// SPDX-License-Identifier: GPL-2.0+
/*
* Surface System Aggregator Module (SSAM) tablet mode switch driver.
*
* Copyright (C) 2022 Maximilian Luz <[email protected]>
*/
#include <linux/unaligned.h>
#include <linux/input.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <linux/surface_aggregator/controller.h>
#include <linux/surface_aggregator/device.h>
/* -- SSAM generic tablet switch driver framework. -------------------------- */
struct ssam_tablet_sw;
struct ssam_tablet_sw_state {
u32 source;
u32 state;
};
struct ssam_tablet_sw_ops {
int (*get_state)(struct ssam_tablet_sw *sw, struct ssam_tablet_sw_state *state);
const char *(*state_name)(struct ssam_tablet_sw *sw,
const struct ssam_tablet_sw_state *state);
bool (*state_is_tablet_mode)(struct ssam_tablet_sw *sw,
const struct ssam_tablet_sw_state *state);
};
struct ssam_tablet_sw {
struct ssam_device *sdev;
struct ssam_tablet_sw_state state;
struct work_struct update_work;
struct input_dev *mode_switch;
struct ssam_tablet_sw_ops ops;
struct ssam_event_notifier notif;
};
struct ssam_tablet_sw_desc {
struct {
const char *name;
const char *phys;
} dev;
struct {
u32 (*notify)(struct ssam_event_notifier *nf, const struct ssam_event *event);
int (*get_state)(struct ssam_tablet_sw *sw, struct ssam_tablet_sw_state *state);
const char *(*state_name)(struct ssam_tablet_sw *sw,
const struct ssam_tablet_sw_state *state);
bool (*state_is_tablet_mode)(struct ssam_tablet_sw *sw,
const struct ssam_tablet_sw_state *state);
} ops;
struct {
struct ssam_event_registry reg;
struct ssam_event_id id;
enum ssam_event_mask mask;
u8 flags;
} event;
};
static ssize_t state_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct ssam_tablet_sw *sw = dev_get_drvdata(dev);
const char *state = sw->ops.state_name(sw, &sw->state);
return sysfs_emit(buf, "%s\n", state);
}
static DEVICE_ATTR_RO(state);
static struct attribute *ssam_tablet_sw_attrs[] = {
&dev_attr_state.attr,
NULL,
};
static const struct attribute_group ssam_tablet_sw_group = {
.attrs = ssam_tablet_sw_attrs,
};
static void ssam_tablet_sw_update_workfn(struct work_struct *work)
{
struct ssam_tablet_sw *sw = container_of(work, struct ssam_tablet_sw, update_work);
struct ssam_tablet_sw_state state;
int tablet, status;
status = sw->ops.get_state(sw, &state);
if (status)
return;
if (sw->state.source == state.source && sw->state.state == state.state)
return;
sw->state = state;
/* Send SW_TABLET_MODE event. */
tablet = sw->ops.state_is_tablet_mode(sw, &state);
input_report_switch(sw->mode_switch, SW_TABLET_MODE, tablet);
input_sync(sw->mode_switch);
}
static int __maybe_unused ssam_tablet_sw_resume(struct device *dev)
{
struct ssam_tablet_sw *sw = dev_get_drvdata(dev);
schedule_work(&sw->update_work);
return 0;
}
static SIMPLE_DEV_PM_OPS(ssam_tablet_sw_pm_ops, NULL, ssam_tablet_sw_resume);
static int ssam_tablet_sw_probe(struct ssam_device *sdev)
{
const struct ssam_tablet_sw_desc *desc;
struct ssam_tablet_sw *sw;
int tablet, status;
desc = ssam_device_get_match_data(sdev);
if (!desc) {
WARN(1, "no driver match data specified");
return -EINVAL;
}
sw = devm_kzalloc(&sdev->dev, sizeof(*sw), GFP_KERNEL);
if (!sw)
return -ENOMEM;
sw->sdev = sdev;
sw->ops.get_state = desc->ops.get_state;
