Hi Dmitry,
On Mon, Aug 18, 2025 at 03:42:07AM +0300, Dmitry Baryshkov wrote:
> On Fri, Aug 08, 2025 at 11:52:59AM +0200, Henrik Grimler wrote:
> > Hi Dmitry,
> >
> > On Sun, Jul 27, 2025 at 08:07:37PM +0300, Dmitry Baryshkov wrote:
> > > On Thu, Jul 24, 2025 at 08:50:53PM +0200, Henrik Grimler wrote:
> > > > To use MHL we currently need the MHL chip to be permanently on, which
> > > > consumes unnecessary power. Let's use extcon attached to MUIC to enable
> > > > the MHL chip only if it detects an MHL cable.
> > >
> > > Does HPD GPIO reflect the correct state of the cable?
> >
> > Yes, the HPD gpio pin changes state from low to high when a mhl cable is
> > connected:
> >
> > $ sudo cat /sys/kernel/debug/gpio|grep gpio-755
> > gpio-755 ( |hpd ) in lo IRQ
> > $ sudo cat /sys/kernel/debug/gpio|grep gpio-755
> > gpio-755 ( |hpd ) in hi IRQ
> >
> > so that is described correctly.
> >
>
> Ack.
>
> >
> > and in captured trace I see that on cable connect we get an irq that
> > is handled through:
> > 1. max77693_muic_irq_handler
> > 2. max77693_muic_irq_work
> > 3. max77693_muic_adc_handler
> > 4. sii9234_extcon_notifier
> > 5. sii9234_extcon_work
> > 6. sii9234_cable_in
> > 7. hdmi_irq_thread
> >
> > Raw captured trace dat file can be found here:
> > https://grimler.se/files/sii9234-mhl-connect-trace.dat
> >
> > Maybe you were asking for some other type of order of events log
> > though, please let me know if I misunderstand.
> >
> > > Should the sii9234 signal to Exynos HDMI that the link is established?
> >
> > Maybe.. Sorry, I do not know enough about extcon and drm yet. I assume
> > you mean through drm_helper_hpd_irq_event() and
> > drm_bridge_hpd_notify(), I will experiment a bit and add it to the
> > driver and see if this improves it.
>
> If you are getting the HDMI IRQ event, then I'd suggest checking that
> you are actually getting the 'plugged' event, etc. I was worried that
> you are hijacking the DRM chain. But if you are getting hotplug events,
> then it's fine (and most likely correct).
With some debugging in sii9234_extcon_notifier added:
--- a/drivers/gpu/drm/bridge/sii9234.c
+++ b/drivers/gpu/drm/bridge/sii9234.c
@@ -892,6 +892,8 @@ static int sii9234_extcon_notifier(struct notifier_block
*self,
struct sii9234 *ctx =
container_of(self, struct sii9234, extcon_nb);
+ dev_info(ctx->dev, "extcon event %lu\n", event);
+
schedule_work(&ctx->extcon_wq);
return NOTIFY_DONE;
I see that sii9234 receives the hotplug event. On plug in:
[ 532.132981] sii9234 15-0039: extcon event 0
[ 532.136601] max77693-muic max77693-muic: external connector is attached
(adc:0x00, prev_adc:0x0)
[ 532.142777] sii9234 15-0039: RSEN_HIGH without RGND_1K
[ 532.149815] sii9234 15-0039: extcon event 1
[ 532.155662] max77693-charger max77693-charger: not charging. connector type:
13
[ 532.164801] sii9234 15-0039: extcon event 0
[ 532.168371] max77693-muic max77693-muic: external connector is
detached(chg_type:0x0, prev_chg_type:0x0)
[ 532.178370] sii9234 15-0039: extcon event 0
[ 532.188250] max77693-charger max77693-charger: not charging. connector type:
13
[ 533.097415] i2c i2c-15: sendbytes: NAK bailout.
[ 533.100735] sii9234 15-0039: writebm: TPI[0x3d] <- 0x3e
[ 533.115161] sii9234 15-0039: writeb: TPI[0x3d] <- 0x00
and disconnect:
[ 547.195219] dwc2 12480000.usb: new device is full-speed
[ 547.204912] max77693-muic max77693-muic: external connector is attached
(adc:0x00, prev_adc:0x0)
[ 547.212629] sii9234 15-0039: extcon event 1
[ 547.218304] max77693-charger max77693-charger: not charging. connector type:
13
[ 548.159257] i2c i2c-15: sendbytes: NAK bailout.
[ 548.162602] sii9234 15-0039: writebm: TPI[0x3d] <- 0x3e
[ 548.167990] sii9234 15-0039: extcon event 0
[ 548.172788] max77693-muic max77693-muic: external connector is attached
(adc:0x00, prev_adc:0x0)
[ 548.181336] sii9234 15-0039: extcon event 1
[ 548.186510] max77693-charger max77693-charger: not charging. connector type:
13
It seems a bit weird to me that it receives multiple events, but maybe
that is expected. Will send a v3 shortly, thank you!
Best regards,
Henrik Grimler
