drivers: thermal: tsens: Add critical interrupt support

TSENS IP v2.x adds critical threshold interrupt support for each sensor
in addition to the upper/lower threshold interrupt. Add support in the
driver.

While the critical interrupts themselves aren't currently used by Linux,
the HW line is also used by the TSENS watchdog. So this patch acts as
infrastructure to enable watchdog functionality for the TSENS IP.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/51b22461d4b5f85a817274568459db4579fd4298.1584015867.git.amit.kucheria@linaro.org

drivers/thermal/qcom/tsens-common.c

@@ -23,6 +23,10 @@
  * @low_thresh:     lower threshold temperature value
  * @low_irq_mask:   mask register for lower threshold irqs
  * @low_irq_clear:  clear register for lower threshold irqs
+ * @crit_viol:      critical threshold violated
+ * @crit_thresh:    critical threshold temperature value
+ * @crit_irq_mask:  mask register for critical threshold irqs
+ * @crit_irq_clear: clear register for critical threshold irqs
  *
  * Structure containing data about temperature threshold settings and
  * irq status if they were violated.
@@ -36,6 +40,10 @@ struct tsens_irq_data {
 	int low_thresh;
 	u32 low_irq_mask;
 	u32 low_irq_clear;
+	u32 crit_viol;
+	u32 crit_thresh;
+	u32 crit_irq_mask;
+	u32 crit_irq_clear;
 };
 
 char *qfprom_read(struct device *dev, const char *cname)
@@ -189,6 +197,9 @@ static void tsens_set_interrupt_v1(struct tsens_priv *priv, u32 hw_id,
 	case LOWER:
 		index = LOW_INT_CLEAR_0 + hw_id;
 		break;
+	case CRITICAL:
+		/* No critical interrupts before v2 */
+		return;
 	}
 	regmap_field_write(priv->rf[index], enable ? 0 : 1);
 }
@@ -214,6 +225,10 @@ static void tsens_set_interrupt_v2(struct tsens_priv *priv, u32 hw_id,
 		index_mask  = LOW_INT_MASK_0 + hw_id;
 		index_clear = LOW_INT_CLEAR_0 + hw_id;
 		break;
+	case CRITICAL:
+		index_mask  = CRIT_INT_MASK_0 + hw_id;
+		index_clear = CRIT_INT_CLEAR_0 + hw_id;
+		break;
 	}
 
 	if (enable) {
@@ -268,7 +283,15 @@ static int tsens_threshold_violated(struct tsens_priv *priv, u32 hw_id,
 	ret = regmap_field_read(priv->rf[LOWER_STATUS_0 + hw_id], &d->low_viol);
 	if (ret)
 		return ret;
-	if (d->up_viol || d->low_viol)
+
+	if (priv->feat->crit_int) {
+		ret = regmap_field_read(priv->rf[CRITICAL_STATUS_0 + hw_id],
+					&d->crit_viol);
+		if (ret)
+			return ret;
+	}
+
+	if (d->up_viol || d->low_viol || d->crit_viol)
 		return 1;
 
 	return 0;
@@ -293,22 +316,37 @@ static int tsens_read_irq_state(struct tsens_priv *priv, u32 hw_id,
 		ret = regmap_field_read(priv->rf[LOW_INT_MASK_0 + hw_id], &d->low_irq_mask);
 		if (ret)
 			return ret;
+		ret = regmap_field_read(priv->rf[CRIT_INT_CLEAR_0 + hw_id],
+					&d->crit_irq_clear);
+		if (ret)
+			return ret;
+		ret = regmap_field_read(priv->rf[CRIT_INT_MASK_0 + hw_id],
+					&d->crit_irq_mask);
+		if (ret)
+			return ret;
+
+		d->crit_thresh = tsens_hw_to_mC(s, CRIT_THRESH_0 + hw_id);
 	} else {
 		/* No mask register on older TSENS */
 		d->up_irq_mask = 0;
 		d->low_irq_mask = 0;
+		d->crit_irq_clear = 0;
+		d->crit_irq_mask = 0;
+		d->crit_thresh = 0;
 	}
 
 	d->up_thresh  = tsens_hw_to_mC(s, UP_THRESH_0 + hw_id);
 	d->low_thresh = tsens_hw_to_mC(s, LOW_THRESH_0 + hw_id);
 
