[PATCH 1/3] mtd: spi-nor: don't guard stm_*lock* family by preprocessor conditionals

[Rasmus Villemoes]

Use C instead of cpp to choose whether the stm_lock and friends get
compiled in. This provides better compile testing and reduces the
amount of #ifdeffery. All of the previously guarded functions are
static, so this does not add anything to the binary in the
!(SPI_FLASH_STMICRO or SPI_FLASH_SST) case (and even if they were not
static, the linker would eventually remove them).

The test of SPI_FLASH_STMICRO or SPI_FLASH_SST is done inside the test
for specific manufacturers or SPI_NOR_HAS_LOCK in flags, to prepare
for adding support for locking on Macronix flashes. The compiler is
perfectly capabable of compiling

  if (expression with no side effects) {
    if (0) {
    }
  }

to nothing at all.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes at prevas.dk>
---
 drivers/mtd/spi/spi-nor-core.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 7b6ad495ac..af83d813fc 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -591,7 +591,6 @@ erase_err:
 	return ret;
 }
 
-#if defined(CONFIG_SPI_FLASH_STMICRO) || defined(CONFIG_SPI_FLASH_SST)
 /* Write status register and ensure bits in mask match written values */
 static int write_sr_and_check(struct spi_nor *nor, u8 status_new, u8 mask)
 {
@@ -877,7 +876,6 @@ static int stm_is_locked(struct spi_nor *nor, loff_t ofs, uint64_t len)
 
 	return stm_is_locked_sr(nor, ofs, len, status);
 }
-#endif /* CONFIG_SPI_FLASH_STMICRO */
 
 static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
 {
@@ -2528,17 +2526,17 @@ int spi_nor_scan(struct spi_nor *nor)
 	mtd->_erase = spi_nor_erase;
 	mtd->_read = spi_nor_read;
 
-#if defined(CONFIG_SPI_FLASH_STMICRO) || defined(CONFIG_SPI_FLASH_SST)
 	/* NOR protection support for STmicro/Micron chips and similar */
 	if (JEDEC_MFR(info) == SNOR_MFR_ST ||
 	    JEDEC_MFR(info) == SNOR_MFR_MICRON ||
 	    JEDEC_MFR(info) == SNOR_MFR_SST ||
 			info->flags & SPI_NOR_HAS_LOCK) {
-		nor->flash_lock = stm_lock;
-		nor->flash_unlock = stm_unlock;
-		nor->flash_is_locked = stm_is_locked;
+		if (IS_ENABLED(CONFIG_SPI_FLASH_STMICRO) || IS_ENABLED(CONFIG_SPI_FLASH_SST)) {
+			nor->flash_lock = stm_lock;
+			nor->flash_unlock = stm_unlock;
+			nor->flash_is_locked = stm_is_locked;
+		}
 	}
-#endif
 
 #ifdef CONFIG_SPI_FLASH_SST
 	/*
-- 
2.23.0