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1// SPDX-License-Identifier: GPL-2.0+2/*3 * AC driver for 7th-generation Microsoft Surface devices via Surface System4 * Aggregator Module (SSAM).5 *6 * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com>7 */8 9#include <linux/unaligned.h>10#include <linux/kernel.h>11#include <linux/module.h>12#include <linux/mutex.h>13#include <linux/power_supply.h>14#include <linux/types.h>15 16#include <linux/surface_aggregator/device.h>17 18 19/* -- SAM interface. -------------------------------------------------------- */20 21enum sam_event_cid_bat {22 SAM_EVENT_CID_BAT_ADP = 0x17,23};24 25enum sam_battery_sta {26 SAM_BATTERY_STA_OK = 0x0f,27 SAM_BATTERY_STA_PRESENT = 0x10,28};29 30/* Get battery status (_STA). */31SSAM_DEFINE_SYNC_REQUEST_CL_R(ssam_bat_get_sta, __le32, {32 .target_category = SSAM_SSH_TC_BAT,33 .command_id = 0x01,34});35 36/* Get platform power source for battery (_PSR / DPTF PSRC). */37SSAM_DEFINE_SYNC_REQUEST_CL_R(ssam_bat_get_psrc, __le32, {38 .target_category = SSAM_SSH_TC_BAT,39 .command_id = 0x0d,40});41 42 43/* -- Device structures. ---------------------------------------------------- */44 45struct spwr_psy_properties {46 const char *name;47 struct ssam_event_registry registry;48};49 50struct spwr_ac_device {51 struct ssam_device *sdev;52 53 char name[32];54 struct power_supply *psy;55 struct power_supply_desc psy_desc;56 57 struct ssam_event_notifier notif;58 59 struct mutex lock; /* Guards access to state below. */60 61 __le32 state;62};63 64 65/* -- State management. ----------------------------------------------------- */66 67static int spwr_ac_update_unlocked(struct spwr_ac_device *ac)68{69 __le32 old = ac->state;70 int status;71 72 lockdep_assert_held(&ac->lock);73 74 status = ssam_retry(ssam_bat_get_psrc, ac->sdev, &ac->state);75 if (status < 0)76 return status;77 78 return old != ac->state;79}80 81static int spwr_ac_update(struct spwr_ac_device *ac)82{83 int status;84 85 mutex_lock(&ac->lock);86 status = spwr_ac_update_unlocked(ac);87 mutex_unlock(&ac->lock);88 89 return status;90}91 92static int spwr_ac_recheck(struct spwr_ac_device *ac)93{94 int status;95 96 status = spwr_ac_update(ac);97 if (status > 0)98 power_supply_changed(ac->psy);99 100 return status >= 0 ? 0 : status;101}102 103static u32 spwr_notify_ac(struct ssam_event_notifier *nf, const struct ssam_event *event)104{105 struct spwr_ac_device *ac;106 int status;107 108 ac = container_of(nf, struct spwr_ac_device, notif);109 110 dev_dbg(&ac->sdev->dev, "power event (cid = %#04x, iid = %#04x, tid = %#04x)\n",111 event->command_id, event->instance_id, event->target_id);112 113 /*114 * Allow events of all targets/instances here. Global adapter status115 * seems to be handled via target=1 and instance=1, but events are116 * reported on all targets/instances in use.117 *118 * While it should be enough to just listen on 1/1, listen everywhere to119 * make sure we don't miss anything.120 */121 122 switch (event->command_id) {123 case SAM_EVENT_CID_BAT_ADP:124 status = spwr_ac_recheck(ac);125 return ssam_notifier_from_errno(status) | SSAM_NOTIF_HANDLED;126 127 default:128 return 0;129 }130}131 132 133/* -- Properties. ----------------------------------------------------------- */134 135static const enum power_supply_property spwr_ac_props[] = {136 POWER_SUPPLY_PROP_ONLINE,137};138 139static int spwr_ac_get_property(struct power_supply *psy, enum power_supply_property psp,140 union power_supply_propval *val)141{142 struct spwr_ac_device *ac = power_supply_get_drvdata(psy);143 int status;144 145 mutex_lock(&ac->lock);146 147 status = spwr_ac_update_unlocked(ac);148 if (status)149 