Hi Hans,
[...]
> static int viai2c_wait_bus_ready(struct viai2c *i2c)
> {
> @@ -25,12 +26,35 @@ static int viai2c_wait_bus_ready(struct viai2c *i2c)
> static int viai2c_wait_status(struct viai2c *i2c)
> {
> int ret = 0;
> - unsigned long wait_result;
> + unsigned long time_left;
> + unsigned long delta_ms;
> +
> + time_left = wait_for_completion_timeout(&i2c->complete,
> + VIAI2C_TIMEOUT);
> + if (!time_left) {
> + dev_err(i2c->dev, "bus transfer timeout\n");
> + return -EIO;
> + }
>
> - wait_result = wait_for_completion_timeout(&i2c->complete,
> - msecs_to_jiffies(500));
> - if (!wait_result)
> - return -ETIMEDOUT;
this change is unrelated. Why are you changing the timeout here
from 500 to 1000?
> + /*
> + * During each byte access, the host performs clock stretching.
> + * In this case, the thread may be interrupted by preemption,
> + * resulting in a long stretching time.
> + * However, some touchpad can only tolerate host clock stretching
> + * of no more than 200 ms. We reduce the impact of this through
> + * a retransmission mechanism.
> + */
is the hardware sending the stretching on its own?
> + local_irq_disable();
> + i2c->to = ktime_get();
> + delta_ms = ktime_to_ms(ktime_sub(i2c->to, i2c->ti));
> + if (delta_ms > VIAI2C_STRETCHING_TIMEOUT) {
> + local_irq_enable();
> + dev_warn(i2c->dev, "thread blocked more than %ldms\n",
> + delta_ms);
> + return -EAGAIN;
> + }
> + i2c->ti = i2c->to;
> + local_irq_enable();
>
> if (i2c->cmd_status & VIAI2C_ISR_NACK_ADDR)
> ret = -EIO;
> @@ -184,6 +208,7 @@ int viai2c_xfer(struct i2c_adapter *adap,
> int ret = 0;
> struct viai2c *i2c = i2c_get_adapdata(adap);
>
> + i2c->to = i2c->ti = ktime_get();
> for (i = 0; ret >= 0 && i < num; i++) {
> pmsg = &msgs[i];
> if (!(pmsg->flags & I2C_M_NOSTART)) {
> diff --git a/drivers/i2c/busses/i2c-viai2c-common.h b/drivers/i2c/busses/i2c-viai2c-common.h
> index f171f81e4d0f..73a88398d763 100644
> --- a/drivers/i2c/busses/i2c-viai2c-common.h
> +++ b/drivers/i2c/busses/i2c-viai2c-common.h
> @@ -58,6 +58,8 @@ struct viai2c {
> u16 tcr;
> int irq;
> u16 cmd_status;
> + ktime_t ti;
> + ktime_t to;
don't these need some arbitration?
Andi
