[PATCH net] can: flexcan: Fix probing for m68k/coldfire

[PATCH net] can: flexcan: Fix probing for m68k/coldfire

[Uwe Kleine-König (The Capable Hub)]

When determining the device details was reworked in commit 5e6c3454b405
("net: can: Use device_get_match_data()") there was no replacement for
the previous handling of non-of instantiated devices via the device's
id_entry which then results in a NULL pointer exception. The only
in-tree provider of such a device is arch/m68k/coldfire/device.c.

Given the id_table only contains a single entry just hardcode the result
of `platform_get_device_id(pdev)->driver_data` and drop the unused
assignment to .driver_data from the table.

While touching the id table, drop the unusual comma after the terminator
entry.

Fixes: 5e6c3454b405 ("net: can: Use device_get_match_data()")
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>
---
Hello,

this is essentially v2 of
https://lore.kernel.org/all/20260528094540.1867783-2-u.kleine-koenig@baylibre.com/,
but that patch was intended to be a cleanup, while the discussion then
revealed that there is a crash to be fixed.

Jean-Michel Hautbois confirmed (off-list) that Marc's and my suspicion
is true and probing the flexcan device provided by
arch/m68k/coldfire/device.c indeed crashes.

Best regards
Uwe

 drivers/net/can/flexcan/flexcan-core.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index f5d22c61503f..05b8ca72ca2a 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -2077,10 +2077,9 @@ MODULE_DEVICE_TABLE(of, flexcan_of_match);
 static const struct platform_device_id flexcan_id_table[] = {
 	{
 		.name = "flexcan-mcf5441x",
-		.driver_data = (kernel_ulong_t)&fsl_mcf5441x_devtype_data,
 	}, {
 		/* sentinel */
-	},
+	}
 };
 MODULE_DEVICE_TABLE(platform, flexcan_id_table);
 
@@ -2148,6 +2147,15 @@ static int flexcan_probe(struct platform_device *pdev)
 		return PTR_ERR(regs);
 
 	devtype_data = device_get_match_data(&pdev->dev);
+	if (!devtype_data)
+		/*
+		 * If the device was instantiated via the traditional platform
+		 * mechanisms (i.e. not by device tree), device_get_match_data()
+		 * returns NULL. The only remaining such device is mcf_flexcan0
+		 * (defined in arch/m68k/coldfire/device.c). Pick the right
+		 * device type for that.
+		 */
+		devtype_data = &fsl_mcf5441x_devtype_data;
 
 	if ((devtype_data->quirks & FLEXCAN_QUIRK_SUPPORT_FD) &&
 	    !((devtype_data->quirks &

base-commit: e2cae00c05d196491c318196792297f2dfbaa02c
-- 
2.47.3

Re: [PATCH net] can: flexcan: Fix probing for m68k/coldfire

[Uwe Kleine-König (The Capable Hub)]

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Hello Marc,

On Thu, Jun 18, 2026 at 04:01:47PM +0200, Uwe Kleine-König (The Capable Hub) wrote:
> When determining the device details was reworked in commit 5e6c3454b405
> ("net: can: Use device_get_match_data()") there was no replacement for
> the previous handling of non-of instantiated devices via the device's
> id_entry which then results in a NULL pointer exception. The only
> in-tree provider of such a device is arch/m68k/coldfire/device.c.
> 
> Given the id_table only contains a single entry just hardcode the result
> of `platform_get_device_id(pdev)->driver_data` and drop the unused
> assignment to .driver_data from the table.
> 
> While touching the id table, drop the unusual comma after the terminator
> entry.
> 
> Fixes: 5e6c3454b405 ("net: can: Use device_get_match_data()")
> Cc: stable@vger.kernel.org
> Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>

Given this fixes a crash (NULL pointer exception), it would be great to
get this applied. The issue is already old (Sept 2023, v6.8-rc1), so
there is probably no urge to get this in before 7.2, but getting it into
next and then 7.3-rc1 would be good.

Best regards
Uwe

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