On Wed, Aug 30, 2017 at 10:47:28AM +0200, Daniel Lezcano wrote: > 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 <[email protected]>
Reviewed-by: Leo Yan <[email protected]> Tested-by: Leo Yan <[email protected]> > --- > drivers/thermal/hisi_thermal.c | 41 ++++++++++++++++++++++++++++------------- > 1 file changed, 28 insertions(+), 13 deletions(-) > > diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c > index 67db523..b58ad40 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); > -- > 2.7.4 >
