linux-kernel - [PATCH 18/25] thermal/drivers/hisi: Use round up step value

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Date:   Tue, 10 Oct 2017 20:02:43 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     edubezval@...il.com, rui.zhang@...el.com
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        kevin.wangtao@...aro.org
Subject: [PATCH 18/25] thermal/drivers/hisi: Use round up step value

From: Kevin Wangtao <kevin.wangtao@...aro.org>

Use round up division to ensure the programmed value of threshold and the lag
are not less than what we set, and in order to keep the accuracy while using
round up division, the step value should be a rounded up value.  There is
no need to use hisi_thermal_round_temp.

Signed-off-by: Kevin Wangtao <kevin.wangtao@...aro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
---
 drivers/thermal/hisi_thermal.c | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c
index 02d0ad8..befdb28 100644
--- a/drivers/thermal/hisi_thermal.c
+++ b/drivers/thermal/hisi_thermal.c
@@ -40,7 +40,7 @@
 
 #define HISI_TEMP_BASE			(-60000)
 #define HISI_TEMP_RESET			(100000)
-#define HISI_TEMP_STEP			(784)
+#define HISI_TEMP_STEP			(785)
 #define HISI_TEMP_LAG			(3500)
 
 #define HISI_MAX_SENSORS		4
@@ -63,19 +63,19 @@ struct hisi_thermal_data {
 /*
  * The temperature computation on the tsensor is as follow:
  *	Unit: millidegree Celsius
- *	Step: 255/200 (0.7843)
+ *	Step: 200/255 (0.7843)
  *	Temperature base: -60°C
  *
- * The register is programmed in temperature steps, every step is 784
+ * The register is programmed in temperature steps, every step is 785
  * millidegree and begins at -60 000 m°C
  *
  * The temperature from the steps:
  *
- *	Temp = TempBase + (steps x 784)
+ *	Temp = TempBase + (steps x 785)
  *
  * and the steps from the temperature:
  *
- *	steps = (Temp - TempBase) / 784
+ *	steps = (Temp - TempBase) / 785
  *
  */
 static inline int hisi_thermal_step_to_temp(int step)
@@ -85,13 +85,7 @@ static inline int hisi_thermal_step_to_temp(int step)
 
 static inline int hisi_thermal_temp_to_step(int temp)
 {
-	return (temp - HISI_TEMP_BASE) / HISI_TEMP_STEP;
-}
-
-static inline int hisi_thermal_round_temp(int temp)
-{
-	return hisi_thermal_step_to_temp(
-		hisi_thermal_temp_to_step(temp));
+	return DIV_ROUND_UP(temp - HISI_TEMP_BASE, HISI_TEMP_STEP);
 }
 
 /*
@@ -127,7 +121,7 @@ static inline int hisi_thermal_round_temp(int temp)
  */
 static inline void hisi_thermal_set_lag(void __iomem *addr, int value)
 {
-	writel((value / HISI_TEMP_STEP) & 0x1F, addr + TEMP0_LAG);
+	writel(DIV_ROUND_UP(value, HISI_TEMP_STEP) & 0x1F, addr + TEMP0_LAG);
 }
 
 static inline void hisi_thermal_alarm_clear(void __iomem *addr, int value)
@@ -274,7 +268,7 @@ static int hisi_thermal_register_sensor(struct platform_device *pdev,
 
 	for (i = 0; i < of_thermal_get_ntrips(sensor->tzd); i++) {
 		if (trip[i].type == THERMAL_TRIP_PASSIVE) {
-			sensor->thres_temp = hisi_thermal_round_temp(trip[i].temperature);
+			sensor->thres_temp = trip[i].temperature;
 			break;
 		}
 	}
-- 
2.7.4