From: Tzung-Bi Shih Date: Wed, 18 May 2022 09:18:13 +0000 (+0800) Subject: platform/chrome: cros_ec_proto: update cros_ec_check_result() comment X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=97b11dd6350a1d5fb076df69ebbf504eb5c4fd57;p=linux.git platform/chrome: cros_ec_proto: update cros_ec_check_result() comment At first glance, cros_ec_check_result() is quite like cros_ec_map_error(). They check for `ec_msg->result` and return corresponding errors. However, as calling from `pkt_xfer` and `cmd_xfer`, cros_ec_check_result() should not report furthermore errors. -EAGAIN is the only exception. See [1][2][3] for some known userland programs' code. The return code from ioctl only denotes the EC communication status. Userland programs would further analyze the `result` in struct cros_ec_command* for follow-up actions (e.g. [4]). To clarify, update the function comment. [1]: https://crrev.com/54400e93a75ef440a83d6eaac2cec066daf99cf0/util/comm-dev.c#154 [2]: https://crrev.com/fe32670a89bf59e1aff84bba9dd3295657b85e9b/cros_ec_dev.c#296 [3]: https://crrev.com/4e19eb1d89de0422ff1bbd3f7260b131c761098c/drivers/google/cros_ec_dev.c#120 [4]: https://crrev.com/54400e93a75ef440a83d6eaac2cec066daf99cf0/util/comm-dev.c#164 Signed-off-by: Tzung-Bi Shih Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/20220518091814.2028579-4-tzungbi@kernel.org --- diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c index 01ab58b3269b3..13ced9d2dd71b 100644 --- a/drivers/platform/chrome/cros_ec_proto.c +++ b/drivers/platform/chrome/cros_ec_proto.c @@ -204,9 +204,12 @@ EXPORT_SYMBOL(cros_ec_prepare_tx); * @msg: Message to check. * * This is used by ChromeOS EC drivers to check the ec_msg->result for - * errors and to warn about them. + * EC_RES_IN_PROGRESS and to warn about them. * - * Return: 0 on success or negative error code. + * The function should not check for furthermore error codes. Otherwise, + * it would break the ABI. + * + * Return: -EAGAIN if ec_msg->result == EC_RES_IN_PROGRESS. Otherwise, 0. */ int cros_ec_check_result(struct cros_ec_device *ec_dev, struct cros_ec_command *msg)