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Diffstat (limited to 'drivers/hid/i2c-hid/i2c-hid.c')
-rw-r--r--drivers/hid/i2c-hid/i2c-hid.c45
1 files changed, 13 insertions, 32 deletions
diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index b50860db92f..21aafc8f48c 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -807,34 +807,18 @@ static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
unsigned int dsize;
int ret;
- /* Fetch the length of HID description, retrieve the 4 first bytes:
- * bytes 0-1 -> length
- * bytes 2-3 -> bcdVersion (has to be 1.00) */
- ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer, 4);
-
- i2c_hid_dbg(ihid, "%s, ihid->hdesc_buffer: %4ph\n", __func__,
- ihid->hdesc_buffer);
-
+ /* i2c hid fetch using a fixed descriptor size (30 bytes) */
+ i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
+ ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
+ sizeof(struct i2c_hid_desc));
if (ret) {
- dev_err(&client->dev,
- "unable to fetch the size of HID descriptor (ret=%d)\n",
- ret);
- return -ENODEV;
- }
-
- dsize = le16_to_cpu(hdesc->wHIDDescLength);
- /*
- * the size of the HID descriptor should at least contain
- * its size and the bcdVersion (4 bytes), and should not be greater
- * than sizeof(struct i2c_hid_desc) as we directly fill this struct
- * through i2c_hid_command.
- */
- if (dsize < 4 || dsize > sizeof(struct i2c_hid_desc)) {
- dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
- dsize);
+ dev_err(&client->dev, "hid_descr_cmd failed\n");
return -ENODEV;
}
+ /* Validate the length of HID descriptor, the 4 first bytes:
+ * bytes 0-1 -> length
+ * bytes 2-3 -> bcdVersion (has to be 1.00) */
/* check bcdVersion == 1.0 */
if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
dev_err(&client->dev,
@@ -843,17 +827,14 @@ static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
return -ENODEV;
}
- i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
-
- ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
- dsize);
- if (ret) {
- dev_err(&client->dev, "hid_descr_cmd Fail\n");
+ /* Descriptor length should be 30 bytes as per the specification */
+ dsize = le16_to_cpu(hdesc->wHIDDescLength);
+ if (dsize != sizeof(struct i2c_hid_desc)) {
+ dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
+ dsize);
return -ENODEV;
}
-
i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
-
return 0;
}