[PATCH v3 06/22] soundwire: intel: Add basic power management support

From: Pierre-Louis Bossart
Date: Thu Nov 14 2019 - 13:17:43 EST


Implement suspend/resume capabilities (not runtime_pm for now)
The resume part is essentially a full-blown re-enumeration.

When S0ix is supported, we will select clock stop mode when the ACPI
target state is S0, and tear down the link for S3.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
drivers/soundwire/intel.c | 75 +++++++++++++++++++++++++++++++++++++++
1 file changed, 75 insertions(+)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 00fa5c3a6c1f..c15596c011de 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -1253,10 +1253,85 @@ static int intel_master_remove(struct sdw_master_device *md)
return 0;
}

+/*
+ * PM calls
+ */
+
+#ifdef CONFIG_PM
+
+static int intel_suspend(struct device *dev)
+{
+ struct sdw_cdns *cdns = dev_get_drvdata(dev);
+ struct sdw_intel *sdw = cdns_to_intel(cdns);
+ int ret;
+
+ if (cdns->bus.prop.hw_disabled) {
+ dev_dbg(dev, "SoundWire master %d is disabled, ignoring\n",
+ cdns->bus.link_id);
+ return 0;
+ }
+
+ ret = sdw_cdns_enable_interrupt(cdns, false);
+ if (ret < 0) {
+ dev_err(dev, "cannot disable interrupts on suspend\n");
+ return ret;
+ }
+
+ ret = intel_link_power_down(sdw);
+ if (ret) {
+ dev_err(dev, "Link power down failed: %d", ret);
+ return ret;
+ }
+
+ intel_shim_wake(sdw, false);
+
+ return 0;
+}
+
+static int intel_resume(struct device *dev)
+{
+ struct sdw_cdns *cdns = dev_get_drvdata(dev);
+ struct sdw_intel *sdw = cdns_to_intel(cdns);
+ int ret;
+
+ if (cdns->bus.prop.hw_disabled) {
+ dev_dbg(dev, "SoundWire master %d is disabled, ignoring\n",
+ cdns->bus.link_id);
+ return 0;
+ }
+
+ ret = intel_init(sdw);
+ if (ret) {
+ dev_err(dev, "%s failed: %d", __func__, ret);
+ return ret;
+ }
+
+ ret = sdw_cdns_enable_interrupt(cdns, true);
+ if (ret < 0) {
+ dev_err(dev, "cannot enable interrupts during resume\n");
+ return ret;
+ }
+
+ ret = sdw_cdns_exit_reset(cdns);
+ if (ret < 0) {
+ dev_err(dev, "unable to exit bus reset sequence during resume\n");
+ return ret;
+ }
+
+ return ret;
+}
+
+#endif
+
+static const struct dev_pm_ops intel_pm = {
+ SET_SYSTEM_SLEEP_PM_OPS(intel_suspend, intel_resume)
+};
+
struct sdw_md_driver intel_sdw_driver = {
.driver = {
.name = "intel-sdw",
.owner = THIS_MODULE,
+ .pm = &intel_pm,
},
.probe = intel_master_probe,
.startup = intel_master_startup,
--
2.20.1