Replace dm_i2c_write() / dm_i2c_read() with transaction using
struct i2c_msg[2] in order to allow for i2c controller to detect
write/read cycle to emit a repeated start condition.

Signed-off-by: Moritz Fischer <moritz.fisc...@ettus.com>
Cc: Simon Glass <s...@chromium.org>
Cc: u-boot@lists.denx.de
---
Hi Simon,

since I don't have a v2 protocol EC I couldn't test this,
but I noticed when playing around with a v3 one, that it would simply ignore
the packets if they don't have a repeated start condition (which from my 
understanding)
you can *only* get if you use struct i2c_msg, since otherwise the driver has no 
way of
knowing your intention.

Do you have a v2 board around to test this?

Cheers,

Moritz
---
 drivers/misc/cros_ec_i2c.c | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/drivers/misc/cros_ec_i2c.c b/drivers/misc/cros_ec_i2c.c
index 3de18b2..f2f6961 100644
--- a/drivers/misc/cros_ec_i2c.c
+++ b/drivers/misc/cros_ec_i2c.c
@@ -29,6 +29,8 @@ static int cros_ec_i2c_command(struct udevice *udev, uint8_t 
cmd,
                               int dout_len, uint8_t **dinp, int din_len)
 {
        struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
+       struct dm_i2c_chip *chip = dev_get_parent_platdata(udev);
+       struct i2c_msg i2c_msg[2];
        /* version8, cmd8, arglen8, out8[dout_len], csum8 */
        int out_bytes = dout_len + 4;
        /* response8, arglen8, in8[din_len], checksum8 */
@@ -53,6 +55,11 @@ static int cros_ec_i2c_command(struct udevice *udev, uint8_t 
cmd,
        assert(dout_len >= 0);
        assert(dinp);
 
+       i2c_msg[0].addr = chip->chip_addr;
+       i2c_msg[0].len = out_bytes;
+       i2c_msg[0].buf = dev->dout;
+       i2c_msg[0].flags = 0;
+
        /*
         * Copy command and data into output buffer so we can do a single I2C
         * burst transaction.
@@ -85,24 +92,21 @@ static int cros_ec_i2c_command(struct udevice *udev, 
uint8_t cmd,
        *ptr++ = (uint8_t)
                cros_ec_calc_checksum(dev->dout, dout_len + 3);
 
+       i2c_msg[1].addr = chip->chip_addr;
+       i2c_msg[1].len = in_bytes;
+       i2c_msg[1].buf = in_ptr;
+       i2c_msg[1].flags = I2C_M_RD;
+
        /* Send output data */
        cros_ec_dump_data("out", -1, dev->dout, out_bytes);
-       ret = dm_i2c_write(udev, 0, dev->dout, out_bytes);
+
+       ret = dm_i2c_xfer(udev, &i2c_msg[0], 2);
        if (ret) {
-               debug("%s: Cannot complete I2C write to %s\n", __func__,
+               debug("%s: Could not execute transfer to %s\n", __func__,
                      udev->name);
                ret = -1;
        }
 
-       if (!ret) {
-               ret = dm_i2c_read(udev, 0, in_ptr, in_bytes);
-               if (ret) {
-                       debug("%s: Cannot complete I2C read from %s\n",
-                             __func__, udev->name);
-                       ret = -1;
-               }
-       }
-
        if (*in_ptr != EC_RES_SUCCESS) {
                debug("%s: Received bad result code %d\n", __func__, *in_ptr);
                return -(int)*in_ptr;
-- 
2.7.4

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