| Message ID | 20220830192212.28570-14-farbere@amazon.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | Variety of fixes and new features for mr75203 driver | expand |
On Tue, Aug 30, 2022 at 07:22:06PM +0000, Eliav Farber wrote: > Modify the equation and coefficients used to convert the digital output > to temperature according to series 5 of the Moortec Embedded Temperature > Sensor (METS) datasheet: > T = G + H * (n / cal5 - 0.5) + J * F > > Where: > *) G = 60, H = 200, cal5 = 4094, J = -0.1. > *) F = frequency clock in MHz. > *) n is the digital output. > > In code, the G, H and J coefficients are multiplied by a factor of 1000 > to get the temperature in milli-Celsius. > Final result is clamped in case it exceeds min/max thresholds. > > Change is done since it is not clear where the current equation and not clear -> unclear > coefficients came from. ... > +#define PVT_TEMP_MIN -40000 > +#define PVT_TEMP_MAX 125000 Unit suffix? _mC perhaps would be enough.
On 8/31/2022 3:06 PM, Andy Shevchenko wrote: > On Tue, Aug 30, 2022 at 07:22:06PM +0000, Eliav Farber wrote: >> Modify the equation and coefficients used to convert the digital output >> to temperature according to series 5 of the Moortec Embedded Temperature >> Sensor (METS) datasheet: >> T = G + H * (n / cal5 - 0.5) + J * F >> >> Where: >> *) G = 60, H = 200, cal5 = 4094, J = -0.1. >> *) F = frequency clock in MHz. >> *) n is the digital output. >> >> In code, the G, H and J coefficients are multiplied by a factor of 1000 >> to get the temperature in milli-Celsius. >> Final result is clamped in case it exceeds min/max thresholds. >> >> Change is done since it is not clear where the current equation and > > not clear -> unclear > Fixed. >> coefficients came from. > > ... > >> +#define PVT_TEMP_MIN -40000 >> +#define PVT_TEMP_MAX 125000 > > Unit suffix? _mC perhaps would be enough. Fixed. Added _mC suffix as you suggested. -- Thanks, Eliav
diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c index d1f090a9baac..5b8ca1ee4a54 100644 --- a/drivers/hwmon/mr75203.c +++ b/drivers/hwmon/mr75203.c @@ -103,13 +103,17 @@ #define PVT_POLL_DELAY_US 20 #define PVT_POLL_TIMEOUT_US 20000 -#define PVT_H_CONST 100000 -#define PVT_CAL5_CONST 2047 -#define PVT_G_CONST 40000 +#define PVT_H_CONST 200000 +#define PVT_G_CONST 60000 +#define PVT_J_CONST -100 +#define PVT_CAL5_CONST 4094 #define PVT_CONV_BITS 10 #define PVT_N_CONST 90 #define PVT_R_CONST 245805 +#define PVT_TEMP_MIN -40000 +#define PVT_TEMP_MAX 125000 + #define PRE_SCALER_X1 1 #define PRE_SCALER_X2 2 @@ -157,13 +161,24 @@ static umode_t pvt_is_visible(const void *data, enum hwmon_sensor_types type, return 0; } +static long pvt_calc_temp(struct pvt_device *pvt, u32 nbs) +{ + /* + * Convert the register value to degrees centigrade temperature: + * T = G + H * (n / cal5 - 0.5) + J * F + */ + s64 tmp = PVT_G_CONST + PVT_H_CONST * (s64)nbs / PVT_CAL5_CONST - + PVT_H_CONST / 2 + PVT_J_CONST * (s64)pvt->ip_freq / HZ_PER_MHZ; + + return clamp_val(tmp, PVT_TEMP_MIN, PVT_TEMP_MAX); +} + static int pvt_read_temp(struct device *dev, u32 attr, int channel, long *val) { struct pvt_device *pvt = dev_get_drvdata(dev); struct regmap *t_map = pvt->t_map; u32 stat, nbs; int ret; - u64 tmp; switch (attr) { case hwmon_temp_input: @@ -184,9 +199,7 @@ static int pvt_read_temp(struct device *dev, u32 attr, int channel, long *val) * Convert the register value to * degrees centigrade temperature */ - tmp = nbs * PVT_H_CONST; - do_div(tmp, PVT_CAL5_CONST); - *val = tmp - PVT_G_CONST - pvt->ip_freq; + *val = pvt_calc_temp(pvt, nbs); return 0; default: @@ -311,7 +324,7 @@ static int pvt_init(struct pvt_device *pvt) (key >> 1) << CLK_SYNTH_HI_SFT | (key >> 1) << CLK_SYNTH_HOLD_SFT | CLK_SYNTH_EN; - pvt->ip_freq = sys_freq * 100 / (key + 2); + pvt->ip_freq = clk_get_rate(pvt->clk) / (key + 2); if (t_num) { ret = regmap_write(t_map, SDIF_SMPL_CTRL, 0x0);
Modify the equation and coefficients used to convert the digital output to temperature according to series 5 of the Moortec Embedded Temperature Sensor (METS) datasheet: T = G + H * (n / cal5 - 0.5) + J * F Where: *) G = 60, H = 200, cal5 = 4094, J = -0.1. *) F = frequency clock in MHz. *) n is the digital output. In code, the G, H and J coefficients are multiplied by a factor of 1000 to get the temperature in milli-Celsius. Final result is clamped in case it exceeds min/max thresholds. Change is done since it is not clear where the current equation and coefficients came from. Signed-off-by: Eliav Farber <farbere@amazon.com> --- V3 -> V2: - Protect from overflow. - Add temperature clamping. - Add better documentation. drivers/hwmon/mr75203.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)