Hi Wolfram,
Please review the patch and let me know if you still have any review comments.
Best regards,
Rayagonda
On Thu, Oct 10, 2019 at 3:02 PM Rayagonda Kokatanur
<rayagonda.kokatanur@xxxxxxxxxxxx> wrote:
>
> Hi Wolfram,
>
> Did you get a chance to review this patch.
>
> Best regards,
> Rayagonda
>
>
> On Mon, Sep 30, 2019 at 12:19 PM Rayagonda Kokatanur
> <rayagonda.kokatanur@xxxxxxxxxxxx> wrote:
> >
> > From: Lori Hikichi <lori.hikichi@xxxxxxxxxxxx>
> >
> > Enable handling of i2c repeated start. The current code
> > handles a multi msg i2c transfer as separate i2c bus
> > transactions. This change will now handle this case
> > using the i2c repeated start protocol. The number of msgs
> > in a transfer is limited to two, and must be a write
> > followed by a read.
> >
> > Signed-off-by: Lori Hikichi <lori.hikichi@xxxxxxxxxxxx>
> > Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@xxxxxxxxxxxx>
> > Signed-off-by: Icarus Chau <icarus.chau@xxxxxxxxxxxx>
> > Signed-off-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
> > Signed-off-by: Shivaraj Shetty <sshetty1@xxxxxxxxxxxx>
> > ---
> > changes from v1:
> > - Address following review comments from Wolfarm Sang,
> > Use i2c_8bit_addr_from_msg() api instead of decoding i2c_msg struct and
> > remove check against number of i2c message as it will be taken care
> > by core using quirks flags.
> >
> > drivers/i2c/busses/i2c-bcm-iproc.c | 63 ++++++++++++++++++++++++++++++--------
> > 1 file changed, 50 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
> > index d7fd76b..e478db7 100644
> > --- a/drivers/i2c/busses/i2c-bcm-iproc.c
> > +++ b/drivers/i2c/busses/i2c-bcm-iproc.c
> > @@ -81,6 +81,7 @@
> > #define M_CMD_PROTOCOL_MASK 0xf
> > #define M_CMD_PROTOCOL_BLK_WR 0x7
> > #define M_CMD_PROTOCOL_BLK_RD 0x8
> > +#define M_CMD_PROTOCOL_PROCESS 0xa
> > #define M_CMD_PEC_SHIFT 8
> > #define M_CMD_RD_CNT_SHIFT 0
> > #define M_CMD_RD_CNT_MASK 0xff
> > @@ -675,13 +676,20 @@ static int bcm_iproc_i2c_xfer_wait(struct bcm_iproc_i2c_dev *iproc_i2c,
> > return 0;
> > }
> >
> > -static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
> > - struct i2c_msg *msg)
> > +/*
> > + * If 'process_call' is true, then this is a multi-msg transfer that requires
> > + * a repeated start between the messages.
> > + * More specifically, it must be a write (reg) followed by a read (data).
> > + * The i2c quirks are set to enforce this rule.
