diff options
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/pwm-cros-ec.c | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c index 09c08dee099e..94d3dff9b0e5 100644 --- a/drivers/pwm/pwm-cros-ec.c +++ b/drivers/pwm/pwm-cros-ec.c @@ -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; |