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HID: i2c-hid: check if device is there before really probing 

On many Chromebooks touch devices are multi-sourced; the components are
electrically compatible and one can be freely swapped for another without
changing the OS image or firmware.

To avoid bunch of scary messages when device is not actually present in the
system let's try testing basic communication with it and if there is no
response terminate probe early with -ENXIO.

Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Dmitry Torokhov 2018-05-09 12:12:15 -07:00 committed by Jiri Kosina
parent 2dcc8197fe
commit b3a81b6c4f
1 changed files with 8 additions and 0 deletions
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8
drivers/hid/i2c-hid/i2c-hid.c
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@ -1060,6 +1060,14 @@ static int i2c_hid_probe(struct i2c_client *client,
pm_runtime_enable(&client->dev);
device_enable_async_suspend(&client->dev);
/* Make sure there is something at this address */
ret = i2c_smbus_read_byte(client);
if (ret < 0) {
dev_dbg(&client->dev, "nothing at this address: %d\n", ret);
ret = -ENXIO;
goto err_pm;
}
ret = i2c_hid_fetch_hid_descriptor(ihid);
if (ret < 0)
goto err_pm;