing the number by 1024 should result of in 0, but because ">> 10" is used, and the sign bit is used to fill the vacated bit positions, it results in -1 (0xf...fffff) which is wrong. This change fixes the sign problem and supports negative values by casting n to long and replacing the shift right with div operation. Fixes: 9d823351a337 ("hwmon: Add hardware monitoring driver for Moortec MR75203 PVT controller") Signed-off-by: Eliav Farber <farbere@amazon.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20220908152449.35457-5-farbere@amazon.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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Tip revision: 227a3a2fc31d8e4bb9c88d4804e19530af245b1b authored by Eliav Farber on 08 September 2022, 15:24:32 UTC
hwmon: (mr75203) fix voltage equation for negative source input
hwmon: (mr75203) fix voltage equation for negative source input
Tip revision: 227a3a2
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accessibility | ||
acpi | ||
amba | ||
android | ||
ata | ||
atm | ||
auxdisplay | ||
base | ||
bcma | ||
block | ||
bluetooth | ||
bus | ||
cdrom | ||
char | ||
clk | ||
clocksource | ||
comedi | ||
connector | ||
counter | ||
cpufreq | ||
cpuidle | ||
crypto | ||
cxl | ||
dax | ||
dca | ||
devfreq | ||
dio | ||
dma | ||
dma-buf | ||
edac | ||
eisa | ||
extcon | ||
firewire | ||
firmware | ||
fpga | ||
fsi | ||
gnss | ||
gpio | ||
gpu | ||
greybus | ||
hid | ||
hsi | ||
hte | ||
hv | ||
hwmon | ||
hwspinlock | ||
hwtracing | ||
i2c | ||
i3c | ||
idle | ||
iio | ||
infiniband | ||
input | ||
interconnect | ||
iommu | ||
ipack | ||
irqchip | ||
isdn | ||
leds | ||
macintosh | ||
mailbox | ||
mcb | ||
md | ||
media | ||
memory | ||
memstick | ||
message | ||
mfd | ||
misc | ||
mmc | ||
most | ||
mtd | ||
mux | ||
net | ||
nfc | ||
ntb | ||
nubus | ||
nvdimm | ||
nvme | ||
nvmem | ||
of | ||
opp | ||
parisc | ||
parport | ||
pci | ||
pcmcia | ||
peci | ||
perf | ||
phy | ||
pinctrl | ||
platform | ||
pnp | ||
power | ||
powercap | ||
pps | ||
ps3 | ||
ptp | ||
pwm | ||
rapidio | ||
ras | ||
regulator | ||
remoteproc | ||
reset | ||
rpmsg | ||
rtc | ||
s390 | ||
sbus | ||
scsi | ||
sh | ||
siox | ||
slimbus | ||
soc | ||
soundwire | ||
spi | ||
spmi | ||
ssb | ||
staging | ||
target | ||
tc | ||
tee | ||
thermal | ||
thunderbolt | ||
tty | ||
ufs | ||
uio | ||
usb | ||
vdpa | ||
vfio | ||
vhost | ||
video | ||
virt | ||
virtio | ||
vlynq | ||
w1 | ||
watchdog | ||
xen | ||
zorro | ||
Kconfig | -rw-r--r-- | 3.9 KB |
Makefile | -rw-r--r-- | 5.2 KB |
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