summaryrefslogtreecommitdiff
path: root/drivers/mfd/cros_ec_i2c.c
blob: 123044608b63dc5997f9cf921003814f9ac53f84 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/*
 * ChromeOS EC multi-function device (I2C)
 *
 * Copyright (C) 2012 Google, Inc
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

static inline struct cros_ec_device *to_ec_dev(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);

	return i2c_get_clientdata(client);
}

static int cros_ec_command_xfer(struct cros_ec_device *ec_dev,
				struct cros_ec_msg *msg)
{
	struct i2c_client *client = ec_dev->priv;
	int ret = -ENOMEM;
	int i;
	int packet_len;
	u8 *out_buf = NULL;
	u8 *in_buf = NULL;
	u8 sum;
	struct i2c_msg i2c_msg[2];

	i2c_msg[0].addr = client->addr;
	i2c_msg[0].flags = 0;
	i2c_msg[1].addr = client->addr;
	i2c_msg[1].flags = I2C_M_RD;

	/*
	 * allocate larger packet (one byte for checksum, one byte for
	 * length, and one for result code)
	 */
	packet_len = msg->in_len + 3;
	in_buf = kzalloc(packet_len, GFP_KERNEL);
	if (!in_buf)
		goto done;
	i2c_msg[1].len = packet_len;
	i2c_msg[1].buf = (char *)in_buf;

	/*
	 * allocate larger packet (one byte for checksum, one for
	 * command code, one for length, and one for command version)
	 */
	packet_len = msg->out_len + 4;
	out_buf = kzalloc(packet_len, GFP_KERNEL);
	if (!out_buf)
		goto done;
	i2c_msg[0].len = packet_len;
	i2c_msg[0].buf = (char *)out_buf;

	out_buf[0] = EC_CMD_VERSION0 + msg->version;
	out_buf[1] = msg->cmd;
	out_buf[2] = msg->out_len;

	/* copy message payload and compute checksum */
	sum = out_buf[0] + out_buf[1] + out_buf[2];
	for (i = 0; i < msg->out_len; i++) {
		out_buf[3 + i] = msg->out_buf[i];
		sum += out_buf[3 + i];
	}
	out_buf[3 + msg->out_len] = sum;

	/* send command to EC and read answer */
	ret = i2c_transfer(client->adapter, i2c_msg, 2);
	if (ret < 0) {
		dev_err(ec_dev->dev, "i2c transfer failed: %d\n", ret);
		goto done;
	} else if (ret != 2) {
		dev_err(ec_dev->dev, "failed to get response: %d\n", ret);
		ret = -EIO;
		goto done;
	}

	/* check response error code */
	if (i2c_msg[1].buf[0]) {
		dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n",
			 msg->cmd, i2c_msg[1].buf[0]);
		ret = -EINVAL;
		goto done;
	}

	/* copy response packet payload and compute checksum */
	sum = in_buf[0] + in_buf[1];
	for (i = 0; i < msg->in_len; i++) {
		msg->in_buf[i] = in_buf[2 + i];
		sum += in_buf[2 + i];
	}
	dev_dbg(ec_dev->dev, "packet: %*ph, sum = %02x\n",
		i2c_msg[1].len, in_buf, sum);
	if (sum != in_buf[2 + msg->in_len]) {
		dev_err(ec_dev->dev, "bad packet checksum\n");
		ret = -EBADMSG;
		goto done;
	}

	ret = 0;
 done:
	kfree(in_buf);
	kfree(out_buf);
	return ret;
}

static int cros_ec_probe_i2c(struct i2c_client *client,
			     const struct i2c_device_id *dev_id)
{
	struct device *dev = &client->dev;
	struct cros_ec_device *ec_dev = NULL;
	int err;

 	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
	if (!ec_dev)
		return -ENOMEM;

	i2c_set_clientdata(client, ec_dev);
	ec_dev->name = "I2C";
	ec_dev->dev = dev;
	ec_dev->priv = client;
	ec_dev->irq = client->irq;
	ec_dev->command_xfer = cros_ec_command_xfer;
	ec_dev->ec_name = client->name;
	ec_dev->phys_name = client->adapter->name;
	ec_dev->parent = &client->dev;

	err = cros_ec_register(ec_dev);
	if (err) {
		dev_err(dev, "cannot register EC\n");
		return err;
	}

	return 0;
}

static int cros_ec_remove_i2c(struct i2c_client *client)
{
	struct cros_ec_device *ec_dev = i2c_get_clientdata(client);

	cros_ec_remove(ec_dev);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int cros_ec_i2c_suspend(struct device *dev)
{
	struct cros_ec_device *ec_dev = to_ec_dev(dev);

	return cros_ec_suspend(ec_dev);
}

static int cros_ec_i2c_resume(struct device *dev)
{
	struct cros_ec_device *ec_dev = to_ec_dev(dev);

	return cros_ec_resume(ec_dev);
}
#endif

static SIMPLE_DEV_PM_OPS(cros_ec_i2c_pm_ops, cros_ec_i2c_suspend,
			  cros_ec_i2c_resume);

static const struct i2c_device_id cros_ec_i2c_id[] = {
	{ "cros-ec-i2c", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id);

static struct i2c_driver cros_ec_driver = {
	.driver	= {
		.name	= "cros-ec-i2c",
		.owner	= THIS_MODULE,
		.pm	= &cros_ec_i2c_pm_ops,
	},
	.probe		= cros_ec_probe_i2c,
	.remove		= cros_ec_remove_i2c,
	.id_table	= cros_ec_i2c_id,
};

module_i2c_driver(cros_ec_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ChromeOS EC multi function device");