spi: Make 'default_spi_send_command' the default unless defined

A NULL func pointer is necessary and sufficient for the
condition `NULL func pointer => default_spi_send_command' as to not
need this explicit specification of 'default'.

Therefore drop the explicit need to specify the 'default_spi_send_command'
callback function pointer in the spi_master struct. This is a reasonable default for every other driver in the tree with only a few exceptions.

This simplifies the code and driver development.

Change-Id: I63abcb8c64f233cdbf58a149a31051fa648305a2
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/67480
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Thomas Heijligen <src@posteo.de>
---
M ft2232_spi.c
M spi.c
2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/ft2232_spi.c b/ft2232_spi.c
index dfec1a0..16bcfe3 100644
--- a/ft2232_spi.c
+++ b/ft2232_spi.c
@@ -295,7 +295,6 @@
 	.features	= SPI_MASTER_4BA,
 	.max_data_read	= 64 * 1024,
 	.max_data_write	= 256,
-	.command	= default_spi_send_command,
 	.multicommand	= ft2232_spi_send_multicommand,
 	.read		= default_spi_read,
 	.write_256	= default_spi_write_256,
diff --git a/spi.c b/spi.c
index 6c2c4c4..ca27cbb 100644
--- a/spi.c
+++ b/spi.c
@@ -30,8 +30,9 @@
 		     unsigned int readcnt, const unsigned char *writearr,
 		     unsigned char *readarr)
 {
-	return flash->mst->spi.command(flash, writecnt, readcnt, writearr,
-				       readarr);
+	if (flash->mst->spi.command)
+		return flash->mst->spi.command(flash, writecnt, readcnt, writearr, readarr);
+	return default_spi_send_command(flash, writecnt, readcnt, writearr, readarr);
 }
 
 int spi_send_multicommand(const struct flashctx *flash, struct spi_command *cmds)
@@ -152,9 +153,9 @@
 		}
 	}
 
-	if (!mst->write_256 || !mst->read || !mst->command ||
+	if (!mst->write_256 || !mst->read ||
 	    !mst->multicommand || !mst->probe_opcode ||
-	    ((mst->command == default_spi_send_command) &&
+	    ((mst->command == default_spi_send_command || !mst->command) &&
 	     (mst->multicommand == default_spi_send_multicommand))) {
 		msg_perr("%s called with incomplete master definition. "
 			 "Please report a bug at flashrom@flashrom.org\n",

