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

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Thanks for the review comments

On 07/10/17 09:22, Jonathan Neuschäfer 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 Neuschäfer

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