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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>
This commit is contained in:
Daniel Lezcano 2017-10-19 19:05:46 +02:00 committed by Eduardo Valentin
parent 2cb4de785c
commit 48880b979c
1 changed files with 28 additions and 13 deletions
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41
drivers/thermal/hisi_thermal.c
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@ -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);