[PATCH/RFT] thermal: rcar_gen3_thermal: Update calculation formula due to HW evaluation

* [PATCH/RFT] thermal: rcar_gen3_thermal: Update calculation formula due to HW evaluation
@ 2019-03-21 20:47 Yoshihiro Kaneko
  2019-04-01 13:37 ` Simon Horman
  0 siblings, 1 reply; 6+ messages in thread
From: Yoshihiro Kaneko @ 2019-03-21 20:47 UTC (permalink / raw)
  To: linux-pm
  Cc: Zhang Rui, Eduardo Valentin, Rob Herring, Simon Horman,
	Magnus Damm, linux-renesas-soc

From: Dien Pham <dien.pham.ry@renesas.com>

1/ As evaluation of hardware team, temperature calculation formula
 of M3-W is difference from all other SoCs as below:
 - M3-W: Tj_1: 116 (so Tj_1 - Tj_3 = 157)
 - Others: Tj_1: 126 (so Tj_1 - Tj_3 = 167)

2/ Update the formula to calculate CTEMP:
  Currently, the CTEMP is average of val1 (is calculated by
  formula 1) and val2 (is calculated by formula 2). But,
  as description in HWM (chapter 10A.3.1.1 Setting of Normal Mode)

  If (STEMP < Tj_T) CTEMP value should be val1.
  If (STEMP > Tj_T) CTEMP value should be val2.

3/ Update the formula to calculate temperature:
  Currently, current TEMP is calculated as
  average of val1 (is calculated by formula 1)
  and val2 (is calculated by formula 2). But,
  as description in HWM (chapter 10A.3.1.2 Normal Mode.)

  If (TEMP_CODE < THCODE2[11:0]) CTEMP value should be val1.
  If (TEMP_CODE > THCODE2[11:0]) CTEMP value should be val2.

Signed-off-by: Dien Pham <dien.pham.ry@renesas.com>
[ykaneko0929@gmail.com: use the data field of the of_device_id for Tj_1]
[ykaneko0929@gmail.com: revise a description of case 1 of the commit log]
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
---
 drivers/thermal/rcar_gen3_thermal.c | 86 +++++++++++++++++++++++++------------
 1 file changed, 58 insertions(+), 28 deletions(-)

This patch is based on the master branch of Linus Torvalds's linux tree.

diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c
index 88fa41c..de6f244 100644
--- a/drivers/thermal/rcar_gen3_thermal.c
+++ b/drivers/thermal/rcar_gen3_thermal.c
@@ -63,6 +63,15 @@
 
 #define TSC_MAX_NUM	3
 
+static int tj_2;
+
+/* default THCODE values if FUSEs are missing */
+static int thcode[TSC_MAX_NUM][3] = {
+	{ 3397, 2800, 2221 },
+	{ 3393, 2795, 2216 },
+	{ 3389, 2805, 2237 },
+};
+
 /* Structure for thermal temperature calculation */
 struct equation_coefs {
 	int a1;
@@ -77,6 +86,7 @@ struct rcar_gen3_thermal_tsc {
 	struct equation_coefs coef;
 	int low;
 	int high;
+	int id; /* thermal channel id */
 };
 
 struct rcar_gen3_thermal_priv {
@@ -124,30 +134,29 @@ static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc,
 #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */
 
 /* no idea where these constants come from */
-#define TJ_1 116
-#define TJ_3 -41
+#define TJ_2 (INT_FIXPT(tj_2))	/* Tj_T */
+#define TJ_3 -41		/* Tj_L */
 
 static void rcar_gen3_thermal_calc_coefs(struct equation_coefs *coef,
-					 int *ptat, int *thcode)
+					 int *ptat, int *thcode,
+					 unsigned int ths_tj_1)
 {
-	int tj_2;
-
 	/* TODO: Find documentation and document constant calculation formula */
 
 	/*
 	 * Division is not scaled in BSP and if scaled it might overflow
 	 * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled
 	 */
-	tj_2 = (FIXPT_INT((ptat[1] - ptat[2]) * 157)
-		/ (ptat[0] - ptat[2])) - FIXPT_INT(41);
+	tj_2 = (FIXPT_INT((ptat[1] - ptat[2]) * (ths_tj_1 - TJ_3))
+		/ (ptat[0] - ptat[2])) + FIXPT_INT(TJ_3);
 
 	coef->a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]),
 			     tj_2 - FIXPT_INT(TJ_3));
 	coef->b1 = FIXPT_INT(thcode[2]) - coef->a1 * TJ_3;
 
 	coef->a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]),
-			     tj_2 - FIXPT_INT(TJ_1));
-	coef->b2 = FIXPT_INT(thcode[0]) - coef->a2 * TJ_1;
+			     tj_2 - FIXPT_INT(ths_tj_1));
+	coef->b2 = FIXPT_INT(thcode[0]) - coef->a2 * ths_tj_1;
 }
 
 static int rcar_gen3_thermal_round(int temp)
@@ -163,15 +172,19 @@ static int rcar_gen3_thermal_round(int temp)
 static int rcar_gen3_thermal_get_temp(void *devdata, int *temp)
 {
 	struct rcar_gen3_thermal_tsc *tsc = devdata;
-	int mcelsius, val1, val2;
+	int mcelsius, val;
 	u32 reg;
 
