[PATCH v2 0/2] thermal: rcar_gen3_thermal: Read calibration from fuses

[PATCH v2 0/2] thermal: rcar_gen3_thermal: Read calibration from fuses

[Niklas Söderlund]

Hello,

This series allows the Gen3 thermal driver to read its calibration
values (THCODE and PTAT) from the fuses, if set. If the values are not
set the driver fall-back to the previously used pseudo values from the
datasheet.

Patch 1/2 prepare for reading the values from fuses by moving the
storage of the values used during calculation from global const to
members of the private data structures. While patch 2/2 populates the
private members with data from the fuses if available.

Niklas Söderlund (2):
  thermal: rcar_gen3_thermal: Store thcode and ptat in priv data
  thermal: rcar_gen3_thermal: Read calibration from hardware

 drivers/thermal/rcar_gen3_thermal.c | 113 +++++++++++++++++++++-------
 1 file changed, 86 insertions(+), 27 deletions(-)

-- 
2.33.0

[PATCH v2 1/2] thermal: rcar_gen3_thermal: Store thcode and ptat in priv data

[Niklas Söderlund]

Prepare for reading the THCODE and PTAT values from hardware fuses by
storing the values used during calculations in the drivers private
data structures.

As the values are now stored directly in the private data structures
there is no need to keep track of the TSC channel id as its only usage
was to lookup the THCODE row, drop it.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
* Changes since v1
- Collect tags.

* Changes since RFT
- Keep thcodes array static.
---
 drivers/thermal/rcar_gen3_thermal.c | 51 ++++++++++++++++-------------
 1 file changed, 28 insertions(+), 23 deletions(-)

diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c
index 85228d308dd35b19..7d7e6ebe837a83af 100644
--- a/drivers/thermal/rcar_gen3_thermal.c
+++ b/drivers/thermal/rcar_gen3_thermal.c
@@ -62,15 +62,6 @@
 
 #define TSC_MAX_NUM	5
 
-/* default THCODE values if FUSEs are missing */
-static const int thcodes[TSC_MAX_NUM][3] = {
-	{ 3397, 2800, 2221 },
-	{ 3393, 2795, 2216 },
-	{ 3389, 2805, 2237 },
-	{ 3415, 2694, 2195 },
-	{ 3356, 2724, 2244 },
-};
-
 /* Structure for thermal temperature calculation */
 struct equation_coefs {
 	int a1;
@@ -84,13 +75,14 @@ struct rcar_gen3_thermal_tsc {
 	struct thermal_zone_device *zone;
 	struct equation_coefs coef;
 	int tj_t;
-	unsigned int id; /* thermal channel id */
+	int thcode[3];
 };
 
 struct rcar_gen3_thermal_priv {
 	struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM];
 	unsigned int num_tscs;
 	void (*thermal_init)(struct rcar_gen3_thermal_tsc *tsc);
+	int ptat[3];
 };
 
 static inline u32 rcar_gen3_thermal_read(struct rcar_gen3_thermal_tsc *tsc,
@@ -133,8 +125,8 @@ static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc,
 /* no idea where these constants come from */
 #define TJ_3 -41
 
-static void rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc,
-					 int *ptat, const int *thcode,
+static void rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_priv *priv,
+					 struct rcar_gen3_thermal_tsc *tsc,
 					 int ths_tj_1)
 {
 	/* TODO: Find documentation and document constant calculation formula */
@@ -143,16 +135,16 @@ static void rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc,
 	 * Division is not scaled in BSP and if scaled it might overflow
 	 * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled
 	 */
-	tsc->tj_t = (FIXPT_INT((ptat[1] - ptat[2]) * (ths_tj_1 - TJ_3))
-		     / (ptat[0] - ptat[2])) + FIXPT_INT(TJ_3);
+	tsc->tj_t = (FIXPT_INT((priv->ptat[1] - priv->ptat[2]) * (ths_tj_1 - TJ_3))
+		     / (priv->ptat[0] - priv->ptat[2])) + FIXPT_INT(TJ_3);
 
-	tsc->coef.a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]),
+	tsc->coef.a1 = FIXPT_DIV(FIXPT_INT(tsc->thcode[1] - tsc->thcode[2]),
 				 tsc->tj_t - FIXPT_INT(TJ_3));
-	tsc->coef.b1 = FIXPT_INT(thcode[2]) - tsc->coef.a1 * TJ_3;
+	tsc->coef.b1 = FIXPT_INT(tsc->thcode[2]) - tsc->coef.a1 * TJ_3;
 
