Re: [PATCH v2 1/3] hwmon: ltc2990: refactor value conversion

From: Guenter Roeck
Date: Thu Nov 17 2016 - 12:08:19 EST

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.

Signed-off-by: Tom Levens <tom.levens@xxxxxxx>
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@xxxxxxx>

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.


+#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
@@ -34,19 +38,10 @@

-/* 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.

Can you send me a register map for the chip ? I would like to write a module test.