misc: nct1008: handle remote sensor circuit open

One some boards, tdiode is not connected the nct device. Detect this
state and skip registering the tdiode zone with thermal framework.
This avoids spurious error messages and inaccurate thermal cooling
device actions.

Replaced the old warning about flex connector which was too specific
to 'ardbeg/T114' platform with a more device specific error that
remote circuit is open.

Bug 1454792

Change-Id: I3f5f74765c4ae5fbc9cb06ee53adb8037db6446f
Signed-off-by: Diwakar Tundlam <dtundlam@nvidia.com>

1 files changed, 34 insertions, 27 deletions

diff --git a/drivers/misc/nct1008.c b/drivers/misc/nct1008.c
index a628a7840f64..a79279e7387b 100644
--- a/drivers/misc/nct1008.c
+++ b/drivers/misc/nct1008.c
@@ -804,22 +804,12 @@ static int nct1008_ext_bind(struct thermal_zone_device *thz,
 	struct nct1008_data *data = thz->devdata;
 	int i;
 	bool bind = false;
-	int err;
-	long temp;
 	struct nct1008_sensor_platform_data *sensor;
 
-	err = nct1008_get_temp_common(EXT, data, &temp);
-	if (!err && (temp == NCT1008_MAX_TEMP_MILLI))
-		err = -ENXIO; /* potential faulty skin-tdiode connection  */
-
 	sensor = &data->plat_data.sensors[EXT];
 
 	for (i = 0; i < sensor->num_trips; i++) {
-		if (err && !strcmp(sensor->trips[i].cdev_type, "skin-balanced"))
-			dev_info(&data->client->dev,
-				 "No skin-tdiode flex connector found.\n");
-		else if (!strcmp(sensor->trips[i].cdev_type,
-				cdev->type) &&
+		if (!strcmp(sensor->trips[i].cdev_type, cdev->type) &&
 			 !thermal_zone_bind_cooling_device(thz, i, cdev,
 					sensor->trips[i].upper,
 					sensor->trips[i].lower))
@@ -1242,22 +1232,23 @@ static int nct1008_configure_sensor(struct nct1008_data *data)
 	s16 temp;
 	u8 temp2;
 	int ret;
+	bool ext_err = false;
 
 	if (!pdata || !pdata->supported_hwrev)
 		return -ENODEV;
 
+	ret = nct1008_read_reg(data->client, STATUS_RD);
+	if (ret & BIT(2)) {
+		pr_info("NCT%s: ERR: remote sensor circuit is open (0x%02x)\n",
+			(data->chip == NCT72) ? "72" : "1008", ret);
+		ext_err = true; /* flag the error */
+	}
+
 	/* Initially place in Standby */
 	ret = nct1008_write_reg(client, CONFIG_WR, STANDBY_BIT);
 	if (ret)
 		goto error;
 
-	/* External temperature h/w shutdown limit. */
-	value = temperature_to_value(pdata->extended_range,
-					pdata->sensors[EXT].shutdown_limit);
-	ret = nct1008_write_reg(client, EXT_THERM_LIMIT_WR, value);
-	if (ret)
-		goto error;
-
 	/* Local temperature h/w shutdown limit */
 	value = temperature_to_value(pdata->extended_range,
 					pdata->sensors[LOC].shutdown_limit);
@@ -1290,15 +1281,6 @@ static int nct1008_configure_sensor(struct nct1008_data *data)
 	if (ret)
 		goto error;
 
-	/* Setup external hi and lo limits */
-	ret = nct1008_write_reg(client, EXT_TEMP_LO_LIMIT_HI_BYTE_WR, 0);
-	if (ret)
-		goto error;
-	ret = nct1008_write_reg(client, EXT_TEMP_HI_LIMIT_HI_BYTE_WR,
-			NCT1008_MAX_TEMP);
-	if (ret)
-		goto error;
-
 	/* read initial temperature */
 	ret = nct1008_read_reg(client, LOC_TEMP_RD);
 	if (ret < 0)
@@ -1309,6 +1291,25 @@ static int nct1008_configure_sensor(struct nct1008_data *data)
 	temp = value_to_temperature(pdata->extended_range, value);
 	dev_dbg(&client->dev, "\n initial local temp = %d ", temp);
 
+	if (ext_err)
+		return ext_err; /* skip configuration of EXT sensor */
+
+	/* External temperature h/w shutdown limit. */
+	value = temperature_to_value(pdata->extended_range,
+					pdata->sensors[EXT].shutdown_limit);
+	ret = nct1008_write_reg(client, EXT_THERM_LIMIT_WR, value);
+	if (ret)
+		goto error;
+
+	/* Setup external hi and lo limits */
+	ret = nct1008_write_reg(client, EXT_TEMP_LO_LIMIT_HI_BYTE_WR, 0);
+	if (ret)
+		goto error;
+	ret = nct1008_write_reg(client, EXT_TEMP_HI_LIMIT_HI_BYTE_WR,
+			NCT1008_MAX_TEMP);
+	if (ret)
+		goto error;
+
 	ret = nct1008_read_reg(client, EXT_TEMP_LO_RD);
 	if (ret < 0)
 		goto error;
@@ -1426,6 +1427,7 @@ static int nct1008_probe(struct i2c_client *client,
 	u64 mask = 0;
 	char nct_loc_name[THERMAL_NAME_LENGTH];
 	char nct_ext_name[THERMAL_NAME_LENGTH];
+	bool ext_err;
 	struct nct1008_sensor_platform_data *sensor_data;
 
 	data = kzalloc(sizeof(struct nct1008_data), GFP_KERNEL);
@@ -1448,6 +1450,7 @@ static int nct1008_probe(struct i2c_client *client,
 	/* extended range recommended steps 1 through 4 taken care
 	 * in nct1008_configure_sensor function */
 	err = nct1008_configure_sensor(data);	/* sensor is in standby */
+	ext_err = err;
 	if (err < 0) {
 		dev_err(&client->dev, "\n error file: %s : %s(), line=%d ",
 			__FILE__, __func__, __LINE__);
@@ -1511,6 +1514,10 @@ static int nct1008_probe(struct i2c_client *client,
 	if (IS_ERR_OR_NULL(data->sensors[LOC].thz))
 		goto error;
 
+	/* check ext sensor connection before registering zone */
+	if (ext_err)
+		return 0; /* skip registering unconneted sensor as zone */
+
 	/* Config for the External sensor. */
 	mask = 0;
 	for (i = 0; i < data->plat_data.sensors[EXT].num_trips; i++)