power: ab8500_bm: Support for measuring temperature on BAT_CTRL

Temperature is now measured using the internal current sources
in AB8500. This will enable us to measure temperature in the battery
with higher precision

ST-Ericsson ID: WP320571
ST-Ericsson FOSS-OUT ID: Trivial

Change-Id: I2ebbf60ae8a03f7a0ddd7a6dce778ee93d5559d7
Signed-off-by: Johan Palsson <johan.palsson@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/13637
Reviewed-by: QATOOLS
Reviewed-by: Johan GARDSMARK <johan.gardsmark@stericsson.com>
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>

2 files changed, 233 insertions, 54 deletions

diff --git a/drivers/power/ab8500_btemp.c b/drivers/power/ab8500_btemp.c
index 058386170de..8acd5e598ff 100644
--- a/drivers/power/ab8500_btemp.c
+++ b/drivers/power/ab8500_btemp.c
@@ -32,6 +32,9 @@
 #define BTEMP_THERMAL_HIGH_LIMIT_57	57
 #define BTEMP_THERMAL_HIGH_LIMIT_62	62
 
+#define BTEMP_BATCTRL_CURR_SRC_7UA	7
+#define BTEMP_BATCTRL_CURR_SRC_20UA	20
+
 #define to_ab8500_btemp_device_info(x) container_of((x), \
 	struct ab8500_btemp, btemp_psy);
 
@@ -65,6 +68,7 @@ struct ab8500_btemp_ranges {
  * struct ab8500_btemp - ab8500 BTEMP device information
  * @dev:		Pointer to the structure device
  * @chip_id:		Chip-Id of the AB8500
+ * @curr_source:	What current source we use, in uA
  * @bat_temp:		Battery temperature in degree Celcius
  * @prev_bat_temp	Last dispatched battery temperature
  * @parent:		Pointer to the struct ab8500
@@ -79,6 +83,7 @@ struct ab8500_btemp_ranges {
 struct ab8500_btemp {
 	struct device *dev;
 	u8 chip_id;
+	int curr_source;
 	int bat_temp;
 	int prev_bat_temp;
 	struct ab8500 *parent;
@@ -103,15 +108,13 @@ static enum power_supply_property ab8500_btemp_props[] = {
  * ab8500_btemp_batctrl_volt_to_res() - convert batctrl voltage to resistance
  * @di:		pointer to the ab8500_btemp structure
  * @v_batctrl:	measured batctrl voltage
- * @v_fg:	voltage drop over the FG resistor
  *
  * This function returns the battery resistance that is
- * derived from the BATCTRL voltage. The calculated resistance is
- * compensated with the voltage drop over the FG resistor.
- * Returns value in mOhms.
+ * derived from the BATCTRL voltage.
+ * Returns value in Ohms.
  */
 static int ab8500_btemp_batctrl_volt_to_res(struct ab8500_btemp *di,
-	int v_batctrl, int v_fg)
+	int v_batctrl)
 {
 	int rbs;
 
@@ -122,14 +125,22 @@ static int ab8500_btemp_batctrl_volt_to_res(struct ab8500_btemp *di,
 		 * For ABB cut1.0 and 1.1 BAT_CTRL is internally
 		 * connected to 1.8V through a 450k resistor
 		 */
-		rbs = (450000 * (v_batctrl)) / (1800 - v_batctrl - v_fg);
+		rbs = (450000 * (v_batctrl)) / (1800 - v_batctrl);
 		break;
 	default:
-		/*
-		 * For ABB cut2.0 and onwards BAT_CTRL is internally
-		 * connected to 1.8V through a 80k resistor
-		 */
-		rbs = (80000 * (v_batctrl)) / (1800 - v_batctrl - v_fg);
+		if (di->bat->therm == THERM_BATTERY_PACK) {
+			/*
+			 * If the battery has internal NTC, we use the current
+			 * source to calculate the resistance, 7uA or 20uA
+			 */
+			rbs = v_batctrl * 1000 / di->curr_source;
+		} else {
+			/*
+			 * BAT_CTRL is internally
+			 * connected to 1.8V through a 80k resistor
+			 */
+			rbs = (80000 * (v_batctrl)) / (1800 - v_batctrl);
+		}
 		break;
 	}
 
@@ -164,36 +175,184 @@ static int ab8500_btemp_read_batctrl_voltage(struct ab8500_btemp *di)
 }
 
