thermal/drivers/rcar_gen3_thermal: Add support for hardware trip points

All supported hardware except V3U is capable of generating interrupts
to the CPU when the temperature go below or above a set value. Use this
to implement support for the set_trip() feature of the thermal core on
supported hardware.

The V3U have its interrupts routed to the ECM module and therefore can
not be used to implement set_trip() as the driver can't be made aware of
when the interrupt triggers.

Each TSC is capable of tracking up-to three different temperatures while
only two are needed to implement the tracking of the thermal window.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210804091818.2196806-2-niklas.soderlund+renesas@ragnatech.se

drivers/thermal/rcar_gen3_thermal.c

@@ -190,10 +190,64 @@ static int rcar_gen3_thermal_get_temp(void *devdata, int *temp)
 	return 0;
 }
 
-static const struct thermal_zone_of_device_ops rcar_gen3_tz_of_ops = {
+static int rcar_gen3_thermal_mcelsius_to_temp(struct rcar_gen3_thermal_tsc *tsc,
+					      int mcelsius)
+{
+	int celsius, val;
+
+	celsius = DIV_ROUND_CLOSEST(mcelsius, 1000);
+	if (celsius <= INT_FIXPT(tsc->tj_t))
+		val = celsius * tsc->coef.a1 + tsc->coef.b1;
+	else
+		val = celsius * tsc->coef.a2 + tsc->coef.b2;
+
+	return INT_FIXPT(val);
+}
+
+static int rcar_gen3_thermal_set_trips(void *devdata, int low, int high)
+{
+	struct rcar_gen3_thermal_tsc *tsc = devdata;
+	u32 irqmsk = 0;
+
+	if (low != -INT_MAX) {
+		irqmsk |= IRQ_TEMPD1;
+		rcar_gen3_thermal_write(tsc, REG_GEN3_IRQTEMP1,
+					rcar_gen3_thermal_mcelsius_to_temp(tsc, low));
+	}
+
+	if (high != INT_MAX) {
+		irqmsk |= IRQ_TEMP2;
+		rcar_gen3_thermal_write(tsc, REG_GEN3_IRQTEMP2,
+					rcar_gen3_thermal_mcelsius_to_temp(tsc, high));
+	}
+
+	rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, irqmsk);
+
+	return 0;
+}
+
+static struct thermal_zone_of_device_ops rcar_gen3_tz_of_ops = {
 	.get_temp	= rcar_gen3_thermal_get_temp,
+	.set_trips	= rcar_gen3_thermal_set_trips,
 };
 
+static irqreturn_t rcar_gen3_thermal_irq(int irq, void *data)
+{
+	struct rcar_gen3_thermal_priv *priv = data;
+	unsigned int i;
+	u32 status;
+
+	for (i = 0; i < priv->num_tscs; i++) {
+		status = rcar_gen3_thermal_read(priv->tscs[i], REG_GEN3_IRQSTR);
+		rcar_gen3_thermal_write(priv->tscs[i], REG_GEN3_IRQSTR, 0);
+		if (status)
+			thermal_zone_device_update(priv->tscs[i]->zone,
+						   THERMAL_EVENT_UNSPECIFIED);
+	}
+
+	return IRQ_HANDLED;
+}
+
 static const struct soc_device_attribute r8a7795es1[] = {
 	{ .soc_id = "r8a7795", .revision = "ES1.*" },
 	{ /* sentinel */ }
@@ -210,6 +264,9 @@ static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc)
 
 	rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F);
 	rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0);
+	if (tsc->zone->ops->set_trips)
+		rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN,
+					IRQ_TEMPD1 | IRQ_TEMP2);
 
 	rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,
 				CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN);
@@ -235,6 +292,9 @@ static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
 
 	rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0);
 	rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0);
+	if (tsc->zone->ops->set_trips)
+		rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN,
+					IRQ_TEMPD1 | IRQ_TEMP2);
 
 	reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
 	reg_val |= THCTR_THSST;
@@ -303,6 +363,34 @@ static void rcar_gen3_hwmon_action(void *data)
 	thermal_remove_hwmon_sysfs(zone);
 }
 
+static int rcar_gen3_thermal_request_irqs(struct rcar_gen3_thermal_priv *priv,
+					  struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	unsigned int i;
+	char *irqname;
+	int ret, irq;
+
+	for (i = 0; i < 2; i++) {
+		irq = platform_get_irq_optional(pdev, i);
+		if (irq < 0)
+			return irq;
+
+		irqname = devm_kasprintf(dev, GFP_KERNEL, "%s:ch%d",
+					 dev_name(dev), i);
+		if (!irqname)
+			return -ENOMEM;
+
+		ret = devm_request_threaded_irq(dev, irq, NULL,
+						rcar_gen3_thermal_irq,
+						IRQF_ONESHOT, irqname, priv);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 {
 	struct rcar_gen3_thermal_priv *priv;
@@ -326,6 +414,9 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, priv);
 
+	if (rcar_gen3_thermal_request_irqs(priv, pdev))
+		rcar_gen3_tz_of_ops.set_trips = NULL;
+
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);
 
@@ -351,9 +442,6 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 
 		priv->tscs[i] = tsc;
 
-		priv->thermal_init(tsc);
-		rcar_gen3_thermal_calc_coefs(tsc, ptat, thcodes[i], *ths_tj_1);
-
 		zone = devm_thermal_zone_of_sensor_register(dev, i, tsc,
 							    &rcar_gen3_tz_of_ops);
 		if (IS_ERR(zone)) {
@@ -363,6 +451,9 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 		}
 		tsc->zone = zone;
 
+		priv->thermal_init(tsc);
+		rcar_gen3_thermal_calc_coefs(tsc, ptat, thcodes[i], *ths_tj_1);
+
 		tsc->zone->tzp->no_hwmon = false;
 		ret = thermal_add_hwmon_sysfs(tsc->zone);
 		if (ret)
@@ -401,8 +492,12 @@ static int __maybe_unused rcar_gen3_thermal_resume(struct device *dev)
 
 	for (i = 0; i < priv->num_tscs; i++) {
 		struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];
+		struct thermal_zone_device *zone = tsc->zone;
 
 		priv->thermal_init(tsc);
+		if (zone->ops->set_trips)
+			rcar_gen3_thermal_set_trips(tsc, zone->prev_low_trip,
+						    zone->prev_high_trip);
 	}
 
 	return 0;