2021-02-19 21:58:19

by Lyude Paul

[permalink] [raw]
Subject: [PATCH 04/30] drm/bridge/tc358767: Don't register DP AUX channel until bridge is attached

Since this is a bridge, we don't start out with a respective DRM device.
Likewise this means we don't have a connector, which also means that we
should be following drm_dp_aux_register()'s documentation advice and not
call drm_dp_aux_register() until we have a matching connector. Instead,
call drm_dp_aux_init() in tc_probe() and wait until tc_bridge_attach() to
register our AUX channel. We also add tc_bridge_detach() to handle
unregistering the AUX adapter once the bridge has been disconnected.

Signed-off-by: Lyude Paul <[email protected]>
---
drivers/gpu/drm/bridge/tc358767.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 34a3e4e9f717..da89922721ed 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1414,11 +1414,15 @@ static int tc_bridge_attach(struct drm_bridge *bridge,
if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
return 0;

+ ret = drm_dp_aux_register(&tc->aux);
+ if (ret < 0)
+ return ret;
+
/* Create DP/eDP connector */
drm_connector_helper_add(&tc->connector, &tc_connector_helper_funcs);
ret = drm_connector_init(drm, &tc->connector, &tc_connector_funcs, tc->bridge.type);
if (ret)
- return ret;
+ goto aux_unregister;

/* Don't poll if don't have HPD connected */
if (tc->hpd_pin >= 0) {
@@ -1438,10 +1442,19 @@ static int tc_bridge_attach(struct drm_bridge *bridge,
drm_connector_attach_encoder(&tc->connector, tc->bridge.encoder);

return 0;
+aux_unregister:
+ drm_dp_aux_unregister(&tc->aux);
+ return ret;
+}
+
+static void tc_bridge_detach(struct drm_bridge *bridge)
+{
+ drm_dp_aux_unregister(&bridge_to_tc(bridge)->aux);
}

static const struct drm_bridge_funcs tc_bridge_funcs = {
.attach = tc_bridge_attach,
+ .detach = tc_bridge_detach,
.mode_valid = tc_mode_valid,
.mode_set = tc_bridge_mode_set,
.enable = tc_bridge_enable,
@@ -1680,9 +1693,7 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
tc->aux.name = "TC358767 AUX i2c adapter";
tc->aux.dev = tc->dev;
tc->aux.transfer = tc_aux_transfer;
- ret = drm_dp_aux_register(&tc->aux);
- if (ret)
- return ret;
+ drm_dp_aux_init(&tc->aux);

tc->bridge.funcs = &tc_bridge_funcs;
if (tc->hpd_pin >= 0)
@@ -1702,7 +1713,6 @@ static int tc_remove(struct i2c_client *client)
struct tc_data *tc = i2c_get_clientdata(client);

drm_bridge_remove(&tc->bridge);
- drm_dp_aux_unregister(&tc->aux);

return 0;
}
--
2.29.2


2021-03-19 14:31:27

by Robert Foss

[permalink] [raw]
Subject: Re: [PATCH 04/30] drm/bridge/tc358767: Don't register DP AUX channel until bridge is attached

Hey Lyude,

This patch looks good to me.

Reviewed-by: Robert Foss <[email protected]>

On Fri, 19 Feb 2021 at 22:56, Lyude Paul <[email protected]> wrote:
>
> Since this is a bridge, we don't start out with a respective DRM device.
> Likewise this means we don't have a connector, which also means that we
> should be following drm_dp_aux_register()'s documentation advice and not
> call drm_dp_aux_register() until we have a matching connector. Instead,
> call drm_dp_aux_init() in tc_probe() and wait until tc_bridge_attach() to
> register our AUX channel. We also add tc_bridge_detach() to handle
> unregistering the AUX adapter once the bridge has been disconnected.
>
> Signed-off-by: Lyude Paul <[email protected]>
> ---
> drivers/gpu/drm/bridge/tc358767.c | 20 +++++++++++++++-----
> 1 file changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> index 34a3e4e9f717..da89922721ed 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -1414,11 +1414,15 @@ static int tc_bridge_attach(struct drm_bridge *bridge,
> if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
> return 0;
>
> + ret = drm_dp_aux_register(&tc->aux);
> + if (ret < 0)
> + return ret;
> +
> /* Create DP/eDP connector */
> drm_connector_helper_add(&tc->connector, &tc_connector_helper_funcs);
> ret = drm_connector_init(drm, &tc->connector, &tc_connector_funcs, tc->bridge.type);
> if (ret)
> - return ret;
> + goto aux_unregister;
>
> /* Don't poll if don't have HPD connected */
> if (tc->hpd_pin >= 0) {
> @@ -1438,10 +1442,19 @@ static int tc_bridge_attach(struct drm_bridge *bridge,
> drm_connector_attach_encoder(&tc->connector, tc->bridge.encoder);
>
> return 0;
> +aux_unregister:
> + drm_dp_aux_unregister(&tc->aux);
> + return ret;
> +}
> +
> +static void tc_bridge_detach(struct drm_bridge *bridge)
> +{
> + drm_dp_aux_unregister(&bridge_to_tc(bridge)->aux);
> }
>
> static const struct drm_bridge_funcs tc_bridge_funcs = {
> .attach = tc_bridge_attach,
> + .detach = tc_bridge_detach,
> .mode_valid = tc_mode_valid,
> .mode_set = tc_bridge_mode_set,
> .enable = tc_bridge_enable,
> @@ -1680,9 +1693,7 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
> tc->aux.name = "TC358767 AUX i2c adapter";
> tc->aux.dev = tc->dev;
> tc->aux.transfer = tc_aux_transfer;
> - ret = drm_dp_aux_register(&tc->aux);
> - if (ret)
> - return ret;
> + drm_dp_aux_init(&tc->aux);
>
> tc->bridge.funcs = &tc_bridge_funcs;
> if (tc->hpd_pin >= 0)
> @@ -1702,7 +1713,6 @@ static int tc_remove(struct i2c_client *client)
> struct tc_data *tc = i2c_get_clientdata(client);
>
> drm_bridge_remove(&tc->bridge);
> - drm_dp_aux_unregister(&tc->aux);
>
> return 0;
> }
> --
> 2.29.2
>