daniel-p-carvalho opened a new pull request, #20449:
URL: https://github.com/apache/nuttx/pull/20449
## Summary
* `arch/mips/pic32mz: do not exceed the requested SPI frequency.`
`spi_setfrequency()` rounded the baud rate divisor down, so the SCK
frequency could be higher than the one requested by the device driver
(e.g. 20 MHz requested with a 100 MHz PBCLK2 gave 25 MHz). A request above
PBCLK/2 gave a zero divisor and a division by zero when computing the
actual frequency; the SST26 driver's default of 64 MHz does that with any
peripheral bus clock below 128 MHz. The divisor is now rounded up.
* `arch/mips/pic32mz: fix nxstyle issues in pic32mz_i2c.c and pic32mz_spi.c.`
and `arch/mips/pic32mz: fix nxstyle issues in pic32mz_serial.c.`
Pre-existing nxstyle errors (mostly switch/case indentation), fixed so that
later changes to these files pass checkpatch. No functional change
(`git show -w` shows only comment re-wrapping, one wrapped call and blank
lines after declarations).
These changes were found while porting NuttX to the PIC32MZ-W1 (draft PR
#20448), which needs to modify these files.
## Impact
* SPI on PIC32MZ: the actual SCK frequency never exceeds the requested one.
Boards whose requested frequency is not an exact divisor of PBCLK/2 now
run SPI at a lower clock than before (e.g. 16.7 MHz instead of 25 MHz for a
20 MHz request with a 100 MHz PBCLK2). Requests above PBCLK/2 now give
PBCLK/2 instead of a division by zero.
* Style commits: no functional change.
* No new Kconfig options, no API changes.
## Testing
* checkpatch: `./tools/checkpatch.sh -c -u -m -g upstream/master..HEAD`
passes.
* Build (Pinguino p32-gcc 4.9.2, as in CI): `pic32mz-starterkit:nsh`,
`flipnclick-pic32mz:nxlines` (uses SPI), `chipkit-wifire:nsh`. No new
warnings.
* Hardware: the divisor change was tested on a PIC32MZ-W1 (WFI32E01PE) board
from the port in #20448, reading the JEDEC ID of an SST26VF032B on SPI1
with the driver's default 64 MHz request (25 MHz actual from a 50 MHz
PBCLK3). With the old code that request gives a zero divisor (found by
reading the code, not run). Not tested on PIC32MZ EC/EF hardware.
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