From c0214f98943b1fe43f7be61b7782b0c8f0836f28 Mon Sep 17 00:00:00 2001 From: Fabio Baltieri Date: Sun, 8 Jun 2014 22:06:24 +0100 Subject: [PATCH] hwmon: (ina2xx) Cast to s16 on shunt and current regs All devices supported by ina2xx are bidirectional and report the measured shunt voltage and power values as a signed 16 bit, but the current driver implementation caches all registers as u16, leading to an incorrect sign extension when reporting to userspace in ina2xx_get_value(). This patch fixes the problem by casting the signed registers to s16. Tested on an INA219. Signed-off-by: Fabio Baltieri Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Guenter Roeck --- drivers/hwmon/ina2xx.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c index 93d26e8af3e2..bfd3f3eeabcd 100644 --- a/drivers/hwmon/ina2xx.c +++ b/drivers/hwmon/ina2xx.c @@ -148,7 +148,8 @@ static int ina2xx_get_value(struct ina2xx_data *data, u8 reg) switch (reg) { case INA2XX_SHUNT_VOLTAGE: - val = DIV_ROUND_CLOSEST(data->regs[reg], + /* signed register */ + val = DIV_ROUND_CLOSEST((s16)data->regs[reg], data->config->shunt_div); break; case INA2XX_BUS_VOLTAGE: @@ -160,8 +161,8 @@ static int ina2xx_get_value(struct ina2xx_data *data, u8 reg) val = data->regs[reg] * data->config->power_lsb; break; case INA2XX_CURRENT: - /* LSB=1mA (selected). Is in mA */ - val = data->regs[reg]; + /* signed register, LSB=1mA (selected), in mA */ + val = (s16)data->regs[reg]; break; default: /* programmer goofed */