sw->ops.state_name = desc->ops.state_name;
sw->ops.state_is_tablet_mode = desc->ops.state_is_tablet_mode;
INIT_WORK(&sw->update_work, ssam_tablet_sw_update_workfn);
ssam_device_set_drvdata(sdev, sw);
/* Get initial state. */
status = sw->ops.get_state(sw, &sw->state);
if (status)
return status;
/* Set up tablet mode switch. */
sw->mode_switch = devm_input_allocate_device(&sdev->dev);
if (!sw->mode_switch)
return -ENOMEM;
sw->mode_switch->name = desc->dev.name;
sw->mode_switch->phys = desc->dev.phys;
sw->mode_switch->id.bustype = BUS_HOST;
sw->mode_switch->dev.parent = &sdev->dev;
tablet = sw->ops.state_is_tablet_mode(sw, &sw->state);
input_set_capability(sw->mode_switch, EV_SW, SW_TABLET_MODE);
input_report_switch(sw->mode_switch, SW_TABLET_MODE, tablet);
status = input_register_device(sw->mode_switch);
if (status)
return status;
/* Set up notifier. */
sw->notif.base.priority = 0;
sw->notif.base.fn = desc->ops.notify;
sw->notif.event.reg = desc->event.reg;
sw->notif.event.id = desc->event.id;
sw->notif.event.mask = desc->event.mask;
sw->notif.event.flags = SSAM_EVENT_SEQUENCED;
status = ssam_device_notifier_register(sdev, &sw->notif);
if (status)
return status;
status = sysfs_create_group(&sdev->dev.kobj, &ssam_tablet_sw_group);
if (status)
goto err;
/* We might have missed events during setup, so check again. */
schedule_work(&sw->update_work);
return 0;
err:
ssam_device_notifier_unregister(sdev, &sw->notif);
cancel_work_sync(&sw->update_work);
return status;
}
static void ssam_tablet_sw_remove(struct ssam_device *sdev)
{
struct ssam_tablet_sw *sw = ssam_device_get_drvdata(sdev);
sysfs_remove_group(&sdev->dev.kobj, &ssam_tablet_sw_group);
ssam_device_notifier_unregister(sdev, &sw->notif);
cancel_work_sync(&sw->update_work);
}
/* -- SSAM KIP tablet switch implementation. -------------------------------- */
#define SSAM_EVENT_KIP_CID_COVER_STATE_CHANGED 0x1d
enum ssam_kip_cover_state {
SSAM_KIP_COVER_STATE_DISCONNECTED = 0x01,
SSAM_KIP_COVER_STATE_CLOSED = 0x02,
SSAM_KIP_COVER_STATE_LAPTOP = 0x03,
SSAM_KIP_COVER_STATE_FOLDED_CANVAS = 0x04,
SSAM_KIP_COVER_STATE_FOLDED_BACK = 0x05,
SSAM_KIP_COVER_STATE_BOOK = 0x06,
};
static const char *ssam_kip_cover_state_name(struct ssam_tablet_sw *sw,
const struct ssam_tablet_sw_state *state)
{
switch (state->state) {
case SSAM_KIP_COVER_STATE_DISCONNECTED:
return "disconnected";
case SSAM_KIP_COVER_STATE_CLOSED:
return "closed";
case SSAM_KIP_COVER_STATE_LAPTOP:
return "laptop";
case SSAM_KIP_COVER_STATE_FOLDED_CANVAS:
return "folded-canvas";
case SSAM_KIP_COVER_STATE_FOLDED_BACK:
return "folded-back";
case SSAM_KIP_COVER_STATE_BOOK:
return "book";
default:
dev_warn(&sw->sdev->dev, "unknown KIP cover state: %u\n", state->state);
return "<unknown>";
}
}
static bool ssam_kip_cover_state_is_tablet_mode(struct ssam_tablet_sw *sw,
const struct ssam_tablet_sw_state *state)
{
switch (state->state) {
case SSAM_KIP_COVER_STATE_DISCONNECTED:
case SSAM_KIP_COVER_STATE_FOLDED_CANVAS:
case SSAM_KIP_COVER_STATE_FOLDED_BACK:
case SSAM_KIP_COVER_STATE_BOOK:
return true;
case SSAM_KIP_COVER_STATE_CLOSED:
case SSAM_KIP_COVER_STATE_LAPTOP:
return false;
default:
dev_warn(&sw->sdev->dev, "unknown KIP cover state: %d\n", state->state);
