mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

iio: magnetometer: yas530: Add temperature calculation to "chip_info" 

Add temperature calculation to the "chip_info" structure to ease the handling
of different YAS variants.

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/1a8bffdb7e807455620a73f2d61981e7f9aab8d5.1660337264.git.jahau@rocketmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Jakob Hauser 2022-08-13 00:05:01 +02:00 committed by Jonathan Cameron
parent 913fd40966
commit 2d6676ecbe
1 changed files with 54 additions and 69 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

123
drivers/iio/magnetometer/yamaha-yas530.c
View File

@ -79,7 +79,6 @@
#define YAS530_DATA_BITS 12
#define YAS530_DATA_CENTER BIT(YAS530_DATA_BITS - 1)
#define YAS530_DATA_OVERFLOW (BIT(YAS530_DATA_BITS) - 1)
#define YAS530_20DEGREES 182 /* Counts starting at -62 °C */
#define YAS532_DEVICE_ID 0x02 /* YAS532/YAS533 (MS-3R/F) */
#define YAS532_VERSION_AB 0 /* YAS532/533 AB (MS-3R/F AB) */
@ -91,7 +90,6 @@
#define YAS532_DATA_BITS 13
#define YAS532_DATA_CENTER BIT(YAS532_DATA_BITS - 1)
#define YAS532_DATA_OVERFLOW (BIT(YAS532_DATA_BITS) - 1)
#define YAS532_20DEGREES 390 /* Counts starting at -50 °C */
/* Turn off device regulators etc after 5 seconds of inactivity */
#define YAS5XX_AUTOSUSPEND_DELAY_MS 5000
@ -131,6 +129,14 @@ struct yas5xx;
* @volatile_reg: device-specific volatile registers
* @volatile_reg_qty: quantity of device-specific volatile registers
* @scaling_val2: scaling value for IIO_CHAN_INFO_SCALE
* @t_ref: number of counts at reference temperature 20 °C
* @min_temp_x10: starting point of temperature counting in 1/10:s degrees Celsius
*
* The "t_ref" value for YAS532/533 is known from the Android driver.
* For YAS530 it was approximately measured.
*
* The temperatures "min_temp_x10" are derived from the temperature resolutions
* given in the data sheets.
*/
struct yas5xx_chip_info {
unsigned int devid;
@ -139,6 +145,8 @@ struct yas5xx_chip_info {
const int *volatile_reg;
int volatile_reg_qty;
u32 scaling_val2;
u16 t_ref;
s16 min_temp_x10;
};
/**
@ -337,6 +345,22 @@ static s32 yas530_linearize(struct yas5xx *yas5xx, u16 val, int axis)
(yas5xx->hard_offsets[axis] - c->r[axis]) * coef;
}
static s32 yas5xx_calc_temperature(struct yas5xx *yas5xx, u16 t)
{
const struct yas5xx_chip_info *ci = yas5xx->chip_info;
s32 to;
u16 t_ref;
s16 min_temp_x10;
int ref_temp_x10;
t_ref = ci->t_ref;
min_temp_x10 = ci->min_temp_x10;
ref_temp_x10 = 200;
to = (min_temp_x10 + ((ref_temp_x10 - min_temp_x10) * t / t_ref)) * 100;
return to;
}
/**
* yas530_get_measure() - Measure a sample of all axis and process
* @yas5xx: The device state
@ -352,7 +376,7 @@ static int yas530_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
{
const struct yas5xx_chip_info *ci = yas5xx->chip_info;
struct yas5xx_calibration *c = &yas5xx->calibration;
u16 t_ref, t, x, y1, y2;
u16 t_ref, t_comp, t, x, y1, y2;
/* These are signed x, signed y1 etc */
s32 sx, sy1, sy2, sy, sz;
int ret;
@ -367,47 +391,30 @@ static int yas530_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
sy1 = yas530_linearize(yas5xx, y1, 1);
sy2 = yas530_linearize(yas5xx, y2, 2);
/* Set the temperature reference value (unit: counts) */
switch (ci->devid) {
case YAS530_DEVICE_ID:
t_ref = YAS530_20DEGREES;
break;
case YAS532_DEVICE_ID:
t_ref = YAS532_20DEGREES;