-	dev_dbg(priv->dev, "[%u] %s%s: status(%u|%u) | clr(%u|%u) | mask(%u|%u)\n",
-		hw_id, __func__, (d->up_viol || d->low_viol) ? "(V)" : "",
-		d->low_viol, d->up_viol, d->low_irq_clear, d->up_irq_clear,
-		d->low_irq_mask, d->up_irq_mask);
-	dev_dbg(priv->dev, "[%u] %s%s: thresh: (%d:%d)\n", hw_id, __func__,
-		(d->up_viol || d->low_viol) ? "(violation)" : "",
-		d->low_thresh, d->up_thresh);
+	dev_dbg(priv->dev, "[%u] %s%s: status(%u|%u|%u) | clr(%u|%u|%u) | mask(%u|%u|%u)\n",
+		hw_id, __func__,
+		(d->up_viol || d->low_viol || d->crit_viol) ? "(V)" : "",
+		d->low_viol, d->up_viol, d->crit_viol,
+		d->low_irq_clear, d->up_irq_clear, d->crit_irq_clear,
+		d->low_irq_mask, d->up_irq_mask, d->crit_irq_mask);
+	dev_dbg(priv->dev, "[%u] %s%s: thresh: (%d:%d:%d)\n", hw_id, __func__,
+		(d->up_viol || d->low_viol || d->crit_viol) ? "(V)" : "",
+		d->low_thresh, d->up_thresh, d->crit_thresh);
 
 	return 0;
 }
@@ -322,6 +360,52 @@ static inline u32 masked_irq(u32 hw_id, u32 mask, enum tsens_ver ver)
 	return 0;
 }
 
+/**
+ * tsens_critical_irq_thread() - Threaded handler for critical interrupts
+ * @irq: irq number
+ * @data: tsens controller private data
+ *
+ * Check all sensors to find ones that violated their critical threshold limits.
+ * Clear and then re-enable the interrupt.
+ *
+ * The level-triggered interrupt might deassert if the temperature returned to
+ * within the threshold limits by the time the handler got scheduled. We
+ * consider the irq to have been handled in that case.
+ *
+ * Return: IRQ_HANDLED
+ */
+irqreturn_t tsens_critical_irq_thread(int irq, void *data)
+{
+	struct tsens_priv *priv = data;
+	struct tsens_irq_data d;
+	int temp, ret, i;
+
+	for (i = 0; i < priv->num_sensors; i++) {
+		const struct tsens_sensor *s = &priv->sensor[i];
+		u32 hw_id = s->hw_id;
+
+		if (IS_ERR(s->tzd))
+			continue;
+		if (!tsens_threshold_violated(priv, hw_id, &d))
+			continue;
+		ret = get_temp_tsens_valid(s, &temp);
+		if (ret) {
+			dev_err(priv->dev, "[%u] %s: error reading sensor\n",
+				hw_id, __func__);
+			continue;
+		}
+
+		tsens_read_irq_state(priv, hw_id, s, &d);
+		if (d.crit_viol &&
+		    !masked_irq(hw_id, d.crit_irq_mask, tsens_version(priv))) {
+			/* Mask critical interrupts, unused on Linux */
+			tsens_set_interrupt(priv, hw_id, CRITICAL, false);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
 /**
  * tsens_irq_thread - Threaded interrupt handler for uplow interrupts
  * @irq: irq number
@@ -684,6 +768,24 @@ int __init init_common(struct tsens_priv *priv)
 		}
 	}
 
+	if (priv->feat->crit_int) {
+		/* Loop might need changes if enum regfield_ids is reordered */
+		for (j = CRITICAL_STATUS_0; j <= CRIT_THRESH_15; j += 16) {
+			for (i = 0; i < priv->feat->max_sensors; i++) {
+				int idx = j + i;
+
+				priv->rf[idx] =
+					devm_regmap_field_alloc(dev,
+								priv->tm_map,
+								priv->fields[idx]);
+				if (IS_ERR(priv->rf[idx])) {
+					ret = PTR_ERR(priv->rf[idx]);
+					goto err_put_device;
+				}
+			}
+		}
+	}
+
 	spin_lock_init(&priv->ul_lock);
 	tsens_enable_irq(priv);
 	tsens_debug_init(op);

drivers/thermal/qcom/tsens-v2.c

@@ -53,6 +53,7 @@ static const struct reg_field tsens_v2_regfields[MAX_REGFIELDS] = {
 	/* TEMPERATURE THRESHOLDS */
 	REG_FIELD_FOR_EACH_SENSOR16(LOW_THRESH,  TM_Sn_UPPER_LOWER_THRESHOLD_OFF,  0,  11),
 	REG_FIELD_FOR_EACH_SENSOR16(UP_THRESH,   TM_Sn_UPPER_LOWER_THRESHOLD_OFF, 12,  23),
+	REG_FIELD_FOR_EACH_SENSOR16(CRIT_THRESH, TM_Sn_CRITICAL_THRESHOLD_OFF,     0,  11),
 
