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pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status

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Since commit c5cd2b47b2 ("platform/chrome: cros_ec_proto: Report command
not supported") we can no longer assume that cros_ec_cmd_xfer_status()
reports -EPROTO for all errors returned by the EC itself. A follow-up
patch will change cros_ec_cmd_xfer_status() to report additional errors
reported by the EC as distinguished Linux error codes.

Handle this change by no longer assuming that only -EPROTO is used
to report all errors returned by the EC itself. Instead, support both
the old and the new error codes.

Add a comment describing cros_ec_num_pwms() to explain its functionality.

Cc: Gwendal Grignou <gwendal@chromium.org>
Cc: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Cc: Prashant Malani <pmalani@chromium.org>
Cc: Brian Norris <briannorris@chromium.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
This commit is contained in:
Guenter Roeck 2020-08-22 08:08:54 -07:00 committed by Enric Balletbo i Serra
parent b646e7db1c
commit d509f8a71a
1 changed files with 22 additions and 7 deletions
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29
drivers/pwm/pwm-cros-ec.c
View File

@ -204,6 +204,11 @@ static const struct pwm_ops cros_ec_pwm_ops = {
.owner = THIS_MODULE,
};
/*
* Determine the number of supported PWMs. The EC does not return the number
* of PWMs it supports directly, so we have to read the pwm duty cycle for
* subsequent channels until we get an error.
*/
static int cros_ec_num_pwms(struct cros_ec_device *ec)
{
int i, ret;
@ -213,20 +218,30 @@ static int cros_ec_num_pwms(struct cros_ec_device *ec)
u32 result = 0;
ret = __cros_ec_pwm_get_duty(ec, i, &result);
/* We want to parse EC protocol errors */
if (ret < 0 && !(ret == -EPROTO && result))
return ret;
/*
* We look for SUCCESS, INVALID_COMMAND, or INVALID_PARAM
* responses; everything else is treated as an error.
* The EC error codes either map to -EOPNOTSUPP / -EINVAL,
* or -EPROTO is returned and the EC error is in the result
* field. Check for both.
*/
if (result == EC_RES_INVALID_COMMAND)
switch (ret) {
case -EOPNOTSUPP: /* invalid command */
return -ENODEV;
else if (result == EC_RES_INVALID_PARAM)
case -EINVAL: /* invalid parameter */
return i;
else if (result)
case -EPROTO:
/* Old or new error return code: Handle both */
if (result == EC_RES_INVALID_COMMAND)
return -ENODEV;
else if (result == EC_RES_INVALID_PARAM)
return i;
return -EPROTO;
default:
if (ret < 0)
return ret;
break;
}
}
return U8_MAX;