thermal: qcom-spmi: Use PMIC thermal stage 2 for critical trip points

There are three thermal stages defined in the PMIC:

stage 1: warning
stage 2: system should shut down
stage 3: emergency shut down

By default the PMIC assumes that the OS isn't doing anything and thus
at stage 2 it does a partial PMIC shutdown and at stage 3 it kills
all power. When switching between thermal stages the PMIC generates an
interrupt which is handled by the driver. The partial PMIC shutdown at
stage 2 can be disabled by software, which allows the OS to initiate a
shutdown at stage 2 with a thermal zone configured accordingly.

If a critical trip point is configured in the thermal zone the driver
adjusts the stage 1-3 temperature thresholds to (closely) match the
critical temperature with a stage 2 threshold (125/130/135/140 °C).
If a suitable match is found the partial shutdown at stage 2 is
disabled. If for some reason the system doesn't shutdown at stage 2
the emergency shutdown at stage 3 kicks in.

The partial shutdown at stage 2 remains enabled in these cases:
- no critical trip point defined
- the temperature of the critical trip point is < 125°C
- the temperature of the critical trip point is > 140°C and no
  ADC channel is configured (thus the OS is not notified when the critical
  temperature is reached)

Suggested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

diff --git a/drivers/thermal/qcom-spmi-temp-alarm.c b/drivers/thermal/qcom-spmi-temp-alarm.c
index ad4f3a8d656056971a05e1bbb3c3ee7fa20d5a11..b2d5d5bf4a9bd1638eb53b8f5d420e719f0ad140 100644 (file)
--- a/drivers/thermal/qcom-spmi-temp-alarm.c
+++ b/drivers/thermal/qcom-spmi-temp-alarm.c
@@ -23,6 +23,8 @@
 #include <linux/regmap.h>
 #include <linux/thermal.h>
 
+#include "thermal_core.h"
+
 #define QPNP_TM_REG_TYPE               0x04
 #define QPNP_TM_REG_SUBTYPE            0x05
 #define QPNP_TM_REG_STATUS             0x08
@@ -37,9 +39,11 @@
 #define STATUS_GEN2_STATE_MASK         GENMASK(6, 4)
 #define STATUS_GEN2_STATE_SHIFT                4
 
-#define SHUTDOWN_CTRL1_OVERRIDE_MASK   GENMASK(7, 6)
+#define SHUTDOWN_CTRL1_OVERRIDE_S2     BIT(6)
 #define SHUTDOWN_CTRL1_THRESHOLD_MASK  GENMASK(1, 0)
 
+#define SHUTDOWN_CTRL1_RATE_25HZ       BIT(3)
+
 #define ALARM_CTRL_FORCE_ENABLE                BIT(7)
 
 /*
@@ -56,12 +60,19 @@
 #define TEMP_THRESH_STEP               5000    /* Threshold step: 5 C */
 
 #define THRESH_MIN                     0
+#define THRESH_MAX                     3
+
+/* Stage 2 Threshold Min: 125 C */
+#define STAGE2_THRESHOLD_MIN           125000
+/* Stage 2 Threshold Max: 140 C */
+#define STAGE2_THRESHOLD_MAX           140000
 
 /* Temperature in Milli Celsius reported during stage 0 if no ADC is present */
 #define DEFAULT_TEMP                   37000
 
 struct qpnp_tm_chip {
        struct regmap                   *map;
+       struct device                   *dev;
        struct thermal_zone_device      *tz_dev;
        unsigned int                    subtype;
        long                            temp;
@@ -69,6 +80,10 @@ struct qpnp_tm_chip {
        unsigned int                    stage;
        unsigned int                    prev_stage;
        unsigned int                    base;
+       /* protects .thresh, .stage and chip registers */
+       struct mutex                    lock;
+       bool                            initialized;
+
        struct iio_channel              *adc;
 };
 
@@ -125,6 +140,8 @@ static int qpnp_tm_update_temp_no_adc(struct qpnp_tm_chip *chip)
        unsigned int stage, stage_new, stage_old;
        int ret;
 