 	/* INTERRUPTS [CLEAR/STATUS/MASK] */
 	REG_FIELD_SPLIT_BITS_0_15(LOW_INT_STATUS,  TM_UPPER_LOWER_INT_STATUS_OFF),
@@ -61,6 +62,9 @@ static const struct reg_field tsens_v2_regfields[MAX_REGFIELDS] = {
 	REG_FIELD_SPLIT_BITS_16_31(UP_INT_STATUS,  TM_UPPER_LOWER_INT_STATUS_OFF),
 	REG_FIELD_SPLIT_BITS_16_31(UP_INT_CLEAR,   TM_UPPER_LOWER_INT_CLEAR_OFF),
 	REG_FIELD_SPLIT_BITS_16_31(UP_INT_MASK,    TM_UPPER_LOWER_INT_MASK_OFF),
+	REG_FIELD_SPLIT_BITS_0_15(CRIT_INT_STATUS, TM_CRITICAL_INT_STATUS_OFF),
+	REG_FIELD_SPLIT_BITS_0_15(CRIT_INT_CLEAR,  TM_CRITICAL_INT_CLEAR_OFF),
+	REG_FIELD_SPLIT_BITS_0_15(CRIT_INT_MASK,   TM_CRITICAL_INT_MASK_OFF),
 
 	/* Sn_STATUS */
 	REG_FIELD_FOR_EACH_SENSOR16(LAST_TEMP,       TM_Sn_STATUS_OFF,  0,  11),

drivers/thermal/qcom/tsens.c

@@ -85,53 +85,66 @@ static const struct thermal_zone_of_device_ops tsens_of_ops = {
 	.set_trips = tsens_set_trips,
 };
 
-static int tsens_register(struct tsens_priv *priv)
+static int tsens_register_irq(struct tsens_priv *priv, char *irqname,
+			      irq_handler_t thread_fn)
 {
-	int i, ret, irq;
-	struct thermal_zone_device *tzd;
 	struct platform_device *pdev;
-
-	for (i = 0;  i < priv->num_sensors; i++) {
-		priv->sensor[i].priv = priv;
-		tzd = devm_thermal_zone_of_sensor_register(priv->dev, priv->sensor[i].hw_id,
-							   &priv->sensor[i],
-							   &tsens_of_ops);
-		if (IS_ERR(tzd))
-			continue;
-		priv->sensor[i].tzd = tzd;
-		if (priv->ops->enable)
-			priv->ops->enable(priv, i);
-	}
+	int ret, irq;
 
 	pdev = of_find_device_by_node(priv->dev->of_node);
 	if (!pdev)
 		return -ENODEV;
 
-	irq = platform_get_irq_byname(pdev, "uplow");
+	irq = platform_get_irq_byname(pdev, irqname);
 	if (irq < 0) {
 		ret = irq;
 		/* For old DTs with no IRQ defined */
 		if (irq == -ENXIO)
 			ret = 0;
-		goto err_put_device;
-	}
-
+	} else {
 		ret = devm_request_threaded_irq(&pdev->dev, irq,
-					NULL, tsens_irq_thread,
+						NULL, thread_fn,
 						IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
 						dev_name(&pdev->dev), priv);
-	if (ret) {
-		dev_err(&pdev->dev, "%s: failed to get irq\n", __func__);
-		goto err_put_device;
-	}
-
+		if (ret)
+			dev_err(&pdev->dev, "%s: failed to get irq\n",
+				__func__);
+		else
 			enable_irq_wake(irq);
+	}
 
-err_put_device:
 	put_device(&pdev->dev);
 	return ret;
 }
 
+static int tsens_register(struct tsens_priv *priv)
+{
+	int i, ret;
+	struct thermal_zone_device *tzd;
+
+	for (i = 0;  i < priv->num_sensors; i++) {
+		priv->sensor[i].priv = priv;
+		tzd = devm_thermal_zone_of_sensor_register(priv->dev, priv->sensor[i].hw_id,
+							   &priv->sensor[i],
+							   &tsens_of_ops);
+		if (IS_ERR(tzd))
+			continue;
+		priv->sensor[i].tzd = tzd;
+		if (priv->ops->enable)
+			priv->ops->enable(priv, i);
+	}
+
+	ret = tsens_register_irq(priv, "uplow", tsens_irq_thread);
+	if (ret < 0)
+		return ret;
+
+	if (priv->feat->crit_int)
+		ret = tsens_register_irq(priv, "critical",
+					 tsens_critical_irq_thread);
+
+	return ret;
+}
+
 static int tsens_probe(struct platform_device *pdev)
 {
 	int ret, i;

drivers/thermal/qcom/tsens.h

@@ -23,6 +23,7 @@
 
 struct tsens_priv;
 
