DEFAULT_SPI_PORT appears to be undefined

[ndim]

The @DEFAULT_SPI_PORT@ from src/avrdude.conf.in appears not to be defined anywhere:

• cmake builds substitute the @DEFAULT_SPI_PORT@ in avrdude.conf as the empty string.

• automake builds keep the @DEFAULT_SPI_PORT@ in avrdude.conf as it is.

• git grep DEFAULT_SPI_PORT shows only one match: the line in src/avrdude.conf.in.

This does not appear to be intentional.

[mcuee]

@ndim

The default value is in the code since the following commit.

• dd1255b

Please also refer to PR #933.

• Fix linuxspi default port #933

But I agree this can be a good improvement.

[mcuee]

I have to specify the linuxspi port since the default value does not work.

• avrdude 8.0 release discussion #1654 (reply in thread)

mcuee@raspberrypi400arm64:~/build/avrdude_git/tools $ ./test-avrdude -d 0 -p "-c linuxspi -P /dev/spidev0.1:/dev/gpiochip0:25 -p m328p"
Testing /usr/local/bin/avrdude 7.3-20240821 (c6d29a16)
Prepare "-c linuxspi -P /dev/spidev0.1:/dev/gpiochip0:25 -p m328p" and press 'enter' or 'space' to continue. Press any other key to skip
✅   0.182 s: fuse access: clear, set and read eesave fuse bit
✅   0.178 s: fuse access: set eesave fusebit to delete EEPROM on chip erase
✅   0.173 s: chip erase
✅   2.501 s: flash -U write/verify holes_rjmp_loops_32768B.hex
✅   2.479 s: flash -T write/verify holes_rjmp_loops_32768B.hex
✅   0.172 s: eeprom check whether programmer can flip 0s to 1s
✅   1.220 s: eeprom -U write/verify holes_pack_my_box_1024B.hex
✅   2.151 s: eeprom -T write/verify holes_{the_five_boxing_wizards,pack_my_box}_1024B.hex
✅   1.307 s: chip erase and spot check flash is actually erased
✅   0.263 s: spot check eeprom is erased, too

[mcuee]

Current code: maybe it needs to specify the default reset pin number.

avrdude/src/linuxspi.c

Lines 146 to 151 in 30e19f2

	static int linuxspi_open(PROGRAMMER *pgm, const char *pt) {
	const char *port_error = "unknown port specification, "
	"please use the format /dev/spidev:/dev/gpiochip[:resetno]\n";
	char port_default[] = "/dev/spidev0.0:/dev/gpiochip0";
	char *spidev, *gpiochip, *reset_pin;
	char *port = mmt_strdup(pt);