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

1 files changed, 110 insertions, 8 deletions

diff --git a/drivers/thermal/qcom/tsens-common.c b/drivers/thermal/qcom/tsens-common.c
index fd3b56d52341..b7d599425605 100644
--- a/drivers/thermal/qcom/tsens-common.c
+++ b/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;
 }
@@ -323,6 +361,52 @@ static inline u32 masked_irq(u32 hw_id, u32 mask, enum tsens_ver ver)
 }
 
 /**
+ * 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
  * @data: tsens controller private data
@@ -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);