hwmon: lps331ap: report data should use 2's complement

BZ: 30050

This patch make sure the report data accurate when pressure or
temperature number is negative -- need do transform from 2's
complement.

Change-Id: Ia907b284e0139e5544863d638e0e7c85e50b8553
Signed-off-by: Chen, Jie <jie.d.chen@intel.com>
Reviewed-on: http://android.intel.com:8080/42021
Reviewed-by: Wang, Zhifeng <zhifeng.wang@intel.com>
Reviewed-by: Du, Alek <alek.du@intel.com>
Tested-by: Wang, Zhifeng <zhifeng.wang@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>

diff --git a/drivers/hwmon/lps331ap.c b/drivers/hwmon/lps331ap.c
index c0086a6..22fba15 100644 (file)
--- a/drivers/hwmon/lps331ap.c
+++ b/drivers/hwmon/lps331ap.c
@@ -115,6 +115,7 @@
 #define LPS331AP_MIN_DELAY     75
 
 #define LPS331AP_DEVICE_NAME "lps331ap"
+#define LPS331AP_DEVICE_ID     0xbb
 
 struct lps331ap_data {
        struct i2c_client *client;
@@ -155,7 +156,7 @@ static int lps331ap_write(struct lps331ap_data *lps331ap, u8 reg, u8 val)
 }
 
 static void lps331ap_get_data(struct lps331ap_data *lps331ap,
-               unsigned long *data)
+               s32 *data)
 {
        int err;
        u8 buf[3];
@@ -165,24 +166,21 @@ static void lps331ap_get_data(struct lps331ap_data *lps331ap,
        if (err < 0)
                return;
 
-       data[0] = 65536 * buf[2];
-       data[0] += 256 * buf[1];
-       data[0] += buf[0];
+       data[0] = (s8)buf[2] << 16 | buf[1] << 8 | buf[0];
 
        err = i2c_smbus_read_i2c_block_data(lps331ap->client,
                        TEMP_OUT_L | I2C_AUTO_INC, 2, buf);
        if (err < 0)
                return;
 
-       data[1] = 256 * buf[1];
-       data[1] += buf[0];
+       data[1] = (s8)buf[1] << 8 | buf[0];
 }
 
 static void lps331ap_report_values(struct lps331ap_data *lps331ap,
-               unsigned long *data)
+               s32 *data)
 {
-       input_report_rel(lps331ap->input_dev, REL_X, data[0]);
-       input_report_rel(lps331ap->input_dev, REL_Y, data[1]);
+       input_report_rel(lps331ap->input_dev, REL_X, (int)data[0]);
+       input_report_rel(lps331ap->input_dev, REL_Y, (int)data[1]);
 
        input_sync(lps331ap->input_dev);
 }
@@ -190,6 +188,16 @@ static void lps331ap_report_values(struct lps331ap_data *lps331ap,
 static int lps331ap_initchip(struct lps331ap_data *lps331ap)
 {
        int ret;
+       u8 val;
+
+       ret = lps331ap_read(lps331ap, WHO_AM_I, &val);
+       if (ret < 0)
+               return ret;
+
+       if (LPS331AP_DEVICE_ID != val) {
+               dev_err(&lps331ap->client->dev, "device id not match\n");
+               return -ENODEV;
+       }
 
        ret = lps331ap_write(lps331ap, RES_CONF, 0x34);
        if (ret < 0)
@@ -259,7 +267,7 @@ static void lps331ap_disable(struct lps331ap_data *lps331ap)
 static void lps331ap_input_work_func(struct work_struct *work)
 {
        struct lps331ap_data *lps331ap;
-       unsigned long pt[2] = { 0 };
+       s32 pt[2] = { 0 };
 
        lps331ap = container_of((struct delayed_work *)work,
                        struct lps331ap_data, input_work);
@@ -459,7 +467,8 @@ static int __devinit lps331ap_probe(struct i2c_client *client,
 
        err = lps331ap_initchip(lps331ap);
        if (err < 0) {
-               dev_err(&client->dev, "lps331ap_initchip failed\n");
+               dev_err(&client->dev,
+                               "lps331ap_initchip failed with %d\n", err);
                goto fail_init;
        }