diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/iio/humidity/hdc3020.c | 325 |
1 files changed, 249 insertions, 76 deletions
diff --git a/drivers/iio/humidity/hdc3020.c b/drivers/iio/humidity/hdc3020.c index 1e5d0d4797..1e702fcc48 100644 --- a/drivers/iio/humidity/hdc3020.c +++ b/drivers/iio/humidity/hdc3020.c @@ -18,6 +18,7 @@ #include <linux/i2c.h> #include <linux/init.h> #include <linux/interrupt.h> +#include <linux/math64.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/units.h> @@ -63,8 +64,10 @@ #define HDC3020_CRC8_POLYNOMIAL 0x31 -#define HDC3020_MIN_TEMP -40 -#define HDC3020_MAX_TEMP 125 +#define HDC3020_MIN_TEMP_MICRO -39872968 +#define HDC3020_MAX_TEMP_MICRO 124875639 +#define HDC3020_MAX_TEMP_HYST_MICRO 164748607 +#define HDC3020_MAX_HUM_MICRO 99220264 struct hdc3020_data { struct i2c_client *client; @@ -363,6 +366,105 @@ static int hdc3020_write_raw(struct iio_dev *indio_dev, return -EINVAL; } +static int hdc3020_thresh_get_temp(u16 thresh) +{ + int temp; + + /* + * Get the temperature threshold from 9 LSBs, shift them to get + * the truncated temperature threshold representation and + * calculate the threshold according to the formula in the + * datasheet. Result is degree celsius scaled by 65535. + */ + temp = FIELD_GET(HDC3020_THRESH_TEMP_MASK, thresh) << + HDC3020_THRESH_TEMP_TRUNC_SHIFT; + + return -2949075 + (175 * temp); +} + +static int hdc3020_thresh_get_hum(u16 thresh) +{ + int hum; + + /* + * Get the humidity threshold from 7 MSBs, shift them to get the + * truncated humidity threshold representation and calculate the + * threshold according to the formula in the datasheet. Result is + * percent scaled by 65535. + */ + hum = FIELD_GET(HDC3020_THRESH_HUM_MASK, thresh) << + HDC3020_THRESH_HUM_TRUNC_SHIFT; + + return hum * 100; +} + +static u16 hdc3020_thresh_set_temp(int s_temp, u16 curr_thresh) +{ + u64 temp; + u16 thresh; + + /* + * Calculate temperature threshold, shift it down to get the + * truncated threshold representation in the 9LSBs while keeping + * the current humidity threshold in the 7 MSBs. + */ + temp = (u64)(s_temp + 45000000) * 65535ULL; + temp = div_u64(temp, 1000000 * 175) >> HDC3020_THRESH_TEMP_TRUNC_SHIFT; + thresh = FIELD_PREP(HDC3020_THRESH_TEMP_MASK, temp); + thresh |= (FIELD_GET(HDC3020_THRESH_HUM_MASK, curr_thresh) << + HDC3020_THRESH_HUM_TRUNC_SHIFT); + + return thresh; +} + +static u16 hdc3020_thresh_set_hum(int s_hum, u16 curr_thresh) +{ + u64 hum; + u16 thresh; + + /* + * Calculate humidity threshold, shift it down and up to get the + * truncated threshold representation in the 7MSBs while keeping + * the current temperature threshold in the 9 LSBs. + */ + hum = (u64)(s_hum) * 65535ULL; + hum = div_u64(hum, 1000000 * 100) >> HDC3020_THRESH_HUM_TRUNC_SHIFT; + thresh = FIELD_PREP(HDC3020_THRESH_HUM_MASK, hum); + thresh |= FIELD_GET(HDC3020_THRESH_TEMP_MASK, curr_thresh); + + return