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| author | Hans de Goede <hdegoede@redhat.com> | 2018-08-12 12:53:20 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2018-08-20 14:08:59 +0200 |
| commit | c463a158cb6c5d9a85b7d894cd4f8116e8bd6be0 (patch) | |
| tree | 79409b9768a4d61566854458924ede06441b4198 /drivers/i2c/i2c-core-acpi.c | |
| parent | 0857f50807709ae109b9d11d7ca88c44dc7ca99f (diff) | |
| download | linux-c463a158cb6c5d9a85b7d894cd4f8116e8bd6be0.tar.bz2 | |
i2c: core: ACPI: Properly set status byte to 0 for multi-byte writes
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>
Diffstat (limited to 'drivers/i2c/i2c-core-acpi.c')
| -rw-r--r-- | drivers/i2c/i2c-core-acpi.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c index 7c3b4740b94b..b8f303dea305 100644 --- a/drivers/i2c/i2c-core-acpi.c +++ b/drivers/i2c/i2c-core-acpi.c @@ -482,11 +482,16 @@ 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 |