+       WARN_ON(!mutex_is_locked(&chip->lock));
+
        ret = qpnp_tm_get_temp_stage(chip);
        if (ret < 0)
                return ret;
@@ -163,8 +180,15 @@ static int qpnp_tm_get_temp(void *data, int *temp)
        if (!temp)
                return -EINVAL;
 
+       if (!chip->initialized) {
+               *temp = DEFAULT_TEMP;
+               return 0;
+       }
+
        if (!chip->adc) {
+               mutex_lock(&chip->lock);
                ret = qpnp_tm_update_temp_no_adc(chip);
+               mutex_unlock(&chip->lock);
                if (ret < 0)
                        return ret;
        } else {
@@ -180,8 +204,72 @@ static int qpnp_tm_get_temp(void *data, int *temp)
        return 0;
 }
 
+static int qpnp_tm_update_critical_trip_temp(struct qpnp_tm_chip *chip,
+                                            int temp)
+{
+       u8 reg;
+       bool disable_s2_shutdown = false;
+
+       WARN_ON(!mutex_is_locked(&chip->lock));
+
+       /*
+        * Default: S2 and S3 shutdown enabled, thresholds at
+        * 105C/125C/145C, monitoring at 25Hz
+        */
+       reg = SHUTDOWN_CTRL1_RATE_25HZ;
+
+       if (temp == THERMAL_TEMP_INVALID ||
+           temp < STAGE2_THRESHOLD_MIN) {
+               chip->thresh = THRESH_MIN;
+               goto skip;
+       }
+
+       if (temp <= STAGE2_THRESHOLD_MAX) {
+               chip->thresh = THRESH_MAX -
+                       ((STAGE2_THRESHOLD_MAX - temp) /
+                        TEMP_THRESH_STEP);
+               disable_s2_shutdown = true;
+       } else {
+               chip->thresh = THRESH_MAX;
+
+               if (chip->adc)
+                       disable_s2_shutdown = true;
+               else
+                       dev_warn(chip->dev,
+                                "No ADC is configured and critical temperature is above the maximum stage 2 threshold of 140 C! Configuring stage 2 shutdown at 140 C.\n");
+       }
+
+skip:
+       reg |= chip->thresh;
+       if (disable_s2_shutdown)
+               reg |= SHUTDOWN_CTRL1_OVERRIDE_S2;
+
+       return qpnp_tm_write(chip, QPNP_TM_REG_SHUTDOWN_CTRL1, reg);
+}
+
+static int qpnp_tm_set_trip_temp(void *data, int trip, int temp)
+{
+       struct qpnp_tm_chip *chip = data;
+       const struct thermal_trip *trip_points;
+       int ret;
+
+       trip_points = of_thermal_get_trip_points(chip->tz_dev);
+       if (!trip_points)
+               return -EINVAL;
+
+       if (trip_points[trip].type != THERMAL_TRIP_CRITICAL)
+               return 0;
+
+       mutex_lock(&chip->lock);
+       ret = qpnp_tm_update_critical_trip_temp(chip, temp);
+       mutex_unlock(&chip->lock);
+
+       return ret;
+}
+
 static const struct thermal_zone_of_device_ops qpnp_tm_sensor_ops = {
        .get_temp = qpnp_tm_get_temp,
+       .set_trip_temp = qpnp_tm_set_trip_temp,
 };
 
 static irqreturn_t qpnp_tm_isr(int irq, void *data)
@@ -193,6 +281,29 @@ static irqreturn_t qpnp_tm_isr(int irq, void *data)
        return IRQ_HANDLED;
 }
 
+static int qpnp_tm_get_critical_trip_temp(struct qpnp_tm_chip *chip)
+{
+       int ntrips;
+       const struct thermal_trip *trips;
+       int i;
+
+       ntrips = of_thermal_get_ntrips(chip->tz_dev);
+       if (ntrips <= 0)
+               return THERMAL_TEMP_INVALID;
+
+       trips = of_thermal_get_trip_points(chip->tz_dev);
+       if (!trips)
+               return THERMAL_TEMP_INVALID;
+
+       for (i = 0; i < ntrips; i++) {
+               if (of_thermal_is_trip_valid(chip->tz_dev, i) &&
+                   trips[i].type == THERMAL_TRIP_CRITICAL)
+                       return trips[i].temperature;
+       }
+
+       return THERMAL_TEMP_INVALID;
+}
+
 /*
  * This function initializes the internal temp value based on only the
  * current thermal stage and threshold. Setup threshold control and
@@ -203,17 +314,20 @@ static int qpnp_tm_init(struct qpnp_tm_chip *chip)
        unsigned int stage;
        int ret;
        u8 reg = 0;
+       int crit_temp;
+
+       mutex_lock(&chip->lock);
 
