imx6: imx: thermal: use CPU temperature grade info for thresholds

This is a backport of a2291badc355d58ead5c19ae0609468947416040 from thermal-soc
accepted upstream.

The IMX6Q/IMX6DL SoC's have a 2-bit temperature grade stored in OTP. Instead
of assuming 85C for passive cooling threshold and 100C for critical base
these thresholds off the thermal gade max CPU temperature:
 - passive threshold: max - 10C
 - critical threshold: max - 5C

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

SVN-Revision: 48011

target/linux/imx6/patches-4.3/045-imx-thermal-use-cpu-temperature-grade-info-for-thresholds

@@ -0,0 +1,114 @@
+Index: linux-4.3/drivers/thermal/imx_thermal.c
+===================================================================
+--- linux-4.3.orig/drivers/thermal/imx_thermal.c	2015-11-01 16:05:25.000000000 -0800
++++ linux-4.3/drivers/thermal/imx_thermal.c	2015-12-18 10:39:44.915158318 -0800
+@@ -55,6 +55,7 @@
+ #define TEMPSENSE2_PANIC_VALUE_SHIFT	16
+ #define TEMPSENSE2_PANIC_VALUE_MASK	0xfff0000
+ 
++#define OCOTP_MEM0			0x0480
+ #define OCOTP_ANA1			0x04e0
+ 
+ /* The driver supports 1 passive trip point and 1 critical trip point */
+@@ -64,12 +65,6 @@
+ 	IMX_TRIP_NUM,
+ };
+ 
+-/*
+- * It defines the temperature in millicelsius for passive trip point
+- * that will trigger cooling action when crossed.
+- */
+-#define IMX_TEMP_PASSIVE		85000
+-
+ #define IMX_POLLING_DELAY		2000 /* millisecond */
+ #define IMX_PASSIVE_DELAY		1000
+ 
+@@ -100,12 +95,14 @@
+ 	u32 c1, c2; /* See formula in imx_get_sensor_data() */
+ 	int temp_passive;
+ 	int temp_critical;
++	unsigned long temp_max;
+ 	int alarm_temp;
+ 	int last_temp;
+ 	bool irq_enabled;
+ 	int irq;
+ 	struct clk *thermal_clk;
+ 	const struct thermal_soc_data *socdata;
++	const char *temp_grade;
+ };
+ 
+ static void imx_set_panic_temp(struct imx_thermal_data *data,
+@@ -285,10 +282,12 @@
+ {
+ 	struct imx_thermal_data *data = tz->devdata;
+ 
++	/* do not allow changing critical threshold */
+ 	if (trip == IMX_TRIP_CRITICAL)
+ 		return -EPERM;
+ 
+-	if (temp > IMX_TEMP_PASSIVE)
++	/* do not allow passive to be set higher than critical */
++	if (temp < 0 || temp > data->temp_critical)
+ 		return -EINVAL;
+ 
+ 	data->temp_passive = temp;
+@@ -404,17 +403,39 @@
+ 	data->c1 = temp64;
+ 	data->c2 = n1 * data->c1 + 1000 * t1;
+ 
+-	/*
+-	 * Set the default passive cooling trip point,
+-	 * can be changed from userspace.
+-	 */
+-	data->temp_passive = IMX_TEMP_PASSIVE;
++	/* use OTP for thermal grade */
++	ret = regmap_read(map, OCOTP_MEM0, &val);
++	if (ret) {
++		dev_err(&pdev->dev, "failed to read temp grade: %d\n", ret);
++		return ret;
++	}
++
++	/* The maximum die temp is specified by the Temperature Grade */
++	switch ((val >> 6) & 0x3) {
++	case 0: /* Commercial (0 to 95C) */
++		data->temp_grade = "Commercial";
++		data->temp_max = 95000;
++		break;
++	case 1: /* Extended Commercial (-20 to 105C) */
++		data->temp_grade = "Extended Commercial";
++		data->temp_max = 105000;
++		break;
++	case 2: /* Industrial (-40 to 105C) */
++		data->temp_grade = "Industrial";
++		data->temp_max = 105000;
++		break;
++	case 3: /* Automotive (-40 to 125C) */
++		data->temp_grade = "Automotive";
++		data->temp_max = 125000;
++		break;
++	}
+ 
+ 	/*
+-	 * The maximum die temperature set to 20 C higher than
+-	 * IMX_TEMP_PASSIVE.
++	 * Set the critical trip point at 5C under max
++	 * Set the passive trip point at 10C under max (can change via sysfs)
+ 	 */
+-	data->temp_critical = 1000 * 20 + data->temp_passive;
++	data->temp_critical = data->temp_max - (1000 * 5);
++	data->temp_passive = data->temp_max - (1000 * 10);
+ 
+ 	return 0;
+ }
+@@ -559,6 +580,11 @@
+ 		return ret;
+ 	}
+ 
++	dev_info(&pdev->dev, "%s CPU temperature grade - max:%ldC"
++		 " critical:%ldC passive:%ldC\n", data->temp_grade,
++		 data->temp_max / 1000, data->temp_critical / 1000,
++		 data->temp_passive / 1000);
++
+ 	/* Enable measurements at ~ 10 Hz */
+ 	regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
+ 	measure_freq = DIV_ROUND_UP(32768, 10); /* 10 Hz */