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89969009 SG |
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 | ||
25 | static 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 | ||
32 | static 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 | ||
192afe5e | 123 | static int cros_ec_i2c_probe(struct i2c_client *client, |
89969009 SG |
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 | ||
192afe5e | 153 | static int cros_ec_i2c_remove(struct i2c_client *client) |
89969009 SG |
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 | |
163 | static 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 | ||
170 | static 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 | ||
178 | static SIMPLE_DEV_PM_OPS(cros_ec_i2c_pm_ops, cros_ec_i2c_suspend, | |
179 | cros_ec_i2c_resume); | |
180 | ||
181 | static const struct i2c_device_id cros_ec_i2c_id[] = { | |
182 | { "cros-ec-i2c", 0 }, | |
183 | { } | |
184 | }; | |
185 | MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id); | |
186 | ||
187 | static 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 | }, | |
192afe5e TR |
193 | .probe = cros_ec_i2c_probe, |
194 | .remove = cros_ec_i2c_remove, | |
89969009 SG |
195 | .id_table = cros_ec_i2c_id, |
196 | }; | |
197 | ||
198 | module_i2c_driver(cros_ec_driver); | |
199 | ||
200 | MODULE_LICENSE("GPL"); | |
201 | MODULE_DESCRIPTION("ChromeOS EC multi function device"); |