On Tue, Dec 3, 2024 at 1:01 PM Uwe Kleine-König
<u.kleine-koenig@xxxxxxxxxxxx> wrote:
>
> It can happen if a previous conversion was aborted the ADC pulls down
> the ̅R̅D̅Y line but the event wasn't handled before. In that case enabling
Interesting use of Unicode, but I suggest to avoid it when it can be
avoided, i.e.
using the notation of #RDY_N might be appropriate as that is how
usually the HW people refer to the active low signals.
> the irq might immediately fire (depending on the irq controller's
controller
> capabilities) and even with a rdy-gpio isn't identified as an unrelated
> one.
>
> To cure that problem check for a pending event before the measurement is
> started and clear it if needed.
...
> + data = kzalloc(data_read_len + 1, GFP_KERNEL);
Yes, I know that's not needed right now, but would make code robust
against changes. I'm talking about using __free() here.
> + if (!data)
> + return -ENOMEM;
> +
> + spi_message_init(&m);
> + if (sigma_delta->info->has_registers) {
> + unsigned int data_reg = sigma_delta->info->data_reg ?: AD_SD_REG_DATA;
> +
> + data[0] = data_reg << sigma_delta->info->addr_shift;
> + data[0] |= sigma_delta->info->read_mask;
> + data[0] |= sigma_delta->comm;
> + t[0].tx_buf = data;
> + spi_message_add_tail(&t[0], &m);
> + }
> +
> + /*
> + * The first transferred byte is part of the real data register,
> + * so this doesn't need to be 0xff. In the remaining
> + * `data_read_len - 1` bytes are less than $num_resetclks ones.
> + */
> + t[1].tx_buf = data + 1;
> + data[1] = 0x00;
> + memset(data + 2, 0xff, data_read_len - 1);
> + spi_message_add_tail(&t[1], &m);
> + ret = spi_sync_locked(sigma_delta->spi, &m);
> +
> + kfree(data);
> +
> + return ret;
With the above this will become just as
return spi_sync_locked(...);
--
With Best Regards,
Andy Shevchenko
