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The initialization of the AS6200 has two shortcomings
- The device-add-commit states "Conversion mode: continuous" but the
the lm75_params structure uses set_mask = 0x94c0. This activates
single shot mode (bit 15). According to the datasheet "The device
features a single shot measurement mode if the device is in sleep
mode (SM=1)". This is quite contradictionary.
- It is the only device that activates polarity active-high (bit 10)
All this is paired with a undefined clear mask bug in function
lm75_write_config() that was introduced with a later refactoring
commit.
[as6200] = {
.config_reg_16bits = true,
.set_mask = 0x94C0,
-> .clr_mask not defined here
.default_resolution = 12,
...
static inline int lm75_write_config(struct lm75_data *data, u16 set_mask,
u16 clr_mask)
{
return regmap_update_bits(data->regmap, LM75_REG_CONF,
clr_mask | LM75_SHUTDOWN, set_mask);
}
regmap_update_bits() requires clr_mask to be a superset of set_mask.
So basically all sensors with "wrong" masks like the AS6200 are not
initialized as intended.
Fix that by
- Change the set_mask to 0xc010 to reflect the current active-low
setup properly and to drive the sensor in continous mode. This
takes into account that the config register is little endian and
the first byte sent to the chip is the LSB.
- Adapt the alarm handling so it can report the alarm correctly
even if it is high active. This is done by comparing config register
bit 5 and 10 (translated to 2 and 13).
This commit does not introduce any ABI breakage as the mutliple bugs
effectly drive the AS6200 in standard active-low mode.
Fixes:
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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