-	tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]),
+	tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(tsc->thcode[1] - tsc->thcode[0]),
 				 tsc->tj_t - FIXPT_INT(ths_tj_1));
-	tsc->coef.b2 = FIXPT_INT(thcode[0]) - tsc->coef.a2 * ths_tj_1;
+	tsc->coef.b2 = FIXPT_INT(tsc->thcode[0]) - tsc->coef.a2 * ths_tj_1;
 }
 
 static int rcar_gen3_thermal_round(int temp)
@@ -174,7 +166,7 @@ static int rcar_gen3_thermal_get_temp(void *devdata, int *temp)
 	/* Read register and convert to mili Celsius */
 	reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;
 
-	if (reg <= thcodes[tsc->id][1])
+	if (reg <= tsc->thcode[1])
 		val = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b1,
 				tsc->coef.a1);
 	else
@@ -401,9 +393,15 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 	unsigned int i;
 	int ret;
 
-	/* default values if FUSEs are missing */
+	/* Default THCODE values in case FUSEs are not set. */
 	/* TODO: Read values from hardware on supported platforms */
-	int ptat[3] = { 2631, 1509, 435 };
+	static const int thcodes[TSC_MAX_NUM][3] = {
+		{ 3397, 2800, 2221 },
+		{ 3393, 2795, 2216 },
+		{ 3389, 2805, 2237 },
+		{ 3415, 2694, 2195 },
+		{ 3356, 2724, 2244 },
+	};
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -413,6 +411,10 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 	if (soc_device_match(r8a7795es1))
 		priv->thermal_init = rcar_gen3_thermal_init_r8a7795es1;
 
+	priv->ptat[0] = 2631;
+	priv->ptat[1] = 1509;
+	priv->ptat[2] = 435;
+
 	platform_set_drvdata(pdev, priv);
 
 	if (rcar_gen3_thermal_request_irqs(priv, pdev))
@@ -439,7 +441,10 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 			ret = PTR_ERR(tsc->base);
 			goto error_unregister;
 		}
-		tsc->id = i;
+
+		tsc->thcode[0] = thcodes[i][0];
+		tsc->thcode[1] = thcodes[i][1];
+		tsc->thcode[2] = thcodes[i][2];
 
 		priv->tscs[i] = tsc;
 
@@ -453,7 +458,7 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 		tsc->zone = zone;
 
 		priv->thermal_init(tsc);
-		rcar_gen3_thermal_calc_coefs(tsc, ptat, thcodes[i], *ths_tj_1);
+		rcar_gen3_thermal_calc_coefs(priv, tsc, *ths_tj_1);
 
 		tsc->zone->tzp->no_hwmon = false;
 		ret = thermal_add_hwmon_sysfs(tsc->zone);
-- 
2.33.0

[PATCH v2 2/2] thermal: rcar_gen3_thermal: Read calibration from hardware

[Niklas Söderlund]

In production hardware the calibration values used to convert register
values to temperatures can be read from hardware. While pre-production
hardware still depends on pseudo values hard-coded in the driver.

Add support for reading out calibration values from hardware if it's
fused. The presence of fused calibration is indicated in the THSCP
register.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
* Changes since v1
- Renamed rcar_gen3_thermal_update_fuses() to
  rcar_gen3_thermal_read_fuses().
- Move static thcodes array inside the 'if' block where it's used.
- Invert dev_info logic to only inform if there are no fused
  calibration values, instead of logging if they are set as this should
  be the default case in production systems.
- Collect tags.

* Changes since RFT
- Keep thcodes array static.
---
 drivers/thermal/rcar_gen3_thermal.c | 94 +++++++++++++++++++++++------
 1 file changed, 74 insertions(+), 20 deletions(-)

diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c
index 7d7e6ebe837a83af..43eb25b167bc006f 100644
--- a/drivers/thermal/rcar_gen3_thermal.c
+++ b/drivers/thermal/rcar_gen3_thermal.c
@@ -34,6 +34,10 @@
 #define REG_GEN3_THCODE1	0x50
 #define REG_GEN3_THCODE2	0x54
 #define REG_GEN3_THCODE3	0x58
+#define REG_GEN3_PTAT1		0x5c
+#define REG_GEN3_PTAT2		0x60
+#define REG_GEN3_PTAT3		0x64
+#define REG_GEN3_THSCP		0x68
 
 /* IRQ{STR,MSK,EN} bits */
 #define IRQ_TEMP1		BIT(0)
@@ -55,6 +59,9 @@
 #define THCTR_PONM	BIT(6)
 #define THCTR_THSST	BIT(0)
 
+/* THSCP bits */
+#define THSCP_COR_PARA_VLD	(BIT(15) | BIT(14))
+
 #define CTEMP_MASK	0xFFF
 
 #define MCELSIUS(temp)	((temp) * 1000)
@@ -245,6 +252,64 @@ static const struct soc_device_attribute r8a7795es1[] = {
 	{ /* sentinel */ }
 };
 
