Messages in this thread | | | Date | Fri, 18 Nov 2016 09:18:44 +0100 | From | Tom Levens <> | Subject | Re: [PATCH v2 1/3] hwmon: ltc2990: refactor value conversion |
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Hi Guenter,
On Thu, 17 Nov 2016, Guenter Roeck wrote:
> On 11/17/2016 08:23 AM, Tom Levens wrote: >> Hi Guenter, >> >> Thanks for taking the time to review the patch. >> >> On Thu, 17 Nov 2016, Guenter Roeck wrote: >> >> > Hi Tom, >> > >> > On 11/17/2016 04:10 AM, Tom Levens wrote: >> > > Conversion from raw values to signed integers has been refactored >> > > using >> > > the macros in bitops.h. >> > > >> > Please also mention that this fixes a bug in negative temperature >> > conversions. >> >> Yes, of course, I will include the information in v3. >> >> > >> > > Signed-off-by: Tom Levens <tom.levens@cern.ch> >> > > --- >> > > drivers/hwmon/ltc2990.c | 27 ++++++++++----------------- >> > > 1 files changed, 10 insertions(+), 17 deletions(-) >> > > >> > > diff --git a/drivers/hwmon/ltc2990.c b/drivers/hwmon/ltc2990.c >> > > index 8f8fe05..0ec4102 100644 >> > > --- a/drivers/hwmon/ltc2990.c >> > > +++ b/drivers/hwmon/ltc2990.c >> > > @@ -9,8 +9,12 @@ >> > > * This driver assumes the chip is wired as a dual current monitor, >> > > and >> > > * reports the voltage drop across two series resistors. It also >> > > reports >> > > * the chip's internal temperature and Vcc power supply voltage. >> > > + * >> > > + * Value conversion refactored >> > > + * by Tom Levens <tom.levens@cern.ch> >> > >> > Kind of unusual to do that for minor changes like this. Imagine if >> > everyone would do that. >> > The commit log is what gives you credit. >> >> Good point, thanks for the hint. I will remove it from v3. >> >> > > */ >> > > >> > > +#include <linux/bitops.h> >> > > #include <linux/err.h> >> > > #include <linux/hwmon.h> >> > > #include <linux/hwmon-sysfs.h> >> > > @@ -34,19 +38,10 @@ >> > > #define LTC2990_CONTROL_MODE_CURRENT 0x06 >> > > #define LTC2990_CONTROL_MODE_VOLTAGE 0x07 >> > > >> > > -/* convert raw register value to sign-extended integer in 16-bit >> > > range */ >> > > -static int ltc2990_voltage_to_int(int raw) >> > > -{ >> > > - if (raw & BIT(14)) >> > > - return -(0x4000 - (raw & 0x3FFF)) << 2; >> > > - else >> > > - return (raw & 0x3FFF) << 2; >> > > -} >> > > - >> > > /* Return the converted value from the given register in uV or mC */ >> > > -static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, int >> > > *result) >> > > +static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, s32 >> > > *result) >> > > { >> > > - int val; >> > > + s32 val; >> > >> > Please just leave the variable type alone. it is also used for the >> > return value >> > from i2c_smbus_read_word_swapped(), which is an int, and changing it to >> > s32 doesn't really make the code better. >> >> According to i2c.h the return type for i2c_smbus_read_word_swapped() is >> s32, which is why I modified it here. But it could be changed back if you >> think it is better to leave it as an int. >> > Ah, ok. Good to know. Please leave it anyway, reason being that there is no > real > reason to change it. Effectively those are just whitespace changes (unlike > the rest, > which is part bug fix, part cleanup). > >> > Can you send me a register map for the chip ? I would like to write a >> > module test. >> >> Here is an example register dump: > > I meant the output of i2cdump (something like "i2cdump -y -f <bus> > <i2c-address> w"). >
The register map wraps at 0x0F, so I only sent you the first 16 bytes. But the fully expanded form is:
0 1 2 3 4 5 6 7 8 9 a b c d e f 00: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 10: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 20: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 30: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 40: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 50: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 60: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 70: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 80: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 90: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 a0: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 b0: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 c0: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 d0: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 e0: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00 f0: 00 00 00 00 01 90 07 d0 2c cd 7d 80 7c 29 20 00
Cheers,
> Thanks, > Guenter > >> >> 00 00 00 00 >> 01 90 07 d0 >> 2c cd 7d 80 >> 7c 29 20 00 >> >> The expected values in this case are: >> >> in0_input 5000 >> in1_input 610 >> in2_input 3500 >> in3_input -195 >> in4_input -299 >> temp1_input 25000 >> temp2_input 125000 >> temp3_input -40000 >> curr1_input 38840 >> curr2_input -12428 >> >> Testing with lltc,mode set to <5>, <6> and <7> should give you all >> measurements. >> >> > Thanks, >> > Guenter >> >> Cheers, >> > >
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