1/*
  2 * ChromeOS EC multi-function device
  3 *
  4 * Copyright (C) 2012 Google, Inc
  5 *
  6 * This software is licensed under the terms of the GNU General Public
  7 * License version 2, as published by the Free Software Foundation, and
  8 * may be copied, distributed, and modified under those terms.
  9 *
 10 * This program is distributed in the hope that it will be useful,
 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13 * GNU General Public License for more details.
 14 *
 15 * The ChromeOS EC multi function device is used to mux all the requests
 16 * to the EC device for its multiple features: keyboard controller,
 17 * battery charging and regulator control, firmware update.
 18 */
 19
 20#include <linux/of_platform.h>
 21#include <linux/interrupt.h>
 22#include <linux/slab.h>
 23#include <linux/module.h>
 24#include <linux/mfd/core.h>
 25#include <linux/mfd/cros_ec.h>
 26#include <linux/suspend.h>
 27#include <asm/unaligned.h>
 28
 29#define CROS_EC_DEV_EC_INDEX 0
 30#define CROS_EC_DEV_PD_INDEX 1
 31
 32static struct cros_ec_platform ec_p = {
 33	.ec_name = CROS_EC_DEV_NAME,
 34	.cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
 35};
 36
 37static struct cros_ec_platform pd_p = {
 38	.ec_name = CROS_EC_DEV_PD_NAME,
 39	.cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
 40};
 41
 42static const struct mfd_cell ec_cell = {
 43	.name = "cros-ec-dev",
 44	.platform_data = &ec_p,
 45	.pdata_size = sizeof(ec_p),
 46};
 47
 48static const struct mfd_cell ec_pd_cell = {
 49	.name = "cros-ec-dev",
 50	.platform_data = &pd_p,
 51	.pdata_size = sizeof(pd_p),
 52};
 53
 54static irqreturn_t ec_irq_thread(int irq, void *data)
 55{
 56	struct cros_ec_device *ec_dev = data;
 57	bool wake_event = true;
 58	int ret;
 59
 60	ret = cros_ec_get_next_event(ec_dev, &wake_event);
 61
 62	/*
 63	 * Signal only if wake host events or any interrupt if
 64	 * cros_ec_get_next_event() returned an error (default value for
 65	 * wake_event is true)
 66	 */
 67	if (wake_event && device_may_wakeup(ec_dev->dev))
 68		pm_wakeup_event(ec_dev->dev, 0);
 69
 70	if (ret > 0)
 71		blocking_notifier_call_chain(&ec_dev->event_notifier,
 72					     0, ec_dev);
 73	return IRQ_HANDLED;
 74}
 75
 76static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
 77{
 78	struct {
 79		struct cros_ec_command msg;
 80		struct ec_params_host_sleep_event req;
 81	} __packed buf;
 82
 83	memset(&buf, 0, sizeof(buf));
 84
 85	buf.req.sleep_event = sleep_event;
 86
 87	buf.msg.command = EC_CMD_HOST_SLEEP_EVENT;
 88	buf.msg.version = 0;
 89	buf.msg.outsize = sizeof(buf.req);
 90
 91	return cros_ec_cmd_xfer(ec_dev, &buf.msg);
 92}
 93
 94int cros_ec_register(struct cros_ec_device *ec_dev)
 95{
 96	struct device *dev = ec_dev->dev;
 97	int err = 0;
 98
 99	BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
100
101	ec_dev->max_request = sizeof(struct ec_params_hello);
102	ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
103	ec_dev->max_passthru = 0;
104
105	ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
106	if (!ec_dev->din)
107		return -ENOMEM;
108
109	ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
110	if (!ec_dev->dout)
111		return -ENOMEM;
112
113	mutex_init(&ec_dev->lock);
114
115	cros_ec_query_all(ec_dev);
116
117	if (ec_dev->irq) {
118		err = request_threaded_irq(ec_dev->irq, NULL, ec_irq_thread,
119					   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
120					   "chromeos-ec", ec_dev);
121		if (err) {
122			dev_err(dev, "Failed to request IRQ %d: %d",
123				ec_dev->irq, err);
124			return err;
125		}
126	}
127
128	err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell, 1,
129			      NULL, ec_dev->irq, NULL);
130	if (err) {
131		dev_err(dev,
132			"Failed to register Embedded Controller subdevice %d\n",
133			err);
134		goto fail_mfd;
135	}
136
137	if (ec_dev->max_passthru) {
138		/*
139		 * Register a PD device as well on top of this device.
