Messages in this thread | | | Subject | Re: [PATCH v2 4/5] thermal: stm32: improve temperature resolution | From | Daniel Lezcano <> | Date | Thu, 5 Dec 2019 12:03:10 +0100 |
| |
On 04/11/2019 14:30, Pascal Paillet wrote: > Currently, the temperature is rounded by 1 or 2 degrees. > Change the way of computing to avoid rounds. > Also simplify the sampling time management.
Give more details about the changes in order to let us understand them.
> Signed-off-by: Pascal Paillet <p.paillet@st.com> > --- > drivers/thermal/st/stm_thermal.c | 58 ++++++++------------------------ > 1 file changed, 14 insertions(+), 44 deletions(-) > > diff --git a/drivers/thermal/st/stm_thermal.c b/drivers/thermal/st/stm_thermal.c > index cb72252f2800..9986716b17c1 100644 > --- a/drivers/thermal/st/stm_thermal.c > +++ b/drivers/thermal/st/stm_thermal.c > @@ -59,7 +59,6 @@ > > /* Less significant bit position definitions */ > #define TS1_T0_POS 16 > -#define TS1_SMP_TIME_POS 16 > #define TS1_HITTHD_POS 16 > #define TS1_LITTHD_POS 0 > #define HSREF_CLK_DIV_POS 24 > @@ -83,15 +82,10 @@ > #define ONE_MHZ 1000000 > #define POLL_TIMEOUT 5000 > #define STARTUP_TIME 40 > -#define TS1_T0_VAL0 30 > -#define TS1_T0_VAL1 130 > +#define TS1_T0_VAL0 30000 /* 30 celsius */ > +#define TS1_T0_VAL1 130000 /* 130 celsius */ > #define NO_HW_TRIG 0 > - > -/* The Thermal Framework expects millidegrees */ > -#define mcelsius(temp) ((temp) * 1000) > - > -/* The Sensor expects oC degrees */ > -#define celsius(temp) ((temp) / 1000) > +#define SAMPLING_TIME 15 > > struct stm_thermal_sensor { > struct device *dev; > @@ -259,27 +253,17 @@ static int stm_thermal_calculate_threshold(struct stm_thermal_sensor *sensor, > int temp, u32 *th) > { > int freqM; > - u32 sampling_time; > - > - /* Retrieve the number of periods to sample */ > - sampling_time = (readl_relaxed(sensor->base + DTS_CFGR1_OFFSET) & > - TS1_SMP_TIME_MASK) >> TS1_SMP_TIME_POS; > > /* Figure out the CLK_PTAT frequency for a given temperature */ > - freqM = ((temp - sensor->t0) * sensor->ramp_coeff) > - + sensor->fmt0; > - > - dev_dbg(sensor->dev, "%s: freqM for threshold = %d Hz", > - __func__, freqM); > + freqM = ((temp - sensor->t0) * sensor->ramp_coeff) / 1000 + > + sensor->fmt0; > > /* Figure out the threshold sample number */ > - *th = clk_get_rate(sensor->clk); > + *th = clk_get_rate(sensor->clk) * SAMPLING_TIME / freqM; > if (!*th) > return -EINVAL; > > - *th = *th / freqM; > - > - *th *= sampling_time; > + dev_dbg(sensor->dev, "freqM=%d Hz, threshold=0x%x", freqM, *th); > > return 0; > } > @@ -371,40 +355,26 @@ static int stm_thermal_set_trips(void *data, int low, int high) > static int stm_thermal_get_temp(void *data, int *temp) > { > struct stm_thermal_sensor *sensor = data; > - u32 sampling_time; > + u32 periods; > int freqM, ret; > > if (sensor->mode != THERMAL_DEVICE_ENABLED) > return -EAGAIN; > > - /* Retrieve the number of samples */ > - ret = readl_poll_timeout(sensor->base + DTS_DR_OFFSET, freqM, > - (freqM & TS1_MFREQ_MASK), STARTUP_TIME, > - POLL_TIMEOUT); > - > + /* Retrieve the number of periods sampled */ > + ret = readl_relaxed_poll_timeout(sensor->base + DTS_DR_OFFSET, periods, > + (periods & TS1_MFREQ_MASK), > + STARTUP_TIME, POLL_TIMEOUT); > if (ret) > return ret; > > - if (!freqM) > - return -ENODATA; > - > - /* Retrieve the number of periods sampled */ > - sampling_time = (readl_relaxed(sensor->base + DTS_CFGR1_OFFSET) & > - TS1_SMP_TIME_MASK) >> TS1_SMP_TIME_POS; > - > - /* Figure out the number of samples per period */ > - freqM /= sampling_time; > - > /* Figure out the CLK_PTAT frequency */ > - freqM = clk_get_rate(sensor->clk) / freqM; > + freqM = (clk_get_rate(sensor->clk) * SAMPLING_TIME) / periods; > if (!freqM) > return -EINVAL; > > - dev_dbg(sensor->dev, "%s: freqM=%d\n", __func__, freqM); > - > /* Figure out the temperature in mili celsius */ > - *temp = mcelsius(sensor->t0 + ((freqM - sensor->fmt0) / > - sensor->ramp_coeff)); > + *temp = (freqM - sensor->fmt0) * 1000 / sensor->ramp_coeff + sensor->t0; > > return 0; > } >
-- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
| |