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  */
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  */
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 
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_command(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 
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 
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 
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 
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 
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 
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 
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 	platform_driver_register(&cros_usbpd_notify_acpi_driver);
243 #endif
244 	return 0;
245 }
246 
247 static void __exit cros_usbpd_notify_exit(void)
248 {
249 #ifdef CONFIG_ACPI
250 	platform_driver_unregister(&cros_usbpd_notify_acpi_driver);
251 #endif
252 	platform_driver_unregister(&cros_usbpd_notify_plat_driver);
253 }
254 
255 module_init(cros_usbpd_notify_init);
256 module_exit(cros_usbpd_notify_exit);
257 
258 MODULE_LICENSE("GPL");
259 MODULE_DESCRIPTION("ChromeOS power delivery notifier device");
260 MODULE_AUTHOR("Jon Flatley <jflat@chromium.org>");
261 MODULE_ALIAS("platform:" DRV_NAME);
262