This commit modifies the STM32 battery voltage sensor driver
to handle erroneous usage more gracefully. More precisely,
it now fails builds with an explicit error message when the
sensor is enabled but the corresponding ADC is not. This can
only happen on STM32 series with more than one ADC (e.g., H7).
Signed-off-by: Mathieu Choplain <mathieu.choplain@st.com>
The STM32 temperature, battery and voltage reference sensors needs to
write the ADC common registers to enable the corresponding ADC features.
For that we need to ensure that the ADC is not suspended by using the
pm_device_runtime_get/put methods.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
The vbat driver requires the adc node to be enabled:
```c
.adc = DEVICE_DT_GET(DT_INST_IO_CHANNELS_CTLR(inst))
```
Update its Kconfig to depend on `DT_HAS_ST_STM32_ADC_ENABLED`,
which is the `"st,stm32-adc"` compat that all ST ADC bindings
include, this will guarantee that at least one ADC node is
enabled, but not necessarily the ADC used by the vbat node.
To make sure that it at least compiles, we init the `adc`
pointer only if the specified ADC node is enabled, otherwise
it will points to `NULL`.
Finally, check if the `adc` points to `NULL` in
`stm32_vbat_init`. We are not relying on the existing
`device_is_ready` check because `DEVICE_DT_GET` will not
return `NULL` if the ADC is enabled. `adc == NULL` means
that the ADC node is not enabled in the devicetree.
Signed-off-by: Yong Cong Sin <ycsin@meta.com>
Instead of using floating point operations to compute the vbat voltage,
it is possible to do the computation using 32-bit variables by
reordering operations and using the sensor_value_from_milli() function.
On a STM32G0, this saves 140 bytes of flash, excluding the FP library
needed on a FPU less MCU.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
