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[0/2] platform/chrome: cros_ec_typec: Link PD object to partner

Message ID 20221121201337.2772216-1-pmalani@chromium.org
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Series platform/chrome: cros_ec_typec: Link PD object to partner | expand

Message

Prashant Malani Nov. 21, 2022, 8:13 p.m. UTC 
This is a short series to link a registered USB PD object to its associated
partner device. This is helpful for userspace services (the ChromeOS Type-C
daemon, for example), to identify which Type-C peripheral a PD object belongs to,
when a uevent for the PD object arrives.

The first patch adds a helper to the Type-C class code to access the device struct
for a partner. The second patch uses that helper to set the parent for the USB PD object
in the port driver code.

There was an earlier patch[1] to solve this issue, but it's been jettisoned (on advice from
GregKH) in favor of the current approach.

[1] https://lore.kernel.org/linux-usb/Y3vNZEuNI3CWzZ0L@chromium.org/T/#m7521020f64d878313d7dd79903ec0e9421aa8737

Series submission suggestions (if the approach is OK):
- Patch 1 goes throug the USB tree and Patch 2 goes in the next release cycle
  through the chrome-platform tree.
- Patch 1 and 2 both go through the USB tree.


Prashant Malani (2):
  usb: typec: Add helper to get partner device struct
  platform/chrome: cros_ec_typec: Set parent of partner PD object

 drivers/platform/chrome/cros_ec_typec.c |  2 +-
 drivers/usb/typec/class.c               | 13 +++++++++++++
 include/linux/usb/typec.h               |  2 ++
 3 files changed, 16 insertions(+), 1 deletion(-)

Comments

Heikki Krogerus Nov. 22, 2022, 9:58 a.m. UTC | #1 
Hi Prashant,

On Mon, Nov 21, 2022 at 08:13:35PM +0000, Prashant Malani wrote:
> +/**
> + * typec_partner_to_dev - Get the device struct of a USB Type-C partner.
> + * @partner: USB Type-C Partner
> + *
> + * Returns a pointer to the device struct or NULL.
> + */
> +struct device *typec_partner_to_dev(struct typec_partner *partner)
> +{
> +	return partner ? &partner->dev : NULL;
> +}
> +EXPORT_SYMBOL_GPL(typec_partner_to_dev);

Let's not loose the protection around these devices unless there is no
other way, and in this case there is.

Please just create a wrapper for usb_power_delivery_register() instead:

struct usb_power_delivery *
typec_partner_usb_power_delivery_register(struct typec_partner *partner,
                                          struct usb_power_delivery_desc *desc)
{
        return usb_power_delivery_register(&partner->dev, desc);
}
EXPORT_SYMBOL_GPL(typec_partner_usb_power_delivery_register);

thanks,
Prashant Malani Nov. 22, 2022, 7:05 p.m. UTC | #2 
Hi Heikki,

Thanks for reviewing the patch.

On Tue, Nov 22, 2022 at 1:58 AM Heikki Krogerus
<heikki.krogerus@linux.intel.com> wrote:
>
> Let's not loose the protection around these devices unless there is no
> other way, and in this case there is.
>
> Please just create a wrapper for usb_power_delivery_register() instead:
>
> struct usb_power_delivery *
> typec_partner_usb_power_delivery_register(struct typec_partner *partner,
>                                           struct usb_power_delivery_desc *desc)
> {
>         return usb_power_delivery_register(&partner->dev, desc);
> }
> EXPORT_SYMBOL_GPL(typec_partner_usb_power_delivery_register);

Sounds good. I'll send a v2 with the above change as patch 1 (instead
of the current patch 1).

I will list you as the "Suggested-by" tag (but please let me know if
you'd like attribution stated differently).

Thanks again!

-Prashant