Merge https://source.denx.de/u-boot/custodians/u-boot-spi

- Fix mtd erase with mtdpart (Marek Behún)
- NXP fspi driver fixes (Kuldeep Singh)

include/linux/mtd/mtd.h

@@ -51,7 +51,6 @@ struct erase_info {
 	u_long retries;
 	unsigned dev;
 	unsigned cell;
-	void (*callback) (struct erase_info *self);
 	u_long priv;
 	u_char state;
 	struct erase_info *next;
@@ -535,16 +534,6 @@ extern int unregister_mtd_user (struct mtd_notifier *old);
 #endif
 void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size);
 
-#ifdef CONFIG_MTD_PARTITIONS
-void mtd_erase_callback(struct erase_info *instr);
-#else
-static inline void mtd_erase_callback(struct erase_info *instr)
-{
-	if (instr->callback)
-		instr->callback(instr);
-}
-#endif
-
 static inline int mtd_is_bitflip(int err) {
 	return err == -EUCLEAN;
 }

include/nand.h

@@ -69,7 +69,6 @@ static inline int nand_erase(struct mtd_info *info, loff_t off, size_t size)
 	instr.mtd = info;
 	instr.addr = off;
 	instr.len = size;
-	instr.callback = 0;
 
 	return mtd_erase(info, &instr);
 }

include/spi_flash.h

@@ -165,6 +165,9 @@ static inline int spi_flash_read(struct spi_flash *flash, u32 offset,
 	struct mtd_info *mtd = &flash->mtd;
 	size_t retlen;
 
+	if (!len)
+		return 0;
+
 	return mtd->_read(mtd, offset, len, &retlen, buf);
 }
 
@@ -174,6 +177,9 @@ static inline int spi_flash_write(struct spi_flash *flash, u32 offset,
 	struct mtd_info *mtd = &flash->mtd;
 	size_t retlen;
 
+	if (!len)
+		return 0;
+
 	return mtd->_write(mtd, offset, len, &retlen, buf);
 }
 
@@ -188,6 +194,9 @@ static inline int spi_flash_erase(struct spi_flash *flash, u32 offset,
 		return -EINVAL;
 	}
 
+	if (!len)
+		return 0;
+
 	memset(&instr, 0, sizeof(instr));
 	instr.addr = offset;
 	instr.len = len;