From 9d8593f22ea33a88f89075b14fc58a95fc15b8ae Mon Sep 17 00:00:00 2001 From: Pascal Paillet Date: Fri, 10 Jan 2020 11:16:04 +0100 Subject: thermal: stm32: Improve temperature computing Change the way of computing to avoid rounds by 1 or 2 degrees. Also simplify the sampling time management that is hard-coded to maximum value during probe. Signed-off-by: Pascal Paillet Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20200110101605.24984-6-p.paillet@st.com --- drivers/thermal/st/stm_thermal.c | 58 ++++++++++------------------------------ 1 file changed, 14 insertions(+), 44 deletions(-) (limited to 'drivers') diff --git a/drivers/thermal/st/stm_thermal.c b/drivers/thermal/st/stm_thermal.c index 29e7ee89adf6..aaf25ca2f118 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; @@ -280,27 +274,17 @@ 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; } @@ -368,40 +352,26 @@ 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; } -- cgit v1.2.3