[RFC PATCH 33/40] soundwire: intel: Add basic power management support

Pierre-Louis Bossart
2019-07-25T23:42:26Z

Implement suspend/resume capabilities (not runtime_pm for now)

Credits: this patch is based on an earlier internal contribution by
Vinod Koul, Sanyog Kale, Shreyas Nc and Hardik Shah.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
drivers/soundwire/intel.c | 102 ++++++++++++++++++++++++++++++++++++++
1 file changed, 102 insertions(+)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 215dc81cdf73..1477c35f616f 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -12,6 +12,7 @@
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <sound/pcm_params.h>
+#include <linux/pm_runtime.h>
#include <sound/soc.h>
#include <linux/soundwire/sdw_registers.h>
#include <linux/soundwire/sdw.h>
@@ -278,6 +279,35 @@ static void intel_debugfs_exit(struct sdw_intel *sdw)
/*
* shim ops
*/
+static int intel_link_power_down(struct sdw_intel *sdw)
+{
+ int link_control, spa_mask, cpa_mask, ret;
+ unsigned int link_id = sdw->instance;
+ void __iomem *shim = sdw->res->shim;
+ u16 ioctl;
+
+ /* Glue logic */
+ ioctl = intel_readw(shim, SDW_SHIM_IOCTL(link_id));
+ ioctl |= SDW_SHIM_IOCTL_BKE;
+ ioctl |= SDW_SHIM_IOCTL_COE;
+ intel_writew(shim, SDW_SHIM_IOCTL(link_id), ioctl);
+
+ ioctl &= ~(SDW_SHIM_IOCTL_MIF);
+ intel_writew(shim, SDW_SHIM_IOCTL(link_id), ioctl);
+
+ /* Link power down sequence */
+ link_control = intel_readl(shim, SDW_SHIM_LCTL);
+ spa_mask = ~(SDW_SHIM_LCTL_SPA << link_id);
+ cpa_mask = (SDW_SHIM_LCTL_CPA << link_id);
+ link_control &= spa_mask;
+
+ ret = intel_clear_bit(shim, SDW_SHIM_LCTL, link_control, cpa_mask);
+ if (ret < 0)
+ return ret;
+
+ sdw->cdns.link_up = false;
+ return 0;
+}

static int intel_link_power_up(struct sdw_intel *sdw)
{
@@ -300,6 +330,29 @@ static int intel_link_power_up(struct sdw_intel *sdw)
return 0;
}

+static void intel_shim_wake(struct sdw_intel *sdw, bool wake_enable)
+{
+ void __iomem *shim = sdw->res->shim;
+ unsigned int link_id = sdw->instance;
+ u16 wake_en, wake_sts;
+
+ if (wake_enable) {
+ /* Enable the wakeup */
+ intel_writew(shim, SDW_SHIM_WAKEEN,
+ (SDW_SHIM_WAKEEN_ENABLE << link_id));
+ } else {
+ /* Disable the wake up interrupt */
+ wake_en = intel_readw(shim, SDW_SHIM_WAKEEN);
+ wake_en &= ~(SDW_SHIM_WAKEEN_ENABLE << link_id);
+ intel_writew(shim, SDW_SHIM_WAKEEN, wake_en);
+
+ /* Clear wake status */
+ wake_sts = intel_readw(shim, SDW_SHIM_WAKESTS);
+ wake_sts |= (SDW_SHIM_WAKEEN_ENABLE << link_id);
+ intel_writew(shim, SDW_SHIM_WAKESTS_STATUS, wake_sts);
+ }
+}
+
static int intel_shim_init(struct sdw_intel *sdw)
{
void __iomem *shim = sdw->res->shim;
@@ -1095,11 +1148,60 @@ static int intel_remove(struct platform_device *pdev)
return 0;
}

+/*
+ * PM calls
+ */
+
+#ifdef CONFIG_PM
+
+static int intel_suspend(struct device *dev)
+{
+ struct sdw_intel *sdw;
+ int ret;
+
+ sdw = dev_get_drvdata(dev);
+
+ 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_intel *sdw;
+ int ret;
+
+ sdw = dev_get_drvdata(dev);
+
+ ret = intel_init(sdw);
+ if (ret) {
+ dev_err(dev, "%s failed: %d", __func__, ret);
+ return ret;
+ }
+
+ sdw_cdns_enable_interrupt(&sdw->cdns);
+
+ return ret;
+}
+
+#endif
+
+static const struct dev_pm_ops intel_pm = {
+ SET_SYSTEM_SLEEP_PM_OPS(intel_suspend, intel_resume)
+};
+
static struct platform_driver sdw_intel_drv = {
.probe = intel_probe,
.remove = intel_remove,
.driver = {
.name = "int-sdw",
+ .pm = &intel_pm,

},
};
--
2.20.1