/* * 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_cmd_xfer_i2c(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_i2c_probe(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->cmd_xfer = cros_ec_cmd_xfer_i2c; 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_i2c_remove(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_i2c_probe, .remove = cros_ec_i2c_remove, .id_table = cros_ec_i2c_id, }; module_i2c_driver(cros_ec_driver); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("ChromeOS EC multi function device");