On Wed, Jan 11, 2023 at 02:05:41AM +0000, Prashant Malani wrote:
> The code to extract a peripheral's currently supported Pin Assignments
> is repeated in a couple of locations. Factor it out into a separate
> function.
>
> This will also make it easier to add fixes (we only need to update 1
> location instead of 2).
>
> Fixes: c1e5c2f0cb8a ("usb: typec: altmodes/displayport: correct pin assignment for UFP receptacles")
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> Signed-off-by: Prashant Malani <pmalani@xxxxxxxxxxxx>
Reviewed-by: Benson Leung <bleung@xxxxxxxxxxxx>
> ---
>
> While this patch doesn't fix anything, it is required by the actual
> fix (which is Patch 2/3 in this series). So, I've add the "Fixes" tag
> and "Cc stable" tag to ensure that both patches are picked.
>
> If this is the incorrect approach and there is a better way, my
> apologies, and please let me know the appropriate process.
>
> drivers/usb/typec/altmodes/displayport.c | 22 ++++++++++++++--------
> 1 file changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
> index 06fb4732f8cd..f9d4a7648bc9 100644
> --- a/drivers/usb/typec/altmodes/displayport.c
> +++ b/drivers/usb/typec/altmodes/displayport.c
> @@ -420,6 +420,18 @@ static const char * const pin_assignments[] = {
> [DP_PIN_ASSIGN_F] = "F",
> };
>
> +/*
> + * Helper function to extract a peripheral's currently supported
> + * Pin Assignments from its DisplayPort alternate mode state.
> + */
> +static u8 get_current_pin_assignments(struct dp_altmode *dp)
> +{
> + if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D)
> + return DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo);
> + else
> + return DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo);
> +}
> +
> static ssize_t
> pin_assignment_store(struct device *dev, struct device_attribute *attr,
> const char *buf, size_t size)
> @@ -446,10 +458,7 @@ pin_assignment_store(struct device *dev, struct device_attribute *attr,
> goto out_unlock;
> }
>
> - if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D)
> - assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo);
> - else
> - assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo);
> + assignments = get_current_pin_assignments(dp);
>
> if (!(DP_CONF_GET_PIN_ASSIGN(conf) & assignments)) {
> ret = -EINVAL;
> @@ -486,10 +495,7 @@ static ssize_t pin_assignment_show(struct device *dev,
>
> cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
>
> - if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D)
> - assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo);
> - else
> - assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo);
> + assignments = get_current_pin_assignments(dp);
>
> for (i = 0; assignments; assignments >>= 1, i++) {
> if (assignments & 1) {
> --
> 2.39.0.314.g84b9a713c41-goog
>
--
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
bleung@xxxxxxxxxx
Chromium OS Project
bleung@xxxxxxxxxxxx
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