cros_usbpd_notify.c

  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(&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(&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, 0, EC_CMD_PD_HOST_EVENT_STATUS,
 78			  NULL, 0, &host_event_status, 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(&cros_usbpd_notifier_list, 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(pdnotify->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, 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->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(dev->fwnode);
125		if (parent_fwnode) {
126			parent_adev = to_acpi_device_node(parent_fwnode);
127			if (parent_adev &&
128			    acpi_dev_hid_match(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(adev->handle,
139					     ACPI_ALL_NOTIFY,
140					     cros_usbpd_notify_acpi,
141					     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(adev->handle, ACPI_ALL_NOTIFY,
157				   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(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->parent);
201	struct cros_usbpd_notify_data *pdnotify;
202	int ret;
203
204	pdnotify = devm_kzalloc(dev, 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, pdnotify);
213
214	ret = blocking_notifier_chain_register(&ecdev->ec_dev->event_notifier,
215					       &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->parent);
228	struct cros_usbpd_notify_data *pdnotify =
229		(struct cros_usbpd_notify_data *)dev_get_drvdata(dev);
230
231	blocking_notifier_chain_unregister(&ecdev->ec_dev->event_notifier,
232					   &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>");