[PATCH 5/9] soc: apple: Add RTKit IPC library

[Alyssa Rosenzweig]

> +enum { APPLE_RTKIT_PWR_STATE_OFF = 0x00,
> +	APPLE_RTKIT_PWR_STATE_SLEEP = 0x01,
> +	APPLE_RTKIT_PWR_STATE_GATED = 0x02,
> +	APPLE_RTKIT_PWR_STATE_QUIESCED = 0x10,
> +	APPLE_RTKIT_PWR_STATE_ON = 0x20,
> +};

It would be great to get comments added explaining what these states
are. It's not obvious how off/sleep/gated/quiesced differ, and it's not
obvious from the code (doesn't look like GATED is used here at all?).
Are these Apple names or r/e'd names or a mix?

> +	if (!rtk->syslog_buffer.size) {
> +		rtk_warn(
> +			"received syslog message but syslog_buffer.size is zero");
> +		goto done;
> +	}
> +	if (!rtk->syslog_buffer.buffer && !rtk->syslog_buffer.iomem) {
> +		rtk_warn("received syslog message but no syslog_buffer.buffer or syslog_buffer.iomem");
> +		goto done;
> +	}

Nit: Wrapping is inconsistent between these two warns.