Commit 5515ae11 authored by Kamlakant Patel's avatar Kamlakant Patel Committed by Wolfram Sang
Browse files

i2c: xlp9xx: Handle I2C_M_RECV_LEN in msg->flags 



The driver needs to handle the flag I2C_M_RECV_LEN during receive to
support SMBus emulation.

Update receive logic to handle the case where the length is received
as the first byte of a transaction.

Also update the code to handle I2C_CLIENT_PEC, which is set when the
client sends a packet error checking code byte.

Signed-off-by: default avatarJayachandran C <jnair@caviumnetworks.com>
Signed-off-by: default avatarKamlakant Patel <kamlakant.patel@cavium.com>
Reviewed-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent c347b8fc

drivers/i2c/busses/i2c-xlp9xx.c

+27 −3
Original line number Diff line number Diff line
@@ -82,6 +82,8 @@ struct xlp9xx_i2c_dev { 
	struct completion msg_complete;

	int irq;

	bool msg_read;

	bool len_recv;

	bool client_pec;

	u32 __iomem *base;

	u32 msg_buf_remaining;

	u32 msg_len;
@@ -143,10 +145,25 @@ static void xlp9xx_i2c_fill_tx_fifo(struct xlp9xx_i2c_dev *priv) 
static void xlp9xx_i2c_drain_rx_fifo(struct xlp9xx_i2c_dev *priv)

{

	u32 len, i;

	u8 *buf = priv->msg_buf;

	u8 rlen, *buf = priv->msg_buf;



	len = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_FIFOWCNT) &

				  XLP9XX_I2C_FIFO_WCNT_MASK;

	if (!len)

		return;

	if (priv->len_recv) {

		/* read length byte */

		rlen = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);

		*buf++ = rlen;

		len--;

		if (priv->client_pec)

			++rlen;

		/* update remaining bytes and message length */

		priv->msg_buf_remaining = rlen;

		priv->msg_len = rlen + 1;

		priv->len_recv = false;

	}



	len = min(priv->msg_buf_remaining, len);

	for (i = 0; i < len; i++, buf++)

		*buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
@@ -230,7 +247,7 @@ static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg, 
			       int last_msg)

{

	unsigned long timeleft;

	u32 intr_mask, cmd, val;

	u32 intr_mask, cmd, val, len;



	priv->msg_buf = msg->buf;

	priv->msg_buf_remaining = priv->msg_len = msg->len;
@@ -263,9 +280,13 @@ static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg, 
	else

		val &= ~XLP9XX_I2C_CTRL_ADDMODE;



	priv->len_recv = msg->flags & I2C_M_RECV_LEN;

	len = priv->len_recv ? XLP9XX_I2C_FIFO_SIZE : msg->len;

	priv->client_pec = msg->flags & I2C_CLIENT_PEC;



	/* set data length to be transferred */

	val = (val & ~XLP9XX_I2C_CTRL_MCTLEN_MASK) |

	      (msg->len << XLP9XX_I2C_CTRL_MCTLEN_SHIFT);

	      (len << XLP9XX_I2C_CTRL_MCTLEN_SHIFT);

	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, val);



	/* fill fifo during tx */
@@ -312,6 +333,9 @@ static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg, 
		return -ETIMEDOUT;

	}



	/* update msg->len with actual received length */

	if (msg->flags & I2C_M_RECV_LEN)

		msg->len = priv->msg_len;

	return 0;

}

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