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
cros_ec_prepare_tx(struct cros_ec_device * ec_dev,struct cros_ec_command * msg)30 int 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 }
48 EXPORT_SYMBOL(cros_ec_prepare_tx);
49
cros_ec_check_result(struct cros_ec_device * ec_dev,struct cros_ec_command * msg)50 int 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 }
66 EXPORT_SYMBOL(cros_ec_check_result);
67
cros_ec_cmd_xfer(struct cros_ec_device * ec_dev,struct cros_ec_command * msg)68 int 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.command = EC_CMD_GET_COMMS_STATUS;
81 status_msg.insize = sizeof(*status);
82
83 /*
84 * Query the EC's status until it's no longer busy or
85 * we encounter an error.
86 */
87 for (i = 0; i < EC_COMMAND_RETRIES; i++) {
88 usleep_range(10000, 11000);
89
90 ret = ec_dev->cmd_xfer(ec_dev, &status_msg);
91 if (ret < 0)
92 break;
93
94 msg->result = status_msg.result;
95 if (status_msg.result != EC_RES_SUCCESS)
96 break;
97
98 status = (struct ec_response_get_comms_status *)
99 status_msg.indata;
100 if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
101 break;
102 }
103 }
104 mutex_unlock(&ec_dev->lock);
105
106 return ret;
107 }
108 EXPORT_SYMBOL(cros_ec_cmd_xfer);
109
110 static const struct mfd_cell cros_devs[] = {
111 {
112 .name = "cros-ec-keyb",
113 .id = 1,
114 .of_compatible = "google,cros-ec-keyb",
115 },
116 {
117 .name = "cros-ec-i2c-tunnel",
118 .id = 2,
119 .of_compatible = "google,cros-ec-i2c-tunnel",
120 },
121 {
122 .name = "cros-ec-ctl",
123 .id = 3,
124 },
125 };
126
cros_ec_register(struct cros_ec_device * ec_dev)127 int cros_ec_register(struct cros_ec_device *ec_dev)
128 {
129 struct device *dev = ec_dev->dev;
130 int err = 0;
131
132 if (ec_dev->din_size) {
133 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
134 if (!ec_dev->din)
135 return -ENOMEM;
136 }
137 if (ec_dev->dout_size) {
138 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
139 if (!ec_dev->dout)
140 return -ENOMEM;
141 }
142
143 mutex_init(&ec_dev->lock);
144
145 err = mfd_add_devices(dev, 0, cros_devs,
146 ARRAY_SIZE(cros_devs),
147 NULL, ec_dev->irq, NULL);
148 if (err) {
149 dev_err(dev, "failed to add mfd devices\n");
150 return err;
151 }
152
153 dev_info(dev, "Chrome EC device registered\n");
154
155 return 0;
156 }
157 EXPORT_SYMBOL(cros_ec_register);
158
cros_ec_remove(struct cros_ec_device * ec_dev)159 int cros_ec_remove(struct cros_ec_device *ec_dev)
160 {
161 mfd_remove_devices(ec_dev->dev);
162
163 return 0;
164 }
165 EXPORT_SYMBOL(cros_ec_remove);
166
167 #ifdef CONFIG_PM_SLEEP
cros_ec_suspend(struct cros_ec_device * ec_dev)168 int cros_ec_suspend(struct cros_ec_device *ec_dev)
169 {
170 struct device *dev = ec_dev->dev;
171
172 if (device_may_wakeup(dev))
173 ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
174
175 disable_irq(ec_dev->irq);
176 ec_dev->was_wake_device = ec_dev->wake_enabled;
177
178 return 0;
179 }
180 EXPORT_SYMBOL(cros_ec_suspend);
181
cros_ec_resume(struct cros_ec_device * ec_dev)182 int cros_ec_resume(struct cros_ec_device *ec_dev)
183 {
184 enable_irq(ec_dev->irq);
185
186 if (ec_dev->wake_enabled) {
187 disable_irq_wake(ec_dev->irq);
188 ec_dev->wake_enabled = 0;
189 }
190
191 return 0;
192 }
193 EXPORT_SYMBOL(cros_ec_resume);
194
195 #endif
196
197 MODULE_LICENSE("GPL");
198 MODULE_DESCRIPTION("ChromeOS EC core driver");
199