Since commit c5cd2b47b203 ("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@xxxxxxxxxxxx>
Cc: Yu-Hsuan Hsu <yuhsuan@xxxxxxxxxxxx>
Cc: Prashant Malani <pmalani@xxxxxxxxxxxx>
Cc: Brian Norris <briannorris@xxxxxxxxxxxx>
Acked-by: Thierry Reding <thierry.reding@xxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
v4: Added comments describing cros_ec_num_pwms() in more detail
Added Thierry's Acked-by: tag
v3: Added patch
drivers/pwm/pwm-cros-ec.c | 29 ++++++++++++++++++++++-------
1 file 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;
--
2.17.1
