superio/ite/common: Add temperature limits

Add devicetree options to set temperature limits that are used to alarm
user when temperature exceeds defined values.

Audio alerts by superio are not implemented yet, but since limits are
visible to userland, some software might use them as is. For instance,
lm-sensors displays "ALERT" when temperature exceeds limits.

Change-Id: I56e041fb78f518d6a9640dc2b3985459991242b9
Signed-off-by: Vagiz Tarkhanov <rakkin@autistici.org>
Reviewed-on: https://review.coreboot.org/21844
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/superio/ite/common/env_ctrl.c

@@ -129,6 +129,12 @@ static void enable_tmpin(const u16 base, const u8 tmpin,
 		ite_ec_write(base, ITE_EC_TEMP_ADJUST[tmpin-1], conf->offset);
 	}
 
+	/* Set temperature limits */
+	u8 max = conf->max;
+	ite_ec_write(base, ITE_EC_HIGH_TEMP_LIMIT(tmpin),
+		     max ? max : 127);
+	ite_ec_write(base, ITE_EC_LOW_TEMP_LIMIT(tmpin), conf->min);
+
 	/* Enable the startup of monitoring operation */
 	reg = ite_ec_read(base, ITE_EC_CONFIGURATION);
 	reg |= ITE_EC_CONFIGURATION_START;

src/superio/ite/common/env_ctrl.h

@@ -86,6 +86,9 @@
 #define   ITE_EC_FAN_CTL_TEMPIN_MASK		(3 << 0)
 #define   ITE_EC_FAN_CTL_TEMPIN(x)		(((x)-1) & 3)
 
+#define ITE_EC_HIGH_TEMP_LIMIT(x)		(0x40 + ((x-1) * 2))
+#define ITE_EC_LOW_TEMP_LIMIT(x)		(0x41 + ((x-1) * 2))
+
 #define ITE_EC_ADC_VOLTAGE_CHANNEL_ENABLE	0x50
 #define ITE_EC_ADC_TEMP_CHANNEL_ENABLE		0x51
 #define   ITE_EC_ADC_TEMP_EXT_REPORTS_TO(x)	(((x) & 3) << 6)

src/superio/ite/common/env_ctrl_chip.h

@@ -32,6 +32,9 @@ struct ite_ec_thermal_config {
 	enum ite_ec_thermal_mode mode;
 	/* Offset is used for diode sensors and PECI */
 	u8 offset;
+	/* Limits */
+	u8 min;
+	u8 max;
 };
 
 /* Bit mask for voltage pins VINx */