Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932685AbaFHVGn (ORCPT ); Sun, 8 Jun 2014 17:06:43 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:50767 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932586AbaFHVGe (ORCPT ); Sun, 8 Jun 2014 17:06:34 -0400 From: Fabio Baltieri To: Guenter Roeck , Jean Delvare Cc: lm-sensors@lm-sensors.org, linux-kernel@vger.kernel.org, Fabio Baltieri Subject: [PATCH v2] hwmon: (ina2xx) Cast to s16 on shunt and current regs Date: Sun, 8 Jun 2014 22:06:24 +0100 Message-Id: <1402261584-5301-1-git-send-email-fabio.baltieri@gmail.com> X-Mailer: git-send-email 1.8.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org All devices supported by ina2xx are bidirectional and reports 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 the 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 --- 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 93d26e8..bfd3f3e 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 */ -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/