 /**
- * ab8500_btemp_read_batctrl_res() - get battery resistance
+ * ab8500_btemp_curr_source_enable() - enable/disable batctrl current source
+ * @di:		pointer to the ab8500_btemp structure
+ * @enable:	enable or disable the current source
+ *
+ * Enable or disable the current sources for the BatCtrl AD channel
+ */
+static int ab8500_btemp_curr_source_enable(struct ab8500_btemp *di,
+	bool enable)
+{
+	int curr;
+	int ret = 0;
+
+	/*
+	 * BATCTRL current sources are included on AB8500 cut2.0
+	 * and future versions
+	 */
+	if (di->chip_id == AB8500_CUT1P0 || di->chip_id == AB8500_CUT1P1)
+		return 0;
+
+	/* Only do this for batteries with internal NTC */
+	if (di->bat->therm == THERM_BATTERY_PACK && enable) {
+		if (di->curr_source == BTEMP_BATCTRL_CURR_SRC_7UA)
+			curr = BAT_CTRL_7U_ENA;
+		else
+			curr = BAT_CTRL_20U_ENA;
+
+		dev_dbg(di->dev, "Set BATCTRL %duA\n", di->curr_source);
+
+		ret = abx500_mask_and_set_register_interruptible(di->dev,
+			AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
+			FORCE_BAT_CTRL_CMP_HIGH, FORCE_BAT_CTRL_CMP_HIGH);
+		if (ret) {
+			dev_err(di->dev, "%s failed setting cmp_force\n",
+				__func__);
+			return ret;
+		}
+
+		/*
+		 * We have to wait one 32kHz cycle before enabling
+		 * the current source, since ForceBatCtrlCmpHigh needs
+		 * to be written in a separate cycle
+		 */
+		udelay(32);
+
+		ret = abx500_set_register_interruptible(di->dev,
+			AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
+			FORCE_BAT_CTRL_CMP_HIGH | curr);
+		if (ret) {
+			dev_err(di->dev, "%s failed enabling current source\n",
+				__func__);
+			goto disable_curr_source;
+		}
+	} else if (di->bat->therm == THERM_BATTERY_PACK && !enable) {
+		dev_dbg(di->dev, "Disable BATCTRL curr source\n");
+
+		/* Write 0 to the curr bits */
+		ret = abx500_mask_and_set_register_interruptible(di->dev,
+			AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
+			BAT_CTRL_7U_ENA | BAT_CTRL_20U_ENA,
+			~(BAT_CTRL_7U_ENA | BAT_CTRL_20U_ENA));
+		if (ret) {
+			dev_err(di->dev, "%s failed disabling current source\n",
+				__func__);
+			goto disable_curr_source;
+		}
+
+		/* Enable Pull-Up and comparator */
+		ret = abx500_mask_and_set_register_interruptible(di->dev,
+			AB8500_CHARGER,	AB8500_BAT_CTRL_CURRENT_SOURCE,
+			BAT_CTRL_PULL_UP_ENA | BAT_CTRL_CMP_ENA,
+			BAT_CTRL_PULL_UP_ENA | BAT_CTRL_CMP_ENA);
+		if (ret) {
+			dev_err(di->dev, "%s failed enabling PU and comp\n",
+				__func__);
+			goto enable_pu_comp;
+		}
+
+		/*
+		 * We have to wait one 32kHz cycle before disabling
+		 * ForceBatCtrlCmpHigh since this needs to be written
+		 * in a separate cycle
+		 */
+		udelay(32);
+
+		/* Disable 'force comparator' */
+		ret = abx500_mask_and_set_register_interruptible(di->dev,
+			AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
+			FORCE_BAT_CTRL_CMP_HIGH, ~FORCE_BAT_CTRL_CMP_HIGH);
+		if (ret) {
+			dev_err(di->dev, "%s failed disabling force comp\n",
+				__func__);
+			goto disable_force_comp;
+		}
+	}
+	return ret;
+
+	/*
+	 * We have to try unsetting FORCE_BAT_CTRL_CMP_HIGH one more time
+	 * if we got an error above
+	 */
+disable_curr_source:
+	/* Write 0 to the curr bits */
+	ret = abx500_mask_and_set_register_interruptible(di->dev,
+			AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
+			BAT_CTRL_7U_ENA | BAT_CTRL_20U_ENA,
+			~(BAT_CTRL_7U_ENA | BAT_CTRL_20U_ENA));
+	if (ret) {
+		dev_err(di->dev, "%s failed disabling current source\n",
+			__func__);
+		return ret;
+	}
+enable_pu_comp:
+	/* Enable Pull-Up and comparator */
+	ret = abx500_mask_and_set_register_interruptible(di->dev,
+		AB8500_CHARGER,	AB8500_BAT_CTRL_CURRENT_SOURCE,
+		BAT_CTRL_PULL_UP_ENA | BAT_CTRL_CMP_ENA,
+		BAT_CTRL_PULL_UP_ENA | BAT_CTRL_CMP_ENA);
+	if (ret) {
+		dev_err(di->dev, "%s failed enabling PU and comp\n",
+			__func__);
+		return ret;
+	}
+
+disable_force_comp:
+	/*
+	 * We have to wait one 32kHz cycle before disabling
+	 * ForceBatCtrlCmpHigh since this needs to be written
+	 * in a separate cycle
+	 */
+	udelay(32);
+
+	/* Disable 'force comparator' */
+	ret = abx500_mask_and_set_register_interruptible(di->dev,
+		AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
+		FORCE_BAT_CTRL_CMP_HIGH, ~FORCE_BAT_CTRL_CMP_HIGH);
+	if (ret) {
+		dev_err(di->dev, "%s failed disabling force comp\n",
+			__func__);
+		return ret;
+	}
+
+	return ret;
+}
+
+/**
+ * ab8500_btemp_get_batctrl_res() - get battery resistance
  * @di:		pointer to the ab8500_btemp structure
- * @curr_comp:	compensate for current or not
  *
  * This function returns the battery pack identification resistance.
- * Returns value in mOhms.
+ * Returns value in Ohms.
  */
-static int ab8500_btemp_read_batctrl_res(struct ab8500_btemp *di,
-	bool curr_comp)
+static int ab8500_btemp_get_batctrl_res(struct ab8500_btemp *di)
 {
-	int inst_curr;
-	int fg_drop;
+	int ret;
 	int batctrl;
 	int res;
 
