Commit d7583c8a authored by Akhil R's avatar Akhil R Committed by Wolfram Sang
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i2c: tegra: Add SMBus block read function 



Emulate SMBus block read using ContinueXfer to read the length byte

Signed-off-by: default avatarAkhil R <akhilrajeev@nvidia.com>
Reviewed-by: default avatarDmitry Osipenko <digetx@gmail.com>
Acked-by: default avatarThierry Reding <treding@nvidia.com>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent 80704a84

drivers/i2c/busses/i2c-tegra.c

+16 −2
Original line number Diff line number Diff line
@@ -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;
@@ -1419,7 +1433,7 @@ static u32 tegra_i2c_func(struct i2c_adapter *adap) 
		  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;

}