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// SPDX-License-Identifier: GPL-2.0+
/*
* AC driver for 7th-generation Microsoft Surface devices via Surface System
* Aggregator Module (SSAM).
*
* Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com>
*/
#include <asm/unaligned.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/power_supply.h>
#include <linux/types.h>
#include <linux/surface_aggregator/device.h>
/* -- SAM interface. -------------------------------------------------------- */
enum sam_event_cid_bat {
SAM_EVENT_CID_BAT_ADP = 0x17,
};
enum sam_battery_sta {
SAM_BATTERY_STA_OK = 0x0f,
SAM_BATTERY_STA_PRESENT = 0x10,
};
/* Get battery status (_STA). */
SSAM_DEFINE_SYNC_REQUEST_CL_R(ssam_bat_get_sta, __le32, {
.target_category = SSAM_SSH_TC_BAT,
.command_id = 0x01,
});
/* Get platform power source for battery (_PSR / DPTF PSRC). */
SSAM_DEFINE_SYNC_REQUEST_CL_R(ssam_bat_get_psrc, __le32, {
.target_category = SSAM_SSH_TC_BAT,
.command_id = 0x0d,
});
/* -- Device structures. ---------------------------------------------------- */
struct spwr_psy_properties {
const char *name;
struct ssam_event_registry registry;
};
struct spwr_ac_device {
struct ssam_device *sdev;
char name[32];
struct power_supply *psy;
struct power_supply_desc psy_desc;
struct ssam_event_notifier notif;
struct mutex lock; /* Guards access to state below. */
__le32 state;
};
/* -- State management. ----------------------------------------------------- */
static int spwr_ac_update_unlocked(struct spwr_ac_device *ac)
{
__le32 old = ac->state;
int status;
lockdep_assert_held(&ac->lock);
status = ssam_retry(ssam_bat_get_psrc, ac->sdev, &ac->state);
if (status < 0)
return status;
return old != ac->state;
}
static int spwr_ac_update(struct spwr_ac_device *ac)
{
int status;
mutex_lock(&ac->lock);
status = spwr_ac_update_unlocked(ac);
mutex_unlock(&ac->lock);
return status;
}
static int spwr_ac_recheck(struct spwr_ac_device *ac)
{
int status;
status = spwr_ac_update(ac);
if (status > 0)
power_supply_changed(ac->psy);
return status >= 0 ? 0 : status;
}
static u32 spwr_notify_ac(struct ssam_event_notifier *nf, const struct ssam_event *event)
{
struct spwr_ac_device *ac;
int status;
ac = container_of(nf, struct spwr_ac_device, notif);
dev_dbg(&ac->sdev->dev, "power event (cid = %#04x, iid = %#04x, tid = %#04x)\n",
event->command_id, event->instance_id, event->target_id);
/*
* Allow events of all targets/instances here. Global adapter status
* seems to be handled via target=1 and instance=1, but events are
* reported on all targets/instances in use.
*
* While it should be enough to just listen on 1/1, listen everywhere to
* make sure we don't miss anything.
