From 94c025b6f735b895285a74f2de263c773a08982b Mon Sep 17 00:00:00 2001 From: Eliav Farber Date: Thu, 8 Sep 2022 15:24:43 +0000 Subject: [PATCH] hwmon: (mr75203) modify the temperature equation according to series 5 datasheet 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 unclear where the current equation and coefficients came from. Signed-off-by: Eliav Farber Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20220908152449.35457-16-farbere@amazon.com Signed-off-by: Guenter Roeck --- drivers/hwmon/mr75203.c | 33 +++++++++++++++++++++++++-------- 1 file changed, 25 insertions(+), 8 deletions(-) diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c index c603132..5ee1666 100644 --- a/drivers/hwmon/mr75203.c +++ b/drivers/hwmon/mr75203.c @@ -102,13 +102,19 @@ #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_CONV_BITS 10 #define PVT_N_CONST 90 #define PVT_R_CONST 245805 +#define PVT_TEMP_MIN_mC -40000 +#define PVT_TEMP_MAX_mC 125000 + +/* Temperature coefficients for series 5 */ +#define PVT_SERIES5_H_CONST 200000 +#define PVT_SERIES5_G_CONST 60000 +#define PVT_SERIES5_J_CONST -100 +#define PVT_SERIES5_CAL5_CONST 4094 + #define PRE_SCALER_X1 1 #define PRE_SCALER_X2 2 @@ -174,13 +180,26 @@ 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_SERIES5_G_CONST + + PVT_SERIES5_H_CONST * (s64)nbs / PVT_SERIES5_CAL5_CONST - + PVT_SERIES5_H_CONST / 2 + + PVT_SERIES5_J_CONST * (s64)pvt->ip_freq / HZ_PER_MHZ; + + return clamp_val(tmp, PVT_TEMP_MIN_mC, PVT_TEMP_MAX_mC); +} + 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: @@ -201,9 +220,7 @@ 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: @@ -327,7 +344,7 @@ 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); -- 2.7.4