140		 * We make the following assumptions:
141		 * - behind an EC, we have a pd
142		 * - only one device added.
143		 * - the EC is responsive at init time (it is not true for a
144		 *   sensor hub.
145		 */
146		err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
147				      &ec_pd_cell, 1, NULL, ec_dev->irq, NULL);
148		if (err) {
149			dev_err(dev,
150				"Failed to register Power Delivery subdevice %d\n",
151				err);
152			goto fail_mfd;
153		}
154	}
155
156	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
157		err = devm_of_platform_populate(dev);
158		if (err) {
159			mfd_remove_devices(dev);
160			dev_err(dev, "Failed to register sub-devices\n");
161			goto fail_mfd;
162		}
163	}
164
165	/*
166	 * Clear sleep event - this will fail harmlessly on platforms that
167	 * don't implement the sleep event host command.
168	 */
169	err = cros_ec_sleep_event(ec_dev, 0);
170	if (err < 0)
171		dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
172			err);
173
174	dev_info(dev, "Chrome EC device registered\n");
175
176	cros_ec_acpi_install_gpe_handler(dev);
177
178	return 0;
179
180fail_mfd:
181	if (ec_dev->irq)
182		free_irq(ec_dev->irq, ec_dev);
183	return err;
184}
185EXPORT_SYMBOL(cros_ec_register);
186
187int cros_ec_remove(struct cros_ec_device *ec_dev)
188{
189	mfd_remove_devices(ec_dev->dev);
190
191	cros_ec_acpi_remove_gpe_handler();
192
193	if (ec_dev->irq)
194		free_irq(ec_dev->irq, ec_dev);
195
196	return 0;
197}
198EXPORT_SYMBOL(cros_ec_remove);
199
200#ifdef CONFIG_PM_SLEEP
201int cros_ec_suspend(struct cros_ec_device *ec_dev)
202{
203	struct device *dev = ec_dev->dev;
204	int ret;
205	u8 sleep_event;
206
207	if (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) {
208		sleep_event = HOST_SLEEP_EVENT_S3_SUSPEND;
209	} else {
210		sleep_event = HOST_SLEEP_EVENT_S0IX_SUSPEND;
211
212		/* Clearing the GPE status for any pending event */
213		cros_ec_acpi_clear_gpe();
214	}
215
216	ret = cros_ec_sleep_event(ec_dev, sleep_event);
217	if (ret < 0)
218		dev_dbg(ec_dev->dev, "Error %d sending suspend event to ec",
219			ret);
220
221	if (device_may_wakeup(dev))
222		ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
223
224	disable_irq(ec_dev->irq);
225	ec_dev->was_wake_device = ec_dev->wake_enabled;
226	ec_dev->suspended = true;
227
228	return 0;
229}
230EXPORT_SYMBOL(cros_ec_suspend);
231
232static void cros_ec_drain_events(struct cros_ec_device *ec_dev)
233{
234	while (cros_ec_get_next_event(ec_dev, NULL) > 0)
235		blocking_notifier_call_chain(&ec_dev->event_notifier,
236					     1, ec_dev);
237}
238
239int cros_ec_resume(struct cros_ec_device *ec_dev)
240{
241	int ret;
242	u8 sleep_event;
243
244	ec_dev->suspended = false;
245	enable_irq(ec_dev->irq);
246
247	sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
248		      HOST_SLEEP_EVENT_S3_RESUME :
249		      HOST_SLEEP_EVENT_S0IX_RESUME;
250
251	ret = cros_ec_sleep_event(ec_dev, sleep_event);
252	if (ret < 0)
253		dev_dbg(ec_dev->dev, "Error %d sending resume event to ec",
254			ret);
255
256	/*
257	 * In some cases, we need to distinguish between events that occur
258	 * during suspend if the EC is not a wake source. For example,
259	 * keypresses during suspend should be discarded if it does not wake
260	 * the system.
261	 *
262	 * If the EC is not a wake source, drain the event queue and mark them
263	 * as "queued during suspend".
264	 */
265	if (ec_dev->wake_enabled) {
266		disable_irq_wake(ec_dev->irq);
267		ec_dev->wake_enabled = 0;
268	} else {
269		cros_ec_drain_events(ec_dev);
270	}
271
272	return 0;
273}
274EXPORT_SYMBOL(cros_ec_resume);
275
276#endif
277
278MODULE_LICENSE("GPL");
279MODULE_DESCRIPTION("ChromeOS EC core driver");