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_cmd_xfer_i2c(struct cros_ec_device *ec_dev, 33 struct cros_ec_command *msg) 34{ 35 struct i2c_client *client = ec_dev->priv; 36 int ret = -ENOMEM; 37 int i; 38 int len; 39 int packet_len; 40 u8 *out_buf = NULL; 41 u8 *in_buf = NULL; 42 u8 sum; 43 struct i2c_msg i2c_msg[2]; 44 45 i2c_msg[0].addr = client->addr; 46 i2c_msg[0].flags = 0; 47 i2c_msg[1].addr = client->addr; 48 i2c_msg[1].flags = I2C_M_RD; 49 50 /* 51 * allocate larger packet (one byte for checksum, one byte for 52 * length, and one for result code) 53 */ 54 packet_len = msg->insize + 3; 55 in_buf = kzalloc(packet_len, GFP_KERNEL); 56 if (!in_buf) 57 goto done; 58 i2c_msg[1].len = packet_len; 59 i2c_msg[1].buf = (char *)in_buf; 60 61 /* 62 * allocate larger packet (one byte for checksum, one for 63 * command code, one for length, and one for command version) 64 */ 65 packet_len = msg->outsize + 4; 66 out_buf = kzalloc(packet_len, GFP_KERNEL); 67 if (!out_buf) 68 goto done; 69 i2c_msg[0].len = packet_len; 70 i2c_msg[0].buf = (char *)out_buf; 71 72 out_buf[0] = EC_CMD_VERSION0 + msg->version; 73 out_buf[1] = msg->command; 74 out_buf[2] = msg->outsize; 75 76 /* copy message payload and compute checksum */ 77 sum = out_buf[0] + out_buf[1] + out_buf[2]; 78 for (i = 0; i < msg->outsize; i++) { 79 out_buf[3 + i] = msg->outdata[i]; 80 sum += out_buf[3 + i]; 81 } 82 out_buf[3 + msg->outsize] = sum; 83 84 /* send command to EC and read answer */ 85 ret = i2c_transfer(client->adapter, i2c_msg, 2); 86 if (ret < 0) { 87 dev_err(ec_dev->dev, "i2c transfer failed: %d\n", ret); 88 goto done; 89 } else if (ret != 2) { 90 dev_err(ec_dev->dev, "failed to get response: %d\n", ret); 91 ret = -EIO; 92 goto done; 93 } 94 95 /* check response error code */ 96 msg->result = i2c_msg[1].buf[0]; 97 ret = cros_ec_check_result(ec_dev, msg); 98 if (ret) 99 goto done; 100 101 len = in_buf[1]; 102 if (len > msg->insize) { 103 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)", 104 len, msg->insize); 105 ret = -ENOSPC; 106 goto done; 107 } 108 109 /* copy response packet payload and compute checksum */ 110 sum = in_buf[0] + in_buf[1]; 111 for (i = 0; i < len; i++) { 112 msg->indata[i] = in_buf[2 + i]; 113 sum += in_buf[2 + i]; 114 } 115 dev_dbg(ec_dev->dev, "packet: %*ph, sum = %02x\n", 116 i2c_msg[1].len, in_buf, sum); 117 if (sum != in_buf[2 + len]) { 118 dev_err(ec_dev->dev, "bad packet checksum\n"); 119 ret = -EBADMSG; 120 goto done; 121 } 122 123 ret = len; 124 done: 125 kfree(in_buf); 126 kfree(out_buf); 127 return ret; 128} 129 130static int cros_ec_i2c_probe(struct i2c_client *client, 131 const struct i2c_device_id *dev_id) 132{ 133 struct device *dev = &client->dev; 134 struct cros_ec_device *ec_dev = NULL; 135 int err; 136 137 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); 138 if (!ec_dev) 139 return -ENOMEM; 140 141 i2c_set_clientdata(client, ec_dev); 142 ec_dev->dev = dev; 143 ec_dev->priv = client; 144 ec_dev->irq = client->irq; 145 ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c; 146 ec_dev->ec_name = client->name; 147 ec_dev->phys_name = client->adapter->name; 148 ec_dev->parent = &client->dev; 149 150 err = cros_ec_register(ec_dev); 151 if (err) { 152 dev_err(dev, "cannot register EC\n"); 153 return err; 154 } 155 156 return 0; 157} 158 159static int cros_ec_i2c_remove(struct i2c_client *client) 160{ 161 struct cros_ec_device *ec_dev = i2c_get_clientdata(client); 162 163 cros_ec_remove(ec_dev); 164 165 return 0; 166} 167 168#ifdef CONFIG_PM_SLEEP 169static int cros_ec_i2c_suspend(struct device *dev) 170{ 171 struct cros_ec_device *ec_dev = to_ec_dev(dev); 172 173 return cros_ec_suspend(ec_dev); 174} 175 176static int cros_ec_i2c_resume(struct device *dev) 177{ 178 struct cros_ec_device *ec_dev = to_ec_dev(dev); 179 180 return cros_ec_resume(ec_dev); 181} 182#endif 183 184static SIMPLE_DEV_PM_OPS(cros_ec_i2c_pm_ops, cros_ec_i2c_suspend, 185 cros_ec_i2c_resume); 186 187static const struct i2c_device_id cros_ec_i2c_id[] = { 188 { "cros-ec-i2c", 0 }, 189 { } 190}; 191MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id); 192 193static struct i2c_driver cros_ec_driver = { 194 .driver = { 195 .name = "cros-ec-i2c", 196 .owner = THIS_MODULE, 197 .pm = &cros_ec_i2c_pm_ops, 198 }, 199 .probe = cros_ec_i2c_probe, 200 .remove = cros_ec_i2c_remove, 201 .id_table = cros_ec_i2c_id, 202}; 203 204module_i2c_driver(cros_ec_driver); 205 206MODULE_LICENSE("GPL"); 207MODULE_DESCRIPTION("ChromeOS EC multi function device"); 208