soundwire: amd: add pm_prepare callback and pm ops support

Add pm_prepare callback and System level pm ops support for
AMD SoundWire manager driver.
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
Signed-off-by: Mastan Katragadda <Mastan.Katragadda@amd.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/lkml/20230310162554.699766-9-Vijendar.Mukunda@amd.com
Link: https://lore.kernel.org/r/20230321050901.115439-9-Vijendar.Mukunda@amd.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/soundwire/amd_manager.c

@@ -1043,6 +1043,88 @@ static int amd_sdw_clock_stop_exit(struct amd_sdw_manager *amd_manager)
 	return 0;
 }
 
+static int amd_resume_child_device(struct device *dev, void *data)
+{
+	struct sdw_slave *slave = dev_to_sdw_dev(dev);
+	int ret;
+
+	if (!slave->probed) {
+		dev_dbg(dev, "skipping device, no probed driver\n");
+		return 0;
+	}
+	if (!slave->dev_num_sticky) {
+		dev_dbg(dev, "skipping device, never detected on bus\n");
+		return 0;
+	}
+	ret = pm_request_resume(dev);
+	if (ret < 0) {
+		dev_err(dev, "pm_request_resume failed: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static int __maybe_unused amd_pm_prepare(struct device *dev)
+{
+	struct amd_sdw_manager *amd_manager = dev_get_drvdata(dev);
+	struct sdw_bus *bus = &amd_manager->bus;
+	int ret;
+
+	if (bus->prop.hw_disabled) {
+		dev_dbg(bus->dev, "SoundWire manager %d is disabled, ignoring\n",
+			bus->link_id);
+		return 0;
+	}
+	/*
+	 * When multiple peripheral devices connected over the same link, if SoundWire manager
+	 * device is not in runtime suspend state, observed that device alerts are missing
+	 * without pm_prepare on AMD platforms in clockstop mode0.
+	 */
+	if (amd_manager->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
+		ret = pm_request_resume(dev);
+		if (ret < 0) {
+			dev_err(bus->dev, "pm_request_resume failed: %d\n", ret);
+			return 0;
+		}
+	}
+	/* To force peripheral devices to system level suspend state, resume the devices
+	 * from runtime suspend state first. Without that unable to dispatch the alert
+	 * status to peripheral driver during system level resume as they are in runtime
+	 * suspend state.
+	 */
+	ret = device_for_each_child(bus->dev, NULL, amd_resume_child_device);
+	if (ret < 0)
+		dev_err(dev, "amd_resume_child_device failed: %d\n", ret);
+	return 0;
+}
+
+static int __maybe_unused amd_suspend(struct device *dev)
+{
+	struct amd_sdw_manager *amd_manager = dev_get_drvdata(dev);
+	struct sdw_bus *bus = &amd_manager->bus;
+	int ret;
+
+	if (bus->prop.hw_disabled) {
+		dev_dbg(bus->dev, "SoundWire manager %d is disabled, ignoring\n",
+			bus->link_id);
+		return 0;
+	}
+
+	if (amd_manager->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
+		return amd_sdw_clock_stop(amd_manager);
+	} else if (amd_manager->power_mode_mask & AMD_SDW_POWER_OFF_MODE) {
+		/*
+		 * As per hardware programming sequence on AMD platforms,
+		 * clock stop should be invoked first before powering-off
+		 */
+		ret = amd_sdw_clock_stop(amd_manager);
+		if (ret)
+			return ret;
+		return amd_deinit_sdw_manager(amd_manager);
+	}
+	return 0;
+}
+
 static int __maybe_unused amd_suspend_runtime(struct device *dev)
 {
 	struct amd_sdw_manager *amd_manager = dev_get_drvdata(dev);
@@ -1105,6 +1187,8 @@ static int __maybe_unused amd_resume_runtime(struct device *dev)
 }
 
 static const struct dev_pm_ops amd_pm = {
+	.prepare = amd_pm_prepare,
+	SET_SYSTEM_SLEEP_PM_OPS(amd_suspend, amd_resume_runtime)
 	SET_RUNTIME_PM_OPS(amd_suspend_runtime, amd_resume_runtime, NULL)
 };