On 20-09-04 08:37, Florian Fainelli wrote:
>
>
> On 9/3/2020 11:15 PM, Marco Felsch wrote:
> > Hi Florian,
> >
> > On 20-09-02 21:39, Florian Fainelli wrote:
> > > The internal Gigabit PHY on Broadcom STB chips has a digital clock which
> > > drives its MDIO interface among other things, the driver now requests
> > > and manage that clock during .probe() and .remove() accordingly.
> > >
> > > Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
> > > ---
> > > drivers/net/phy/bcm7xxx.c | 18 +++++++++++++++++-
> > > 1 file changed, 17 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/phy/bcm7xxx.c b/drivers/net/phy/bcm7xxx.c
> > > index 692048d86ab1..f0ffcdcaef03 100644
> > > --- a/drivers/net/phy/bcm7xxx.c
> > > +++ b/drivers/net/phy/bcm7xxx.c
> > > @@ -11,6 +11,7 @@
> > > #include "bcm-phy-lib.h"
> > > #include <linux/bitops.h>
> > > #include <linux/brcmphy.h>
> > > +#include <linux/clk.h>
> > > #include <linux/mdio.h>
> > > /* Broadcom BCM7xxx internal PHY registers */
> > > @@ -39,6 +40,7 @@
> > > struct bcm7xxx_phy_priv {
> > > u64 *stats;
> > > + struct clk *clk;
> > > };
> > > static int bcm7xxx_28nm_d0_afe_config_init(struct phy_device *phydev)
> > > @@ -534,7 +536,19 @@ static int bcm7xxx_28nm_probe(struct phy_device
> > > *phydev)
> > > if (!priv->stats)
> > > return -ENOMEM;
> > > - return 0;
> > > + priv->clk = devm_clk_get_optional(&phydev->mdio.dev, NULL);
> >
> > Since the clock is binded to the mdio-dev here..
> >
> > > + if (IS_ERR(priv->clk))
> > > + return PTR_ERR(priv->clk);
> > > +
> > > + return clk_prepare_enable(priv->clk);
> >
> > clould we use devm_add_action_or_reset() here so we don't have to
> > register the .remove() hook?
>
> Maybe, more on that below.
>
> >
> > > +}
> > > +
> > > +static void bcm7xxx_28nm_remove(struct phy_device *phydev)
> > > +{
> > > + struct bcm7xxx_phy_priv *priv = phydev->priv;
> > > +
> > > + clk_disable_unprepare(priv->clk);
> > > + devm_clk_put(&phydev->mdio.dev, priv->clk);
> >
> > Is this really necessary? The devm_clk_get_optional() function already
> > registers the devm_clk_release() hook.
>
> Yes, because you can unbind the PHY driver from sysfs, and if you want to
> bind that driver again, which will call .probe() again, you must undo
> strictly everything that .probe() did. The embedded mdio_device does not go
> away, so there will be no automatic freeing of resources.
Okay I got this. Sry. I'm not that deep into the net-stack and the
device live time. Thanks for the clarification.
> Using devm_* may
> be confusing, so using just the plain clk_get() and clk_put() may be clearer
> here.
That would be better for others including me because I detected a
failure on my patchset.
Regards,
Marco
