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
 18static BLOCKING_NOTIFIER_HEAD(cros_usbpd_notifier_list);
 19
 20struct 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 */
 36int cros_usbpd_register_notify(struct notifier_block *nb)
 37{
 38	return blocking_notifier_chain_register(&cros_usbpd_notifier_list,
 39						nb);
 40}
 41EXPORT_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 */
 50void cros_usbpd_unregister_notify(struct notifier_block *nb)
 51{
 52	blocking_notifier_chain_unregister(&cros_usbpd_notifier_list, nb);
 53}
 54EXPORT_SYMBOL_GPL(cros_usbpd_unregister_notify);
 55
 56static 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
 83send_notify:
 84	blocking_notifier_call_chain(&cros_usbpd_notifier_list, event, NULL);
 85}
 86
 87#ifdef CONFIG_ACPI
 88
 89static 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
 96static 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
137static 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
148static const struct acpi_device_id cros_usbpd_notify_acpi_device_ids[] = {
149	{ ACPI_DRV_NAME, 0 },
150	{ }
151};
152MODULE_DEVICE_TABLE(acpi, cros_usbpd_notify_acpi_device_ids);
153
154static 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
165static 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
185static 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
212static 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
225static 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
233static 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
251static 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
259module_init(cros_usbpd_notify_init);
260module_exit(cros_usbpd_notify_exit);
261
262MODULE_LICENSE("GPL");
263MODULE_DESCRIPTION("ChromeOS power delivery notifier device");
264MODULE_AUTHOR("Jon Flatley <jflat@chromium.org>");
265MODULE_ALIAS("platform:" DRV_NAME);