thermal/drivers/tsens: Add suspend to RAM support for tsens

As part of suspend to RAM, tsens hardware will be turned off.
While resume callback, re-initialize tsens hardware.

Signed-off-by: Priyansh Jain <quic_priyjain@quicinc.com>
Acked-by: Amit Kucheria <amitk@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20240328050230.31770-1-quic_priyjain@quicinc.com

Author: Priyansh Jain

drivers/thermal/qcom/tsens-v2.c

@@ -107,6 +107,7 @@ static const struct reg_field tsens_v2_regfields[MAX_REGFIELDS] = {
 static const struct tsens_ops ops_generic_v2 = {
 	.init		= init_common,
 	.get_temp	= get_temp_tsens_valid,
+	.resume		= tsens_resume_common,
 };
 
 struct tsens_plat_data data_tsens_v2 = {

drivers/thermal/qcom/tsens.c

@@ -17,6 +17,7 @@
 #include <linux/pm.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
+#include <linux/suspend.h>
 #include <linux/thermal.h>
 #include "../thermal_hwmon.h"
 #include "tsens.h"
@@ -1193,6 +1194,36 @@ static int tsens_register_irq(struct tsens_priv *priv, char *irqname,
 	return ret;
 }
 
+#ifdef CONFIG_SUSPEND
+static int tsens_reinit(struct tsens_priv *priv)
+{
+	if (tsens_version(priv) >= VER_2_X) {
+		/*
+		 * Re-enable the watchdog, unmask the bark.
+		 * Disable cycle completion monitoring
+		 */
+		if (priv->feat->has_watchdog) {
+			regmap_field_write(priv->rf[WDOG_BARK_MASK], 0);
+			regmap_field_write(priv->rf[CC_MON_MASK], 1);
+		}
+
+		/* Re-enable interrupts */
+		tsens_enable_irq(priv);
+	}
+
+	return 0;
+}
+
+int tsens_resume_common(struct tsens_priv *priv)
+{
+	if (pm_suspend_target_state == PM_SUSPEND_MEM)
+		tsens_reinit(priv);
+
+	return 0;
+}
+
+#endif /* !CONFIG_SUSPEND */
+
 static int tsens_register(struct tsens_priv *priv)
 {
 	int i, ret;

drivers/thermal/qcom/tsens.h

@@ -634,6 +634,11 @@ void compute_intercept_slope(struct tsens_priv *priv, u32 *pt1, u32 *pt2, u32 mo
 int init_common(struct tsens_priv *priv);
 int get_temp_tsens_valid(const struct tsens_sensor *s, int *temp);
 int get_temp_common(const struct tsens_sensor *s, int *temp);
+#ifdef CONFIG_SUSPEND
+int tsens_resume_common(struct tsens_priv *priv);
+#else
+#define tsens_resume_common            NULL
+#endif
 
 /* TSENS target */
 extern struct tsens_plat_data data_8960;