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i2c: xlp9xx: Handle I2C_M_RECV_LEN in msg->flags

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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: Jayachandran C <jnair@caviumnetworks.com>
Signed-off-by: Kamlakant Patel <kamlakant.patel@cavium.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Kamlakant Patel 2017-10-10 11:57:56 +05:30 committed by Wolfram Sang
parent c347b8fc22
commit 5515ae1121
1 changed files with 27 additions and 3 deletions
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30
drivers/i2c/busses/i2c-xlp9xx.c
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@ -82,6 +82,8 @@ struct xlp9xx_i2c_dev {
struct completion msg_complete; struct completion msg_complete;
int irq; int irq;
bool msg_read; bool msg_read;
bool len_recv;
bool client_pec;
u32 __iomem *base; u32 __iomem *base;
u32 msg_buf_remaining; u32 msg_buf_remaining;
u32 msg_len; 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) static void xlp9xx_i2c_drain_rx_fifo(struct xlp9xx_i2c_dev *priv)
{ {
u32 len, i; u32 len, i;
u8 *buf = priv->msg_buf; u8 rlen, *buf = priv->msg_buf;
len = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_FIFOWCNT) & len = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_FIFOWCNT) &
XLP9XX_I2C_FIFO_WCNT_MASK; 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); len = min(priv->msg_buf_remaining, len);
for (i = 0; i < len; i++, buf++) for (i = 0; i < len; i++, buf++)
*buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO); *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) int last_msg)
{ {
unsigned long timeleft; unsigned long timeleft;
u32 intr_mask, cmd, val; u32 intr_mask, cmd, val, len;
priv->msg_buf = msg->buf; priv->msg_buf = msg->buf;
priv->msg_buf_remaining = priv->msg_len = msg->len; 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 else
val &= ~XLP9XX_I2C_CTRL_ADDMODE; 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 */ /* set data length to be transferred */
val = (val & ~XLP9XX_I2C_CTRL_MCTLEN_MASK) | 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); xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, val);
/* fill fifo during tx */ /* 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; return -ETIMEDOUT;
} }
/* update msg->len with actual received length */
if (msg->flags & I2C_M_RECV_LEN)
msg->len = priv->msg_len;
return 0; return 0;
} }