Re: [Patch v6 5/7] slimbus: qcom: Add runtime-pm support using clock-pause feature

[Srinivas Kandagatla]

Thanks for the review comments

On 07/10/17 09:22, Jonathan NeuschÃfer wrote:
> Hi, some more trivial comments below.
>
> On Fri, Oct 06, 2017 at 05:51:34PM +0200, srinivas.kandagatla@xxxxxxxxxx wrote:
> > From: Sagar Dharia <sdharia@xxxxxxxxxxxxxx>
> >
> > Slimbus HW mandates that clock-pause sequence has to be executed
> > before disabling relevant interface and core clocks.
> > Runtime-PM's autosuspend feature is used here to enter/exit low
> > power mode for Qualcomm's Slimbus controller. Autosuspend feature
> > enables driver to avoid changing power-modes too frequently since
> > entering clock-pause is an expensive sequence
> >
> > Signed-off-by: Sagar Dharia <sdharia@xxxxxxxxxxxxxx>
> > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > ---
> [...]
> > +static int msm_clk_pause_wakeup(struct slim_controller *ctrl)
> > +{
> > +	struct msm_slim_ctrl *dev = slim_get_ctrldata(ctrl);
> > +
> > +	clk_prepare_enable(dev->hclk);
> > +	clk_prepare_enable(dev->rclk);
> > +	enable_irq(dev->irq);
> > +
> > +	writel_relaxed(1, dev->base + FRM_WAKEUP);
> > +	/* Make sure framer wakeup write goes through before ISR fires */
> > +	mb();
> > +	/**
>
> This isn't really a kerneldoc comment.
Yep I agree will fix all such instances.

> > +	 * HW Workaround: Currently, slave is reporting lost-sync messages
> > +	 * after slimbus comes out of clock pause.
> > +	 * Transaction with slave fail before slave reports that message
> > +	 * Give some time for that report to come
> > +	 * Slimbus wakes up in clock gear 10 at 24.576MHz. With each superframe
> > +	 * being 250 usecs, we wait for 5-10 superframes here to ensure
> > +	 * we get the message
> > +	 */
> > +	usleep_range(1250, 2500);
> > +	return 0;
> > +}
> [...]
> > +#ifdef CONFIG_PM_SLEEP
> > +static int msm_slim_suspend(struct device *dev)
> > +{
> > +	int ret = 0;
> > +
> > +	if (!pm_runtime_enabled(dev) ||
> > +		(!pm_runtime_suspended(dev))) {
> > +		dev_dbg(dev, "system suspend");
> > +		ret = msm_slim_runtime_suspend(dev);
> > +	}
> > +	if (ret == -EISCONN) {
> > +	/**
>
> ditto.
> Also, it looks misindented.
Yep. will fix this too.

> > +	 * If the clock pause failed due to active channels, there is
> > +	 * a possibility that some audio stream is active during suspend.
> > +	 * (e.g. modem usecase during suspend)
> > +	 * We dont want to return suspend failure in that case so that
> > +	 * display and relevant components can still go to suspend.
> > +	 * If there is some other error, then it should prevent
> > +	 * system level suspend
> > +	 */
> > +		ret = 0;
> > +	}
> > +	return ret;
> > +}
>
>
> Thanks,
> Jonathan NeuschÃfer