mtd: rawnand: NAND controller write protect

Allow NAND controller to be responsible for write protect pin
handling during fast path and exec_op destructive operation
when controller_wp flag is set.

Signed-off-by: David Regan <dregan@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20231125012438.15191-2-dregan@broadcom.com

Author: David Regan

drivers/mtd/nand/raw/nand_base.c

@@ -366,6 +366,10 @@ static int nand_check_wp(struct nand_chip *chip)
 	if (chip->options & NAND_BROKEN_XD)
 		return 0;
 
+	/* controller responsible for NAND write protect */
+	if (chip->controller->controller_wp)
+		return 0;
+
 	/* Check the WP bit */
 	ret = nand_status_op(chip, &status);
 	if (ret)

include/linux/mtd/rawnand.h

@@ -1115,6 +1115,7 @@ struct nand_controller_ops {
  *			the bus without restarting an entire read operation nor
  *			changing the column.
  * @supported_op.cont_read: The controller supports sequential cache reads.
+ * @controller_wp:	the controller is in charge of handling the WP pin.
  */
 struct nand_controller {
 	struct mutex lock;
@@ -1123,6 +1124,7 @@ struct nand_controller {
 		unsigned int data_only_read: 1;
 		unsigned int cont_read: 1;
 	} supported_op;
+	bool controller_wp;
 };
 
 static inline void nand_controller_init(struct nand_controller *nfc)