thresh; +} + +static +int hdc3020_thresh_clr(s64 s_thresh, s64 s_hyst, enum iio_event_direction dir) +{ + s64 s_clr; + + /* + * Include directions when calculation the clear value, + * since hysteresis is unsigned by definition and the + * clear value is an absolute value which is signed. + */ + if (dir == IIO_EV_DIR_RISING) + s_clr = s_thresh - s_hyst; + else + s_clr = s_thresh + s_hyst; + + /* Divide by 65535 to get units of micro */ + return div_s64(s_clr, 65535); +} + +static int _hdc3020_write_thresh(struct hdc3020_data *data, u16 reg, u16 val) +{ + u8 buf[5]; + + put_unaligned_be16(reg, buf); + put_unaligned_be16(val, buf + 2); + buf[4] = crc8(hdc3020_crc8_table, buf + 2, 2, CRC8_INIT_VALUE); + + return hdc3020_write_bytes(data, buf, 5); +} + static int hdc3020_write_thresh(struct iio_dev *indio_dev, const struct iio_chan_spec *chan, enum iio_event_type type, @@ -371,67 +473,126 @@ static int hdc3020_write_thresh(struct iio_dev *indio_dev, int val, int val2) { struct hdc3020_data *data = iio_priv(indio_dev); - u8 buf[5]; - u64 tmp; - u16 reg; - int ret; - - /* Supported temperature range is from –40 to 125 degree celsius */ - if (val < HDC3020_MIN_TEMP || val > HDC3020_MAX_TEMP) - return -EINVAL; - - /* Select threshold register */ - if (info == IIO_EV_INFO_VALUE) { - if (dir == IIO_EV_DIR_RISING) - reg = HDC3020_S_T_RH_THRESH_HIGH; - else - reg = HDC3020_S_T_RH_THRESH_LOW; + u16 reg, reg_val, reg_thresh_rd, reg_clr_rd, reg_thresh_wr, reg_clr_wr; + s64 s_thresh, s_hyst, s_clr; + int s_val, thresh, clr, ret; + + /* Select threshold registers */ + if (dir == IIO_EV_DIR_RISING) { + reg_thresh_rd = HDC3020_R_T_RH_THRESH_HIGH; + reg_thresh_wr = HDC3020_S_T_RH_THRESH_HIGH; + reg_clr_rd = HDC3020_R_T_RH_THRESH_HIGH_CLR; + reg_clr_wr = HDC3020_S_T_RH_THRESH_HIGH_CLR; } else { - if (dir == IIO_EV_DIR_RISING) - reg = HDC3020_S_T_RH_THRESH_HIGH_CLR; - else - reg = HDC3020_S_T_RH_THRESH_LOW_CLR; + reg_thresh_rd = HDC3020_R_T_RH_THRESH_LOW; + reg_thresh_wr = HDC3020_S_T_RH_THRESH_LOW; + reg_clr_rd = HDC3020_R_T_RH_THRESH_LOW_CLR; + reg_clr_wr = HDC3020_S_T_RH_THRESH_LOW_CLR; } guard(mutex)(&data->lock); - ret = hdc3020_read_be16(data, reg); + ret = hdc3020_read_be16(data, reg_thresh_rd); if (ret < 0) return ret; + thresh = ret; + ret = hdc3020_read_be16(data, reg_clr_rd); + if (ret < 0) + return ret; + + clr = ret; + /* Scale value to include decimal part into calculations */ + s_val = (val < 0) ? (val * 1000000 - val2) : (val * 1000000 + val2); switch (chan->type) { case IIO_TEMP: - /* - * Calculate temperature threshold, shift it down to get the - * truncated threshold representation in the 9LSBs while keeping - * the current humidity threshold in the 7 MSBs. - */ - tmp = ((u64)(((val + 45) * MICRO) + val2)) * 65535ULL; - tmp = div_u64(tmp, MICRO * 175); - val = tmp >> HDC3020_THRESH_TEMP_TRUNC_SHIFT; - val = FIELD_PREP(HDC3020_THRESH_TEMP_MASK, val); - val |= (FIELD_GET(HDC3020_THRESH_HUM_MASK, ret) << - HDC3020_THRESH_HUM_TRUNC_SHIFT); + switch (info) { + case IIO_EV_INFO_VALUE: + s_val = max(s_val, HDC3020_MIN_TEMP_MICRO); + s_val = min(s_val, HDC3020_MAX_TEMP_MICRO); + reg = reg_thresh_wr; + reg_val = hdc3020_thresh_set_temp(s_val, thresh); + ret = _hdc3020_write_thresh(data, reg, reg_val); + if (ret < 0) + return ret; + + /* Calculate old hysteresis */ + s_thresh = (s64)hdc3020_thresh_get_temp(thresh) * 1000000; + s_clr = (s64)hdc3020_thresh_get_temp(clr) * 1000000; + s_hyst = div_s64(abs(s_thresh - s_clr), 65535); + /* Set new threshold */ + thresh = reg_val; + /* Set old hysteresis */ + s_val = s_hyst; + fallthrough; + case IIO_EV_INFO_HYSTERESIS: + /* + * Function hdc3020_thresh_get_temp returns temperature + * in degree celsius scaled by 65535. Scale by 1000000 + * to be able to subtract scaled hysteresis value. + */ + s_thresh = (s64)hdc3020_thresh_get_temp(thresh) * 1000000; + /* + * Units of s_val are in micro degree celsius, scale by + * 65535 to get same units as s_thresh. + */ + s_val = min(abs(s_val), HDC3020_MAX_TEMP_HYST_MICRO); + s_hyst = (s64)s_val * 65535; + s_clr = hdc3020_thresh_clr(s_thresh, s_hyst, dir); + s_clr = max(s_clr, HDC3020_MIN_TEMP_MICRO); + s_clr = min(s_clr, HDC3020_MAX_TEMP_MICRO); + reg = reg_clr_wr; + reg_val = hdc3020_thresh_set_temp(s_clr, clr); + break; + default: + return -EOPNOTSUPP; + } break; case IIO_HUMIDITYRELATIVE: - /* - * Calculate humidity threshold, shift it down and up to get the - * truncated threshold representation in the 7MSBs while keeping - * the current temperature threshold in the 9 LSBs. - */ - tmp = ((u64)((val * MICRO) + val2)) * 65535ULL; - tmp = div_u64(tmp, MICRO * 100); - val = tmp >> HDC3020_THRESH_HUM_TRUNC_SHIFT; - val = FIELD_PREP(HDC3020_THRESH_HUM_MASK, val); - val |= FIELD_GET(HDC3020_THRESH_TEMP_MASK, ret); + s_val = (s_val < 0) ? 0 : min(s_val, HDC3020_MAX_HUM_MICRO); + switch (info) { + case IIO_EV_INFO_VALUE: + reg = reg_thresh_wr; + reg_val = hdc3020_thresh_set_hum(s_val, thresh); + ret = _hdc3020_write_thresh(data, reg, reg_val); + if (ret < 0) + return ret; + + /* Calculate old hysteresis */ + s_thresh = (s64)hdc3020_thresh_get_hum(thresh) * 1000000; + s_clr = (s64)hdc3020_thresh_get_hum(clr) * 1000000; + s_hyst = div_s64(abs(s_thresh - s_clr), 65535); + /* Set new threshold */ + thresh = reg_val; + /* Try to set old hysteresis */ + s_val = min(abs(s_hyst), HDC3020_MAX_HUM_MICRO); + fallthrough; + case IIO_EV_INFO_HYSTERESIS: + /* + * Function hdc3020_thresh_get_hum returns relative + * humidity in percent scaled by 65535. Scale by 1000000 + * to be able to subtract scaled hysteresis value. + */ + s_thresh = (s64)hdc3020_thresh_get_hum(thresh) * 1000000; + /* + * Units of s_val are in micro percent, scale by 65535 + * to get same units as s_thresh. + */ + s_hyst = (s64)s_val * 65535; + s_clr = hdc3020_thresh_clr(s_thresh, s_hyst, dir); + s_clr = max(s_clr, 0); + s_clr = min(s_clr, HDC3020_MAX_HUM_MICRO); + reg = reg_clr_wr; + reg_val = hdc3020_thresh_set_hum(s_clr, clr); + break; + default: + return -EOPNOTSUPP; + } break; default: return -EOPNOTSUPP; } - put_unaligned_be16(reg, buf); - put_unaligned_be16(val, buf + 2); - buf[4] = crc8(hdc3020_crc8_table, buf + 2, 2, CRC8_INIT_VALUE); - return hdc3020_write_bytes(data, buf, 5); + return _hdc3020_write_thresh(data, reg, reg_val); } static int hdc3020_read_thresh(struct iio_dev *indio_dev, @@ -442,48 +603,60 @@ static int hdc3020_read_thresh(struct iio_dev *indio_dev, int *val, int *val2) { struct hdc3020_data *data = iio_priv(indio_dev); - u16 reg; - int ret; + u16 reg_thresh, reg_clr; + int thresh, clr, ret; - /* Select threshold register */ - if (info == IIO_EV_INFO_VALUE) { - if (dir == IIO_EV_DIR_RISING) - reg = HDC3020_R_T_RH_THRESH_HIGH; - else - reg = HDC3020_R_T_RH_THRESH_LOW; + /* Select threshold registers */ + if (dir == IIO_EV_DIR_RISING) { + reg_thresh = HDC3020_R_T_RH_THRESH_HIGH; + reg_clr = HDC3020_R_T_RH_THRESH_HIGH_CLR; } else { - if (dir == IIO_EV_DIR_RISING) - reg = HDC3020_R_T_RH_THRESH_HIGH_CLR; - else - reg = HDC3020_R_T_RH_THRESH_LOW_CLR; + reg_thresh = HDC3020_R_T_RH_THRESH_LOW; + reg_clr = HDC3020_R_T_RH_THRESH_LOW_CLR; } guard(mutex)(&data->lock); - ret = hdc3020_read_be16(data, reg); + ret = hdc3020_read_be16(data, reg_thresh); if (ret < 0) return ret; switch (chan->type) { case IIO_TEMP: - /* - * Get the temperature threshold from 9 LSBs, shift them to get - * the truncated temperature threshold representation and - * calculate the threshold according to the formula in the - * datasheet. - */ - *val = FIELD_GET(HDC3020_THRESH_TEMP_MASK, ret); - *val = *val << HDC3020_THRESH_TEMP_TRUNC_SHIFT; - *val = -2949075 + (175 * (*val)); + thresh = hdc3020_thresh_get_temp(ret); + switch (info) { + case IIO_EV_INFO_VALUE: + *val = thresh; + break; + case IIO_EV_INFO_HYSTERESIS: + ret = hdc3020_read_be16(data, reg_clr); + if (ret < 0) + return ret; + + clr = hdc3020_thresh_get_temp(ret); + *val = abs(thresh - clr); + break; + default: + return -EOPNOTSUPP; + } *val2 = 65535; return IIO_VAL_FRACTIONAL; case IIO_HUMIDITYRELATIVE: - /* - * Get the humidity threshold from 7 MSBs, shift them to get the - * truncated humidity threshold representation and calculate the - * threshold according to the formula in the datasheet. - */ - *val = FIELD_GET(HDC3020_THRESH_HUM_MASK, ret); - *val = (*val << HDC3020_THRESH_HUM_TRUNC_SHIFT) * 100; + thresh = hdc3020_thresh_get_hum(ret); + switch (info) { + case IIO_EV_INFO_VALUE: + *val = thresh; + break; + case IIO_EV_INFO_HYSTERESIS: + ret = hdc3020_read_be16(data, reg_clr); + if (ret < 0) + return ret; + + clr = hdc3020_thresh_get_hum(ret); + *val = abs(thresh - clr); + break; + default: + return -EOPNOTSUPP; + } *val2 = 65535; return IIO_VAL_FRACTIONAL; default: |