diff options
Diffstat (limited to 'drivers/mfd/cros_ec_i2c.c')
| -rw-r--r-- | drivers/mfd/cros_ec_i2c.c | 166 |
1 files changed, 162 insertions, 4 deletions
diff --git a/drivers/mfd/cros_ec_i2c.c b/drivers/mfd/cros_ec_i2c.c index b400bfa2772a..22e8a4ae1711 100644 --- a/drivers/mfd/cros_ec_i2c.c +++ b/drivers/mfd/cros_ec_i2c.c @@ -13,6 +13,7 @@ * GNU General Public License for more details. */ +#include <linux/delay.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/i2c.h> @@ -22,6 +23,32 @@ #include <linux/platform_device.h> #include <linux/slab.h> +/** + * Request format for protocol v3 + * byte 0 0xda (EC_COMMAND_PROTOCOL_3) + * byte 1-8 struct ec_host_request + * byte 10- response data + */ +struct ec_host_request_i2c { + /* Always 0xda to backward compatible with v2 struct */ + uint8_t command_protocol; + struct ec_host_request ec_request; +} __packed; + + +/* + * Response format for protocol v3 + * byte 0 result code + * byte 1 packet_length + * byte 2-9 struct ec_host_response + * byte 10- response data + */ +struct ec_host_response_i2c { + uint8_t result; + uint8_t packet_length; + struct ec_host_response ec_response; +} __packed; + static inline struct cros_ec_device *to_ec_dev(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); @@ -29,6 +56,134 @@ static inline struct cros_ec_device *to_ec_dev(struct device *dev) return i2c_get_clientdata(client); } +static int cros_ec_pkt_xfer_i2c(struct cros_ec_device *ec_dev, + struct cros_ec_command *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]; + struct ec_host_response *ec_response; + struct ec_host_request_i2c *ec_request_i2c; + struct ec_host_response_i2c *ec_response_i2c; + int request_header_size = sizeof(struct ec_host_request_i2c); + int response_header_size = sizeof(struct ec_host_response_i2c); + + i2c_msg[0].addr = client->addr; + i2c_msg[0].flags = 0; + i2c_msg[1].addr = client->addr; + i2c_msg[1].flags = I2C_M_RD; + + packet_len = msg->insize + response_header_size; + BUG_ON(packet_len > ec_dev->din_size); + in_buf = ec_dev->din; + i2c_msg[1].len = packet_len; + i2c_msg[1].buf = (char *) in_buf; + + packet_len = msg->outsize + request_header_size; + BUG_ON(packet_len > ec_dev->dout_size); + out_buf = ec_dev->dout; + i2c_msg[0].len = packet_len; + i2c_msg[0].buf = (char *) out_buf; + + /* create request data */ + ec_request_i2c = (struct ec_host_request_i2c *) out_buf; + ec_request_i2c->command_protocol = EC_COMMAND_PROTOCOL_3; + + ec_dev->dout++; + ret = cros_ec_prepare_tx(ec_dev, msg); + ec_dev->dout--; + + /* send command to EC and read answer */ + ret = i2c_transfer(client->adapter, i2c_msg, 2); + if (ret < 0) { + dev_dbg(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; + } + + ec_response_i2c = (struct ec_host_response_i2c *) in_buf; + msg->result = ec_response_i2c->result; + ec_response = &ec_response_i2c->ec_response; + + switch (msg->result) { + case EC_RES_SUCCESS: + break; + case EC_RES_IN_PROGRESS: + ret = -EAGAIN; + dev_dbg(ec_dev->dev, "command 0x%02x in progress\n", + msg->command); + goto done; + + default: + dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n", + msg->command, msg->result); + /* + * When we send v3 request to v2 ec, ec won't recognize the + * 0xda (EC_COMMAND_PROTOCOL_3) and will return with status + * EC_RES_INVALID_COMMAND with zero data length. + * + * In case of invalid command for v3 protocol the data length + * will be at least sizeof(struct ec_host_response) + */ + if (ec_response_i2c->result == EC_RES_INVALID_COMMAND && + ec_response_i2c->packet_length == 0) { + ret = -EPROTONOSUPPORT; + goto done; + } + } + + if (ec_response_i2c->packet_length < sizeof(struct ec_host_response)) { + dev_err(ec_dev->dev, + "response of %u bytes too short; not a full header\n", + ec_response_i2c->packet_length); + ret = -EBADMSG; + goto done; + } + + if (msg->insize < ec_response->data_len) { + dev_err(ec_dev->dev, + "response data size is too large: expected %u, got %u\n", + msg->insize, + ec_response->data_len); + ret = -EMSGSIZE; + goto done; + } + + /* copy response packet payload and compute checksum */ + sum = 0; + for (i = 0; i < sizeof(struct ec_host_response); i++) + sum += ((u8 *)ec_response)[i]; + + memcpy(msg->data, + in_buf + response_header_size, + ec_response->data_len); + for (i = 0; i < ec_response->data_len; i++) + sum += msg->data[i]; + + /* All bytes should sum to zero */ + if (sum) { + dev_err(ec_dev->dev, "bad packet checksum\n"); + ret = -EBADMSG; + goto done; + } + + ret = ec_response->data_len; + +done: + if (msg->command == EC_CMD_REBOOT_EC) + msleep(EC_REBOOT_DELAY_MS); + + return ret; +} + static int cros_ec_cmd_xfer_i2c(struct cros_ec_device *ec_dev, struct cros_ec_command *msg) { @@ -121,9 +276,12 @@ static int cros_ec_cmd_xfer_i2c(struct cros_ec_device *ec_dev, } ret = len; - done: +done: kfree(in_buf); kfree(out_buf); + if (msg->command == EC_CMD_REBOOT_EC) + msleep(EC_REBOOT_DELAY_MS); + return ret; } @@ -143,12 +301,12 @@ static int cros_ec_i2c_probe(struct i2c_client *client, ec_dev->priv = client; ec_dev->irq = client->irq; ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c; - ec_dev->pkt_xfer = NULL; + ec_dev->pkt_xfer = cros_ec_pkt_xfer_i2c; ec_dev->ec_name = client->name; ec_dev->phys_name = client->adapter->name; - ec_dev->din_size = sizeof(struct ec_host_response) + + ec_dev->din_size = sizeof(struct ec_host_response_i2c) + sizeof(struct ec_response_get_protocol_info); - ec_dev->dout_size = sizeof(struct ec_host_request); + ec_dev->dout_size = sizeof(struct ec_host_request_i2c); err = cros_ec_register(ec_dev); if (err) { |