+/* IP version numbers in ascending order */
 enum tsens_ver {
 	VER_0_1 = 0,
 	VER_1_X,
@@ -32,6 +33,7 @@ enum tsens_ver {
 enum tsens_irq_type {
 	LOWER,
 	UPPER,
+	CRITICAL,
 };
 
 /**
@@ -374,6 +376,70 @@ enum regfield_ids {
 	CRITICAL_STATUS_13,
 	CRITICAL_STATUS_14,
 	CRITICAL_STATUS_15,
+	CRIT_INT_STATUS_0,	/* CRITICAL interrupt status */
+	CRIT_INT_STATUS_1,
+	CRIT_INT_STATUS_2,
+	CRIT_INT_STATUS_3,
+	CRIT_INT_STATUS_4,
+	CRIT_INT_STATUS_5,
+	CRIT_INT_STATUS_6,
+	CRIT_INT_STATUS_7,
+	CRIT_INT_STATUS_8,
+	CRIT_INT_STATUS_9,
+	CRIT_INT_STATUS_10,
+	CRIT_INT_STATUS_11,
+	CRIT_INT_STATUS_12,
+	CRIT_INT_STATUS_13,
+	CRIT_INT_STATUS_14,
+	CRIT_INT_STATUS_15,
+	CRIT_INT_CLEAR_0,	/* CRITICAL interrupt clear */
+	CRIT_INT_CLEAR_1,
+	CRIT_INT_CLEAR_2,
+	CRIT_INT_CLEAR_3,
+	CRIT_INT_CLEAR_4,
+	CRIT_INT_CLEAR_5,
+	CRIT_INT_CLEAR_6,
+	CRIT_INT_CLEAR_7,
+	CRIT_INT_CLEAR_8,
+	CRIT_INT_CLEAR_9,
+	CRIT_INT_CLEAR_10,
+	CRIT_INT_CLEAR_11,
+	CRIT_INT_CLEAR_12,
+	CRIT_INT_CLEAR_13,
+	CRIT_INT_CLEAR_14,
+	CRIT_INT_CLEAR_15,
+	CRIT_INT_MASK_0,	/* CRITICAL interrupt mask */
+	CRIT_INT_MASK_1,
+	CRIT_INT_MASK_2,
+	CRIT_INT_MASK_3,
+	CRIT_INT_MASK_4,
+	CRIT_INT_MASK_5,
+	CRIT_INT_MASK_6,
+	CRIT_INT_MASK_7,
+	CRIT_INT_MASK_8,
+	CRIT_INT_MASK_9,
+	CRIT_INT_MASK_10,
+	CRIT_INT_MASK_11,
+	CRIT_INT_MASK_12,
+	CRIT_INT_MASK_13,
+	CRIT_INT_MASK_14,
+	CRIT_INT_MASK_15,
+	CRIT_THRESH_0,		/* CRITICAL threshold values */
+	CRIT_THRESH_1,
+	CRIT_THRESH_2,
+	CRIT_THRESH_3,
+	CRIT_THRESH_4,
+	CRIT_THRESH_5,
+	CRIT_THRESH_6,
+	CRIT_THRESH_7,
+	CRIT_THRESH_8,
+	CRIT_THRESH_9,
+	CRIT_THRESH_10,
+	CRIT_THRESH_11,
+	CRIT_THRESH_12,
+	CRIT_THRESH_13,
+	CRIT_THRESH_14,
+	CRIT_THRESH_15,
 	MIN_STATUS_0,		/* MIN threshold violated */
 	MIN_STATUS_1,
 	MIN_STATUS_2,
@@ -460,6 +526,7 @@ struct tsens_context {
  * @srot_map: pointer to SROT register address space
  * @tm_offset: deal with old device trees that don't address TM and SROT
  *             address space separately
+ * @crit_lock: lock while processing critical threshold interrupts
  * @rf: array of regmap_fields used to store value of the field
  * @ctx: registers to be saved and restored during suspend/resume
  * @feat: features of the IP
@@ -500,6 +567,7 @@ int tsens_enable_irq(struct tsens_priv *priv);
 void tsens_disable_irq(struct tsens_priv *priv);
 int tsens_set_trips(void *_sensor, int low, int high);
 irqreturn_t tsens_irq_thread(int irq, void *data);
+irqreturn_t tsens_critical_irq_thread(int irq, void *data);
 
 /* TSENS target */
 extern struct tsens_plat_data data_8960;