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cros_ec: i2c: Add support for version 3 of the EC protocol

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Add support for version 3 of the ec protocol. It basically works by
stitching some additional header in front (special command code),
and having a result and packet_length stitched on for the reply.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: u-boot@lists.denx.de
Acked-by: Simon Glass <sjg@chromium.org>
Tested on snow:
Tested-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Moritz Fischer 2017-01-20 12:35:03 -08:00 committed by Simon Glass
parent 6943ee14e5
commit 147f785f67
1 changed files with 84 additions and 0 deletions
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84
drivers/misc/cros_ec_i2c.c
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@ -24,6 +24,89 @@
#define debug_trace(fmt, b...)
#endif
/**
* 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 int cros_ec_i2c_packet(struct udevice *udev, int out_bytes, int in_bytes)
{
struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
struct dm_i2c_chip *chip = dev_get_parent_platdata(udev);
struct ec_host_request_i2c *ec_request_i2c =
(struct ec_host_request_i2c *)dev->dout;
struct ec_host_response_i2c *ec_response_i2c =
(struct ec_host_response_i2c *)dev->din;
struct i2c_msg i2c_msg[2];
int ret;
i2c_msg[0].addr = chip->chip_addr;
i2c_msg[0].flags = 0;
i2c_msg[1].addr = chip->chip_addr;
i2c_msg[1].flags = I2C_M_RD;
/* one extra byte, to indicate v3 */
i2c_msg[0].len = out_bytes + 1;
i2c_msg[0].buf = dev->dout;
/* stitch on EC_COMMAND_PROTOCOL_3 */
memmove(&ec_request_i2c->ec_request, dev->dout, out_bytes);
ec_request_i2c->command_protocol = EC_COMMAND_PROTOCOL_3;
/* two extra bytes for v3 */
i2c_msg[1].len = in_bytes + 2;
i2c_msg[1].buf = dev->din;
ret = dm_i2c_xfer(udev, &i2c_msg[0], 2);
if (ret) {
printf("%s: Could not execute transfer: %d\n", __func__, ret);
return ret;
}
/* When we send a 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)
return -EPROTONOSUPPORT;
if (ec_response_i2c->packet_length < sizeof(struct ec_host_response)) {
printf("%s: response of %u bytes too short; not a full hdr\n",
__func__, ec_response_i2c->packet_length);
return -EBADMSG;
}
/* drop result and packet_len */
memmove(dev->din, &ec_response_i2c->ec_response, in_bytes);
return in_bytes;
}
static int cros_ec_i2c_command(struct udevice *udev, uint8_t cmd,
int cmd_version, const uint8_t *dout,
int dout_len, uint8_t **dinp, int din_len)
@ -140,6 +223,7 @@ static int cros_ec_probe(struct udevice *dev)
static struct dm_cros_ec_ops cros_ec_ops = {
.command = cros_ec_i2c_command,
.packet = cros_ec_i2c_packet,
};
static const struct udevice_id cros_ec_ids[] = {