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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: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
This commit is contained in:
Akhil R 2022-02-10 21:06:03 +05:30 committed by Wolfram Sang
parent 80704a84a9
commit d7583c8a57
1 changed files with 16 additions and 2 deletions
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18
drivers/i2c/busses/i2c-tegra.c
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@ -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;
}