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author | Christopher Bostic <cbostic@linux.vnet.ibm.com> | 2019-05-20 21:13:33 -0500 |
---|---|---|
committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2019-05-27 10:51:58 +0100 |
commit | cc8baffe176197645ed674b38cef1d8548769a69 (patch) | |
tree | 432a6c2d3cce3d91a020bd0ce3a98083e45020ab /drivers/iio/pressure | |
parent | ba6ec48e76bcd405c47d90b4497ddbcd4c9a578f (diff) | |
download | linux-cc8baffe176197645ed674b38cef1d8548769a69.tar.gz linux-cc8baffe176197645ed674b38cef1d8548769a69.tar.bz2 linux-cc8baffe176197645ed674b38cef1d8548769a69.zip |
iio: dps310: Temperature measurement errata
Add a manufacturer's suggested workaround to deal with early revisions
of chip that don't indicate correct temperature. Readings can be in the
~60C range when they should be in the ~20's.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers/iio/pressure')
-rw-r--r-- | drivers/iio/pressure/dps310.c | 52 |
1 files changed, 50 insertions, 2 deletions
diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c index 9acfccba1d50..a093e3a15665 100644 --- a/drivers/iio/pressure/dps310.c +++ b/drivers/iio/pressure/dps310.c @@ -53,7 +53,6 @@ #define DPS310_RESET 0x0c #define DPS310_RESET_MAGIC 0x09 #define DPS310_COEF_BASE 0x10 -#define DPS310_COEF_SRC 0x28 /* Make sure sleep time is <= 20ms for usleep_range */ #define DPS310_POLL_SLEEP_US(t) min(20000, (t) / 8) @@ -234,6 +233,10 @@ static bool dps310_is_writeable_reg(struct device *dev, unsigned int reg) case DPS310_MEAS_CFG: case DPS310_CFG_REG: case DPS310_RESET: + /* No documentation available on the registers below */ + case 0x0e: + case 0x0f: + case 0x62: return true; default: return false; @@ -250,6 +253,7 @@ static bool dps310_is_volatile_reg(struct device *dev, unsigned int reg) case DPS310_TMP_B1: case DPS310_TMP_B2: case DPS310_MEAS_CFG: + case 0x32: /* No documentation available on this register */ return true; default: return false; @@ -360,7 +364,7 @@ static const struct regmap_config dps310_regmap_config = { .writeable_reg = dps310_is_writeable_reg, .volatile_reg = dps310_is_volatile_reg, .cache_type = REGCACHE_RBTREE, - .max_register = DPS310_COEF_SRC, + .max_register = 0x62, /* No documentation available on this register */ }; static const struct iio_info dps310_info = { @@ -368,6 +372,46 @@ static const struct iio_info dps310_info = { .write_raw = dps310_write_raw, }; +/* + * Some verions of chip will read temperatures in the ~60C range when + * its actually ~20C. This is the manufacturer recommended workaround + * to correct the issue. The registers used below are undocumented. + */ +static int dps310_temp_workaround(struct dps310_data *data) +{ + int rc; + int reg; + + rc = regmap_read(data->regmap, 0x32, ®); + if (rc < 0) + return rc; + + /* + * If bit 1 is set then the device is okay, and the workaround does not + * need to be applied + */ + if (reg & BIT(1)) + return 0; + + rc = regmap_write(data->regmap, 0x0e, 0xA5); + if (rc < 0) + return rc; + + rc = regmap_write(data->regmap, 0x0f, 0x96); + if (rc < 0) + return rc; + + rc = regmap_write(data->regmap, 0x62, 0x02); + if (rc < 0) + return rc; + + rc = regmap_write(data->regmap, 0x0e, 0x00); + if (rc < 0) + return rc; + + return regmap_write(data->regmap, 0x0f, 0x00); +} + static int dps310_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -439,6 +483,10 @@ static int dps310_probe(struct i2c_client *client, if (rc < 0) return rc; + rc = dps310_temp_workaround(data); + if (rc < 0) + return rc; + rc = devm_iio_device_register(&client->dev, iio); if (rc) return rc; |