[PATCH 1/3] HID: i2c-hid: Rely on HID descriptor fetch to probe

From: Kenny Levinsen
Date: Mon Apr 15 2024 - 13:09:07 EST


To avoid error messages when a device is not present, b3a81b6c4fc6 added
an initial bus probe using a dummy i2c_smbus_read_byte() call.

Without this probe, i2c_hid_fetch_hid_descriptor() will fail with
EREMOTEIO. Propagate the error up so the caller can handle EREMOTEIO
gracefully, and remove the probe as it is no longer necessary.

Signed-off-by: Kenny Levinsen <kl@xxxxxx>
---
drivers/hid/i2c-hid/i2c-hid-core.c | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index 2df1ab3c31cc..515a80dbf6c7 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -894,12 +894,8 @@ static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
ihid->wHIDDescRegister,
&ihid->hdesc,
sizeof(ihid->hdesc));
- if (error) {
- dev_err(&ihid->client->dev,
- "failed to fetch HID descriptor: %d\n",
- error);
- return -ENODEV;
- }
+ if (error)
+ return error;
}

/* Validate the length of HID descriptor, the 4 first bytes:
@@ -1014,17 +1010,13 @@ static int __i2c_hid_core_probe(struct i2c_hid *ihid)
struct hid_device *hid = ihid->hid;
int ret;

- /* Make sure there is something at this address */
- ret = i2c_smbus_read_byte(client);
- if (ret < 0) {
+ ret = i2c_hid_fetch_hid_descriptor(ihid);
+ if (ret == -EREMOTEIO) {
i2c_hid_dbg(ihid, "nothing at this address: %d\n", ret);
return -ENXIO;
- }
-
- ret = i2c_hid_fetch_hid_descriptor(ihid);
- if (ret < 0) {
+ } else if (ret < 0) {
dev_err(&client->dev,
- "Failed to fetch the HID Descriptor\n");
+ "failed to fetch HID descriptor: %d\n", ret);
return ret;
}

--
2.44.0