thermal/drivers/mediatek/lvts: Disable monitor mode during suspend

When configured in filtered mode, the LVTS thermal controller will
monitor the temperature from the sensors and trigger an interrupt once a
thermal threshold is crossed.

Currently this is true even during suspend and resume. The problem with
that is that when enabling the internal clock of the LVTS controller in
lvts_ctrl_set_enable() during resume, the temperature reading can glitch
and appear much higher than the real one, resulting in a spurious
interrupt getting generated.

Disable the temperature monitoring and give some time for the signals to
stabilize during suspend in order to prevent such spurious interrupts.

Cc: stable@vger.kernel.org
Reported-by: Hsin-Te Yuan <yuanhsinte@chromium.org>
Closes: https://lore.kernel.org/all/20241108-lvts-v1-1-eee339c6ca20@chromium.org/
Fixes: 8137bb90600d ("thermal/drivers/mediatek/lvts_thermal: Add suspend and resume")
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20250113-mt8192-lvts-filtered-suspend-fix-v2-1-07a25200c7c6@collabora.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

diff --git a/drivers/thermal/mediatek/lvts_thermal.c b/drivers/thermal/mediatek/lvts_thermal.c
index 07f7f3b7a2fb569cfc300dc2126ea426e161adff..a1a438ebad33c1fff8ca9781e12ef9e278eef785 100644 (file)
--- a/drivers/thermal/mediatek/lvts_thermal.c
+++ b/drivers/thermal/mediatek/lvts_thermal.c
@@ -860,6 +860,32 @@ static int lvts_ctrl_init(struct device *dev, struct lvts_domain *lvts_td,
        return 0;
 }
 
+static void lvts_ctrl_monitor_enable(struct device *dev, struct lvts_ctrl *lvts_ctrl, bool enable)
+{
+       /*
+        * Bitmaps to enable each sensor on filtered mode in the MONCTL0
+        * register.
+        */
+       static const u8 sensor_filt_bitmap[] = { BIT(0), BIT(1), BIT(2), BIT(3) };
+       u32 sensor_map = 0;
+       int i;
+
+       if (lvts_ctrl->mode != LVTS_MSR_FILTERED_MODE)
+               return;
+
+       if (enable) {
+               lvts_for_each_valid_sensor(i, lvts_ctrl)
+                       sensor_map |= sensor_filt_bitmap[i];
+       }
+
+       /*
+        * Bits:
+        *      9: Single point access flow
+        *    0-3: Enable sensing point 0-3
+        */
+       writel(sensor_map | BIT(9), LVTS_MONCTL0(lvts_ctrl->base));
+}
+
 /*
  * At this point the configuration register is the only place in the
  * driver where we write multiple values. Per hardware constraint,
@@ -1381,8 +1407,11 @@ static int lvts_suspend(struct device *dev)
 
        lvts_td = dev_get_drvdata(dev);
 
-       for (i = 0; i < lvts_td->num_lvts_ctrl; i++)
+       for (i = 0; i < lvts_td->num_lvts_ctrl; i++) {
+               lvts_ctrl_monitor_enable(dev, &lvts_td->lvts_ctrl[i], false);
+               usleep_range(100, 200);
                lvts_ctrl_set_enable(&lvts_td->lvts_ctrl[i], false);
+       }
 
        clk_disable_unprepare(lvts_td->clk);
 
@@ -1400,8 +1429,11 @@ static int lvts_resume(struct device *dev)
        if (ret)
                return ret;
 
-       for (i = 0; i < lvts_td->num_lvts_ctrl; i++)
+       for (i = 0; i < lvts_td->num_lvts_ctrl; i++) {
                lvts_ctrl_set_enable(&lvts_td->lvts_ctrl[i], true);
+               usleep_range(100, 200);
+               lvts_ctrl_monitor_enable(dev, &lvts_td->lvts_ctrl[i], true);
+       }
 
        return 0;
 }