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author | Maximilian Luz <luzmaximilian@gmail.com> | 2022-05-27 04:34:46 +0200 |
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committer | Hans de Goede <hdegoede@redhat.com> | 2022-06-13 17:25:08 +0200 |
commit | d420185489e52f414b18cef10487279a9a005b27 (patch) | |
tree | 7103641b4f65f82b1f2dd4446cdb7b3eff785347 /drivers/platform/surface/surface_aggregator_registry.c | |
parent | 58a4d884b50947c0ffb494f690b2d7a1422a45c7 (diff) | |
download | linux-stable-d420185489e52f414b18cef10487279a9a005b27.tar.gz linux-stable-d420185489e52f414b18cef10487279a9a005b27.tar.bz2 linux-stable-d420185489e52f414b18cef10487279a9a005b27.zip |
platform/surface: aggregator_registry: Add KIP device hub
Add a Surface System Aggregator Module (SSAM) client device hub for
hot-removable devices managed via the KIP subsystem.
The KIP subsystem (full name unknown, abbreviation has been obtained
through reverse engineering) is a subsystem that manages hot-removable
SSAM client devices. Specifically, it manages HID input devices
contained in the detachable keyboard cover of the Surface Pro 8 and
Surface Pro X.
The KIP subsystem handles a single group of devices (e.g. all devices
contained in the keyboard cover) and cannot handle devices individually.
Thus we model it as a client device hub, which (hot-)removes all devices
contained under it once removal of the hub (e.g. keyboard cover) has
been detected and (re-)adds all devices once the physical hub device has
been (re-)attached. To do this, use the previously generified SSAM
subsystem hub framework.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220527023447.2460025-12-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Diffstat (limited to 'drivers/platform/surface/surface_aggregator_registry.c')
-rw-r--r-- | drivers/platform/surface/surface_aggregator_registry.c | 103 |
1 files changed, 101 insertions, 2 deletions
diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c index b11ce87c7184..f15cef60630f 100644 --- a/drivers/platform/surface/surface_aggregator_registry.c +++ b/drivers/platform/surface/surface_aggregator_registry.c @@ -551,6 +551,93 @@ static struct ssam_device_driver ssam_base_hub_driver = { }; +/* -- SSAM KIP-subsystem hub driver. ---------------------------------------- */ + +/* + * Some devices may need a bit of time to be fully usable after being + * (re-)connected. This delay has been determined via experimentation. + */ +#define SSAM_KIP_UPDATE_CONNECT_DELAY msecs_to_jiffies(250) + +#define SSAM_EVENT_KIP_CID_CONNECTION 0x2c + +SSAM_DEFINE_SYNC_REQUEST_R(__ssam_kip_get_connection_state, u8, { + .target_category = SSAM_SSH_TC_KIP, + .target_id = 0x01, + .command_id = 0x2c, + .instance_id = 0x00, +}); + +static int ssam_kip_get_connection_state(struct ssam_hub *hub, enum ssam_hub_state *state) +{ + int status; + u8 connected; + + status = ssam_retry(__ssam_kip_get_connection_state, hub->sdev->ctrl, &connected); + if (status < 0) { + dev_err(&hub->sdev->dev, "failed to query KIP connection state: %d\n", status); + return status; + } + + *state = connected ? SSAM_HUB_CONNECTED : SSAM_HUB_DISCONNECTED; + return 0; +} + +static u32 ssam_kip_hub_notif(struct ssam_event_notifier *nf, const struct ssam_event *event) +{ + struct ssam_hub *hub = container_of(nf, struct ssam_hub, notif); + + if (event->command_id != SSAM_EVENT_KIP_CID_CONNECTION) + return 0; /* Return "unhandled". */ + + if (event->length < 1) { + dev_err(&hub->sdev->dev, "unexpected payload size: %u\n", event->length); + return 0; + } + + ssam_hub_update(hub, event->data[0]); + return SSAM_NOTIF_HANDLED; +} + +static int ssam_kip_hub_probe(struct ssam_device *sdev) +{ + struct ssam_hub *hub; + + hub = devm_kzalloc(&sdev->dev, sizeof(*hub), GFP_KERNEL); + if (!hub) + return -ENOMEM; + + hub->notif.base.priority = INT_MAX; /* This notifier should run first. */ + hub->notif.base.fn = ssam_kip_hub_notif; + hub->notif.event.reg = SSAM_EVENT_REGISTRY_SAM; + hub->notif.event.id.target_category = SSAM_SSH_TC_KIP, + hub->notif.event.id.instance = 0, + hub->notif.event.mask = SSAM_EVENT_MASK_TARGET; + hub->notif.event.flags = SSAM_EVENT_SEQUENCED; + + hub->connect_delay = SSAM_KIP_UPDATE_CONNECT_DELAY; + hub->get_state = ssam_kip_get_connection_state; + + return ssam_hub_setup(sdev, hub); +} + +static const struct ssam_device_id ssam_kip_hub_match[] = { + { SSAM_VDEV(HUB, 0x01, SSAM_SSH_TC_KIP, 0x00) }, + { }, +}; + +static struct ssam_device_driver ssam_kip_hub_driver = { + .probe = ssam_kip_hub_probe, + .remove = ssam_hub_remove, + .match_table = ssam_kip_hub_match, + .driver = { + .name = "surface_kip_hub", + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + .pm = &ssam_hub_pm_ops, + }, +}; + + /* -- SSAM platform/meta-hub driver. ---------------------------------------- */ static const struct acpi_device_id ssam_platform_hub_match[] = { @@ -673,18 +760,30 @@ static int __init ssam_device_hub_init(void) status = platform_driver_register(&ssam_platform_hub_driver); if (status) - return status; + goto err_platform; status = ssam_device_driver_register(&ssam_base_hub_driver); if (status) - platform_driver_unregister(&ssam_platform_hub_driver); + goto err_base; + + status = ssam_device_driver_register(&ssam_kip_hub_driver); + if (status) + goto err_kip; + return 0; + +err_kip: + ssam_device_driver_unregister(&ssam_base_hub_driver); +err_base: + platform_driver_unregister(&ssam_platform_hub_driver); +err_platform: return status; } module_init(ssam_device_hub_init); static void __exit ssam_device_hub_exit(void) { + ssam_device_driver_unregister(&ssam_kip_hub_driver); ssam_device_driver_unregister(&ssam_base_hub_driver); platform_driver_unregister(&ssam_platform_hub_driver); } |