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/mod_devicetable.h>
10 #include <linux/module.h>
11 #include <linux/platform_data/cros_ec_proto.h>
12 #include <linux/platform_data/cros_usbpd_notify.h>
13 #include <linux/platform_device.h>
14
15 #define DRV_NAME "cros-usbpd-notify"
16 #define DRV_NAME_PLAT_ACPI "cros-usbpd-notify-acpi"
17 #define ACPI_DRV_NAME "GOOG0003"
18
19 static BLOCKING_NOTIFIER_HEAD(cros_usbpd_notifier_list);
20
21 struct cros_usbpd_notify_data {
22 struct device *dev;
23 struct cros_ec_device *ec;
24 struct notifier_block nb;
25 };
26
27 /**
28 * cros_usbpd_register_notify - Register a notifier callback for PD events.
29 * @nb: Notifier block pointer to register
30 *
31 * On ACPI platforms this corresponds to host events on the ECPD
32 * "GOOG0003" ACPI device. On non-ACPI platforms this will filter mkbp events
33 * for USB PD events.
34 *
35 * Return: 0 on success or negative error code.
36 */
cros_usbpd_register_notify(struct notifier_block * nb)37 int cros_usbpd_register_notify(struct notifier_block *nb)
38 {
39 return blocking_notifier_chain_register(&cros_usbpd_notifier_list,
40 nb);
41 }
42 EXPORT_SYMBOL_GPL(cros_usbpd_register_notify);
43
44 /**
45 * cros_usbpd_unregister_notify - Unregister notifier callback for PD events.
46 * @nb: Notifier block pointer to unregister
47 *
48 * Unregister a notifier callback that was previously registered with
49 * cros_usbpd_register_notify().
50 */
cros_usbpd_unregister_notify(struct notifier_block * nb)51 void cros_usbpd_unregister_notify(struct notifier_block *nb)
52 {
53 blocking_notifier_chain_unregister(&cros_usbpd_notifier_list, nb);
54 }
55 EXPORT_SYMBOL_GPL(cros_usbpd_unregister_notify);
56
cros_usbpd_get_event_and_notify(struct device * dev,struct cros_ec_device * ec_dev)57 static void cros_usbpd_get_event_and_notify(struct device *dev,
58 struct cros_ec_device *ec_dev)
59 {
60 struct ec_response_host_event_status host_event_status;
61 u32 event = 0;
62 int ret;
63
64 /*
65 * We still send a 0 event out to older devices which don't
66 * have the updated device heirarchy.
67 */
68 if (!ec_dev) {
69 dev_dbg(dev,
70 "EC device inaccessible; sending 0 event status.\n");
71 goto send_notify;
72 }
73
74 /* Check for PD host events on EC. */
75 ret = cros_ec_cmd(ec_dev, 0, EC_CMD_PD_HOST_EVENT_STATUS,
76 NULL, 0, &host_event_status, sizeof(host_event_status));
77 if (ret < 0) {
78 dev_warn(dev, "Can't get host event status (err: %d)\n", ret);
79 goto send_notify;
80 }
81
82 event = host_event_status.status;
83
84 send_notify:
85 blocking_notifier_call_chain(&cros_usbpd_notifier_list, event, NULL);
86 }
87
88 #ifdef CONFIG_ACPI
89
cros_usbpd_notify_acpi(acpi_handle device,u32 event,void * data)90 static void cros_usbpd_notify_acpi(acpi_handle device, u32 event, void *data)
91 {
92 struct cros_usbpd_notify_data *pdnotify = data;
93
94 cros_usbpd_get_event_and_notify(pdnotify->dev, pdnotify->ec);
95 }
96
cros_usbpd_notify_probe_acpi(struct platform_device * pdev)97 static int cros_usbpd_notify_probe_acpi(struct platform_device *pdev)
98 {
99 struct cros_usbpd_notify_data *pdnotify;
100 struct device *dev = &pdev->dev;
101 struct acpi_device *adev;
102 struct cros_ec_device *ec_dev;
103 acpi_status status;
104
105 adev = ACPI_COMPANION(dev);
106
107 pdnotify = devm_kzalloc(dev, sizeof(*pdnotify), GFP_KERNEL);
108 if (!pdnotify)
109 return -ENOMEM;
110
111 /* Get the EC device pointer needed to talk to the EC. */
112 ec_dev = dev_get_drvdata(dev->parent);
113 if (!ec_dev) {
114 /*
115 * We continue even for older devices which don't have the
116 * correct device heirarchy, namely, GOOG0003 is a child
117 * of GOOG0004.
