[PATCH] ASoC: SDCA: restore the settings if power is lost during suspend

[PATCH] ASoC: SDCA: restore the settings if power is lost during suspend

[shumingf]

From: Shuming Fan <shumingf@realtek.com>

We should restore the MIPI-defined registers when the device is attached.
If a function status interrupt occurs, the device will trigger an interrupt to reload the settings.

Signed-off-by: Shuming Fan <shumingf@realtek.com>
---
 sound/soc/sdca/sdca_class.c      |  4 ++++
 sound/soc/sdca/sdca_interrupts.c | 10 +++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/sound/soc/sdca/sdca_class.c b/sound/soc/sdca/sdca_class.c
index 7af4e5d1b347..d1feaa57eae7 100644
--- a/sound/soc/sdca/sdca_class.c
+++ b/sound/soc/sdca/sdca_class.c
@@ -49,6 +49,10 @@ static int class_sdw_update_status(struct sdw_slave *sdw, enum sdw_slave_status
 		drv->attached = true;
 
 		complete(&drv->device_attach);
+
+		/* resync the MIPI-defined registers if the device loses power */
+		regcache_mark_dirty(drv->dev_regmap);
+		regcache_sync(drv->dev_regmap);
 		break;
 	case SDW_SLAVE_UNATTACHED:
 		dev_dbg(drv->dev, "device detach\n");
diff --git a/sound/soc/sdca/sdca_interrupts.c b/sound/soc/sdca/sdca_interrupts.c
index 1838dabcdf60..ee69486e6b68 100644
--- a/sound/soc/sdca/sdca_interrupts.c
+++ b/sound/soc/sdca/sdca_interrupts.c
@@ -24,6 +24,7 @@
 #include <sound/sdca_interrupts.h>
 #include <sound/sdca_jack.h>
 #include <sound/sdca_ump.h>
+#include <sound/sdca_regmap.h>
 #include <sound/soc-component.h>
 #include <sound/soc.h>
 
@@ -121,7 +122,14 @@ static irqreturn_t function_status_handler(int irq, void *data)
 
 		switch (mask) {
 		case SDCA_CTL_ENTITY_0_FUNCTION_NEEDS_INITIALIZATION:
-			//FIXME: Add init writes
+			dev_info(dev, "%s function needs initialisation\n", interrupt->function->desc->name);
+			ret = sdca_regmap_write_init(dev, interrupt->device_regmap,
+					     interrupt->function);
+			if (ret)
+				return ret;
+			/* resync the function registers */
+			regcache_mark_dirty(interrupt->function_regmap);
+			regcache_sync(interrupt->function_regmap);
 			break;
 		case SDCA_CTL_ENTITY_0_FUNCTION_FAULT:
 			dev_err(dev, "function fault\n");
-- 
2.53.0

Re: [PATCH] ASoC: SDCA: restore the settings if power is lost during suspend

[Charles Keepax]

On Wed, Apr 08, 2026 at 04:56:07PM +0800, shumingf@realtek.com wrote:
> From: Shuming Fan <shumingf@realtek.com>
> 
> We should restore the MIPI-defined registers when the device is attached.
> If a function status interrupt occurs, the device will trigger an interrupt to reload the settings.
> 

Are you actually hitting this in practice? What is the situation
where the device loses power but it isn't covered by the normal
suspend/resume flow?

Thanks,
Charles

RE: [PATCH] ASoC: SDCA: restore the settings if power is lost during suspend

[Shuming [范書銘]]

> On Wed, Apr 08, 2026 at 04:56:07PM +0800, shumingf@realtek.com wrote:
> > From: Shuming Fan <shumingf@realtek.com>
> >
> > We should restore the MIPI-defined registers when the device is attached.
> > If a function status interrupt occurs, the device will trigger an interrupt to
> reload the settings.
> >
> 
> Are you actually hitting this in practice? What is the situation where the device
> loses power but it isn't covered by the normal suspend/resume flow?

This is a scenario where the machine enters hibernation and cuts power to the codec.
I simulated this case and verified that it works as expected.

Re: [PATCH] ASoC: SDCA: restore the settings if power is lost during suspend

[Charles Keepax]

On Wed, Apr 08, 2026 at 09:40:15AM +0000, Shuming [范書銘] wrote:
> > On Wed, Apr 08, 2026 at 04:56:07PM +0800, shumingf@realtek.com wrote:
> > > From: Shuming Fan <shumingf@realtek.com>
> > >
> > > We should restore the MIPI-defined registers when the device is attached.
> > > If a function status interrupt occurs, the device will trigger an interrupt to
> > reload the settings.
> > >
> > 
> > Are you actually hitting this in practice? What is the situation where the device
> > loses power but it isn't covered by the normal suspend/resume flow?
> 
> This is a scenario where the machine enters hibernation and cuts power to the codec.
> I simulated this case and verified that it works as expected.
> 

But in that case the suspend/resume callback should be called and
the cache should be synchronised on that path. Are you not seeing
those run?

Thanks,
Charles

Re: [PATCH] ASoC: SDCA: restore the settings if power is lost during suspend

[Richard Fitzgerald]

On 08/04/2026 10:40 am, Shuming [范書銘] wrote:
>> On Wed, Apr 08, 2026 at 04:56:07PM +0800, shumingf@realtek.com wrote:
>>> From: Shuming Fan <shumingf@realtek.com>
>>>
>>> We should restore the MIPI-defined registers when the device is attached.
>>> If a function status interrupt occurs, the device will trigger an interrupt to
>> reload the settings.
>>>
>>
>> Are you actually hitting this in practice? What is the situation where the device
>> loses power but it isn't covered by the normal suspend/resume flow?
> 
> This is a scenario where the machine enters hibernation and cuts power to the codec.
> I simulated this case and verified that it works as expected.
> 

class_runtime_resume() already does:

	regcache_mark_dirty(drv->dev_regmap);

	ret = regcache_sync(drv->dev_regmap);