[PATCH v3 3/4] thermal: qoriq: workaround unexpected temperature readings from tmu

[Jacky Bai]

Invalid temperature measurements may be observed across the temperature
range specified in the device data sheet. The invalid temperature can be
read from any remote site and from any capture or report registers. The
invalid change in temperature can be positive or negative and the resulting
temperature can be outside the calibrated range, in which case the TSR[ORL]
or TSR[ORH] bit will be set.

Workaround:
Use the raising/falling edge threshold to filter out the invalid temp.
Check the TIDR register to make sure no jump happens When reading the temp.

i.MX93 ERR052243:
(https://www.nxp.com/webapp/Download?colCode=IMX93_2P87F&appType=license)

Signed-off-by: Jacky Bai <ping.bai at nxp.com>
---
 - v3 changes:
  - refine the code with FIELD_PREP macro
  - add errata doc url link and refine the commit log

 - v2 changes:
  - no
---
 drivers/thermal/qoriq_thermal.c | 42 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/qoriq_thermal.c b/drivers/thermal/qoriq_thermal.c
index b2e634547271dcf512c714907baa162921d2d527..134a63abb482d44b5cc78e672e6312fbdce5ba31 100644
--- a/drivers/thermal/qoriq_thermal.c
+++ b/drivers/thermal/qoriq_thermal.c
@@ -30,6 +30,9 @@
 #define TMU_VER1		0x1
 #define TMU_VER2		0x2
 
+/* errata ID info define */
+#define TMU_ERR052243	BIT(0)
+
 #define REGS_TMR	0x000	/* Mode Register */
 #define TMR_DISABLE	0x0
 #define TMR_ME		0x80000000
@@ -45,6 +48,13 @@
 #define REGS_TIER	0x020	/* Interrupt Enable Register */
 #define TIER_DISABLE	0x0
 
+#define REGS_TIDR	0x24
+#define TMRTRCTR	0x70
+#define TMRTRCTR_EN	BIT(31)
+#define TMRTRCTR_TEMP_MASK	GENMASK(7, 0)
+#define TMFTRCTR	0x74
+#define TMFTRCTR_EN	BIT(31)
+#define TMFTRCTR_TEMP_MASK	GENMASK(7, 0)
 
 #define REGS_TTCFGR	0x080	/* Temperature Configuration Register */
 #define REGS_TSCFGR	0x084	/* Sensor Configuration Register */
@@ -69,6 +79,7 @@
 #define REGS_V2_TEUMR(n)	(0xf00 + 4 * (n))
 
 #define GET_TEUMR0(drvdata)	(drvdata && drvdata->teumr0 ? drvdata->teumr0 : TEUMR0_V2)
+#define CHECK_ERRATA_FLAG(drvdata, flag) (drvdata ? drvdata->tmu_errata & (flag) : 0)
 
 /*
  * Thermal zone data
@@ -79,6 +90,7 @@ struct qoriq_sensor {
 
 struct tmu_drvdata {
 	u32 teumr0;
+	u32 tmu_errata;
 };
 
 struct qoriq_tmu_data {
@@ -99,7 +111,7 @@ static int tmu_get_temp(struct thermal_zone_device *tz, int *temp)
 {
 	struct qoriq_sensor *qsensor = thermal_zone_device_priv(tz);
 	struct qoriq_tmu_data *qdata = qoriq_sensor_to_data(qsensor);
-	u32 val;
+	u32 val, tidr;
 	/*
 	 * REGS_TRITSR(id) has the following layout:
 	 *
@@ -124,6 +136,15 @@ static int tmu_get_temp(struct thermal_zone_device *tz, int *temp)
 	if (!(val & TMR_ME))
 		return -EAGAIN;
 
+	/* ERR052243: If a raising or falling edge happens, try later */
+	if (CHECK_ERRATA_FLAG(qdata->drvdata, TMU_ERR052243)) {
+		regmap_read(qdata->regmap, REGS_TIDR, &tidr);
+		if (tidr & GENMASK(25, 24)) {
+			regmap_write(qdata->regmap, REGS_TIDR, GENMASK(25, 24));
+			return -EAGAIN;
+		}
+	}
+
 	if (regmap_read_poll_timeout(qdata->regmap,
 				     REGS_TRITSR(qsensor->id),
 				     val,
@@ -132,6 +153,15 @@ static int tmu_get_temp(struct thermal_zone_device *tz, int *temp)
 				     10 * USEC_PER_MSEC))
 		return -ENODATA;
 
+	/*ERR052243: If a raising or falling edge happens, try later */
+	if (CHECK_ERRATA_FLAG(qdata->drvdata, TMU_ERR052243)) {
+		regmap_read(qdata->regmap, REGS_TIDR, &tidr);
+		if (tidr & GENMASK(25, 24)) {
+			regmap_write(qdata->regmap, REGS_TIDR, GENMASK(25, 24));
+			return -EAGAIN;
+		}
+	}
+
 	if (qdata->ver == TMU_VER1) {
 		*temp = (val & GENMASK(7, 0)) * MILLIDEGREE_PER_DEGREE;
 	} else {
@@ -238,7 +268,6 @@ static void qoriq_tmu_init_device(struct qoriq_tmu_data *data)
 	regmap_write(data->regmap, REGS_TIER, TIER_DISABLE);
 
 	/* Set update_interval */
-
 	if (data->ver == TMU_VER1) {
 		regmap_write(data->regmap, REGS_TMTMIR, TMTMIR_DEFAULT);
 	} else {
@@ -246,6 +275,14 @@ static void qoriq_tmu_init_device(struct qoriq_tmu_data *data)
 		regmap_write(data->regmap, REGS_V2_TEUMR(0), GET_TEUMR0(data->drvdata));
 	}
 
+	/* ERR052243: Set the raising & falling edge monitor */
+	if (CHECK_ERRATA_FLAG(data->drvdata, TMU_ERR052243)) {
+		regmap_write(data->regmap, TMRTRCTR, TMRTRCTR_EN |
+			     FIELD_PREP(TMRTRCTR_TEMP_MASK, 0x7));
+		regmap_write(data->regmap, TMFTRCTR, TMFTRCTR_EN |
+			     FIELD_PREP(TMFTRCTR_TEMP_MASK, 0x7));
+
+	}
 	/* Disable monitoring */
 	regmap_write(data->regmap, REGS_TMR, TMR_DISABLE);
 }
@@ -389,6 +426,7 @@ static DEFINE_SIMPLE_DEV_PM_OPS(qoriq_tmu_pm_ops,
 
 static const struct tmu_drvdata imx93_data = {
 	.teumr0 = TEUMR0_V21,
+	.tmu_errata = TMU_ERR052243,
 };
 
 static const struct of_device_id qoriq_tmu_match[] = {

-- 
2.34.1