Messages in this thread | | | Date | Thu, 19 Mar 2020 18:10:19 +0100 | From | Andrew Lunn <> | Subject | Re: [PATCH net-next 3/7] net: phy: introduce phy_read_mmd_poll_timeout macro |
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On Thu, Mar 19, 2020 at 05:56:39PM +0100, Heiner Kallweit wrote: > On 19.03.2020 17:39, Dejin Zheng wrote: > > it is sometimes necessary to poll a phy register by phy_read_mmd() > > function until its value satisfies some condition. introduce > > phy_read_mmd_poll_timeout() macros that do this. > > > > Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com> > > --- > > include/linux/phy.h | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/include/linux/phy.h b/include/linux/phy.h > > index 36d9dea04016..a30e9008647f 100644 > > --- a/include/linux/phy.h > > +++ b/include/linux/phy.h > > @@ -24,6 +24,7 @@ > > #include <linux/mod_devicetable.h> > > #include <linux/u64_stats_sync.h> > > #include <linux/irqreturn.h> > > +#include <linux/iopoll.h> > > > > #include <linux/atomic.h> > > > > @@ -784,6 +785,9 @@ static inline int __phy_modify_changed(struct phy_device *phydev, u32 regnum, > > */ > > int phy_read_mmd(struct phy_device *phydev, int devad, u32 regnum); > > > > +#define phy_read_mmd_poll_timeout(val, cond, sleep_us, timeout_us, args...) \ > > + read_poll_timeout(phy_read_mmd, val, cond, sleep_us, timeout_us, args) > > + > > /** > > * __phy_read_mmd - Convenience function for reading a register > > * from an MMD on a given PHY. > > > I'm not fully convinced. Usage of the new macro with its lots of > parameters makes the code quite hard to read. Therefore I'm also > not a big fan of readx_poll_timeout.
One issue is that people often implement polling wrong. They don't take into account where extra delays can happen, and return -ETIMEOUT when in fact the operation was successful. readx_poll_timeout gives us a core which is known to be good.
What i don't like here is phy_read_mmd_poll_timeout() takes args... We know it should be passed a phydev, and device address and a reg. I would prefer these to be explicit parameters. We can then get the compiler to check the correct number of parameters are passed.
Andrew
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