Re: [PATCH V3 8/8] soundwire: amd: add pm_prepare callback and pm ops support

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

> +static int amd_resume_child_device(struct device *dev, void *data)
> +{
> +	int ret;
> +	struct sdw_slave *slave = dev_to_sdw_dev(dev);

style: invert two lines?

> +
> +	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;
> +	}
> +	if (!pm_runtime_suspended(dev))
> +		return 0;
> +	ret = pm_request_resume(dev);

why not resume unconditionally and let the pm_runtime framework figure
things out?

That's what we did for Intel...

> +	if (ret < 0)
> +		dev_err(dev, "pm_request_resume failed: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +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 (pm_runtime_suspended(dev) && amd_manager->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
> +		ret = pm_request_resume(dev);

same, why not simplify and use:

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) {
> +		ret = amd_sdw_clock_stop(amd_manager);
> +		if (ret)
> +			return ret;

you could do a 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;
> +		ret = amd_deinit_sdw_manager(amd_manager);
> +		if (ret)
> +			return ret;
> +	}
> +	return 0;
> +}