1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2020 Google LLC
4 *
5 * This driver serves as the receiver of cros_ec PD host events.
6 */
7
8 #include <linux/acpi.h>
9 #include <linux/module.h>
10 #include <linux/platform_data/cros_ec_proto.h>
11 #include <linux/platform_data/cros_usbpd_notify.h>
12 #include <linux/platform_device.h>
13
14 #define DRV_NAME "cros-usbpd-notify"
15 #define DRV_NAME_PLAT_ACPI "cros-usbpd-notify-acpi"
16 #define ACPI_DRV_NAME "GOOG0003"
17
18 static BLOCKING_NOTIFIER_HEAD(cros_usbpd_notifier_list);
19
20 struct cros_usbpd_notify_data {
21 struct device *dev;
22 struct cros_ec_device *ec;
23 struct notifier_block nb;
24 };
25
26 /**
27 * cros_usbpd_register_notify - Register a notifier callback for PD events.
28 * @nb: Notifier block pointer to register
29 *
30 * On ACPI platforms this corresponds to host events on the ECPD
31 * "GOOG0003" ACPI device. On non-ACPI platforms this will filter mkbp events
32 * for USB PD events.
33 *
34 * Return: 0 on success or negative error code.
35 */
cros_usbpd_register_notify(struct notifier_block * nb)36 int cros_usbpd_register_notify(struct notifier_block *nb)
37 {
38 return blocking_notifier_chain_register(&cros_usbpd_notifier_list,
39 nb);
40 }
41 EXPORT_SYMBOL_GPL(cros_usbpd_register_notify);
42
43 /**
44 * cros_usbpd_unregister_notify - Unregister notifier callback for PD events.
45 * @nb: Notifier block pointer to unregister
46 *
47 * Unregister a notifier callback that was previously registered with
48 * cros_usbpd_register_notify().
49 */
cros_usbpd_unregister_notify(struct notifier_block * nb)50 void cros_usbpd_unregister_notify(struct notifier_block *nb)
51 {
52 blocking_notifier_chain_unregister(&cros_usbpd_notifier_list, nb);
53 }
54 EXPORT_SYMBOL_GPL(cros_usbpd_unregister_notify);
55
cros_usbpd_get_event_and_notify(struct device * dev,struct cros_ec_device * ec_dev)56 static void cros_usbpd_get_event_and_notify(struct device *dev,
57 struct cros_ec_device *ec_dev)
58 {
59 struct ec_response_host_event_status host_event_status;
60 u32 event = 0;
61 int ret;
62
63 /*
64 * We still send a 0 event out to older devices which don't
65 * have the updated device heirarchy.
66 */
67 if (!ec_dev) {
68 dev_dbg(dev,
69 "EC device inaccessible; sending 0 event status.\n");
70 goto send_notify;
71 }
72
73 /* Check for PD host events on EC. */
74 ret = cros_ec_cmd(ec_dev, 0, EC_CMD_PD_HOST_EVENT_STATUS,
75 NULL, 0, &host_event_status, sizeof(host_event_status));
76 if (ret < 0) {
77 dev_warn(dev, "Can't get host event status (err: %d)\n", ret);
78 goto send_notify;
79 }
80
81 event = host_event_status.status;
82
83 send_notify:
84 blocking_notifier_call_chain(&cros_usbpd_notifier_list, event, NULL);
85 }
86
87 #ifdef CONFIG_ACPI
88
cros_usbpd_notify_acpi(acpi_handle device,u32 event,void * data)89 static void cros_usbpd_notify_acpi(acpi_handle device, u32 event, void *data)
90 {
91 struct cros_usbpd_notify_data *pdnotify = data;
92
93 cros_usbpd_get_event_and_notify(pdnotify->dev, pdnotify->ec);
94 }
95
cros_usbpd_notify_probe_acpi(struct platform_device * pdev)96 static int cros_usbpd_notify_probe_acpi(struct platform_device *pdev)
97 {
98 struct cros_usbpd_notify_data *pdnotify;
99 struct device *dev = &pdev->dev;
100 struct acpi_device *adev;
101 struct cros_ec_device *ec_dev;
102 acpi_status status;
103
104 adev = ACPI_COMPANION(dev);
105
106 pdnotify = devm_kzalloc(dev, sizeof(*pdnotify), GFP_KERNEL);
107 if (!pdnotify)
108 return -ENOMEM;
109
110 /* Get the EC device pointer needed to talk to the EC. */
111 ec_dev = dev_get_drvdata(dev->parent);
112 if (!ec_dev) {
113 /*
114 * We continue even for older devices which don't have the
115 * correct device heirarchy, namely, GOOG0003 is a child
116 * of GOOG0004.
