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authorKamlakant Patel <kamlakant.patel@cavium.com>2017-10-10 11:57:56 +0530
committerWolfram Sang <wsa@the-dreams.de>2017-10-17 23:53:28 +0200
commit5515ae112172e20667f02b16f45fbf992923dcb0 (patch)
tree8f55504663432f580091f434941c3a3c268671ca /drivers/i2c
parentc347b8fc22b21899154cc153a4951aaf226b4e1a (diff)
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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: 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>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-xlp9xx.c30
1 files changed, 27 insertions, 3 deletions
diff --git a/drivers/i2c/busses/i2c-xlp9xx.c b/drivers/i2c/busses/i2c-xlp9xx.c
index f0bef2d5306c..b970bf8f38e5 100644
--- a/drivers/i2c/busses/i2c-xlp9xx.c
+++ b/drivers/i2c/busses/i2c-xlp9xx.c
@@ -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;
}