break;
default:
dev_err(yas5xx->dev, "unknown device type\n");
return -EINVAL;
}
/* Temperature compensation for x, y1, y2 respectively */
/*
* Set the temperature for compensation (unit: counts):
* YAS532/YAS533 version AC uses the temperature deviation as a
* multiplier. YAS530 and YAS532 version AB use solely the t value.
*/
t_ref = ci->t_ref;
if (ci->devid == YAS532_DEVICE_ID &&
yas5xx->version == YAS532_VERSION_AC) {
/*
* YAS532 version AC uses the temperature deviation as a
* multiplier.
*
* Cx * (t - t_ref)
* x' = x - ----------------
* 100
*/
sx = sx - (c->Cx * (t - t_ref)) / 100;
sy1 = sy1 - (c->Cy1 * (t - t_ref)) / 100;
sy2 = sy2 - (c->Cy2 * (t - t_ref)) / 100;
t_comp = t - t_ref;
} else {
/*
* YAS530 and YAS532 version AB use solely the t value as a
* multiplier.
*
* Cx * t
* x' = x - ------
* 100
*/
sx = sx - (c->Cx * t) / 100;
sy1 = sy1 - (c->Cy1 * t) / 100;
sy2 = sy2 - (c->Cy2 * t) / 100;
t_comp = t;
}
/*
* Temperature compensation for x, y1, y2 respectively:
*
* Cx * t_comp
* x' = x - -----------
* 100
*/
sx = sx - (c->Cx * t_comp) / 100;
sy1 = sy1 - (c->Cy1 * t_comp) / 100;
sy2 = sy2 - (c->Cy2 * t_comp) / 100;
/*
* Break y1 and y2 into y and z, y1 and y2 are apparently encoding
* y and z.
@ -415,36 +422,8 @@ static int yas530_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
sy = sy1 - sy2;
sz = -sy1 - sy2;
/* Process temperature readout */
switch (ci->devid) {
case YAS530_DEVICE_ID:
/*
* Raw temperature value t is the number of counts starting
* at -62 °C. Reference value t_ref is the number of counts
* between -62 °C and 20 °C (82 °C range).
*
* Temperature in °C would be (82 / t_ref * t) - 62.
*
* Contrary to this, perform multiplication first and division
* second due to calculating with integers.
*
* To get a nicer result, calculate with 1/10:s degrees Celsius
* and finally multiply by 100 to return millidegrees Celsius.
*/
*to = ((820 * t / t_ref) - 620) * 100;
break;
case YAS532_DEVICE_ID:
/*
* Actually same procedure for YAS532 but the starting point is
* at -50 °C. Reference value t_ref is the number of counts
* between -50 °C and 20 °C (70 °C range).
*/
*to = ((700 * t / t_ref) - 500) * 100;
break;
default:
dev_err(yas5xx->dev, "unknown device type\n");
return -EINVAL;
}
/* Calculate temperature readout */
*to = yas5xx_calc_temperature(yas5xx, t);
/*
* Calibrate [x,y,z] with some formulas like this:
@ -935,6 +914,8 @@ static const struct yas5xx_chip_info yas5xx_chip_info_tbl[] = {
.volatile_reg = yas530_volatile_reg,
.volatile_reg_qty = ARRAY_SIZE(yas530_volatile_reg),
.scaling_val2 = 100000000, /* picotesla to Gauss */
.t_ref = 182, /* counts */
.min_temp_x10 = -620, /* 1/10:s degrees Celsius */
},
[yas532] = {
.devid = YAS532_DEVICE_ID,
@ -943,6 +924,8 @@ static const struct yas5xx_chip_info yas5xx_chip_info_tbl[] = {
.volatile_reg = yas530_volatile_reg,
.volatile_reg_qty = ARRAY_SIZE(yas530_volatile_reg),
.scaling_val2 = 100000, /* nanotesla to Gauss */
.t_ref = 390, /* counts */
.min_temp_x10 = -500, /* 1/10:s degrees Celsius */
},
[yas533] = {
.devid = YAS532_DEVICE_ID,
@ -951,6 +934,8 @@ static const struct yas5xx_chip_info yas5xx_chip_info_tbl[] = {
.volatile_reg = yas530_volatile_reg,
.volatile_reg_qty = ARRAY_SIZE(yas530_volatile_reg),
.scaling_val2 = 100000, /* nanotesla to Gauss */
.t_ref = 390, /* counts */
.min_temp_x10 = -500, /* 1/10:s degrees Celsius */
},
};