> > + */
> > +static int bcm_iproc_i2c_xfer_internal(struct bcm_iproc_i2c_dev *iproc_i2c,
> > + struct i2c_msg *msgs, bool process_call)
> > {
> > int i;
> > u8 addr;
> > u32 val, tmp, val_intr_en;
> > unsigned int tx_bytes;
> > + struct i2c_msg *msg = &msgs[0];
> >
> > /* check if bus is busy */
> > if (!!(iproc_i2c_rd_reg(iproc_i2c,
> > @@ -707,14 +715,29 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
> > val = msg->buf[i];
> >
> > /* mark the last byte */
> > - if (i == msg->len - 1)
> > - val |= BIT(M_TX_WR_STATUS_SHIFT);
> > + if (!process_call && (i == msg->len - 1))
> > + val |= 1 << M_TX_WR_STATUS_SHIFT;
> >
> > iproc_i2c_wr_reg(iproc_i2c, M_TX_OFFSET, val);
> > }
> > iproc_i2c->tx_bytes = tx_bytes;
> > }
> >
> > + /* Process the read message if this is process call */
> > + if (process_call) {
> > + msg++;
> > + iproc_i2c->msg = msg; /* point to second msg */
> > +
> > + /*
> > + * The last byte to be sent out should be a slave
> > + * address with read operation
> > + */
> > + addr = i2c_8bit_addr_from_msg(msg);
> > + /* mark it the last byte out */
> > + val = addr | (1 << M_TX_WR_STATUS_SHIFT);
> > + iproc_i2c_wr_reg(iproc_i2c, M_TX_OFFSET, val);
> > + }
> > +
> > /* mark as incomplete before starting the transaction */
> > if (iproc_i2c->irq)
> > reinit_completion(&iproc_i2c->done);
> > @@ -733,7 +756,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
> > * underrun interrupt, which will be triggerred when the TX FIFO is
> > * empty. When that happens we can then pump more data into the FIFO
> > */
> > - if (!(msg->flags & I2C_M_RD) &&
> > + if (!process_call && !(msg->flags & I2C_M_RD) &&
> > msg->len > iproc_i2c->tx_bytes)
> > val_intr_en |= BIT(IE_M_TX_UNDERRUN_SHIFT);
> >
> > @@ -743,6 +766,8 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
> > */
> > val = BIT(M_CMD_START_BUSY_SHIFT);
> > if (msg->flags & I2C_M_RD) {
> > + u32 protocol;
> > +
> > iproc_i2c->rx_bytes = 0;
> > if (msg->len > M_RX_FIFO_MAX_THLD_VALUE)
> > iproc_i2c->thld_bytes = M_RX_FIFO_THLD_VALUE;
> > @@ -758,7 +783,10 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
> > /* enable the RX threshold interrupt */
> > val_intr_en |= BIT(IE_M_RX_THLD_SHIFT);
> >
> > - val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) |
> > + protocol = process_call ?
> > + M_CMD_PROTOCOL_PROCESS : M_CMD_PROTOCOL_BLK_RD;
> > +
> > + val |= (protocol << M_CMD_PROTOCOL_SHIFT) |
> > (msg->len << M_CMD_RD_CNT_SHIFT);
> > } else {
> > val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT);
> > @@ -774,17 +802,24 @@ static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter,
> > struct i2c_msg msgs[], int num)
> > {
> > struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adapter);
> > - int ret, i;
> > + bool process_call = false;
> > + int ret;
> >
> > - /* go through all messages */
> > - for (i = 0; i < num; i++) {
> > - ret = bcm_iproc_i2c_xfer_single_msg(iproc_i2c, &msgs[i]);
> > - if (ret) {
> > - dev_dbg(iproc_i2c->device, "xfer failed\n");
> > - return ret;
> > + if (num == 2) {
> > + /* Repeated start, use process call */
> > + process_call = true;
> > + if (msgs[1].flags & I2C_M_NOSTART) {
> > + dev_err(iproc_i2c->device, "Invalid repeated start\n");
> > + return -EOPNOTSUPP;
> > }
> > }
> >
> > + ret = bcm_iproc_i2c_xfer_internal(iproc_i2c, msgs, process_call);
> > + if (ret) {
> > + dev_dbg(iproc_i2c->device, "xfer failed\n");
> > + return ret;
> > + }
> > +
> > return num;
> > }
> >
> > @@ -806,6 +841,8 @@ static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap)
> > };
> >
> > static struct i2c_adapter_quirks bcm_iproc_i2c_quirks = {
> > + .flags = I2C_AQ_COMB_WRITE_THEN_READ,
> > + .max_comb_1st_msg_len = M_TX_RX_FIFO_SIZE,
> > .max_read_len = M_RX_MAX_READ_LEN,
> > };
> >
> > --
> > 1.9.1
> >
