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/interrupt.h>
 21#include <linux/slab.h>
 22#include <linux/module.h>
 23#include <linux/mfd/core.h>
 24#include <linux/mfd/cros_ec.h>
 25#include <linux/mfd/cros_ec_commands.h>
 26
 27int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
 28		       struct cros_ec_msg *msg)
 29{
 30	uint8_t *out;
 31	int csum, i;
 32
 33	BUG_ON(msg->out_len > EC_HOST_PARAM_SIZE);
 34	out = ec_dev->dout;
 35	out[0] = EC_CMD_VERSION0 + msg->version;
 36	out[1] = msg->cmd;
 37	out[2] = msg->out_len;
 38	csum = out[0] + out[1] + out[2];
 39	for (i = 0; i < msg->out_len; i++)
 40		csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->out_buf[i];
 41	out[EC_MSG_TX_HEADER_BYTES + msg->out_len] = (uint8_t)(csum & 0xff);
 42
 43	return EC_MSG_TX_PROTO_BYTES + msg->out_len;
 44}
 45EXPORT_SYMBOL(cros_ec_prepare_tx);
 46
 47static int cros_ec_command_sendrecv(struct cros_ec_device *ec_dev,
 48		uint16_t cmd, void *out_buf, int out_len,
 49		void *in_buf, int in_len)
 50{
 51	struct cros_ec_msg msg;
 52
 53	msg.version = cmd >> 8;
 54	msg.cmd = cmd & 0xff;
 55	msg.out_buf = out_buf;
 56	msg.out_len = out_len;
 57	msg.in_buf = in_buf;
 58	msg.in_len = in_len;
 59
 60	return ec_dev->command_xfer(ec_dev, &msg);
 61}
 62
 63static int cros_ec_command_recv(struct cros_ec_device *ec_dev,
 64		uint16_t cmd, void *buf, int buf_len)
 65{
 66	return cros_ec_command_sendrecv(ec_dev, cmd, NULL, 0, buf, buf_len);
 67}
 68
 69static int cros_ec_command_send(struct cros_ec_device *ec_dev,
 70		uint16_t cmd, void *buf, int buf_len)
 71{
 72	return cros_ec_command_sendrecv(ec_dev, cmd, buf, buf_len, NULL, 0);
 73}
 74
 75static irqreturn_t ec_irq_thread(int irq, void *data)
 76{
 77	struct cros_ec_device *ec_dev = data;
 78
 79	if (device_may_wakeup(ec_dev->dev))
 80		pm_wakeup_event(ec_dev->dev, 0);
 81
 82	blocking_notifier_call_chain(&ec_dev->event_notifier, 1, ec_dev);
 83
 84	return IRQ_HANDLED;
 85}
 86
 87static const struct mfd_cell cros_devs[] = {
 88	{
 89		.name = "cros-ec-keyb",
 90		.id = 1,
 91		.of_compatible = "google,cros-ec-keyb",
 92	},
 93};
 94
 95int cros_ec_register(struct cros_ec_device *ec_dev)
 96{
 97	struct device *dev = ec_dev->dev;
 98	int err = 0;
 99
100	BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
101
102	ec_dev->command_send = cros_ec_command_send;
103	ec_dev->command_recv = cros_ec_command_recv;
104	ec_dev->command_sendrecv = cros_ec_command_sendrecv;
105
106	if (ec_dev->din_size) {
107		ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
108		if (!ec_dev->din)
109			return -ENOMEM;
110	}
111	if (ec_dev->dout_size) {
112		ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
113		if (!ec_dev->dout)
114			return -ENOMEM;
115	}
116
117	if (!ec_dev->irq) {
118		dev_dbg(dev, "no valid IRQ: %d\n", ec_dev->irq);
119		return err;
120	}
121
122	err = request_threaded_irq(ec_dev->irq, NULL, ec_irq_thread,
123				   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
124				   "chromeos-ec", ec_dev);
125	if (err) {
126		dev_err(dev, "request irq %d: error %d\n", ec_dev->irq, err);
127		return err;
128	}
129
130	err = mfd_add_devices(dev, 0, cros_devs,
131			      ARRAY_SIZE(cros_devs),
132			      NULL, ec_dev->irq, NULL);
133	if (err) {
134		dev_err(dev, "failed to add mfd devices\n");
135		goto fail_mfd;
136	}
137
138	dev_info(dev, "Chrome EC (%s)\n", ec_dev->name);
139
140	return 0;
141
142fail_mfd:
143	free_irq(ec_dev->irq, ec_dev);
144
145	return err;
146}
147EXPORT_SYMBOL(cros_ec_register);
148
149int cros_ec_remove(struct cros_ec_device *ec_dev)
150{
151	mfd_remove_devices(ec_dev->dev);
152	free_irq(ec_dev->irq, ec_dev);
153
154	return 0;
155}
156EXPORT_SYMBOL(cros_ec_remove);
157
158#ifdef CONFIG_PM_SLEEP
159int cros_ec_suspend(struct cros_ec_device *ec_dev)
160{
161	struct device *dev = ec_dev->dev;
162
163	if (device_may_wakeup(dev))
164		ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
165
166	disable_irq(ec_dev->irq);
167	ec_dev->was_wake_device = ec_dev->wake_enabled;
168
169	return 0;
170}
171EXPORT_SYMBOL(cros_ec_suspend);
172
173int cros_ec_resume(struct cros_ec_device *ec_dev)
174{
175	enable_irq(ec_dev->irq);
176
177	if (ec_dev->wake_enabled) {
178		disable_irq_wake(ec_dev->irq);
179		ec_dev->wake_enabled = 0;
180	}
181
182	return 0;
183}
184EXPORT_SYMBOL(cros_ec_resume);
185
186#endif