*/
switch (event->command_id) {
case SAM_EVENT_CID_BAT_ADP:
status = spwr_ac_recheck(ac);
return ssam_notifier_from_errno(status) | SSAM_NOTIF_HANDLED;
default:
return 0;
}
}
/* -- Properties. ----------------------------------------------------------- */
static const enum power_supply_property spwr_ac_props[] = {
POWER_SUPPLY_PROP_ONLINE,
};
static int spwr_ac_get_property(struct power_supply *psy, enum power_supply_property psp,
union power_supply_propval *val)
{
struct spwr_ac_device *ac = power_supply_get_drvdata(psy);
int status;
mutex_lock(&ac->lock);
status = spwr_ac_update_unlocked(ac);
if (status)
goto out;
switch (psp) {
case POWER_SUPPLY_PROP_ONLINE:
val->intval = !!le32_to_cpu(ac->state);
break;
default:
status = -EINVAL;
goto out;
}
out:
mutex_unlock(&ac->lock);
return status;
}
/* -- Device setup. --------------------------------------------------------- */
static char *battery_supplied_to[] = {
"BAT1",
"BAT2",
};
static void spwr_ac_init(struct spwr_ac_device *ac, struct ssam_device *sdev,
struct ssam_event_registry registry, const char *name)
{
mutex_init(&ac->lock);
strncpy(ac->name, name, ARRAY_SIZE(ac->name) - 1);
ac->sdev = sdev;
ac->notif.base.priority = 1;
ac->notif.base.fn = spwr_notify_ac;
ac->notif.event.reg = registry;
ac->notif.event.id.target_category = sdev->uid.category;
ac->notif.event.id.instance = 0;
ac->notif.event.mask = SSAM_EVENT_MASK_NONE;
ac->notif.event.flags = SSAM_EVENT_SEQUENCED;
ac->psy_desc.name = ac->name;
ac->psy_desc.type = POWER_SUPPLY_TYPE_MAINS;
ac->psy_desc.properties = spwr_ac_props;
ac->psy_desc.num_properties = ARRAY_SIZE(spwr_ac_props);
ac->psy_desc.get_property = spwr_ac_get_property;
}
static int spwr_ac_register(struct spwr_ac_device *ac)
{
struct power_supply_config psy_cfg = {};
__le32 sta;
int status;
/* Make sure the device is there and functioning properly. */
status = ssam_retry(ssam_bat_get_sta, ac->sdev, &sta);
if (status)
return status;
if ((le32_to_cpu(sta) & SAM_BATTERY_STA_OK) != SAM_BATTERY_STA_OK)
return -ENODEV;
psy_cfg.drv_data = ac;
psy_cfg.supplied_to = battery_supplied_to;
psy_cfg.num_supplicants = ARRAY_SIZE(battery_supplied_to);
ac->psy = devm_power_supply_register(&ac->sdev->dev, &ac->psy_desc, &psy_cfg);
if (IS_ERR(ac->psy))
return PTR_ERR(ac->psy);
return ssam_device_notifier_register(ac->sdev, &ac->notif);
}
/* -- Driver setup. --------------------------------------------------------- */
static int __maybe_unused surface_ac_resume(struct device *dev)
{
return spwr_ac_recheck(dev_get_drvdata(dev));
}
static SIMPLE_DEV_PM_OPS(surface_ac_pm_ops, NULL, surface_ac_resume);
static int surface_ac_probe(struct ssam_device *sdev)
{
const struct spwr_psy_properties *p;
struct spwr_ac_device *ac;
p = ssam_device_get_match_data(sdev);
if (!p)
return -ENODEV;
ac = devm_kzalloc(&sdev->dev, sizeof(*ac), GFP_KERNEL);
if (!ac)
return -ENOMEM;
spwr_ac_init(ac, sdev, p->registry, p->name);
ssam_device_set_drvdata(sdev, ac);
return spwr_ac_register(ac);
}
static void surface_ac_remove(struct ssam_device *sdev)
{
struct spwr_ac_device *ac = ssam_device_get_drvdata(sdev);
ssam_device_notifier_unregister(sdev, &ac->notif);
}
static const struct spwr_psy_properties spwr_psy_props_adp1 = {
.name = "ADP1",
.registry = SSAM_EVENT_REGISTRY_SAM,
};
static const struct ssam_device_id surface_ac_match[] = {
{ SSAM_SDEV(BAT, SAM, 0x01, 0x01), (unsigned long)&spwr_psy_props_adp1 },
{ },
};
MODULE_DEVICE_TABLE(ssam, surface_ac_match);
static struct ssam_device_driver surface_ac_driver = {
.probe = surface_ac_probe,
.remove = surface_ac_remove,
.match_table = surface_ac_match,
.driver = {
.name = "surface_ac",
.pm = &surface_ac_pm_ops,
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
},
};
module_ssam_device_driver(surface_ac_driver);
MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
MODULE_DESCRIPTION("AC driver for Surface System Aggregator Module");
MODULE_LICENSE("GPL");
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