117 */
118 dev_warn(dev, "Couldn't get Chrome EC device pointer.\n");
119 }
120
121 pdnotify->dev = dev;
122 pdnotify->ec = ec_dev;
123
124 status = acpi_install_notify_handler(adev->handle,
125 ACPI_ALL_NOTIFY,
126 cros_usbpd_notify_acpi,
127 pdnotify);
128 if (ACPI_FAILURE(status)) {
129 dev_warn(dev, "Failed to register notify handler %08x\n",
130 status);
131 return -EINVAL;
132 }
133
134 return 0;
135 }
136
cros_usbpd_notify_remove_acpi(struct platform_device * pdev)137 static int cros_usbpd_notify_remove_acpi(struct platform_device *pdev)
138 {
139 struct device *dev = &pdev->dev;
140 struct acpi_device *adev = ACPI_COMPANION(dev);
141
142 acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
143 cros_usbpd_notify_acpi);
144
145 return 0;
146 }
147
148 static const struct acpi_device_id cros_usbpd_notify_acpi_device_ids[] = {
149 { ACPI_DRV_NAME, 0 },
150 { }
151 };
152 MODULE_DEVICE_TABLE(acpi, cros_usbpd_notify_acpi_device_ids);
153
154 static struct platform_driver cros_usbpd_notify_acpi_driver = {
155 .driver = {
156 .name = DRV_NAME_PLAT_ACPI,
157 .acpi_match_table = cros_usbpd_notify_acpi_device_ids,
158 },
159 .probe = cros_usbpd_notify_probe_acpi,
160 .remove = cros_usbpd_notify_remove_acpi,
161 };
162
163 #endif /* CONFIG_ACPI */
164
cros_usbpd_notify_plat(struct notifier_block * nb,unsigned long queued_during_suspend,void * data)165 static int cros_usbpd_notify_plat(struct notifier_block *nb,
166 unsigned long queued_during_suspend,
167 void *data)
168 {
169 struct cros_usbpd_notify_data *pdnotify = container_of(nb,
170 struct cros_usbpd_notify_data, nb);
171 struct cros_ec_device *ec_dev = (struct cros_ec_device *)data;
172 u32 host_event = cros_ec_get_host_event(ec_dev);
173
174 if (!host_event)
175 return NOTIFY_DONE;
176
177 if (host_event & (EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU) |
178 EC_HOST_EVENT_MASK(EC_HOST_EVENT_USB_MUX))) {
179 cros_usbpd_get_event_and_notify(pdnotify->dev, ec_dev);
180 return NOTIFY_OK;
181 }
182 return NOTIFY_DONE;
183 }
184
cros_usbpd_notify_probe_plat(struct platform_device * pdev)185 static int cros_usbpd_notify_probe_plat(struct platform_device *pdev)
186 {
187 struct device *dev = &pdev->dev;
188 struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
189 struct cros_usbpd_notify_data *pdnotify;
190 int ret;
191
192 pdnotify = devm_kzalloc(dev, sizeof(*pdnotify), GFP_KERNEL);
193 if (!pdnotify)
194 return -ENOMEM;
195
196 pdnotify->dev = dev;
197 pdnotify->ec = ecdev->ec_dev;
198 pdnotify->nb.notifier_call = cros_usbpd_notify_plat;
199
200 dev_set_drvdata(dev, pdnotify);
201
202 ret = blocking_notifier_chain_register(&ecdev->ec_dev->event_notifier,
203 &pdnotify->nb);
204 if (ret < 0) {
205 dev_err(dev, "Failed to register notifier\n");
206 return ret;
207 }
208
209 return 0;
210 }
211
cros_usbpd_notify_remove_plat(struct platform_device * pdev)212 static int cros_usbpd_notify_remove_plat(struct platform_device *pdev)
213 {
214 struct device *dev = &pdev->dev;
215 struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
216 struct cros_usbpd_notify_data *pdnotify =
217 (struct cros_usbpd_notify_data *)dev_get_drvdata(dev);
218
219 blocking_notifier_chain_unregister(&ecdev->ec_dev->event_notifier,
220 &pdnotify->nb);
221
222 return 0;
223 }
224
225 static struct platform_driver cros_usbpd_notify_plat_driver = {
226 .driver = {
227 .name = DRV_NAME,
228 },
229 .probe = cros_usbpd_notify_probe_plat,
230 .remove = cros_usbpd_notify_remove_plat,
231 };
232
cros_usbpd_notify_init(void)233 static int __init cros_usbpd_notify_init(void)
234 {
235 int ret;
236
237 ret = platform_driver_register(&cros_usbpd_notify_plat_driver);
238 if (ret < 0)
239 return ret;
240
241 #ifdef CONFIG_ACPI
242 ret = platform_driver_register(&cros_usbpd_notify_acpi_driver);
243 if (ret) {
244 platform_driver_unregister(&cros_usbpd_notify_plat_driver);
245 return ret;
246 }
247 #endif
248 return 0;
249 }
250
cros_usbpd_notify_exit(void)251 static void __exit cros_usbpd_notify_exit(void)
252 {
253 #ifdef CONFIG_ACPI
254 platform_driver_unregister(&cros_usbpd_notify_acpi_driver);
255 #endif
256 platform_driver_unregister(&cros_usbpd_notify_plat_driver);
257 }
258
259 module_init(cros_usbpd_notify_init);
260 module_exit(cros_usbpd_notify_exit);
261
262 MODULE_LICENSE("GPL");
263 MODULE_DESCRIPTION("ChromeOS power delivery notifier device");
264 MODULE_AUTHOR("Jon Flatley <jflat@chromium.org>");
265 MODULE_ALIAS("platform:" DRV_NAME);
266