[PATCH v2] can: c_can: Use platform id data when OF data is absent

[Pengpeng Hou]

The platform driver keeps controller metadata in both the OF match table
and the platform id table. Probe reads the metadata with
device_get_match_data(), which does not fall back to platform id-table
driver_data.

When the device is matched through the platform id table, drvdata can
therefore be NULL before it is dereferenced for msg_obj_num and the
controller type. Fall back to platform_get_device_id() when firmware
match data is not available.

Fixes: 5e6c3454b405 ("net: can: Use device_get_match_data()")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Vincent Mailhol <mailhol@xxxxxxxxxx>
Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
Changes in v2:
- Add the Fixes tag requested by Vincent.
- Scope the platform id variable inside the fallback block.
- Carry Vincent's Reviewed-by for the requested v2 shape.

 drivers/net/can/c_can/c_can_platform.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
index 19c86b94a40e..8a0c88839d24 100644
--- a/drivers/net/can/c_can/c_can_platform.c
+++ b/drivers/net/can/c_can/c_can_platform.c
@@ -267,6 +267,14 @@ static int c_can_plat_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 
 	drvdata = device_get_match_data(&pdev->dev);
+	if (!drvdata) {
+		const struct platform_device_id *id;
+
+		id = platform_get_device_id(pdev);
+		if (!id)
+			return -ENODEV;
+		drvdata = (const struct c_can_driver_data *)id->driver_data;
+	}
 
 	/* get the appropriate clk */
 	clk = devm_clk_get(&pdev->dev, NULL);
-- 
2.50.1