goto out;150 151 switch (psp) {152 case POWER_SUPPLY_PROP_ONLINE:153 val->intval = !!le32_to_cpu(ac->state);154 break;155 156 default:157 status = -EINVAL;158 goto out;159 }160 161out:162 mutex_unlock(&ac->lock);163 return status;164}165 166 167/* -- Device setup. --------------------------------------------------------- */168 169static char *battery_supplied_to[] = {170 "BAT1",171 "BAT2",172};173 174static void spwr_ac_init(struct spwr_ac_device *ac, struct ssam_device *sdev,175 struct ssam_event_registry registry, const char *name)176{177 mutex_init(&ac->lock);178 strscpy(ac->name, name, sizeof(ac->name));179 180 ac->sdev = sdev;181 182 ac->notif.base.priority = 1;183 ac->notif.base.fn = spwr_notify_ac;184 ac->notif.event.reg = registry;185 ac->notif.event.id.target_category = sdev->uid.category;186 ac->notif.event.id.instance = 0;187 ac->notif.event.mask = SSAM_EVENT_MASK_NONE;188 ac->notif.event.flags = SSAM_EVENT_SEQUENCED;189 190 ac->psy_desc.name = ac->name;191 ac->psy_desc.type = POWER_SUPPLY_TYPE_MAINS;192 ac->psy_desc.properties = spwr_ac_props;193 ac->psy_desc.num_properties = ARRAY_SIZE(spwr_ac_props);194 ac->psy_desc.get_property = spwr_ac_get_property;195}196 197static int spwr_ac_register(struct spwr_ac_device *ac)198{199 struct power_supply_config psy_cfg = {};200 __le32 sta;201 int status;202 203 /* Make sure the device is there and functioning properly. */204 status = ssam_retry(ssam_bat_get_sta, ac->sdev, &sta);205 if (status)206 return status;207 208 if ((le32_to_cpu(sta) & SAM_BATTERY_STA_OK) != SAM_BATTERY_STA_OK)209 return -ENODEV;210 211 psy_cfg.drv_data = ac;212 psy_cfg.supplied_to = battery_supplied_to;213 psy_cfg.num_supplicants = ARRAY_SIZE(battery_supplied_to);214 215 ac->psy = devm_power_supply_register(&ac->sdev->dev, &ac->psy_desc, &psy_cfg);216 if (IS_ERR(ac->psy))217 return PTR_ERR(ac->psy);218 219 return ssam_device_notifier_register(ac->sdev, &ac->notif);220}221 222 223/* -- Driver setup. --------------------------------------------------------- */224 225static int __maybe_unused surface_ac_resume(struct device *dev)226{227 return spwr_ac_recheck(dev_get_drvdata(dev));228}229static SIMPLE_DEV_PM_OPS(surface_ac_pm_ops, NULL, surface_ac_resume);230 231static int surface_ac_probe(struct ssam_device *sdev)232{233 const struct spwr_psy_properties *p;234 struct spwr_ac_device *ac;235 236 p = ssam_device_get_match_data(sdev);237 if (!p)238 return -ENODEV;239 240 ac = devm_kzalloc(&sdev->dev, sizeof(*ac), GFP_KERNEL);241 if (!ac)242 return -ENOMEM;243 244 spwr_ac_init(ac, sdev, p->registry, p->name);245 ssam_device_set_drvdata(sdev, ac);246 247 return spwr_ac_register(ac);248}249 250static void surface_ac_remove(struct ssam_device *sdev)251{252 struct spwr_ac_device *ac = ssam_device_get_drvdata(sdev);253 254 ssam_device_notifier_unregister(sdev, &ac->notif);255}256 257static const struct spwr_psy_properties spwr_psy_props_adp1 = {258 .name = "ADP1",259 .registry = SSAM_EVENT_REGISTRY_SAM,260};261 262static const struct ssam_device_id surface_ac_match[] = {263 { SSAM_SDEV(BAT, SAM, 0x01, 0x01), (unsigned long)&spwr_psy_props_adp1 },264 { },265};266MODULE_DEVICE_TABLE(ssam, surface_ac_match);267 268static struct ssam_device_driver surface_ac_driver = {269 .probe = surface_ac_probe,270 .remove = surface_ac_remove,271 .match_table = surface_ac_match,272 .driver = {273 .name = "surface_ac",274 .pm = &surface_ac_pm_ops,275 .probe_type = PROBE_PREFER_ASYNCHRONOUS,276 },277};278module_ssam_device_driver(surface_ac_driver);279 280MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");281MODULE_DESCRIPTION("AC driver for Surface System Aggregator Module");282MODULE_LICENSE("GPL");283