+static bool rcar_gen3_thermal_read_fuses(struct rcar_gen3_thermal_priv *priv)
+{
+	unsigned int i;
+	u32 thscp;
+
+	/* If fuses are not set, fallback to pseudo values. */
+	thscp = rcar_gen3_thermal_read(priv->tscs[0], REG_GEN3_THSCP);
+	if ((thscp & THSCP_COR_PARA_VLD) != THSCP_COR_PARA_VLD) {
+		/* Default THCODE values in case FUSEs are not set. */
+		static const int thcodes[TSC_MAX_NUM][3] = {
+			{ 3397, 2800, 2221 },
+			{ 3393, 2795, 2216 },
+			{ 3389, 2805, 2237 },
+			{ 3415, 2694, 2195 },
+			{ 3356, 2724, 2244 },
+		};
+
+		priv->ptat[0] = 2631;
+		priv->ptat[1] = 1509;
+		priv->ptat[2] = 435;
+
+		for (i = 0; i < priv->num_tscs; i++) {
+			struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];
+
+			tsc->thcode[0] = thcodes[i][0];
+			tsc->thcode[1] = thcodes[i][1];
+			tsc->thcode[2] = thcodes[i][2];
+		}
+
+		return false;
+	}
+
+	/*
+	 * Set the pseudo calibration points with fused values.
+	 * PTAT is shared between all TSCs but only fused for the first
+	 * TSC while THCODEs are fused for each TSC.
+	 */
+	priv->ptat[0] = rcar_gen3_thermal_read(priv->tscs[0], REG_GEN3_PTAT1) &
+		GEN3_FUSE_MASK;
+	priv->ptat[1] = rcar_gen3_thermal_read(priv->tscs[0], REG_GEN3_PTAT2) &
+		GEN3_FUSE_MASK;
+	priv->ptat[2] = rcar_gen3_thermal_read(priv->tscs[0], REG_GEN3_PTAT3) &
+		GEN3_FUSE_MASK;
+
+	for (i = 0; i < priv->num_tscs; i++) {
+		struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];
+
+		tsc->thcode[0] = rcar_gen3_thermal_read(tsc, REG_GEN3_THCODE1) &
+			GEN3_FUSE_MASK;
+		tsc->thcode[1] = rcar_gen3_thermal_read(tsc, REG_GEN3_THCODE2) &
+			GEN3_FUSE_MASK;
+		tsc->thcode[2] = rcar_gen3_thermal_read(tsc, REG_GEN3_THCODE3) &
+			GEN3_FUSE_MASK;
+	}
+
+	return true;
+}
+
 static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc)
 {
 	rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,  CTSR_THBGR);
@@ -393,16 +458,6 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 	unsigned int i;
 	int ret;
 
-	/* Default THCODE values in case FUSEs are not set. */
-	/* TODO: Read values from hardware on supported platforms */
-	static const int thcodes[TSC_MAX_NUM][3] = {
-		{ 3397, 2800, 2221 },
-		{ 3393, 2795, 2216 },
-		{ 3389, 2805, 2237 },
-		{ 3415, 2694, 2195 },
-		{ 3356, 2724, 2244 },
-	};
-
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
@@ -411,10 +466,6 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 	if (soc_device_match(r8a7795es1))
 		priv->thermal_init = rcar_gen3_thermal_init_r8a7795es1;
 
-	priv->ptat[0] = 2631;
-	priv->ptat[1] = 1509;
-	priv->ptat[2] = 435;
-
 	platform_set_drvdata(pdev, priv);
 
 	if (rcar_gen3_thermal_request_irqs(priv, pdev))
@@ -442,11 +493,16 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 			goto error_unregister;
 		}
 
-		tsc->thcode[0] = thcodes[i][0];
-		tsc->thcode[1] = thcodes[i][1];
-		tsc->thcode[2] = thcodes[i][2];
-
 		priv->tscs[i] = tsc;
+	}
+
+	priv->num_tscs = i;
+
+	if (!rcar_gen3_thermal_read_fuses(priv))
+		dev_info(dev, "No calibration values fused, fallback to driver values\n");
+
+	for (i = 0; i < priv->num_tscs; i++) {
+		struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];
 
 		zone = devm_thermal_zone_of_sensor_register(dev, i, tsc,
 							    &rcar_gen3_tz_of_ops);
@@ -476,8 +532,6 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 		dev_info(dev, "TSC%u: Loaded %d trip points\n", i, ret);
 	}
 
-	priv->num_tscs = i;
-
 	if (!priv->num_tscs) {
 		ret = -ENODEV;
 		goto error_unregister;
-- 
2.33.0