[PATCH v3] mfd: syscon: Decouple syscon interface from platform devices

[...]

quoted

I think there should have been a check for NULL on "dev" in
"regmap_get_val_endian", so that if dev pointer exist then only it makes
sense to get
endianness property from DT.

I will suggest following fix in regmap.c for this. With following fix I
tested it and it works well
on linux-next also. So if you can confirm following fix is working for you
then I can post this
patch.

I tested the patch work.
But as Xiubo pointed in another mail, it may still cause other issues.
Looking at regmap.c, there're still some other places using the device pointer,
e.g. dev_xxx debug information and some tracepoints also take device pointer
as parameter(not sure if it will break if dev is NULL).
Another thing is that if dev is NULL, we may not be able to use regmap debugfs
feature which seems also not as our expected.

Maybe we could consider create device structure for each syscon compatible
device in syscon driver in of_syscon_register in first time which seems to
be reasonable.

Regards
Dong Aisheng

quoted

--------------------------------------------
Subject: [PATCH] regmap: fix NULL pointer dereference in
 regmap_get_val_endian

Recent commits for getting reg endianess causing NULL pointer
dereference if dev is passed NULL in regmap_init_mmio. This patch
fixes this issue, and allows to parse reg endianess only if dev
and dev->of_node exist.

Signed-off-by: Pankaj Dubey <redacted>
---
 drivers/base/regmap/regmap.c |   23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index f2281af..455a877 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c

@@ -477,7 +477,7 @@ static enum regmap_endian regmap_get_val_endian(struct

device *dev,
 					const struct regmap_bus *bus,
 					const struct regmap_config *config)
 {
-	struct device_node *np = dev->of_node;
+	struct device_node *np;

And the 'np' must be NULL as default.

Isn't it ?

Thanks,

BRs
Xiubo

quoted

 	enum regmap_endian endian;

 	/* Retrieve the endianness specification from the regmap config */

@@ -487,15 +487,20 @@ static enum regmap_endian regmap_get_val_endian(struct

device *dev,
 	if (endian != REGMAP_ENDIAN_DEFAULT)
 		return endian;

-	/* Parse the device's DT node for an endianness specification */
-	if (of_property_read_bool(np, "big-endian"))
-		endian = REGMAP_ENDIAN_BIG;
-	else if (of_property_read_bool(np, "little-endian"))
-		endian = REGMAP_ENDIAN_LITTLE;
+	/* If the dev and dev->of_node exist try to get endianness from DT
*/
+	if (dev && dev->of_node) {
+		np = dev->of_node;

-	/* If the endianness was specified in DT, use that */
-	if (endian != REGMAP_ENDIAN_DEFAULT)
-		return endian;
+		/* Parse the device's DT node for an endianness
specification */
+		if (of_property_read_bool(np, "big-endian"))
+			endian = REGMAP_ENDIAN_BIG;
+		else if (of_property_read_bool(np, "little-endian"))
+			endian = REGMAP_ENDIAN_LITTLE;
+
+		/* If the endianness was specified in DT, use that */
+		if (endian != REGMAP_ENDIAN_DEFAULT)
+			return endian;
+	}

 	/* Retrieve the endianness specification from the bus config */
 	if (bus && bus->val_format_endian_default)
--

Thanks,
Pankaj Dubey

quoted

Regards
Dong Aisheng

quoted

Thanks,
Pankaj Dubey

quoted

Regards
Dong Aisheng

quoted

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