return true;
}
}
SSAM_DEFINE_SYNC_REQUEST_R(__ssam_kip_get_cover_state, u8, {
.target_category = SSAM_SSH_TC_KIP,
.target_id = SSAM_SSH_TID_SAM,
.command_id = 0x1d,
.instance_id = 0x00,
});
static int ssam_kip_get_cover_state(struct ssam_tablet_sw *sw, struct ssam_tablet_sw_state *state)
{
int status;
u8 raw;
status = ssam_retry(__ssam_kip_get_cover_state, sw->sdev->ctrl, &raw);
if (status < 0) {
dev_err(&sw->sdev->dev, "failed to query KIP lid state: %d\n", status);
return status;
}
state->source = 0; /* Unused for KIP switch. */
state->state = raw;
return 0;
}
static u32 ssam_kip_sw_notif(struct ssam_event_notifier *nf, const struct ssam_event *event)
{
struct ssam_tablet_sw *sw = container_of(nf, struct ssam_tablet_sw, notif);
if (event->command_id != SSAM_EVENT_KIP_CID_COVER_STATE_CHANGED)
return 0; /* Return "unhandled". */
if (event->length < 1)
dev_warn(&sw->sdev->dev, "unexpected payload size: %u\n", event->length);
schedule_work(&sw->update_work);
return SSAM_NOTIF_HANDLED;
}
static const struct ssam_tablet_sw_desc ssam_kip_sw_desc = {
.dev = {
.name = "Microsoft Surface KIP Tablet Mode Switch",
.phys = "ssam/01:0e:01:00:01/input0",
},
.ops = {
.notify = ssam_kip_sw_notif,
.get_state = ssam_kip_get_cover_state,
.state_name = ssam_kip_cover_state_name,
.state_is_tablet_mode = ssam_kip_cover_state_is_tablet_mode,
},
.event = {
.reg = SSAM_EVENT_REGISTRY_SAM,
.id = {
.target_category = SSAM_SSH_TC_KIP,
.instance = 0,
},
.mask = SSAM_EVENT_MASK_TARGET,
},
};
/* -- SSAM POS tablet switch implementation. -------------------------------- */
static bool tablet_mode_in_slate_state = true;
module_param(tablet_mode_in_slate_state, bool, 0644);
MODULE_PARM_DESC(tablet_mode_in_slate_state, "Enable tablet mode in slate device posture, default is 'true'");
#define SSAM_EVENT_POS_CID_POSTURE_CHANGED 0x03
#define SSAM_POS_MAX_SOURCES 4
enum ssam_pos_source_id {
SSAM_POS_SOURCE_COVER = 0x00,
SSAM_POS_SOURCE_SLS = 0x03,
};
enum ssam_pos_state_cover {
SSAM_POS_COVER_DISCONNECTED = 0x01,
SSAM_POS_COVER_CLOSED = 0x02,
SSAM_POS_COVER_LAPTOP = 0x03,
SSAM_POS_COVER_FOLDED_CANVAS = 0x04,
SSAM_POS_COVER_FOLDED_BACK = 0x05,
SSAM_POS_COVER_BOOK = 0x06,
};
enum ssam_pos_state_sls {
SSAM_POS_SLS_LID_CLOSED = 0x00,
SSAM_POS_SLS_LAPTOP = 0x01,
SSAM_POS_SLS_SLATE = 0x02,
SSAM_POS_SLS_TABLET = 0x03,
};
struct ssam_sources_list {
__le32 count;
__le32 id[SSAM_POS_MAX_SOURCES];
} __packed;
static const char *ssam_pos_state_name_cover(struct ssam_tablet_sw *sw, u32 state)
{
switch (state) {
case SSAM_POS_COVER_DISCONNECTED:
return "disconnected";
case SSAM_POS_COVER_CLOSED:
return "closed";
case SSAM_POS_COVER_LAPTOP:
return "laptop";
case SSAM_POS_COVER_FOLDED_CANVAS:
return "folded-canvas";
case SSAM_POS_COVER_FOLDED_BACK:
return "folded-back";
case SSAM_POS_COVER_BOOK:
return "book";
default:
dev_warn(&sw->sdev->dev, "unknown device posture for type-cover: %u\n", state);
return "<unknown>";
}
}
static const char *ssam_pos_state_name_sls(struct ssam_tablet_sw *sw, u32 state)
{
switch (state) {
case SSAM_POS_SLS_LID_CLOSED:
return "closed";
case SSAM_POS_SLS_LAPTOP:
return "laptop";
case SSAM_POS_SLS_SLATE:
return "slate";
case SSAM_POS_SLS_TABLET:
