[PATCH v2 02/60] mtd: core: set some defaults when dev.parent is set

[Frans Klaver]

If a parent device is set, add_mtd_device() has enough knowledge to fill
in some sane default values for the module name and owner. Do so if they
aren't already set.

Signed-off-by: Frans Klaver <fransklaver at gmail.com>

---
v1..v2
  - Apparently we can get here without a driver set, causing a NULL
    dereference[0]. Check that a driver is there before copying the
    owner. It does mean that parent devices that don't seem to be
    having a driver lying around still can't produce an owner. I suppose
    the effect is not much different from it was before.
  - Change wording of debug message to mention the fact we're talking
    about parent device symlinks here.

[0] https://lkml.org/lkml/2015/4/16/15
---
 drivers/mtd/mtdcore.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index d7967cc..0bd1761 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -413,6 +413,15 @@ int add_mtd_device(struct mtd_info *mtd)
 	mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
 	mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
 
+	if (mtd->dev.parent) {
+		if (!mtd->owner && mtd->dev.parent->driver)
+			mtd->owner = mtd->dev.parent->driver->owner;
+		if (!mtd->name)
+			mtd->name = dev_name(mtd->dev.parent);
+	} else {
+		pr_debug("mtd device won't show a device symlink in sysfs\n");
+	}
+
 	/* Some chips always power up locked. Unlock them now */
 	if ((mtd->flags & MTD_WRITEABLE) && (mtd->flags & MTD_POWERUP_LOCK)) {
 		error = mtd_unlock(mtd, 0, mtd->size);
-- 
2.4.0