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i2c: core: ACPI: Properly set status byte to 0 for multi-byte writes 

commit c463a158cb upstream.

acpi_gsb_i2c_write_bytes() returns i2c_transfer()'s return value, which
is the number of transfers executed on success, so 1.

The ACPI code expects us to store 0 in gsb->status for success, not 1.

Specifically this breaks the following code in the Thinkpad 8 DSDT:

            ECWR = I2CW = ECWR /* \_SB_.I2C1.BAT0.ECWR */
            If ((ECST == Zero))
            {
                ECRD = I2CR /* \_SB_.I2C1.I2CR */
            }

Before this commit we set ECST to 1, causing the read to never happen
breaking battery monitoring on the Thinkpad 8.

This commit makes acpi_gsb_i2c_write_bytes() return 0 when i2c_transfer()
returns 1, so the single write transfer completed successfully, and
makes it return -EIO on for other (unexpected) return values >= 0.

Cc: stable@vger.kernel.org
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
Hans de Goede 2018-08-12 12:53:20 +02:00 committed by Greg Kroah-Hartman
parent b5b7417ed9
commit 415a02d8b6
1 changed files with 8 additions and 3 deletions
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11
drivers/i2c/i2c-core-acpi.c
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@ -475,11 +475,16 @@ static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
msgs[0].buf = buffer;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0)
dev_err(&client->adapter->dev, "i2c write failed\n");
kfree(buffer);
return ret;
if (ret < 0) {
dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
return ret;
}
/* 1 transfer must have completed successfully */
return (ret == 1) ? 0 : -EIO;
}
static acpi_status