This change marks each instance of the 'spi_driver_api' as 'static const'.
The rationale is that 'spi_driver_api' is used for declaring internal
module interfaces and is not intended to be modified at runtime.
By using 'static const', we ensure immutability, leading to usage of only
.rodata and a reduction in the .data area.
Signed-off-by: Pisit Sawangvonganan <pisit@ndrsolution.com>
The instruction length can only be 0~5.
Use am_hal_iom_blocking_transfer and specify clearly the TX/RX direction.
Hold CS to continue to RX expected response after instruction transmission.
Signed-off-by: Aaron Ye <aye@ambiq.com>
The commit fixes the SPI mode improper configuration.
Otherwise the MODE_3 and MODE_0 cases would never be entered as expected.
Signed-off-by: Aaron Ye <aye@ambiq.com>
