HID: mcp2221: Set driver data before I2C adapter add

commit f2d4a5834638bbc967371b9168c0b481519f7c5e upstream.

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/[email protected]/

Signed-off-by: Hamish Martin <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
Signed-off-by: Sumanth Gavini <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Hamish Martin

drivers/hid/hid-mcp2221.c

@@ -879,12 +879,12 @@ 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 = i2c_add_adapter(&mcp->adapter);
 	if (ret) {
 		hid_err(hdev, "can't add usb-i2c adapter: %d\n", ret);
 		goto err_i2c;
 	}
-	i2c_set_adapdata(&mcp->adapter, mcp);
 
 	/* Setup GPIO chip */
 	mcp->gc = devm_kzalloc(&hdev->dev, sizeof(*mcp->gc), GFP_KERNEL);