On Tue, Sep 15, 2015 at 04:55:02PM -0700, Rafael Antognolli wrote:
> This list will be used to get the aux channels registered through the
> helpers. One function is provided to set a callback for added/removed
> aux channels, and another function to iterate over the list of aux
> channels.
>
> Signed-off-by: Rafael Antognolli
> ---
> drivers/gpu/drm/drm_dp_helper.c | 73
> +
> include/drm/drm_dp_helper.h | 5 +++
> 2 files changed, 78 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index 9535c5b..41bdd93 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -746,6 +746,56 @@ static const struct i2c_algorithm drm_dp_i2c_algo = {
> .master_xfer = drm_dp_i2c_xfer,
> };
>
> +struct drm_dp_aux_node {
> + struct klist_node list;
> + struct drm_dp_aux *aux;
> +};
> +
> +static DEFINE_KLIST(drm_dp_aux_list, NULL, NULL);
> +
> +static int (*aux_dev_cb)(int action, struct drm_dp_aux *aux) = NULL;
> +
> +void drm_dp_aux_set_aux_dev(int (*fn)(int, struct drm_dp_aux *))
> +{
> + aux_dev_cb = fn;
> +}
> +EXPORT_SYMBOL(drm_dp_aux_set_aux_dev);
> +
> +static struct drm_dp_aux *next_aux(struct klist_iter *i)
> +{
> + struct klist_node *n = klist_next(i);
> + struct drm_dp_aux *aux = NULL;
> + struct drm_dp_aux_node *aux_node;
> +
> + if (n) {
> + aux_node = container_of(n, struct drm_dp_aux_node, list);
> + aux = aux_node->aux;
> + }
> + return aux;
> +}
> +
> +int drm_dp_aux_for_each(void *data, int (*fn)(struct drm_dp_aux *, void *))
> +{
> + struct klist_iter i;
> + struct drm_dp_aux *aux;
> + int error = 0;
> +
> + klist_iter_init(&drm_dp_aux_list, &i);
> + while ((aux = next_aux(&i)) && !error)
> + error = fn(aux, data);
> + klist_iter_exit(&i);
> + return error;
> +}
> +EXPORT_SYMBOL(drm_dp_aux_for_each);
> +
> +static int drm_dp_aux_dev_inform(int action, struct drm_dp_aux *aux)
> +{
> + if (aux_dev_cb) {
> + return aux_dev_cb(action, aux);
> + }
> + return 0;
> +}
> +
> /**
> * drm_dp_aux_register() - initialise and register aux channel
> * @aux: DisplayPort AUX channel
> @@ -754,6 +804,7 @@ static const struct i2c_algorithm drm_dp_i2c_algo = {
> */
> int drm_dp_aux_register(struct drm_dp_aux *aux)
> {
> + struct drm_dp_aux_node *aux_node;
> mutex_init(&aux->hw_mutex);
>
> aux->ddc.algo = &drm_dp_i2c_algo;
> @@ -768,6 +819,14 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
> strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
> sizeof(aux->ddc.name));
>
> + /* add aux to list and notify listeners */
> + aux_node = kzalloc(sizeof(*aux_node), GFP_KERNEL);
> + if (!aux_node)
> + return -ENOMEM;
> + aux_node->aux = aux;
> + klist_add_tail(&aux_node->list, &drm_dp_aux_list);
> + drm_dp_aux_dev_inform(DRM_DP_ADD_AUX, aux);
If you go with the direct function call approach there's no need for all
this indirection, just do something like
drm_dp_aux_register_devnode(aux);
And drop all the list book-keeping (since there will never be a time when
the aux stuff isn't loaded yet). Essentially you're reinventing notifier
chains here (but without the required locking).
With that this patch just adds 2 lines, probably best to squash it in with
the last one.
-Daniel
> +
> return i2c_add_adapter(&aux->ddc);
> }
> EXPORT_SYMBOL(drm_dp_aux_register);
> @@ -778,6 +837,20 @@ EXPORT_SYMBOL(drm_dp_aux_register);
> */
> void drm_dp_aux_unregister(struct drm_dp_aux *aux)
> {
> + struct klist_iter i;
> + struct klist_node *n;
> +
> + klist_iter_init(&drm_dp_aux_list, &i);
> + while ((n = klist_next(&i))) {
> + struct drm_dp_aux_node *aux_node =
> + container_of(n, struct drm_dp_aux_node, list);
> + if (aux_node->aux == aux) {
> + klist_del(n);
> + kfree(aux_node);
> + break;
> + }
> + }
> + drm_dp_aux_dev_inform(DRM_DP_DEL_AUX, aux);
> i2c_del_adapter(&aux->ddc);
> }
> EXPORT_SYMBOL(drm_dp_aux_unregister);
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 9ec4716..f92de26 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -763,7 +763,12 @@ int drm_dp_link_power_up(struct drm_dp_aux *aux, struct
> drm_dp_link *link);
> int drm_dp_link_power_down(struct drm_dp_aux *aux, struct drm_dp_link *link);
> int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link);
>
> +#define DRM_DP_ADD_AUX 0x01
> +#define DRM_DP_DEL_AUX 0x02
> +
> int drm_dp_aux_register(struct drm_dp_aux *aux);
> void drm_dp_aux_unregister(struct drm_dp_aux *aux);
> +void drm_dp_aux_set_aux_dev(int (*fn)(int, struct drm_dp_aux *));
> +int drm_dp_aux_for_eac