return "tablet";
default:
dev_warn(&sw->sdev->dev, "unknown device posture for SLS: %u\n", state);
return "<unknown>";
}
}
static const char *ssam_pos_state_name(struct ssam_tablet_sw *sw,
const struct ssam_tablet_sw_state *state)
{
switch (state->source) {
case SSAM_POS_SOURCE_COVER:
return ssam_pos_state_name_cover(sw, state->state);
case SSAM_POS_SOURCE_SLS:
return ssam_pos_state_name_sls(sw, state->state);
default:
dev_warn(&sw->sdev->dev, "unknown device posture source: %u\n", state->source);
return "<unknown>";
}
}
static bool ssam_pos_state_is_tablet_mode_cover(struct ssam_tablet_sw *sw, u32 state)
{
switch (state) {
case SSAM_POS_COVER_DISCONNECTED:
case SSAM_POS_COVER_FOLDED_CANVAS:
case SSAM_POS_COVER_FOLDED_BACK:
case SSAM_POS_COVER_BOOK:
return true;
case SSAM_POS_COVER_CLOSED:
case SSAM_POS_COVER_LAPTOP:
return false;
default:
dev_warn(&sw->sdev->dev, "unknown device posture for type-cover: %u\n", state);
return true;
}
}
static bool ssam_pos_state_is_tablet_mode_sls(struct ssam_tablet_sw *sw, u32 state)
{
switch (state) {
case SSAM_POS_SLS_LAPTOP:
case SSAM_POS_SLS_LID_CLOSED:
return false;
case SSAM_POS_SLS_SLATE:
return tablet_mode_in_slate_state;
case SSAM_POS_SLS_TABLET:
return true;
default:
dev_warn(&sw->sdev->dev, "unknown device posture for SLS: %u\n", state);
return true;
}
}
static bool ssam_pos_state_is_tablet_mode(struct ssam_tablet_sw *sw,
const struct ssam_tablet_sw_state *state)
{
switch (state->source) {
case SSAM_POS_SOURCE_COVER:
return ssam_pos_state_is_tablet_mode_cover(sw, state->state);
case SSAM_POS_SOURCE_SLS:
return ssam_pos_state_is_tablet_mode_sls(sw, state->state);
default:
dev_warn(&sw->sdev->dev, "unknown device posture source: %u\n", state->source);
return true;
}
}
static int ssam_pos_get_sources_list(struct ssam_tablet_sw *sw, struct ssam_sources_list *sources)
{
struct ssam_request rqst;
struct ssam_response rsp;
int status;
rqst.target_category = SSAM_SSH_TC_POS;
rqst.target_id = SSAM_SSH_TID_SAM;
rqst.command_id = 0x01;
rqst.instance_id = 0x00;
rqst.flags = SSAM_REQUEST_HAS_RESPONSE;
rqst.length = 0;
rqst.payload = NULL;
rsp.capacity = sizeof(*sources);
rsp.length = 0;
rsp.pointer = (u8 *)sources;
status = ssam_retry(ssam_request_do_sync_onstack, sw->sdev->ctrl, &rqst, &rsp, 0);
if (status)
return status;
/* We need at least the 'sources->count' field. */
if (rsp.length < sizeof(__le32)) {
dev_err(&sw->sdev->dev, "received source list response is too small\n");
return -EPROTO;
}
/* Make sure 'sources->count' matches with the response length. */
if (get_unaligned_le32(&sources->count) * sizeof(__le32) + sizeof(__le32) != rsp.length) {
dev_err(&sw->sdev->dev, "mismatch between number of sources and response size\n");
return -EPROTO;
}
return 0;
}
static int ssam_pos_get_source(struct ssam_tablet_sw *sw, u32 *source_id)
{
struct ssam_sources_list sources = {};
int status;
status = ssam_pos_get_sources_list(sw, &sources);
if (status)
return status;
if (get_unaligned_le32(&sources.count) == 0) {
dev_err(&sw->sdev->dev, "no posture sources found\n");
return -ENODEV;
}
/*
* We currently don't know what to do with more than one posture
* source. At the moment, only one source seems to be used/provided.
