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 (I2C)
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
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/i2c.h>
19#include <linux/interrupt.h>
20#include <linux/mfd/cros_ec.h>
21#include <linux/mfd/cros_ec_commands.h>
22#include <linux/platform_device.h>
23#include <linux/slab.h>
24
25static inline struct cros_ec_device *to_ec_dev(struct device *dev)
26{
27 struct i2c_client *client = to_i2c_client(dev);
28
29 return i2c_get_clientdata(client);
30}
31
32static int cros_ec_command_xfer(struct cros_ec_device *ec_dev,
33 struct cros_ec_msg *msg)
34{
35 struct i2c_client *client = ec_dev->priv;
36 int ret = -ENOMEM;
37 int i;
38 int packet_len;
39 u8 *out_buf = NULL;
40 u8 *in_buf = NULL;
41 u8 sum;
42 struct i2c_msg i2c_msg[2];
43
44 i2c_msg[0].addr = client->addr;
45 i2c_msg[0].flags = 0;
46 i2c_msg[1].addr = client->addr;
47 i2c_msg[1].flags = I2C_M_RD;
48
49 /*
50 * allocate larger packet (one byte for checksum, one byte for
51 * length, and one for result code)
52 */
53 packet_len = msg->in_len + 3;
54 in_buf = kzalloc(packet_len, GFP_KERNEL);
55 if (!in_buf)
56 goto done;
57 i2c_msg[1].len = packet_len;
58 i2c_msg[1].buf = (char *)in_buf;
59
60 /*
61 * allocate larger packet (one byte for checksum, one for
62 * command code, one for length, and one for command version)
63 */
64 packet_len = msg->out_len + 4;
65 out_buf = kzalloc(packet_len, GFP_KERNEL);
66 if (!out_buf)
67 goto done;
68 i2c_msg[0].len = packet_len;
69 i2c_msg[0].buf = (char *)out_buf;
70
71 out_buf[0] = EC_CMD_VERSION0 + msg->version;
72 out_buf[1] = msg->cmd;
73 out_buf[2] = msg->out_len;
74
75 /* copy message payload and compute checksum */
76 sum = out_buf[0] + out_buf[1] + out_buf[2];
77 for (i = 0; i < msg->out_len; i++) {
78 out_buf[3 + i] = msg->out_buf[i];
79 sum += out_buf[3 + i];
80 }
81 out_buf[3 + msg->out_len] = sum;
82
83 /* send command to EC and read answer */
84 ret = i2c_transfer(client->adapter, i2c_msg, 2);
85 if (ret < 0) {
86 dev_err(ec_dev->dev, "i2c transfer failed: %d\n", ret);
87 goto done;
88 } else if (ret != 2) {
89 dev_err(ec_dev->dev, "failed to get response: %d\n", ret);
90 ret = -EIO;
91 goto done;
92 }
93
94 /* check response error code */
95 if (i2c_msg[1].buf[0]) {
96 dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n",
97 msg->cmd, i2c_msg[1].buf[0]);
98 ret = -EINVAL;
99 goto done;
100 }
101
102 /* copy response packet payload and compute checksum */
103 sum = in_buf[0] + in_buf[1];
104 for (i = 0; i < msg->in_len; i++) {
105 msg->in_buf[i] = in_buf[2 + i];
106 sum += in_buf[2 + i];
107 }
108 dev_dbg(ec_dev->dev, "packet: %*ph, sum = %02x\n",
109 i2c_msg[1].len, in_buf, sum);
110 if (sum != in_buf[2 + msg->in_len]) {
111 dev_err(ec_dev->dev, "bad packet checksum\n");
112 ret = -EBADMSG;
113 goto done;
114 }
115
116 ret = 0;
117 done:
118 kfree(in_buf);
119 kfree(out_buf);
120 return ret;
121}
122
123static int cros_ec_probe_i2c(struct i2c_client *client,
124 const struct i2c_device_id *dev_id)
125{
126 struct device *dev = &client->dev;
127 struct cros_ec_device *ec_dev = NULL;
128 int err;
129
130 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
131 if (!ec_dev)
132 return -ENOMEM;
133
134 i2c_set_clientdata(client, ec_dev);
135 ec_dev->name = "I2C";
136 ec_dev->dev = dev;
137 ec_dev->priv = client;
138 ec_dev->irq = client->irq;
139 ec_dev->command_xfer = cros_ec_command_xfer;
140 ec_dev->ec_name = client->name;
141 ec_dev->phys_name = client->adapter->name;
142 ec_dev->parent = &client->dev;
143
144 err = cros_ec_register(ec_dev);
145 if (err) {
146 dev_err(dev, "cannot register EC\n");
147 return err;
148 }
149
150 return 0;
151}
152
153static int cros_ec_remove_i2c(struct i2c_client *client)
154{
155 struct cros_ec_device *ec_dev = i2c_get_clientdata(client);
156
157 cros_ec_remove(ec_dev);
158
159 return 0;
160}
161
162#ifdef CONFIG_PM_SLEEP
163static int cros_ec_i2c_suspend(struct device *dev)
164{
165 struct cros_ec_device *ec_dev = to_ec_dev(dev);
166
167 return cros_ec_suspend(ec_dev);
168}
169
170static int cros_ec_i2c_resume(struct device *dev)
171{
172 struct cros_ec_device *ec_dev = to_ec_dev(dev);
173
174 return cros_ec_resume(ec_dev);
175}
176#endif
177
178static SIMPLE_DEV_PM_OPS(cros_ec_i2c_pm_ops, cros_ec_i2c_suspend,
179 cros_ec_i2c_resume);
180
181static const struct i2c_device_id cros_ec_i2c_id[] = {
182 { "cros-ec-i2c", 0 },
183 { }
184};
185MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id);
186
187static struct i2c_driver cros_ec_driver = {
188 .driver = {
189 .name = "cros-ec-i2c",
190 .owner = THIS_MODULE,
191 .pm = &cros_ec_i2c_pm_ops,
192 },
193 .probe = cros_ec_probe_i2c,
194 .remove = cros_ec_remove_i2c,
195 .id_table = cros_ec_i2c_id,
196};
197
198module_i2c_driver(cros_ec_driver);
199
200MODULE_LICENSE("GPL");
201MODULE_DESCRIPTION("ChromeOS EC multi function device");