-	if (di->bat->fg_ops.get_inst_curr && curr_comp)
-		inst_curr = di->bat->fg_ops.get_inst_curr(di->parent->fg);
-	else
-		inst_curr = 0;
+	/*
+	 * BATCTRL current sources are included on AB8500 cut2.0
+	 * and future versions
+	 */
+	ret = ab8500_btemp_curr_source_enable(di, true);
+	if (ret) {
+		dev_err(di->dev, "%s curr source enabled failed\n", __func__);
+		return ret;
+	}
 
-	fg_drop = -inst_curr * di->bat->fg_res / 1000;
 	batctrl = ab8500_btemp_read_batctrl_voltage(di);
-	res = ab8500_btemp_batctrl_volt_to_res(di, batctrl, fg_drop);
+	res = ab8500_btemp_batctrl_volt_to_res(di, batctrl);
+
+	ret = ab8500_btemp_curr_source_enable(di, false);
+	if (ret) {
+		dev_err(di->dev, "%s curr source disable failed\n", __func__);
+		return ret;
+	}
 
-	dev_dbg(di->dev, "%s inst_curr: %d fg_drop: %d batctrl: %d res: %d ",
-		__func__,
-		inst_curr,
-		fg_drop,
-		batctrl,
-		res);
+	dev_dbg(di->dev, "%s batctrl: %d res: %d ",
+		__func__, batctrl, res);
 
 	return res;
 }
@@ -237,11 +396,10 @@ static int ab8500_btemp_res_to_temp(struct ab8500_btemp *di,
 /**
  * ab8500_btemp_measure_temp() - measure battery temperature
  * @di:		pointer to the ab8500_btemp structure
- * @curr_comp:	compensate for current or not
  *
  * Returns battery temperature (on success) else the previous temperature
  */
-static int ab8500_btemp_measure_temp(struct ab8500_btemp *di, bool curr_comp)
+static int ab8500_btemp_measure_temp(struct ab8500_btemp *di)
 {
 	int data;
 	int temp;
@@ -254,7 +412,17 @@ static int ab8500_btemp_measure_temp(struct ab8500_btemp *di, bool curr_comp)
 
 		t = di->bat->batt_id;
 
-		rbat = ab8500_btemp_read_batctrl_res(di, curr_comp);
+		rbat = ab8500_btemp_get_batctrl_res(di);
+		if (rbat < 0) {
+			dev_err(di->dev, "%s get batctrl res failed\n",
+				__func__);
+			/*
+			 * Return out-of-range temperature so that
+			 * charging is stopped
+			 */
+			return BTEMP_THERMAL_LOW_LIMIT;
+		}
+
 		temp = ab8500_btemp_res_to_temp(di,
 			di->bat->bat_type[t].r_to_t_tbl,
 			di->bat->bat_type[t].n_temp_tbl_elements, rbat);
@@ -278,6 +446,7 @@ static int ab8500_btemp_measure_temp(struct ab8500_btemp *di, bool curr_comp)
 
 		temp = ab8500_btemp_res_to_temp(di, di->bat->pcb_ntc,
 			di->bat->n_temp_tbl_elements, rntc);
+		prev = temp;
 	}
 	dev_dbg(di->dev, "Battery temperature is %d\n", temp);
 	return temp;
@@ -296,7 +465,14 @@ static int ab8500_btemp_id(struct ab8500_btemp *di)
 	int res;
 	u8 i;
 