* The WARN_ON() here should hopefully let us know quickly once there
* is a device that provides multiple sources, at which point we can
* then try to figure out how to handle them.
*/
WARN_ON(get_unaligned_le32(&sources.count) > 1);
*source_id = get_unaligned_le32(&sources.id[0]);
return 0;
}
SSAM_DEFINE_SYNC_REQUEST_WR(__ssam_pos_get_posture_for_source, __le32, __le32, {
.target_category = SSAM_SSH_TC_POS,
.target_id = SSAM_SSH_TID_SAM,
.command_id = 0x02,
.instance_id = 0x00,
});
static int ssam_pos_get_posture_for_source(struct ssam_tablet_sw *sw, u32 source_id, u32 *posture)
{
__le32 source_le = cpu_to_le32(source_id);
__le32 rspval_le = 0;
int status;
status = ssam_retry(__ssam_pos_get_posture_for_source, sw->sdev->ctrl,
&source_le, &rspval_le);
if (status)
return status;
*posture = le32_to_cpu(rspval_le);
return 0;
}
static int ssam_pos_get_posture(struct ssam_tablet_sw *sw, struct ssam_tablet_sw_state *state)
{
u32 source_id;
u32 source_state;
int status;
status = ssam_pos_get_source(sw, &source_id);
if (status) {
dev_err(&sw->sdev->dev, "failed to get posture source ID: %d\n", status);
return status;
}
status = ssam_pos_get_posture_for_source(sw, source_id, &source_state);
if (status) {
dev_err(&sw->sdev->dev, "failed to get posture value for source %u: %d\n",
source_id, status);
return status;
}
state->source = source_id;
state->state = source_state;
return 0;
}
static u32 ssam_pos_sw_notif(struct ssam_event_notifier *nf, const struct ssam_event *event)
{
struct ssam_tablet_sw *sw = container_of(nf, struct ssam_tablet_sw, notif);
if (event->command_id != SSAM_EVENT_POS_CID_POSTURE_CHANGED)
return 0; /* Return "unhandled". */
if (event->length != sizeof(__le32) * 3)
dev_warn(&sw->sdev->dev, "unexpected payload size: %u\n", event->length);
schedule_work(&sw->update_work);
return SSAM_NOTIF_HANDLED;
}
static const struct ssam_tablet_sw_desc ssam_pos_sw_desc = {
.dev = {
.name = "Microsoft Surface POS Tablet Mode Switch",
.phys = "ssam/01:26:01:00:01/input0",
},
.ops = {
.notify = ssam_pos_sw_notif,
.get_state = ssam_pos_get_posture,
.state_name = ssam_pos_state_name,
.state_is_tablet_mode = ssam_pos_state_is_tablet_mode,
},
.event = {
.reg = SSAM_EVENT_REGISTRY_SAM,
.id = {
.target_category = SSAM_SSH_TC_POS,
.instance = 0,
},
.mask = SSAM_EVENT_MASK_TARGET,
},
};
/* -- Driver registration. -------------------------------------------------- */
static const struct ssam_device_id ssam_tablet_sw_match[] = {
{ SSAM_SDEV(KIP, SAM, 0x00, 0x01), (unsigned long)&ssam_kip_sw_desc },
{ SSAM_SDEV(POS, SAM, 0x00, 0x01), (unsigned long)&ssam_pos_sw_desc },
{ },
};
MODULE_DEVICE_TABLE(ssam, ssam_tablet_sw_match);
static struct ssam_device_driver ssam_tablet_sw_driver = {
.probe = ssam_tablet_sw_probe,
.remove = ssam_tablet_sw_remove,
.match_table = ssam_tablet_sw_match,
.driver = {
.name = "surface_aggregator_tablet_mode_switch",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.pm = &ssam_tablet_sw_pm_ops,
},
};
module_ssam_device_driver(ssam_tablet_sw_driver);
MODULE_AUTHOR("Maximilian Luz <[email protected]>");
MODULE_DESCRIPTION("Tablet mode switch driver for Surface devices using the Surface Aggregator Module");
MODULE_LICENSE("GPL");
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