tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#include <linux/delay.h>
27
28#define EC_COMMAND_RETRIES 50
29
30int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
31 struct cros_ec_command *msg)
32{
33 uint8_t *out;
34 int csum, i;
35
36 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
37 out = ec_dev->dout;
38 out[0] = EC_CMD_VERSION0 + msg->version;
39 out[1] = msg->command;
40 out[2] = msg->outsize;
41 csum = out[0] + out[1] + out[2];
42 for (i = 0; i < msg->outsize; i++)
43 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->outdata[i];
44 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = (uint8_t)(csum & 0xff);
45
46 return EC_MSG_TX_PROTO_BYTES + msg->outsize;
47}
48EXPORT_SYMBOL(cros_ec_prepare_tx);
49
50int cros_ec_check_result(struct cros_ec_device *ec_dev,
51 struct cros_ec_command *msg)
52{
53 switch (msg->result) {
54 case EC_RES_SUCCESS:
55 return 0;
56 case EC_RES_IN_PROGRESS:
57 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
58 msg->command);
59 return -EAGAIN;
60 default:
61 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
62 msg->command, msg->result);
63 return 0;
64 }
65}
66EXPORT_SYMBOL(cros_ec_check_result);
67
68int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
69 struct cros_ec_command *msg)
70{
71 int ret;
72
73 mutex_lock(&ec_dev->lock);
74 ret = ec_dev->cmd_xfer(ec_dev, msg);
75 if (msg->result == EC_RES_IN_PROGRESS) {
76 int i;
77 struct cros_ec_command status_msg;
78 struct ec_response_get_comms_status status;
79
80 status_msg.version = 0;
81 status_msg.command = EC_CMD_GET_COMMS_STATUS;
82 status_msg.outdata = NULL;
83 status_msg.outsize = 0;
84 status_msg.indata = (uint8_t *)&status;
85 status_msg.insize = sizeof(status);
86
87 /*
88 * Query the EC's status until it's no longer busy or
89 * we encounter an error.
90 */
91 for (i = 0; i < EC_COMMAND_RETRIES; i++) {
92 usleep_range(10000, 11000);
93
94 ret = ec_dev->cmd_xfer(ec_dev, &status_msg);
95 if (ret < 0)
96 break;
97
98 msg->result = status_msg.result;
99 if (status_msg.result != EC_RES_SUCCESS)
100 break;
101 if (!(status.flags & EC_COMMS_STATUS_PROCESSING))
102 break;
103 }
104 }
105 mutex_unlock(&ec_dev->lock);
106
107 return ret;
108}
109EXPORT_SYMBOL(cros_ec_cmd_xfer);
110
111static const struct mfd_cell cros_devs[] = {
112 {
113 .name = "cros-ec-keyb",
114 .id = 1,
115 .of_compatible = "google,cros-ec-keyb",
116 },
117 {
118 .name = "cros-ec-i2c-tunnel",
119 .id = 2,
120 .of_compatible = "google,cros-ec-i2c-tunnel",
121 },
122};
123
124int cros_ec_register(struct cros_ec_device *ec_dev)
125{
126 struct device *dev = ec_dev->dev;
127 int err = 0;
128
129 if (ec_dev->din_size) {
130 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
131 if (!ec_dev->din)
132 return -ENOMEM;
133 }
134 if (ec_dev->dout_size) {
135 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
136 if (!ec_dev->dout)
137 return -ENOMEM;
138 }
139
140 mutex_init(&ec_dev->lock);
141
142 err = mfd_add_devices(dev, 0, cros_devs,
143 ARRAY_SIZE(cros_devs),
144 NULL, ec_dev->irq, NULL);
145 if (err) {
146 dev_err(dev, "failed to add mfd devices\n");
147 return err;
148 }
149
150 dev_info(dev, "Chrome EC device registered\n");
151
152 return 0;
153}
154EXPORT_SYMBOL(cros_ec_register);
155
156int cros_ec_remove(struct cros_ec_device *ec_dev)
157{
158 mfd_remove_devices(ec_dev->dev);
159
160 return 0;
161}
162EXPORT_SYMBOL(cros_ec_remove);
163
164#ifdef CONFIG_PM_SLEEP
165int cros_ec_suspend(struct cros_ec_device *ec_dev)
166{
167 struct device *dev = ec_dev->dev;
168
169 if (device_may_wakeup(dev))
170 ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
171
172 disable_irq(ec_dev->irq);
173 ec_dev->was_wake_device = ec_dev->wake_enabled;
174
175 return 0;
176}
177EXPORT_SYMBOL(cros_ec_suspend);
178
179int cros_ec_resume(struct cros_ec_device *ec_dev)
180{
181 enable_irq(ec_dev->irq);
182
183 if (ec_dev->wake_enabled) {
184 disable_irq_wake(ec_dev->irq);
185 ec_dev->wake_enabled = 0;
186 }
187
188 return 0;
189}
190EXPORT_SYMBOL(cros_ec_resume);
191
192#endif
193
194MODULE_LICENSE("GPL");
195MODULE_DESCRIPTION("ChromeOS EC core driver");