[PATCH v2] mtd: rawnand: fsmc: Default to autodetect buswidth

[Linus Walleij]

If you don't specify buswidth 2 (16 bits) in the device
tree, FSMC doesn't even probe anymore:

fsmc-nand 10100000.flash: FSMC device partno 090,
  manufacturer 80, revision 00, config 00
nand: device found, Manufacturer ID: 0x20, Chip ID: 0xb1
nand: ST Micro 10100000.flash
nand: bus width 8 instead of 16 bits
nand: No NAND device found
fsmc-nand 10100000.flash: probe with driver fsmc-nand failed
  with error -22

With this patch to use autodetection unless buswidth is
specified, the device is properly detected again:

fsmc-nand 10100000.flash: FSMC device partno 090,
  manufacturer 80, revision 00, config 00
nand: device found, Manufacturer ID: 0x20, Chip ID: 0xb1
nand: ST Micro NAND 128MiB 1,8V 16-bit
nand: 128 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64
fsmc-nand 10100000.flash: Using 1-bit HW ECC scheme
Scanning device for bad blocks

I don't know where or how this happened, I think some change
in the nand core.

Cc: stable at vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
Changes in v2:
- Drop surplus semicolon.
- Also add NAND_BUSWIDTH_AUTO if 8bit buswidth is specified.
- Link to v1: https://lore.kernel.org/r/20250914-fsmc-v1-1-6d86d8b48552@linaro.org
---
 drivers/mtd/nand/raw/fsmc_nand.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/fsmc_nand.c b/drivers/mtd/nand/raw/fsmc_nand.c
index df61db8ce466593d533e617c141a8d2498b3a180..b13b2b0c3f300c7a611a36a402f1587d28166fab 100644
--- a/drivers/mtd/nand/raw/fsmc_nand.c
+++ b/drivers/mtd/nand/raw/fsmc_nand.c
@@ -876,10 +876,14 @@ static int fsmc_nand_probe_config_dt(struct platform_device *pdev,
 	if (!of_property_read_u32(np, "bank-width", &val)) {
 		if (val == 2) {
 			nand->options |= NAND_BUSWIDTH_16;
-		} else if (val != 1) {
+		} else if (val == 1) {
+			nand->options |= NAND_BUSWIDTH_AUTO;
+		} else {
 			dev_err(&pdev->dev, "invalid bank-width %u\n", val);
 			return -EINVAL;
 		}
+	} else {
+		nand->options |= NAND_BUSWIDTH_AUTO;
 	}
 
 	if (of_property_read_bool(np, "nand-skip-bbtscan"))

---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20250914-fsmc-bd18e1a8116f

Best regards,
-- 
Linus Walleij <linus.walleij at linaro.org>