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authorDaniel Lezcano <daniel.lezcano@linaro.org>2017-10-19 20:05:46 +0300
committerEduardo Valentin <edubezval@gmail.com>2017-11-01 05:32:15 +0300
commit48880b979cdc9ef5a70af020f42b8ba1e51dbd34 (patch)
treee1318ec32d7d49f47db5b8612ff088e35c509e13 /drivers/thermal
parent2cb4de785c40d4a2132cfc13e63828f5a28c3351 (diff)
downloadlinux-48880b979cdc9ef5a70af020f42b8ba1e51dbd34.tar.xz
thermal/drivers/hisi: Simplify the temperature/step computation
The step and the base temperature are fixed values, we can simplify the computation by converting the base temperature to milli celsius and use a pre-computed step value. That saves us a lot of mult + div for nothing at runtime. Take also the opportunity to change the function names to be consistent with the rest of the code. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Leo Yan <leo.yan@linaro.org> Tested-by: Leo Yan <leo.yan@linaro.org> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Diffstat (limited to 'drivers/thermal')
-rw-r--r--drivers/thermal/hisi_thermal.c41
1 files changed, 28 insertions, 13 deletions
diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c
index f69aea0b2fe3..583bc1934127 100644
--- a/drivers/thermal/hisi_thermal.c
+++ b/drivers/thermal/hisi_thermal.c
@@ -35,8 +35,9 @@
#define TEMP0_RST_MSK (0x1C)
#define TEMP0_VALUE (0x28)
-#define HISI_TEMP_BASE (-60)
+#define HISI_TEMP_BASE (-60000)
#define HISI_TEMP_RESET (100000)
+#define HISI_TEMP_STEP (784)
#define HISI_MAX_SENSORS 4
#define HISI_DEFAULT_SENSOR 2
@@ -61,19 +62,32 @@ struct hisi_thermal_data {
void __iomem *regs;
};
-/* in millicelsius */
-static inline int _step_to_temp(int step)
+/*
+ * The temperature computation on the tsensor is as follow:
+ * Unit: millidegree Celsius
+ * Step: 255/200 (0.7843)
+ * Temperature base: -60°C
+ *
+ * The register is programmed in temperature steps, every step is 784
+ * millidegree and begins at -60 000 m°C
+ *
+ * The temperature from the steps:
+ *
+ * Temp = TempBase + (steps x 784)
+ *
+ * and the steps from the temperature:
+ *
+ * steps = (Temp - TempBase) / 784
+ *
+ */
+static inline int hisi_thermal_step_to_temp(int step)
{
- /*
- * Every step equals (1 * 200) / 255 celsius, and finally
- * need convert to millicelsius.
- */
- return (HISI_TEMP_BASE * 1000 + (step * 200000 / 255));
+ return HISI_TEMP_BASE + (step * HISI_TEMP_STEP);
}
-static inline long _temp_to_step(long temp)
+static inline long hisi_thermal_temp_to_step(long temp)
{
- return ((temp - HISI_TEMP_BASE * 1000) * 255) / 200000;
+ return (temp - HISI_TEMP_BASE) / HISI_TEMP_STEP;
}
static long hisi_thermal_get_sensor_temp(struct hisi_thermal_data *data,
@@ -99,7 +113,7 @@ static long hisi_thermal_get_sensor_temp(struct hisi_thermal_data *data,
usleep_range(3000, 5000);
val = readl(data->regs + TEMP0_VALUE);
- val = _step_to_temp(val);
+ val = hisi_thermal_step_to_temp(val);
mutex_unlock(&data->thermal_lock);
@@ -126,10 +140,11 @@ static void hisi_thermal_enable_bind_irq_sensor
writel((sensor->id << 12), data->regs + TEMP0_CFG);
/* enable for interrupt */
- writel(_temp_to_step(sensor->thres_temp) | 0x0FFFFFF00,
+ writel(hisi_thermal_temp_to_step(sensor->thres_temp) | 0x0FFFFFF00,
data->regs + TEMP0_TH);
- writel(_temp_to_step(HISI_TEMP_RESET), data->regs + TEMP0_RST_TH);
+ writel(hisi_thermal_temp_to_step(HISI_TEMP_RESET),
+ data->regs + TEMP0_RST_TH);
/* enable module */
writel(0x1, data->regs + TEMP0_RST_MSK);