-	res =  ab8500_btemp_read_batctrl_res(di, false);
+	di->curr_source = BTEMP_BATCTRL_CURR_SRC_7UA;
+	di->bat->batt_id = BATTERY_UNKNOWN;
+
+	res =  ab8500_btemp_get_batctrl_res(di);
+	if (res < 0) {
+		dev_err(di->dev, "%s get batctrl res failed\n", __func__);
+		return -ENXIO;
+	}
 
 	/* BATTERY_UNKNOWN is defined on position 0, skip it! */
 	for (i = BATTERY_UNKNOWN + 1; i < di->bat->n_btypes; i++) {
@@ -309,16 +485,28 @@ static int ab8500_btemp_id(struct ab8500_btemp *di)
 				di->bat->therm,
 				di->bat->bat_type[i].resis_low, res,
 				di->bat->bat_type[i].resis_high, i);
-				di->bat->batt_id = i;
-			return i;
+
+			di->bat->batt_id = i;
+			break;
 		}
 	}
 
-	/* This is the unknown battery type to be used */
-	dev_err(di->dev, "Battery identified as unknown"
-		", resistance %d Ohm\n", res);
-	di->bat->batt_id = BATTERY_UNKNOWN;
-	return -ENXIO;
+	if (di->bat->batt_id == BATTERY_UNKNOWN) {
+		dev_warn(di->dev, "Battery identified as unknown"
+			", resistance %d Ohm\n", res);
+		return -ENXIO;
+	}
+
+	/*
+	 * We only have to change current source if the
+	 * detected type is Type 1, else we use the 7uA source
+	 */
+	if (di->bat->therm == THERM_BATTERY_PACK && di->bat->batt_id == 1) {
+		dev_dbg(di->dev, "Set BATCTRL current source to 20uA\n");
+		di->curr_source = BTEMP_BATCTRL_CURR_SRC_20UA;
+	}
+
+	return di->bat->batt_id;
 }
 
 /**
@@ -332,7 +520,7 @@ static void ab8500_btemp_periodic_work(struct work_struct *work)
 	struct ab8500_btemp *di = container_of(work,
 		struct ab8500_btemp, btemp_periodic_work.work);
 
-	di->bat_temp = ab8500_btemp_measure_temp(di, true);
+	di->bat_temp = ab8500_btemp_measure_temp(di);
 
 	if (di->bat_temp != di->prev_bat_temp) {
 		di->prev_bat_temp = di->bat_temp;
@@ -796,9 +984,8 @@ static int __devinit ab8500_btemp_probe(struct platform_device *pdev)
 		di->chip_id);
 
 	/* Identify the battery */
-	di->bat->batt_id = BATTERY_UNKNOWN;
-	if (ab8500_btemp_id(di) == -ENXIO)
-		dev_err(di->dev, "failed to identify the battery\n");
+	if (ab8500_btemp_id(di) < 0)
+		dev_warn(di->dev, "failed to identify the battery\n");
 
 	/* Set BTEMP thermal limits. Low and Med are fixed */
 	di->btemp_ranges.btemp_low_limit = BTEMP_THERMAL_LOW_LIMIT;
@@ -827,7 +1014,7 @@ static int __devinit ab8500_btemp_probe(struct platform_device *pdev)
 	}
 
 	/* Measure temperature once initially */
-	di->bat_temp = ab8500_btemp_measure_temp(di, false);
+	di->bat_temp = ab8500_btemp_measure_temp(di);
 
 	/* Register BTEMP power supply class */
 	ret = power_supply_register(di->dev, &di->btemp_psy);
diff --git a/drivers/power/ab8500_fg.c b/drivers/power/ab8500_fg.c
index 8fcd08d4aee..e3788345579 100644
--- a/drivers/power/ab8500_fg.c
+++ b/drivers/power/ab8500_fg.c
@@ -452,10 +452,6 @@ static int ab8500_fg_inst_curr(struct ab8500_fg *di)
 	return val;
 }
 
-static struct ab8500_fg_ops fg_ops = {
-	.get_inst_curr = ab8500_fg_inst_curr
-};
-
 /**
  * ab8500_fg_acc_cur_work() - average battery current
  * @work:	pointer to the work_struct structure
@@ -1597,9 +1593,6 @@ static int __devinit ab8500_fg_probe(struct platform_device *pdev)
 	}
 	di->bat = plat->battery;
 
-	/* Set up function pointers to be used by BTEMP */
-	di->bat->fg_ops = fg_ops;
-
 	di->fg_psy.name = "ab8500_fg";
 	di->fg_psy.type = POWER_SUPPLY_TYPE_BATTERY;
 	di->fg_psy.properties = ab8500_fg_props;
@@ -1675,7 +1668,6 @@ static int __devinit ab8500_fg_probe(struct platform_device *pdev)
 	}
 
 	platform_set_drvdata(pdev, di);
-	di->parent->fg = di;
 
 	/* Run the FG algorithm */
 	queue_delayed_work(di->fg_wq, &di->fg_periodic_work, 0);