drivers: spi_nor: generalize support for ULBPR instruction

Replace the hard-coded check for JEDEC IDs with a property that must
be set in the devicetree entry.

Signed-off-by: Peter A. Bigot <[email protected]>

Author: pabigot

drivers/flash/spi_nor.c

@@ -290,11 +290,11 @@ static int spi_nor_write_protection_set(struct device *dev, bool write_protect)
 	ret = spi_nor_cmd_write(dev, (write_protect) ?
 	      SPI_NOR_CMD_WRDI : SPI_NOR_CMD_WREN);
 
-#if DT_INST_0_JEDEC_SPI_NOR_JEDEC_ID_0 == 0xbf && DT_INST_0_JEDEC_SPI_NOR_JEDEC_ID_1 == 0x26
-	if (ret == 0 && !write_protect) {
-		ret = spi_nor_cmd_write(dev, SPI_NOR_CMD_MCHP_UNLOCK);
+	if (IS_ENABLED(DT_INST_0_JEDEC_SPI_NOR_REQUIRES_ULBPR)
+	    && (ret == 0)
+	    && !write_protect) {
+		ret = spi_nor_cmd_write(dev, SPI_NOR_CMD_ULBPR);
 	}
-#endif
 
 	SYNC_UNLOCK();
 

drivers/flash/spi_nor.h

@@ -38,7 +38,7 @@ struct spi_nor_config {
 #define SPI_NOR_CMD_BE          0xD8    /* Block erase */
 #define SPI_NOR_CMD_CE          0xC7    /* Chip erase */
 #define SPI_NOR_CMD_RDID        0x9F    /* Read JEDEC ID */
-#define SPI_NOR_CMD_MCHP_UNLOCK 0x98    /* Microchip: Global unblock */
+#define SPI_NOR_CMD_ULBPR       0x98    /* Global Block Protection Unlock */
 
 /* Page, sector, and block size are standard, not configurable. */
 #define SPI_NOR_PAGE_SIZE    0x0100U

dts/bindings/mtd/jedec,spi-nor.yaml

@@ -19,7 +19,18 @@ properties:
   has-be32k:
     type: boolean
     required: false
-    description: Indicates the device supports the BE32K command
+    description: Indicates the device supports the BE32K (0xD8) command
+
+  requires-ulbpr:
+    type: boolean
+    required: false
+    description: |
+      Indicates the device requires the ULBPR (0x98) command.
+
+      Some flash chips such as the Microchip SST26VF series have a block
+      protection register that initializes to write-protected.  Use this
+      property to indicate that the BPR must be unlocked before write
+      operations can proceed.
 
   size:
     type: int