118 */
119 dev_warn(dev, "Couldn't get Chrome EC device pointer.\n");
120 }
121
122 pdnotify->dev = dev;
123 pdnotify->ec = ec_dev;
124
125 status = acpi_install_notify_handler(adev->handle,
126 ACPI_ALL_NOTIFY,
127 cros_usbpd_notify_acpi,
128 pdnotify);
129 if (ACPI_FAILURE(status)) {
130 dev_warn(dev, "Failed to register notify handler %08x\n",
131 status);
132 return -EINVAL;
133 }
134
135 return 0;
136 }
137
cros_usbpd_notify_remove_acpi(struct platform_device * pdev)138 static void cros_usbpd_notify_remove_acpi(struct platform_device *pdev)
139 {
140 struct device *dev = &pdev->dev;
141 struct acpi_device *adev = ACPI_COMPANION(dev);
142
143 acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
144 cros_usbpd_notify_acpi);
145 }
146
147 static const struct acpi_device_id cros_usbpd_notify_acpi_device_ids[] = {
148 { ACPI_DRV_NAME, 0 },
149 { }
150 };
151 MODULE_DEVICE_TABLE(acpi, cros_usbpd_notify_acpi_device_ids);
152
153 static struct platform_driver cros_usbpd_notify_acpi_driver = {
154 .driver = {
155 .name = DRV_NAME_PLAT_ACPI,
156 .acpi_match_table = cros_usbpd_notify_acpi_device_ids,
157 },
158 .probe = cros_usbpd_notify_probe_acpi,
159 .remove_new = cros_usbpd_notify_remove_acpi,
160 };
161
162 #endif /* CONFIG_ACPI */
163
cros_usbpd_notify_plat(struct notifier_block * nb,unsigned long queued_during_suspend,void * data)164 static int cros_usbpd_notify_plat(struct notifier_block *nb,
165 unsigned long queued_during_suspend,
166 void *data)
167 {
168 struct cros_usbpd_notify_data *pdnotify = container_of(nb,
169 struct cros_usbpd_notify_data, nb);
170 struct cros_ec_device *ec_dev = (struct cros_ec_device *)data;
171 u32 host_event = cros_ec_get_host_event(ec_dev);
172
173 if (!host_event)
174 return NOTIFY_DONE;
175
176 if (host_event & (EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU) |
177 EC_HOST_EVENT_MASK(EC_HOST_EVENT_USB_MUX))) {
178 cros_usbpd_get_event_and_notify(pdnotify->dev, ec_dev);
179 return NOTIFY_OK;
180 }
181 return NOTIFY_DONE;
182 }
183
cros_usbpd_notify_probe_plat(struct platform_device * pdev)184 static int cros_usbpd_notify_probe_plat(struct platform_device *pdev)
185 {
186 struct device *dev = &pdev->dev;
187 struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
188 struct cros_usbpd_notify_data *pdnotify;
189 int ret;
190
191 pdnotify = devm_kzalloc(dev, sizeof(*pdnotify), GFP_KERNEL);
192 if (!pdnotify)
193 return -ENOMEM;
194
195 pdnotify->dev = dev;
196 pdnotify->ec = ecdev->ec_dev;
197 pdnotify->nb.notifier_call = cros_usbpd_notify_plat;
198
199 dev_set_drvdata(dev, pdnotify);
200
201 ret = blocking_notifier_chain_register(&ecdev->ec_dev->event_notifier,
202 &pdnotify->nb);
203 if (ret < 0) {
204 dev_err(dev, "Failed to register notifier\n");
205 return ret;
206 }
207
208 return 0;
209 }
210
cros_usbpd_notify_remove_plat(struct platform_device * pdev)211 static void cros_usbpd_notify_remove_plat(struct platform_device *pdev)
212 {
213 struct device *dev = &pdev->dev;
214 struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
215 struct cros_usbpd_notify_data *pdnotify =
216 (struct cros_usbpd_notify_data *)dev_get_drvdata(dev);
217
218 blocking_notifier_chain_unregister(&ecdev->ec_dev->event_notifier,
219 &pdnotify->nb);
220 }
221
222 static const struct platform_device_id cros_usbpd_notify_id[] = {
223 { DRV_NAME, 0 },
224 {}
225 };
226 MODULE_DEVICE_TABLE(platform, cros_usbpd_notify_id);
227
228 static struct platform_driver cros_usbpd_notify_plat_driver = {
229 .driver = {
230 .name = DRV_NAME,
231 },
232 .probe = cros_usbpd_notify_probe_plat,
233 .remove_new = cros_usbpd_notify_remove_plat,
234 .id_table = cros_usbpd_notify_id,
235 };
236
cros_usbpd_notify_init(void)237 static int __init cros_usbpd_notify_init(void)
238 {
239 int ret;
240
241 ret = platform_driver_register(&cros_usbpd_notify_plat_driver);
242 if (ret < 0)
243 return ret;
244
245 #ifdef CONFIG_ACPI
246 ret = platform_driver_register(&cros_usbpd_notify_acpi_driver);
247 if (ret) {
248 platform_driver_unregister(&cros_usbpd_notify_plat_driver);
249 return ret;
250 }
251 #endif
252 return 0;
253 }
254
cros_usbpd_notify_exit(void)255 static void __exit cros_usbpd_notify_exit(void)
256 {
257 #ifdef CONFIG_ACPI
258 platform_driver_unregister(&cros_usbpd_notify_acpi_driver);
259 #endif
260 platform_driver_unregister(&cros_usbpd_notify_plat_driver);
261 }
262
263 module_init(cros_usbpd_notify_init);
264 module_exit(cros_usbpd_notify_exit);
265
266 MODULE_LICENSE("GPL");
267 MODULE_DESCRIPTION("ChromeOS power delivery notifier device");
268 MODULE_AUTHOR("Jon Flatley <jflat@chromium.org>");
269