On Wed, Jun 22, 2016 at 03:42:07PM +0200, Geert Uytterhoeven wrote: > Add an SPI slave handler responding with the time of reception of the > last SPI message. > > This can be used by an external microcontroller as a dead man's switch.
The subject says boot up time, this says time of reception of the last
message. Which is it?
> +static int spi_slave_time_send(struct spi_device *spi)
> +{
> + __be32 msg[2];
> + u32 rem_ns;
> + u64 ts;
> +
> + ts = local_clock();
> + rem_ns = do_div(ts, 1000000000) / 1000;
> +
> + msg[0] = cpu_to_be32(ts);
> + msg[1] = cpu_to_be32(rem_ns);
> +
> + return spi_write(spi, &msg, sizeof(msg));
> +}
Looks like uptime which is a third thing.
> +static int spi_slave_time_remove(struct spi_device *spi)
> +{
> + struct spi_slave_time_priv *priv = spi_get_drvdata(spi);
> +
> + /* FIXME Doesn't work, as spi_write() is blocked on a completion */
> + kthread_stop(priv->thread);
spi_async()? Still no cancellation on the actual operation but it
pushes it more inside the framework.
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