thermal: rcar_gen3_thermal: Update value of Tj_1 [Linux 5.2]

thermal: rcar_gen3_thermal: Update value of Tj_1 [Linux 5.2]

This Linux kernel change "thermal: rcar_gen3_thermal: Update value of Tj_1" is included in the Linux 5.2 release. This change is authored by Yoshihiro Kaneko <ykaneko0929 [at] gmail.com> on Tue May 14 05:03:53 2019 +0900. The commit for this change in Linux stable tree is 4eb39f7 (patch).

thermal: rcar_gen3_thermal: Update value of Tj_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)

Signed-off-by: Yoshihiro Kaneko <[email protected]>
Signed-off-by: Eduardo Valentin <[email protected]>

There are 41 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/thermal/rcar_gen3_thermal.c | 41 +++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c
index 83f3062..3d56fe5 100644
--- a/drivers/thermal/rcar_gen3_thermal.c
+++ b/drivers/thermal/rcar_gen3_thermal.c
@@ -122,11 +122,11 @@ 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

 static void rcar_gen3_thermal_calc_coefs(struct equation_coefs *coef,
-                    int *ptat, int *thcode)
+                    int *ptat, int *thcode,
+                    int ths_tj_1)
 {
    int tj_2;

@@ -137,15 +137,15 @@ static void rcar_gen3_thermal_calc_coefs(struct equation_coefs *coef,
     * 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);
+       / (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)
@@ -294,12 +294,29 @@ static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
    usleep_range(1000, 2000);
 }

+static const int rcar_gen3_ths_tj_1 = 126;
+static const 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);
@@ -328,6 +345,7 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 {
    struct rcar_gen3_thermal_priv *priv;
    struct device *dev = &pdev->dev;
+   const int *rcar_gen3_ths_tj_1 = of_device_get_match_data(dev);
    struct resource *res;
    struct thermal_zone_device *zone;
    int ret, irq, i;
@@ -399,7 +417,8 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
        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);

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