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/fwnode.h>
10#include <linux/mod_devicetable.h>
11#include <linux/module.h>
12#include <linux/platform_data/cros_ec_proto.h>
13#include <linux/platform_data/cros_usbpd_notify.h>
14#include <linux/platform_device.h>
15
16#define DRV_NAME "cros-usbpd-notify"
17#define DRV_NAME_PLAT_ACPI "cros-usbpd-notify-acpi"
18#define ACPI_DRV_NAME "GOOG0003"
19#define CREC_DRV_NAME "GOOG0004"
20
21static BLOCKING_NOTIFIER_HEAD(cros_usbpd_notifier_list);
22
23struct cros_usbpd_notify_data {
24 struct device *dev;
25 struct cros_ec_device *ec;
26 struct notifier_block nb;
27};
28
29/**
30 * cros_usbpd_register_notify - Register a notifier callback for PD events.
31 * @nb: Notifier block pointer to register
32 *
33 * On ACPI platforms this corresponds to host events on the ECPD
34 * "GOOG0003" ACPI device. On non-ACPI platforms this will filter mkbp events
35 * for USB PD events.
36 *
37 * Return: 0 on success or negative error code.
38 */
39int cros_usbpd_register_notify(struct notifier_block *nb)
40{
41 return blocking_notifier_chain_register(nh: &cros_usbpd_notifier_list,
42 nb);
43}
44EXPORT_SYMBOL_GPL(cros_usbpd_register_notify);
45
46/**
47 * cros_usbpd_unregister_notify - Unregister notifier callback for PD events.
48 * @nb: Notifier block pointer to unregister
49 *
50 * Unregister a notifier callback that was previously registered with
51 * cros_usbpd_register_notify().
52 */
53void cros_usbpd_unregister_notify(struct notifier_block *nb)
54{
55 blocking_notifier_chain_unregister(nh: &cros_usbpd_notifier_list, nb);
56}
57EXPORT_SYMBOL_GPL(cros_usbpd_unregister_notify);
58
59static void cros_usbpd_get_event_and_notify(struct device *dev,
60 struct cros_ec_device *ec_dev)
61{
62 struct ec_response_host_event_status host_event_status;
63 u32 event = 0;
64 int ret;
65
66 /*
67 * We still send a 0 event out to older devices which don't
68 * have the updated device heirarchy.
69 */
70 if (!ec_dev) {
71 dev_dbg(dev,
72 "EC device inaccessible; sending 0 event status.\n");
73 goto send_notify;
74 }
75
76 /* Check for PD host events on EC. */
77 ret = cros_ec_cmd(ec_dev, version: 0, EC_CMD_PD_HOST_EVENT_STATUS,
78 NULL, outsize: 0, indata: &host_event_status, insize: sizeof(host_event_status));
79 if (ret < 0) {
80 dev_warn(dev, "Can't get host event status (err: %d)\n", ret);
81 goto send_notify;
82 }
83
84 event = host_event_status.status;
85
86send_notify:
87 blocking_notifier_call_chain(nh: &cros_usbpd_notifier_list, val: event, NULL);
88}
89
90#ifdef CONFIG_ACPI
91
92static void cros_usbpd_notify_acpi(acpi_handle device, u32 event, void *data)
93{
94 struct cros_usbpd_notify_data *pdnotify = data;
95
96 cros_usbpd_get_event_and_notify(dev: pdnotify->dev, ec_dev: pdnotify->ec);
97}
98
99static int cros_usbpd_notify_probe_acpi(struct platform_device *pdev)
100{
101 struct cros_usbpd_notify_data *pdnotify;
102 struct device *dev = &pdev->dev;
103 struct acpi_device *adev, *parent_adev;
104 struct cros_ec_device *ec_dev;
105 struct fwnode_handle *parent_fwnode;
106 acpi_status status;
107
108 adev = ACPI_COMPANION(dev);
109
110 pdnotify = devm_kzalloc(dev, size: sizeof(*pdnotify), GFP_KERNEL);
111 if (!pdnotify)
112 return -ENOMEM;
113
114 /* Get the EC device pointer needed to talk to the EC. */
115 ec_dev = dev_get_drvdata(dev: dev->parent);
116 if (!ec_dev) {
117 /*
118 * We continue even for older devices which don't have the
119 * correct device heirarchy, namely, GOOG0003 is a child
120 * of GOOG0004. If GOOG0003 is a child of GOOG0004 and we
121 * can't get a pointer to the Chrome EC device, defer the
122 * probe function.
