linux-kernel - RE: [PATCH v3 net-next 04/15] ptp: netc: add NETC V4 Timer PTP driver support

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Message-ID:
 <PAXPR04MB8510193754000AB8FE6E1C47882AA@PAXPR04MB8510.eurprd04.prod.outlook.com>
Date: Wed, 13 Aug 2025 02:21:08 +0000
From: Wei Fang <wei.fang@....com>
To: Vladimir Oltean <vladimir.oltean@....com>
CC: "robh@...nel.org" <robh@...nel.org>, "krzk+dt@...nel.org"
	<krzk+dt@...nel.org>, "conor+dt@...nel.org" <conor+dt@...nel.org>,
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Subject: RE: [PATCH v3 net-next 04/15] ptp: netc: add NETC V4 Timer PTP driver
 support

> On Tue, Aug 12, 2025 at 05:46:23PM +0800, Wei Fang wrote:
> > +int netc_timer_get_phc_index(struct pci_dev *timer_pdev) {
> > +	struct netc_timer *priv;
> > +
> > +	if (!timer_pdev)
> > +		return -ENODEV;
> > +
> > +	priv = pci_get_drvdata(timer_pdev);
> > +	if (!priv)
> > +		return -EINVAL;
> > +
> > +	return priv->phc_index;
> > +}
> > +EXPORT_SYMBOL_GPL(netc_timer_get_phc_index);
> ...
> > @@ -16,4 +17,13 @@ static inline void netc_write(void __iomem *reg, u32
> val)
> >  	iowrite32(val, reg);
> >  }
> >
> > +#if IS_ENABLED(CONFIG_PTP_NETC_V4_TIMER)
> > +int netc_timer_get_phc_index(struct pci_dev *timer_pdev); #else
> > +static inline int netc_timer_get_phc_index(struct pci_dev
> > +*timer_pdev) {
> > +	return -ENODEV;
> > +}
> > +#endif
> > +
> 
> I was expecting that with the generic ptp-timer phandle you'd also offer
> a generic mechanism of retrieving the PHC index, instead of cooking up a
> custom API convention between the NETC MAC and the NETC timer.
> 

Good advice, I did not realize that, I will try to apply your proposal,
many thanks.

> Something like below, completely untested:
> 
> struct ptp_clock_fwnode_match {
> 	struct fwnode_handle *fwnode;
> 	struct ptp_clock *clock;
> };
> 
> static int ptp_clock_fwnode_match(struct device *dev, void *data)
> {
> 	struct ptp_clock_fwnode_match *match = data;
> 
> 	if (!dev->parent || dev_fwnode(dev->parent) != match->fwnode)
> 		return 0;
> 
> 	match->clock = dev_get_drvdata(dev);
> 	return 1;
> }
> 
> static struct ptp_clock *ptp_clock_find_by_fwnode(struct fwnode_handle
> *fwnode)
> {
> 	struct ptp_clock_fwnode_match match = { .fwnode = fwnode };
> 
> 	class_for_each_device(&ptp_class, NULL, &match,
> ptp_clock_fwnode_match);
> 
> 	return match.clock;
> }
> 
> int ptp_clock_index_by_fwnode_handle(struct fwnode_handle *fwnode)
> {
> 	struct fwnode_handle *ptp_fwnode;
> 	struct ptp_clock *clock;
> 	int phc_index;
> 
> 	ptp_fwnode = fwnode_find_reference(fwnode, "ptp-timer", 0);
> 	if (!ptp_fwnode)
> 		return -1;
> 
> 	clock = ptp_clock_find_by_fwnode(ptp_fwnode);
> 	fwnode_handle_put(ptp_fwnode);
> 	if (!clock)
> 		return -1;
> 
> 	phc_index = ptp_clock_index(clock);
> 	put_device(&clock->dev);
> 
> 	return phc_index;
> }
> EXPORT_SYMBOL_GPL(ptp_clock_index_by_fwnode_handle);