From f2d4a5834638bbc967371b9168c0b481519f7c5e Mon Sep 17 00:00:00 2001 From: Hamish Martin Date: Wed, 25 Oct 2023 16:55:10 +1300 Subject: HID: mcp2221: Set driver data before I2C adapter add 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 Signed-off-by: Jiri Kosina --- drivers/hid/hid-mcp2221.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/hid/hid-mcp2221.c') 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 */ -- cgit v1.2.3 From 73ce9f1f2741a38f5d27393e627702ae2c46e6f2 Mon Sep 17 00:00:00 2001 From: Hamish Martin Date: Wed, 25 Oct 2023 16:55:11 +1300 Subject: HID: mcp2221: Allow IO to start during probe During the probe we add an I2C adapter and as soon as we add that adapter it may be used for a transfer (e.g via the code in i2cdetect()). Those transfers are not able to complete and time out. This is because the HID raw_event callback (mcp2221_raw_event) will not be invoked until the HID device's 'driver_input_lock' is marked up at the completion of the probe in hid_device_probe(). This starves the driver of the responses it is waiting for. In order to allow the I2C transfers to complete while we are still in the probe, start the IO once we have completed init of the HID device. This issue seems to have been seen before and a patch was submitted but it seems it was never accepted. See: https://lore.kernel.org/all/20221103222714.21566-3-Enrik.Berkhan@inka.de/ Signed-off-by: Hamish Martin Signed-off-by: Jiri Kosina --- drivers/hid/hid-mcp2221.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/hid/hid-mcp2221.c') diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index b95f31cf0fa2..aef0785c91cc 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -1142,6 +1142,8 @@ static int mcp2221_probe(struct hid_device *hdev, if (ret) return ret; + hid_device_io_start(hdev); + /* Set I2C bus clock diviser */ if (i2c_clk_freq > 400) i2c_clk_freq = 400; -- cgit v1.2.3