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Subject[PATCH 4.18 055/197] i2c: core: ACPI: Make acpi_gsb_i2c_read_bytes() check i2c_transfer return value
Date
4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit 0a30446c0dca3483c384b54a431cc951e15f7e79 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/i2c/i2c-core-acpi.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

--- 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(struc
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, acp
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);

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