Emulate SMBus block read using ContinueXfer to read the length byte
Signed-off-by: Akhil R <[email protected]>
---
drivers/i2c/busses/i2c-tegra.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 03cea10..2941e42 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1233,6 +1233,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
return err;
i2c_dev->msg_buf = msg->buf;
+
+ /* The condition true implies smbus block read and len is already read */
+ if (msg->flags & I2C_M_RECV_LEN && end_state != MSG_END_CONTINUE)
+ i2c_dev->msg_buf = msg->buf + 1;
+
i2c_dev->msg_buf_remaining = msg->len;
i2c_dev->msg_err = I2C_ERR_NONE;
i2c_dev->msg_read = !!(msg->flags & I2C_M_RD);
@@ -1389,6 +1394,15 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
else
end_type = MSG_END_REPEAT_START;
}
+ /* If M_RECV_LEN use ContinueXfer to read the first byte */
+ if (msgs[i].flags & I2C_M_RECV_LEN) {
+ ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], MSG_END_CONTINUE);
+ if (ret)
+ break;
+ /* Set the read byte as msg len */
+ msgs[i].len = msgs[i].buf[0];
+ dev_dbg(i2c_dev->dev, "reading %d bytes\n", msgs[i].len);
+ }
ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], end_type);
if (ret)
break;
@@ -1416,10 +1430,10 @@ static u32 tegra_i2c_func(struct i2c_adapter *adap)
{
struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
u32 ret = I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
- I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
+ I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
if (i2c_dev->hw->has_continue_xfer_support)
- ret |= I2C_FUNC_NOSTART;
+ ret |= I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
return ret;
}
--
2.7.4