On Wed, May 17, 2017 at 3:47 PM, Geert Uytterhoeven
<geert+rene...@glider.be> wrote:
> Add an example SPI slave handler responding with the uptime at the time
> of reception of the last SPI message.
>
> This can be used by an external microcontroller as a dead man's switch.
> +static int spi_slave_time_submit(struct spi_slave_time_priv *priv)
> +{
> + u32 rem_ns;
> + int ret;
> + u64 ts;
> +
> + ts = local_clock();
> + rem_ns = do_div(ts, 1000000000) / 1000;
You divide ts by 10^9, which makes it seconds if it was nanoseconds.
But reminder is still in nanoseconds and you divide it by 10^3.
If I didn't miss anything it should be called like
rem_ns -> reminder_ms
> +
> + priv->buf[0] = cpu_to_be32(ts);
> + priv->buf[1] = cpu_to_be32(rem_ns);
> +
> + spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1);
> +
> + priv->msg.complete = spi_slave_time_complete;
> + priv->msg.context = priv;
> +
> + ret = spi_async(priv->spi, &priv->msg);
> + if (ret)
> + pr_err("%s: spi_async() failed %d\n", __func__, ret);
Perhaps dev_err() ?
> +
> + return ret;
> +}
> +static int spi_slave_time_probe(struct spi_device *spi)
> +{
> + struct spi_slave_time_priv *priv;
> + int ret;
> +
> + /*
> + * bits_per_word cannot be configured in platform data
> + */
> + spi->bits_per_word = 8;
Is it worth to define it? If so, can we use device properties for that?
--
With Best Regards,
Andy Shevchenko
