mtd: nand: fsmc: fix NAND width handling

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=ee56874f23e5c11576540bd695177a5ebc4f4352
Commit:     ee56874f23e5c11576540bd695177a5ebc4f4352
Parent:     4ca8c1d4979cc60cc129318ce0a89d075c9eb49f
Author:     Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
AuthorDate: Tue Mar 21 11:03:53 2017 +0100
Committer:  Boris Brezillon <boris.brezillon at free-electrons.com>
CommitDate: Thu Mar 23 11:10:08 2017 +0100

    mtd: nand: fsmc: fix NAND width handling
    
    In commit eea628199d5b ("mtd: Add device-tree support to fsmc_nand"),
    Device Tree support was added to the fmsc_nand driver. However, this
    code has a bug in how it handles the bank-width DT property to set the
    bus width.
    
    Indeed, in the function fsmc_nand_probe_config_dt() that parses the
    Device Tree, it sets pdata->width to either 8 or 16 depending on the
    value of the bank-width DT property.
    
    Then, the ->probe() function will test if pdata->width is equal to
    FSMC_NAND_BW16 (which is 2) to set NAND_BUSWIDTH_16 in
    nand->options. Therefore, with the DT probing, this condition will never
    match.
    
    This commit fixes that by removing the "width" field from
    fsmc_nand_platform_data and instead have the fsmc_nand_probe_config_dt()
    function directly set the appropriate nand->options value.
    
    It is worth mentioning that if this commit gets backported to older
    kernels, prior to the drop of non-DT probing, then non-DT probing will
    be broken because nand->options will no longer be set to
    NAND_BUSWIDTH_16.
    
    Fixes: eea628199d5b ("mtd: Add device-tree support to fsmc_nand")
    Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
    Reviewed-by: Linus Walleij <linus.walleij at linaro.org>
    Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
---
 drivers/mtd/nand/fsmc_nand.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/nand/fsmc_nand.c b/drivers/mtd/nand/fsmc_nand.c
index bda1e46..66aece9 100644
--- a/drivers/mtd/nand/fsmc_nand.c
+++ b/drivers/mtd/nand/fsmc_nand.c
@@ -150,7 +150,6 @@ struct fsmc_nand_platform_data {
 	struct mtd_partition	*partitions;
 	unsigned int		nr_partitions;
 	unsigned int		options;
-	unsigned int		width;
 	unsigned int		bank;
 
 	enum access_mode	mode;
@@ -844,18 +843,19 @@ static int fsmc_nand_probe_config_dt(struct platform_device *pdev,
 	u32 val;
 	int ret;
 
-	/* Set default NAND width to 8 bits */
-	pdata->width = 8;
+	pdata->options = 0;
+
 	if (!of_property_read_u32(np, "bank-width", &val)) {
 		if (val == 2) {
-			pdata->width = 16;
+			pdata->options |= NAND_BUSWIDTH_16;
 		} else if (val != 1) {
 			dev_err(&pdev->dev, "invalid bank-width %u\n", val);
 			return -EINVAL;
 		}
 	}
+
 	if (of_get_property(np, "nand-skip-bbtscan", NULL))
-		pdata->options = NAND_SKIP_BBTSCAN;
+		pdata->options |= NAND_SKIP_BBTSCAN;
 
 	pdata->nand_timings = devm_kzalloc(&pdev->dev,
 				sizeof(*pdata->nand_timings), GFP_KERNEL);
@@ -992,9 +992,6 @@ static int __init fsmc_nand_probe(struct platform_device *pdev)
 	nand->badblockbits = 7;
 	nand_set_flash_node(nand, np);
 
-	if (pdata->width == FSMC_NAND_BW16)
-		nand->options |= NAND_BUSWIDTH_16;
-
 	switch (host->mode) {
 	case USE_DMA_ACCESS:
 		dma_cap_zero(mask);