[PATCH] mtd: spi-nor: allow NULL as spi_device_id in spi_nor_scan

["Rafał Miłecki" <zajec5@gmail.com>]

Now we allow customized read_id handlers we should allow passing NULL
as a struct spi_device_id pointer. In such case we should simply make
use of the read_id callback and let driver read the flash ID.
At some point we may try to remove this argument completely.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
This is based on top of
mtd: move support for struct flash_platform_data's "type" into m25p80
---
 drivers/mtd/spi-nor/spi-nor.c | 34 ++++++++++++++--------------------
 1 file changed, 14 insertions(+), 20 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d733b16..45610b2 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -906,29 +906,23 @@ int spi_nor_scan(struct spi_nor *nor, const struct spi_device_id *id,
 	if (ret)
 		return ret;
 
-	info = (void *)id->driver_data;
-
-	if (info->jedec_id) {
-		const struct spi_device_id *jid;
-
-		jid = nor->read_id(nor);
-		if (IS_ERR(jid)) {
-			return PTR_ERR(jid);
-		} else if (jid != id) {
-			/*
-			 * JEDEC knows better, so overwrite platform ID. We
-			 * can't trust partitions any longer, but we'll let
-			 * mtd apply them anyway, since some partitions may be
-			 * marked read-only, and we don't want to lose that
-			 * information, even if it's not 100% accurate.
-			 */
-			dev_warn(dev, "found %s, expected %s\n",
-				 jid->name, id->name);
-			id = jid;
-			info = (void *)jid->driver_data;
+	if (id) {
+		info = (void *)id->driver_data;
+		if (info->jedec_id) {
+			dev_warn(dev,
+				 "passed SPI device ID (%s) contains JEDEC, ignoring it, driver should be fixed!\n",
+				 id->name);
+			id = NULL;
 		}
 	}
 
+	if (!id) {
+		id = nor->read_id(nor);
+		if (IS_ERR(id))
+			return PTR_ERR(id);
+	}
+	info = (void *)id->driver_data;
+
 	mutex_init(&nor->lock);
 
 	/*
-- 
1.8.4.5