123 */
124 parent_fwnode = fwnode_get_parent(fwnode: dev->fwnode);
125 if (parent_fwnode) {
126 parent_adev = to_acpi_device_node(parent_fwnode);
127 if (parent_adev &&
128 acpi_dev_hid_match(adev: parent_adev, CREC_DRV_NAME)) {
129 return -EPROBE_DEFER;
130 }
131 }
132 dev_warn(dev, "Couldn't get Chrome EC device pointer.\n");
133 }
134
135 pdnotify->dev = dev;
136 pdnotify->ec = ec_dev;
137
138 status = acpi_install_notify_handler(device: adev->handle,
139 ACPI_ALL_NOTIFY,
140 handler: cros_usbpd_notify_acpi,
141 context: pdnotify);
142 if (ACPI_FAILURE(status)) {
143 dev_warn(dev, "Failed to register notify handler %08x\n",
144 status);
145 return -EINVAL;
146 }
147
148 return 0;
149}
150
151static void cros_usbpd_notify_remove_acpi(struct platform_device *pdev)
152{
153 struct device *dev = &pdev->dev;
154 struct acpi_device *adev = ACPI_COMPANION(dev);
155
156 acpi_remove_notify_handler(device: adev->handle, ACPI_ALL_NOTIFY,
157 handler: cros_usbpd_notify_acpi);
158}
159
160static const struct acpi_device_id cros_usbpd_notify_acpi_device_ids[] = {
161 { ACPI_DRV_NAME, 0 },
162 { }
163};
164MODULE_DEVICE_TABLE(acpi, cros_usbpd_notify_acpi_device_ids);
165
166static struct platform_driver cros_usbpd_notify_acpi_driver = {
167 .driver = {
168 .name = DRV_NAME_PLAT_ACPI,
169 .acpi_match_table = cros_usbpd_notify_acpi_device_ids,
170 },
171 .probe = cros_usbpd_notify_probe_acpi,
172 .remove = cros_usbpd_notify_remove_acpi,
173};
174
175#endif /* CONFIG_ACPI */
176
177static int cros_usbpd_notify_plat(struct notifier_block *nb,
178 unsigned long queued_during_suspend,
179 void *data)
180{
181 struct cros_usbpd_notify_data *pdnotify = container_of(nb,
182 struct cros_usbpd_notify_data, nb);
183 struct cros_ec_device *ec_dev = (struct cros_ec_device *)data;
184 u32 host_event = cros_ec_get_host_event(ec_dev);
185
186 if (!host_event)
187 return NOTIFY_DONE;
188
189 if (host_event & (EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU) |
190 EC_HOST_EVENT_MASK(EC_HOST_EVENT_USB_MUX))) {
191 cros_usbpd_get_event_and_notify(dev: pdnotify->dev, ec_dev);
192 return NOTIFY_OK;
193 }
194 return NOTIFY_DONE;
195}
196
197static int cros_usbpd_notify_probe_plat(struct platform_device *pdev)
198{
199 struct device *dev = &pdev->dev;
200 struct cros_ec_dev *ecdev = dev_get_drvdata(dev: dev->parent);
201 struct cros_usbpd_notify_data *pdnotify;
202 int ret;
203
204 pdnotify = devm_kzalloc(dev, size: sizeof(*pdnotify), GFP_KERNEL);
205 if (!pdnotify)
206 return -ENOMEM;
207
208 pdnotify->dev = dev;
209 pdnotify->ec = ecdev->ec_dev;
210 pdnotify->nb.notifier_call = cros_usbpd_notify_plat;
211
212 dev_set_drvdata(dev, data: pdnotify);
213
214 ret = blocking_notifier_chain_register(nh: &ecdev->ec_dev->event_notifier,
215 nb: &pdnotify->nb);
216 if (ret < 0) {
217 dev_err(dev, "Failed to register notifier\n");
218 return ret;
219 }
220
221 return 0;
222}
223
224static void cros_usbpd_notify_remove_plat(struct platform_device *pdev)
225{
226 struct device *dev = &pdev->dev;
227 struct cros_ec_dev *ecdev = dev_get_drvdata(dev: dev->parent);
228 struct cros_usbpd_notify_data *pdnotify =
229 (struct cros_usbpd_notify_data *)dev_get_drvdata(dev);
230
231 blocking_notifier_chain_unregister(nh: &ecdev->ec_dev->event_notifier,
232 nb: &pdnotify->nb);
233}
234
235static const struct platform_device_id cros_usbpd_notify_id[] = {
236 { DRV_NAME, 0 },
237 {}
238};
239MODULE_DEVICE_TABLE(platform, cros_usbpd_notify_id);
240
241static struct platform_driver cros_usbpd_notify_plat_driver = {
242 .driver = {
243 .name = DRV_NAME,
244 },
245 .probe = cros_usbpd_notify_probe_plat,
246 .remove = cros_usbpd_notify_remove_plat,
247 .id_table = cros_usbpd_notify_id,
248};
249
250static int __init cros_usbpd_notify_init(void)
251{
252 int ret;
253
254 ret = platform_driver_register(&cros_usbpd_notify_plat_driver);
255 if (ret < 0)
256 return ret;
257
258#ifdef CONFIG_ACPI
259 ret = platform_driver_register(&cros_usbpd_notify_acpi_driver);
260 if (ret) {
261 platform_driver_unregister(&cros_usbpd_notify_plat_driver);
262 return ret;
263 }
264#endif
265 return 0;
266}
267
268static void __exit cros_usbpd_notify_exit(void)
269{
270#ifdef CONFIG_ACPI
271 platform_driver_unregister(&cros_usbpd_notify_acpi_driver);
272#endif
273 platform_driver_unregister(&cros_usbpd_notify_plat_driver);
274}
275
276module_init(cros_usbpd_notify_init);
277module_exit(cros_usbpd_notify_exit);
278
279MODULE_LICENSE("GPL");
280MODULE_DESCRIPTION("ChromeOS power delivery notifier device");
281MODULE_AUTHOR("Jon Flatley <jflat@chromium.org>");
282

source code of linux/drivers/platform/chrome/cros_usbpd_notify.c