[PATCH 1/5] HID: mcp2221: Set driver data before I2C adapter add

[Hamish Martin <hamish.martin@alliedtelesis.co.nz>]

The process of adding an I2C adapter can invoke I2C accesses on that new
adapter (see i2c_detect()).

Ensure we have set the adapter's driver data to avoid null pointer
dereferences in the xfer functions during the adapter add.

This has been noted in the past and the same fix proposed but not
completed. See:
https://lore.kernel.org/lkml/ef597e73-ed71-168e-52af-0d19b03734ac@vigem.de/

Signed-off-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
---
 drivers/hid/hid-mcp2221.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c
index 72883e0ce757..b95f31cf0fa2 100644
--- a/drivers/hid/hid-mcp2221.c
+++ b/drivers/hid/hid-mcp2221.c
@@ -1157,12 +1157,12 @@ static int mcp2221_probe(struct hid_device *hdev,
 	snprintf(mcp->adapter.name, sizeof(mcp->adapter.name),
 			"MCP2221 usb-i2c bridge");
 
+	i2c_set_adapdata(&mcp->adapter, mcp);
 	ret = devm_i2c_add_adapter(&hdev->dev, &mcp->adapter);
 	if (ret) {
 		hid_err(hdev, "can't add usb-i2c adapter: %d\n", ret);
 		return ret;
 	}
-	i2c_set_adapdata(&mcp->adapter, mcp);
 
 #if IS_REACHABLE(CONFIG_GPIOLIB)
 	/* Setup GPIO chip */
-- 
2.42.0