On 1/11/23 03:02, Vijendar Mukunda wrote:
> Add pm_prepare callback and System level pm ops support for
> AMD master driver.
>
> Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@xxxxxxx>
> Signed-off-by: Mastan Katragadda <Mastan.Katragadda@xxxxxxx>
> ---
> drivers/soundwire/amd_master.c | 76 ++++++++++++++++++++++++++++++++++
> 1 file changed, 76 insertions(+)
>
> diff --git a/drivers/soundwire/amd_master.c b/drivers/soundwire/amd_master.c
> index 2fd77a673c22..f4478cc17aac 100644
> --- a/drivers/soundwire/amd_master.c
> +++ b/drivers/soundwire/amd_master.c
> @@ -1552,6 +1552,80 @@ static int amd_sdwc_clock_stop_exit(struct amd_sdwc_ctrl *ctrl)
> return 0;
> }
>
> +static int amd_resume_child_device(struct device *dev, void *data)
> +{
> + int ret;
> + struct sdw_slave *slave = dev_to_sdw_dev(dev);
> +
> + 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);
> + if (ret < 0)
> + dev_err(dev, "%s: pm_request_resume failed: %d\n", __func__, ret);
> +
> + return ret;
> +}
> +
> +static int __maybe_unused amd_pm_prepare(struct device *dev)
> +{
> + struct amd_sdwc_ctrl *ctrl = dev_get_drvdata(dev);
> + struct sdw_bus *bus = &ctrl->bus;
> + int ret;
> +
> + if (bus->prop.hw_disabled || !ctrl->startup_done) {
> + dev_dbg(bus->dev, "SoundWire master %d is disabled or not-started, ignoring\n",
> + bus->link_id);
> + return 0;
> + }
> + ret = device_for_each_child(bus->dev, NULL, amd_resume_child_device);
> + if (ret < 0)
> + dev_err(dev, "%s: amd_resume_child_device failed: %d\n", __func__, ret);
> + if (pm_runtime_suspended(dev) && ctrl->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;
> + }
> + }
> + return 0;
> +}
This seems to be inspired by the Intel code, but is this necessary here?
For Intel, we saw cases where we had to pm_resume before doing a system
suspend, otherwise the hardware was in a bad state.
Do you actually need to do so, or is is possible to do a system suspend
when the clock is stopped.
And in the case where the bus is in 'power-off' mode, do you actually
need to resume at all?
> +
> +static int __maybe_unused amd_suspend(struct device *dev)
> +{
> + struct amd_sdwc_ctrl *ctrl = dev_get_drvdata(dev);
> + struct sdw_bus *bus = &ctrl->bus;
> + int ret;
> +
> + if (bus->prop.hw_disabled || !ctrl->startup_done) {
> + dev_dbg(bus->dev, "SoundWire master %d is disabled or not-started, ignoring\n",
> + bus->link_id);
> + return 0;
> + }
> +
> + if (ctrl->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
> + ret = amd_sdwc_clock_stop(ctrl);
> + if (ret)
> + return ret;
> + } else if (ctrl->power_mode_mask & AMD_SDW_POWER_OFF_MODE) {
> + ret = amd_sdwc_clock_stop(ctrl);
do you actually need to stop the clock before powering-off? This seems
counter intuitive and not so useful?
> + if (ret)
> + return ret;
> + ret = amd_deinit_sdw_controller(ctrl);
> + if (ret)
> + return ret;
> + }
> + return 0;
> +}
> +
> static int __maybe_unused amd_suspend_runtime(struct device *dev)
> {
> struct amd_sdwc_ctrl *ctrl = dev_get_drvdata(dev);
> @@ -1638,6 +1712,8 @@ 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)
> };
>
