linux-kernel - [PATCH v1 1/4] HID: mcp2221: don't connect hidraw

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Message-Id: <20220926202239.16379-2-Enrik.Berkhan@inka.de>
Date:   Mon, 26 Sep 2022 22:22:36 +0200
From:   Enrik Berkhan <Enrik.Berkhan@...a.de>
To:     linux-input@...r.kernel.org
Cc:     linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
        Rishi Gupta <gupt21@...il.com>,
        Enrik Berkhan <Enrik.Berkhan@...a.de>
Subject: [PATCH v1 1/4] HID: mcp2221: don't connect hidraw

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).

Signed-off-by: Enrik Berkhan <Enrik.Berkhan@...a.de>
---
 drivers/hid/hid-mcp2221.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c
index de52e9f7bb8c..0ca2a7b96825 100644
--- a/drivers/hid/hid-mcp2221.c
+++ b/drivers/hid/hid-mcp2221.c
@@ -840,12 +840,17 @@ static int mcp2221_probe(struct hid_device *hdev,
 		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 +875,7 @@ static int mcp2221_probe(struct hid_device *hdev,
 	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) {
-- 
2.34.1