[PATCH v5 0/7] platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes

[Guenter Roeck]

The EC reports a variety of error codes. Most of those, with the exception
of EC_RES_INVALID_VERSION, are converted to -EPROTO. As result, the actual
error code gets lost. In cros_ec_cmd_xfer_status(), convert all EC errors
to Linux error codes to report a more meaningful error to the caller to aid
debugging.

To prepare for this change, handle error codes other than -EPROTO for all
callers of cros_ec_cmd_xfer_status(). Specifically, no longer assume that
-EPROTO reflects an error from the EC and all other error codes reflect a
transfer error.

v2: Add patches 1/4 to 3/4 to handle callers of cros_ec_cmd_xfer_status()
v3: Add patches 4/6 and 5/6 to handle additional callers of
	cros_ec_cmd_xfer_status()
    Use -ENOPROTOOPT for EC_RES_INVALID_VERSION
    Implement function to convert error codes
v4: Add coments describing the functionality of cros_ec_num_pwms().
    Add patch 7/7 to clean up cros_ec_num_pwms() after the new error code
    support has been implemented.
    Rebased series to v5.8.
v5: If there is no error, cros_ec_cmd_xfer_status() needs to return the
    number of received bytes, not 0. While fixing that (in patch 6/7),
    rearranged the function to reduce its indentation.
    Rebased series to v5.9-rc1

----------------------------------------------------------------
Guenter Roeck (7):
      iio: cros_ec: Accept -EOPNOTSUPP as 'not supported' error code
      cros_ec_lightbar: Accept more error codes from cros_ec_cmd_xfer_status
      platform/chrome: cros_ec_sysfs: Report range of error codes from EC
      pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status
      platform/input: cros_ec: Replace -ENOTSUPP with -ENOPROTOOPT
      platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes
      pwm: cros-ec: Simplify EC error handling

 .../iio/common/cros_ec_sensors/cros_ec_sensors.c   |  2 +-
 drivers/input/keyboard/cros_ec_keyb.c              |  2 +-
 drivers/platform/chrome/cros_ec_lightbar.c         | 10 ++--
 drivers/platform/chrome/cros_ec_proto.c            | 57 +++++++++++++++++-----
 drivers/platform/chrome/cros_ec_sysfs.c            | 24 ++++-----
 drivers/pwm/pwm-cros-ec.c                          | 37 +++++++-------
 6 files changed, 78 insertions(+), 54 deletions(-)