 	/* Read register and convert to mili Celsius */
 	reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;
 
-	val1 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b1, tsc->coef.a1);
-	val2 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b2, tsc->coef.a2);
-	mcelsius = FIXPT_TO_MCELSIUS((val1 + val2) / 2);
+	if (reg <= thcode[tsc->id][1])
+		val = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b1,
+				tsc->coef.a1);
+	else
+		val = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b2,
+				tsc->coef.a2);
+	mcelsius = FIXPT_TO_MCELSIUS(val);
 
 	/* Make sure we are inside specifications */
 	if ((mcelsius < MCELSIUS(-40)) || (mcelsius > MCELSIUS(125)))
@@ -186,13 +199,15 @@ static int rcar_gen3_thermal_get_temp(void *devdata, int *temp)
 static int rcar_gen3_thermal_mcelsius_to_temp(struct rcar_gen3_thermal_tsc *tsc,
 					      int mcelsius)
 {
-	int celsius, val1, val2;
+	int celsius, val;
 
 	celsius = DIV_ROUND_CLOSEST(mcelsius, 1000);
-	val1 = celsius * tsc->coef.a1 + tsc->coef.b1;
-	val2 = celsius * tsc->coef.a2 + tsc->coef.b2;
+	if (celsius <= TJ_2)
+		val = celsius * tsc->coef.a1 + tsc->coef.b1;
+	else
+		val = celsius * tsc->coef.a2 + tsc->coef.b2;
 
-	return INT_FIXPT((val1 + val2) / 2);
+	return INT_FIXPT(val);
 }
 
 static int rcar_gen3_thermal_set_trips(void *devdata, int low, int high)
@@ -318,12 +333,29 @@ static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
 	usleep_range(1000, 2000);
 }
 
+static const unsigned int rcar_gen3_ths_tj_1 = 126;
+static const unsigned int rcar_gen3_ths_tj_1_m3_w = 116;
 static const struct of_device_id rcar_gen3_thermal_dt_ids[] = {
-	{ .compatible = "renesas,r8a774a1-thermal", },
-	{ .compatible = "renesas,r8a7795-thermal", },
-	{ .compatible = "renesas,r8a7796-thermal", },
-	{ .compatible = "renesas,r8a77965-thermal", },
-	{ .compatible = "renesas,r8a77980-thermal", },
+	{
+		.compatible = "renesas,r8a774a1-thermal",
+		.data = &rcar_gen3_ths_tj_1_m3_w,
+	},
+	{
+		.compatible = "renesas,r8a7795-thermal",
+		.data = &rcar_gen3_ths_tj_1,
+	},
+	{
+		.compatible = "renesas,r8a7796-thermal",
+		.data = &rcar_gen3_ths_tj_1_m3_w,
+	},
+	{
+		.compatible = "renesas,r8a77965-thermal",
+		.data = &rcar_gen3_ths_tj_1,
+	},
+	{
+		.compatible = "renesas,r8a77980-thermal",
+		.data = &rcar_gen3_ths_tj_1,
+	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, rcar_gen3_thermal_dt_ids);
@@ -349,6 +381,7 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 {
 	struct rcar_gen3_thermal_priv *priv;
 	struct device *dev = &pdev->dev;
+	const unsigned int *rcar_gen3_ths_tj_1 = of_device_get_match_data(dev);
 	struct resource *res;
 	struct thermal_zone_device *zone;
 	int ret, irq, i;
@@ -357,11 +390,6 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 	/* default values if FUSEs are missing */
 	/* TODO: Read values from hardware on supported platforms */
 	int ptat[3] = { 2631, 1509, 435 };
-	int thcode[TSC_MAX_NUM][3] = {
-		{ 3397, 2800, 2221 },
-		{ 3393, 2795, 2216 },
-		{ 3389, 2805, 2237 },
-	};
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -418,11 +446,13 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 			ret = PTR_ERR(tsc->base);
 			goto error_unregister;
 		}
+		tsc->id = i;
 
 		priv->tscs[i] = tsc;
 
 		priv->thermal_init(tsc);
-		rcar_gen3_thermal_calc_coefs(&tsc->coef, ptat, thcode[i]);
+		rcar_gen3_thermal_calc_coefs(&tsc->coef, ptat, thcode[i],
+					     *rcar_gen3_ths_tj_1);
 
 		zone = devm_thermal_zone_of_sensor_register(dev, i, tsc,
 							    &rcar_gen3_tz_of_ops);
-- 
1.9.1


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