i2c: core: ACPI: Make acpi_gsb_i2c_read_bytes() check i2c_transfer return value

Currently acpi_gsb_i2c_read_bytes() directly returns i2c_transfer's return
value. i2c_transfer returns a value < 0 on error and 2 (for 2 successfully
executed transfers) on success. But the ACPI code expects 0 on success, so
currently acpi_gsb_i2c_read_bytes()'s caller does:

        if (status > 0)
                status = 0;

This commit makes acpi_gsb_i2c_read_bytes() return a value which can be
directly consumed by the ACPI code, mirroring acpi_gsb_i2c_write_bytes(),
this commit also makes acpi_gsb_i2c_read_bytes() explitcly check that
i2c_transfer returns 2, rather then accepting any value > 0.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index b8f303d..32affd3 100644 (file)
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -453,8 +453,12 @@ static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
                else
                        dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
                                data_len, client->addr, cmd, ret);
-       } else {
+       /* 2 transfers must have completed successfully */
+       } else if (ret == 2) {
                memcpy(data, buffer, data_len);
+               ret = 0;
+       } else {
+               ret = -EIO;
        }
 
        kfree(buffer);
@@ -595,8 +599,6 @@ i2c_acpi_space_handler(u32 function, acpi_physical_address command,
                if (action == ACPI_READ) {
                        status = acpi_gsb_i2c_read_bytes(client, command,
                                        gsb->data, info->access_length);
-                       if (status > 0)
-                               status = 0;
                } else {
                        status = acpi_gsb_i2c_write_bytes(client, command,
                                        gsb->data, info->access_length);