Hi Marek,
> Hi Torsten,
>
>
> You're right, thanks for finding this! Does the following fix look OK ? I
> added some more comments and "decompressed" the code some more.
>
> diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
> index fb6f110..ee17b6a 100644
> --- a/drivers/i2c/busses/i2c-mxs.c
> +++ b/drivers/i2c/busses/i2c-mxs.c
> @@ -366,7 +366,7 @@ static int mxs_i2c_pio_setup_xfer(struct i2c_adapter
> *adap, struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
> uint32_t addr_data = msg->addr << 1;
> uint32_t data = 0;
> - int i, ret, xlen = 0;
> + int i, ret, xlen = 0, xmit = 0;
> uint32_t start;
>
> /* Mute IRQs coming from this block. */
> @@ -463,20 +463,42 @@ static int mxs_i2c_pio_setup_xfer(struct i2c_adapter
> *adap,
> data >>= 8;
> data |= (msg->buf[i] << 24);
>
> + xmit = 0;
> +
> + /* This is the last transfer of the message. */
> if (i + 1 == msg->len) {
> - /* This is the last transfer. */
> + /* Add optional STOP flag. */
> start |= flags;
> + /* Remove RETAIN_CLOCK bit. */
> start &= ~MXS_I2C_CTRL0_RETAIN_CLOCK;
> - xlen = (i + 2) % 4;
> - data >>= (4 - xlen) * 8;
> - } else if ((i & 3) == 2) {
> - /* Regular transfer. */
> - xlen = 4;
> - } else {
> - /* Just stuff data. */
> - continue;
> + xmit = 1;
> }
>
> + /* Four bytes are ready in the "data" variable. */
> + if ((i & 3) == 2)
> + xmit = 1;
> +
> + /* Nothing interesting happened, continue stuffing.
> */ + if (!xmit)
> + continue;
> +
> + /*
> + * Compute the size of the transfer and shift the
> + * data accordingly.
> + *
> + * i = (4k + 0) .... xlen = 2
> + * i = (4k + 1) .... xlen = 3
> + * i = (4k + 2) .... xlen = 4
> + * i = (4k + 3) .... xlen = 1
> + */
> +
> + if ((i % 4) == 3)
> + xlen = 1;
> + else
> + xlen = (i % 4) + 2;
> +
> + data >>= (4 - xlen) * 8;
> +
> dev_dbg(i2c->dev,
> "PIO: len=%i pos=%i total=%i [W%s%s%s]\n",
> xlen, i, msg->len,
The patch looks OK. I will test it when I'm back in the office. But this is
not before August 12.
Best regards,
Torsten Fleischer
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