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@xxxxxxxxxxxxxxx
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v2:
-Modify the value which acpi_gsb_i2c_write_bytes() returns instead of
checking + modifying the return value in its caller
---
drivers/i2c/i2c-core-acpi.c | 11 ++++++++---
1 file 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
--
2.18.0
