[PATCH v3 3/7] board: rock5b-rk3588: add USB-C controller support

[Sebastian Reichel]

Hi Jonas,

On Fri, Aug 02, 2024 at 10:42:56PM GMT, Jonas Karlman wrote:
> On 2024-08-02 19:59, Sebastian Reichel wrote:
> > Enable support for the fusb302 USB Type-C controller.
> > 
> > This will do early USB PD (power deliver) negotiation, which must happen
> > within 5 seconds after the USB-C connector has plugged in according to
> > the specification. It takes almost 5 seconds to go through the bootchain
> > on Rock 5B and jump to the operating system. When the Linux initializes
> > the fusb302 usually 20-30 seconds have gone since the device has been
> > plugged, which is far too late. The USB PD power source reacts with a
> > hard reset, which disables VBUS for some time. This is not a problem for
> > a battery driven device, but Rock 5B will loose its power-supply and
> > reset. By initializing PD in U-Boot, this can be avoided.
> > 
> > Signed-off-by: Sebastian Reichel <sebastian.reichel at collabora.com>
> > ---
> >  board/radxa/rock5b-rk3588/Makefile        |  6 ++++
> >  board/radxa/rock5b-rk3588/rock5b-rk3588.c | 35 +++++++++++++++++++++++
> >  2 files changed, 41 insertions(+)
> >  create mode 100644 board/radxa/rock5b-rk3588/Makefile
> >  create mode 100644 board/radxa/rock5b-rk3588/rock5b-rk3588.c
> > 
> > diff --git a/board/radxa/rock5b-rk3588/Makefile b/board/radxa/rock5b-rk3588/Makefile
> > new file mode 100644
> > index 000000000000..95d813596da4
> > --- /dev/null
> > +++ b/board/radxa/rock5b-rk3588/Makefile
> > @@ -0,0 +1,6 @@
> > +# SPDX-License-Identifier:     GPL-2.0+
> > +#
> > +# Copyright (c) 2022 Collabora Ltd.
> > +#
> > +
> > +obj-y += rock5b-rk3588.o
> > diff --git a/board/radxa/rock5b-rk3588/rock5b-rk3588.c b/board/radxa/rock5b-rk3588/rock5b-rk3588.c
> > new file mode 100644
> > index 000000000000..1c17ae93c76c
> > --- /dev/null
> > +++ b/board/radxa/rock5b-rk3588/rock5b-rk3588.c
> > @@ -0,0 +1,35 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (c) 2023-2024 Collabora Ltd.
> > + */
> > +
> > +#include <usb/tcpm.h>
> > +
> > +#ifdef CONFIG_MISC_INIT_R
> > +int misc_init_r(void)
> 
> You should not override misc_init_r() here as it will override the
> rockchip board common misc_init_r() function that read cpuid, set serial
> and ethernet mac address env vars.
> 
> I would suggest you instead of tcpm_get() add something similar to
> 
> int tcpm_probe_all()
> {
> 	struct udevice *dev;
> 	struct uclass *uc;
> 	int ret;
> 
> 	ret = uclass_get(UCLASS_TCPM, &uc);
> 	if (ret)
> 		return ret;
> 
> 	for (ret = uclass_first_device_check(UCLASS_TCPM, &dev);
> 	     dev;
> 	     ret = uclass_next_device_check(&dev)) {
> 		if (ret)
> 			printf("Failed to probe Type-C controller '%s' (ret=%d)\n",
> 			       dev->name, ret);
> 	}
> 
> 	return 0;
> }
> 
> or if we do not care about the error message this could use
> 
> 	uclass_probe_all(UCLASS_TCPM);
> 
> and call it from the rockchip board common code in mach-rockchip/board.c
> directly after the call to regulators_enable_boot_on() in board_init().
> 
> Alternatively you could call following in a tcpm_post_bind()
> 
> 	dev_or_flags(dev, DM_FLAG_PROBE_AFTER_BIND);
> 
> to automatically probe the device as soon as possible after all devices
> have been bind, this is how the rockchip-io-domain driver does it.
> 
> Otherwise we need to add custom board code for each board using USB PD,
> something to avoid.

All of your suggestions result in any USB-PD controllers being
probed automatically. I intentionally did not go that way, since
probing can be quite slow depending on the remote side. For most
power-supplies it seems to be quite fast, but I've seen a boot
with one of the supplies being delayed by 2-3 seconds. Seems not
nice to add this penality for a device not depending on it.

Greetings,

-- Sebastian

> 
> Regards,
> Jonas
> 
> > +{
> > +	struct udevice *dev;
> > +	int ret;
> > +
> > +	/*
> > +	 * This will do early USB PD (power deliver) negotiation, which must
> > +	 * happen within 5 seconds after the USB-C connector has plugged in
> > +	 * according to the specification. It takes almost 5 seconds to go
> > +	 * through the bootchain on Rock 5B and jump to the operating system.
> > +	 * When the Linux initializes the fusb302 usually 20-30 seconds have
> > +	 * gone since the device has been plugged, which is far too late.
> > +	 *
> > +	 * The USB PD power source reacts with a hard reset, which disables
> > +	 * VBUS for some time. This is not a problem for a battery driven
> > +	 * device, but Rock 5B will loose its power-supply and reset. By
> > +	 * initializing PD in U-Boot, this can be avoided.
> > +	 */
> > +	ret = tcpm_get("usb-typec at 22", &dev);
> > +	if (ret) {
> > +		printf("Failed to probe Type-C controller\n");
> > +		return 0;
> > +	}
> > +
> > +	return 0;
> > +}
> > +#endif
> 
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