misc: nct1008: extended mode first reading fixtegra-12r4

nct1008 first temperature reading in extended mode is incorrect.
A valid temperature is available in next measurement cycle after
changing temperature range.
- using table with delay expected for supported conversion
  rate of nct1008.

bug 852754

Change-Id: I1e2911e283aba27a8d807b6346948202061b73f0
Reviewed-on: http://git-master/r/41938
Reviewed-by: Karan Jhavar <kjhavar@nvidia.com>
Tested-by: Karan Jhavar <kjhavar@nvidia.com>
Reviewed-by: Bitan Biswas <bbiswas@nvidia.com>
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>
Tested-by: Diwakar Tundlam <dtundlam@nvidia.com>

1 files changed, 47 insertions, 6 deletions

diff --git a/drivers/misc/nct1008.c b/drivers/misc/nct1008.c
index 748697a64ba9..1ae425ceb6df 100644
--- a/drivers/misc/nct1008.c
+++ b/drivers/misc/nct1008.c
@@ -121,6 +121,7 @@ static int nct1008_get_temp(struct device *dev, u8 *pTemp)
 	else
 		*pTemp = max(temp1, temp);
 
+	dev_dbg(dev, "\n %s: ret temp=%dC ", __func__, *pTemp);
 	return 0;
 error:
 	dev_err(&client->dev, "\n error in file=: %s %s() line=%d: "
@@ -537,7 +538,7 @@ static irqreturn_t nct1008_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static void nct1008_power_control(struct nct1008_data* data, bool is_enable)
+static void nct1008_power_control(struct nct1008_data *data, bool is_enable)
 {
 	int ret;
 	if (!data->nct_reg) {
@@ -617,15 +618,18 @@ static int __devinit nct1008_configure_sensor(struct nct1008_data* data)
 		/* setup alarm */
 		hi_limit = pdata->thermal_zones[0];
 
-		err = i2c_smbus_write_byte_data(client, EXT_TEMP_LO_LIMIT_HI_BYTE_WR, 0);
+		err = i2c_smbus_write_byte_data(client,
+			EXT_TEMP_LO_LIMIT_HI_BYTE_WR, 0);
 		if (err)
 			goto error;
 
-		err = i2c_smbus_write_byte_data(client, LOCAL_TEMP_HI_LIMIT_WR, NCT1008_MAX_TEMP);
+		err = i2c_smbus_write_byte_data(client,
+			LOCAL_TEMP_HI_LIMIT_WR, NCT1008_MAX_TEMP);
 		if (err)
 			goto error;
 
-		err = i2c_smbus_write_byte_data(client, LOCAL_TEMP_LO_LIMIT_WR, 0);
+		err = i2c_smbus_write_byte_data(client,
+			LOCAL_TEMP_LO_LIMIT_WR, 0);
 		if (err)
 			goto error;
 	} else {
@@ -707,12 +711,42 @@ static int __devinit nct1008_configure_irq(struct nct1008_data *data)
 			DRIVER_NAME, data);
 }
 
+static unsigned int get_ext_mode_delay_ms(unsigned int conv_rate)
+{
+	switch (conv_rate) {
+	case 0:
+		return 16000;
+	case 1:
+		return 8000;
+	case 2:
+		return 4000;
+	case 3:
+		return 2000;
+	case 4:
+		return 1000;
+	case 5:
+		return 500;
+	case 6:
+		return 250;
+	case 7:
+		return 125;
+	case 9:
+		return 32;
+	case 10:
+		return 16;
+	case 8:
+	default:
+		return 63;
+	}
+}
+
 static int __devinit nct1008_probe(struct i2c_client *client,
 				const struct i2c_device_id *id)
 {
 	struct nct1008_data *data;
 	int err;
 	u8 temperature;
+	unsigned int delay;
 
 	data = kzalloc(sizeof(struct nct1008_data), GFP_KERNEL);
 
@@ -743,6 +777,13 @@ static int __devinit nct1008_probe(struct i2c_client *client,
 
 	nct1008_enable(client);		/* sensor is running */
 
+	/* switch to extended mode reports correct temperature
+	 * from next measurement cycle */
+	if (data->plat_data.ext_range) {
+		delay = get_ext_mode_delay_ms(
+			data->plat_data.conv_rate);
+		msleep(delay); /* 63msec for default conv rate 0x8 */
+	}
 	err = nct1008_get_temp(&data->client->dev, &temperature);
 	if (err) {
 		pr_err("%s: get temp fail(%d)", __func__, err);
@@ -829,5 +870,5 @@ static void __exit nct1008_exit(void)
 MODULE_DESCRIPTION("Temperature sensor driver for OnSemi NCT1008");
 MODULE_LICENSE("GPL");
 
-module_init (nct1008_init);
-module_exit (nct1008_exit);
+module_init(nct1008_init);
+module_exit(nct1008_exit);