        ret = qpnp_tm_read(chip, QPNP_TM_REG_SHUTDOWN_CTRL1, &reg);
        if (ret < 0)
-               return ret;
+               goto out;
 
        chip->thresh = reg & SHUTDOWN_CTRL1_THRESHOLD_MASK;
        chip->temp = DEFAULT_TEMP;
 
        ret = qpnp_tm_get_temp_stage(chip);
        if (ret < 0)
-               return ret;
+               goto out;
        chip->stage = ret;
 
        stage = chip->subtype == QPNP_TM_SUBTYPE_GEN1
@@ -224,21 +338,19 @@ static int qpnp_tm_init(struct qpnp_tm_chip *chip)
                             (stage - 1) * TEMP_STAGE_STEP +
                             TEMP_THRESH_MIN;
 
-       /*
-        * Set threshold and disable software override of stage 2 and 3
-        * shutdowns.
-        */
-       chip->thresh = THRESH_MIN;
-       reg &= ~(SHUTDOWN_CTRL1_OVERRIDE_MASK | SHUTDOWN_CTRL1_THRESHOLD_MASK);
-       reg |= chip->thresh & SHUTDOWN_CTRL1_THRESHOLD_MASK;
-       ret = qpnp_tm_write(chip, QPNP_TM_REG_SHUTDOWN_CTRL1, reg);
+       crit_temp = qpnp_tm_get_critical_trip_temp(chip);
+       ret = qpnp_tm_update_critical_trip_temp(chip, crit_temp);
        if (ret < 0)
-               return ret;
+               goto out;
 
        /* Enable the thermal alarm PMIC module in always-on mode. */
        reg = ALARM_CTRL_FORCE_ENABLE;
        ret = qpnp_tm_write(chip, QPNP_TM_REG_ALARM_CTRL, reg);
 
+       chip->initialized = true;
+
+out:
+       mutex_unlock(&chip->lock);
        return ret;
 }
 
@@ -257,6 +369,9 @@ static int qpnp_tm_probe(struct platform_device *pdev)
                return -ENOMEM;
 
        dev_set_drvdata(&pdev->dev, chip);
+       chip->dev = &pdev->dev;
+
+       mutex_init(&chip->lock);
 
        chip->map = dev_get_regmap(pdev->dev.parent, NULL);
        if (!chip->map)
@@ -302,6 +417,18 @@ static int qpnp_tm_probe(struct platform_device *pdev)
 
        chip->subtype = subtype;
 
+       /*
+        * Register the sensor before initializing the hardware to be able to
+        * read the trip points. get_temp() returns the default temperature
+        * before the hardware initialization is completed.
+        */
+       chip->tz_dev = devm_thermal_zone_of_sensor_register(
+               &pdev->dev, 0, chip, &qpnp_tm_sensor_ops);
+       if (IS_ERR(chip->tz_dev)) {
+               dev_err(&pdev->dev, "failed to register sensor\n");
+               return PTR_ERR(chip->tz_dev);
+       }
+
        ret = qpnp_tm_init(chip);
        if (ret < 0) {
                dev_err(&pdev->dev, "init failed\n");
@@ -313,12 +440,7 @@ static int qpnp_tm_probe(struct platform_device *pdev)
        if (ret < 0)
                return ret;
 
-       chip->tz_dev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, chip,
-                                                       &qpnp_tm_sensor_ops);
-       if (IS_ERR(chip->tz_dev)) {
-               dev_err(&pdev->dev, "failed to register sensor\n");
-               return PTR_ERR(chip->tz_dev);
-       }
+       thermal_zone_device_update(chip->tz_dev, THERMAL_EVENT_UNSPECIFIED);
 
        return 0;
 }