[PATCH 5.15 713/731] HID: mcp2221: dont connect hidraw

Greg Kroah-Hartman
2022-12-28T16:02:45Z

From: Enrik Berkhan <Enrik.Berkhan@inka.de>

commit 67c90d14018775556d5420382ace86521421f9ff upstream.

The MCP2221 driver should not connect to the hidraw userspace interface,
as it needs exclusive access to the chip.

If you want to use /dev/hidrawX with the MCP2221, you need to avoid
binding this driver to the device and use the hid generic driver instead
(e.g. using udev rules).

Cc: stable@vger.kernel.org
Reported-by: Sven Zühlsdorf <sven.zuehlsdorf@vigem.de>
Signed-off-by: Enrik Berkhan <Enrik.Berkhan@inka.de>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20221103222714.21566-2-Enrik.Berkhan@inka.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hid/hid-mcp2221.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

--- a/drivers/hid/hid-mcp2221.c
+++ b/drivers/hid/hid-mcp2221.c
@@ -840,12 +840,19 @@ static int mcp2221_probe(struct hid_devi
return ret;
}

- ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+ /*
+ * This driver uses the .raw_event callback and therefore does not need any
+ * HID_CONNECT_xxx flags.
+ */
+ ret = hid_hw_start(hdev, 0);
if (ret) {
hid_err(hdev, "can't start hardware\n");
return ret;
}

+ hid_info(hdev, "USB HID v%x.%02x Device [%s] on %s\n", hdev->version >> 8,
+ hdev->version & 0xff, hdev->name, hdev->phys);
+
ret = hid_hw_open(hdev);
if (ret) {
hid_err(hdev, "can't open device\n");
@@ -870,8 +877,7 @@ static int mcp2221_probe(struct hid_devi
mcp->adapter.retries = 1;
mcp->adapter.dev.parent = &hdev->dev;
snprintf(mcp->adapter.name, sizeof(mcp->adapter.name),
- "MCP2221 usb-i2c bridge on hidraw%d",
- ((struct hidraw *)hdev->hidraw)->minor);
+ "MCP2221 usb-i2c bridge");

ret = i2c_add_adapter(&mcp->adapter);
if (ret) {