[PATCH] imx: thermal: use CPU temperature grade info for thresholds

[tharvey@gateworks.com (Tim Harvey)]

The IMX6Q/IMX6DL SoC's have a 2-bit temperature grade stored in OTP. Instead
of assuming 85C for passive cooling threshold and 105C for critical use
the thermal grade for these configurations. For IMX6SX which does not have
a temperature grade in OTP (according to the ref manual) assume 105C critical.
We will default the user-settable passive threshold to crit - 20C.

Cc: Anson Huang <b20788@freescale.com>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
---
 drivers/thermal/imx_thermal.c | 64 +++++++++++++++++++++++++++++++++----------
 1 file changed, 49 insertions(+), 15 deletions(-)

diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
index 2ccbc07..c6a4eed 100644
--- a/drivers/thermal/imx_thermal.c
+++ b/drivers/thermal/imx_thermal.c
@@ -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 @@ enum imx_thermal_trip {
 	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
 
@@ -106,6 +101,7 @@ struct imx_thermal_data {
 	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,
@@ -289,7 +285,8 @@ static int imx_set_trip_temp(struct thermal_zone_device *tz, int trip,
 	if (trip == IMX_TRIP_CRITICAL)
 		return -EPERM;
 
-	if (temp > IMX_TEMP_PASSIVE)
+	/* do not allow passive to be set higher than critical - 20C */
+	if (temp > (data->temp_critical - (1000 * 20)))
 		return -EINVAL;
 
 	data->temp_passive = temp;
@@ -404,17 +401,50 @@ static int imx_get_sensor_data(struct platform_device *pdev)
 	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;
+	/* Assume Extended Commercial temperature grade limits (105C max) */
+	data->temp_grade = "unknown";
+	data->temp_critical = 105000;
+
+	/* For IMX6Q use OTP for thermal grade */
+	if (data->socdata->version == TEMPMON_IMX6Q) {
+		ret = regmap_read(map, OCOTP_MEM0, &val);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to read temp grade: %d\n",
+				ret);
+			return ret;
+		}
+
+		if (val == 0 || val == ~0) {
+			dev_err(&pdev->dev, "invalid temp grade data\n");
+			return -EINVAL;
+		}
+
+		/* 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_critical = 95000;
+			break;
+		case 1: /* Extended Commercial (-20 to 105C) */
+			data->temp_grade = "Extended Commercial";
+			data->temp_critical = 105000;
+			break;
+		case 2: /* Industrial (-40 to 105C) */
+			data->temp_grade = "Industrial";
+			data->temp_critical = 105000;
+			break;
+		case 3: /* Automotive (-40 to 125C) */
+			data->temp_grade = "Automotive";
+			data->temp_critical = 125000;
+			break;
+		}
+	}
 
 	/*
-	 * The maximum die temperature set to 20 C higher than
-	 * IMX_TEMP_PASSIVE.
+	 * Set the default passive cooling trip point to critical - 20C
+	 * (can be changed from userspace)
 	 */
-	data->temp_critical = 1000 * 20 + data->temp_passive;
+	data->temp_passive = data->temp_critical - (1000 * 20);
 
 	return 0;
 }
@@ -559,6 +589,10 @@ static int imx_thermal_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	dev_info(&pdev->dev, "%s CPU temperature grade - "
+		 "thresholds: crit:%ldC passive:%ldC\n", data->temp_grade,
+		 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 */
-- 
1.9.1