On Wed, 8 May 2019 07:41:18 +0000 Peng Fan <peng....@nxp.com> wrote: > > -----Original Message----- > > From: Lukasz Majewski [mailto:lu...@denx.de] > > Sent: 2019年5月8日 15:31 > > To: Peng Fan <peng....@nxp.com> > > Cc: sba...@denx.de; feste...@gmail.com; dl-uboot-imx > > <uboot-...@nxp.com>; s...@chromium.org; ja...@amarulasolutions.com; > > s...@denx.de; u-boot@lists.denx.de; tr...@konsulko.com > > Subject: Re: [i.MX8MM+CCF 03/41] clk: introduce clk_dev_binded > > > > On Tue, 7 May 2019 13:22:24 +0000 > > Peng Fan <peng....@nxp.com> wrote: > > > > > > Subject: Re: [i.MX8MM+CCF 03/41] clk: introduce clk_dev_binded > > > > > > > > On Tue, 30 Apr 2019 10:17:40 +0000 > > > > Peng Fan <peng....@nxp.com> wrote: > > > > > > > > > When support Clock Common Framework, U-Boot use dev for clk > > > > > tree information, there is no clk->parent. > > > > > > > > There is a function in clk uclass named: > > > > clk_get_parent() to provide parent of the clock. > > > > > > > > > When > > > > > support composite clk, it contains mux/gate/divider, but the > > > > > mux/gate/divider is not binded with device. > > > > > > > > There is a binding: > > > > struct clk_pllv3 { > > > > struct clk clk; > > > > ... > > > > }; > > > > > > > > The clk.dev points to corresponding device. > > > > > > > > In the opposite direction we do have dev->driver_data, which > > > > points to struct clk embedded in for example struct clk_pllv3. > > > > (as struct clk_pllv3 and struct clk share the same address it > > > > is up to us to cast it properly). > > > > > > > > I've written my thoughts and considerations about using > > > > dev->private and dev->driver_data in the patch cover letter [1] > > > > > > > > > > > > > So we could not use dev_get_driver_data to get the correct > > > > > clk_mux/gate/divider. > > > > > > > > Maybe I've overlooked something, but dev_get_driver_data() shall > > > > provide correct reference to udevice. > > > > > > A composite clk contains a mux/gate/divider clk. Only the > > > composite clk needs to binded with a udevice. > > > > So, if I understood correctly we do need to have another reference > > to udevice (or clock)? > > The composite clk structure > struct clk_composite { > struct clk clk; > struct clk_ops ops; > > struct clk *mux; > struct clk *rate; > struct clk *gate; > > const struct clk_ops *mux_ops; > const struct clk_ops *rate_ops; > const struct clk_ops *gate_ops; > }; > > Only the first clk needs to be binded with a udevice. > The mux/rate/gate pointer is only used for composite clk > internal usage and no udevice will be binded with them. > > > > > Please correct my understanding: > > > > - Composite clock would use clk->dev (to have pointer to struct > > udevice) and dev->driver_data to have pointer to clk. > > Yes, for the composite clk. > > > > > - Then we use udevice flag DM_FLAG_BOUND to indicate if this device > > has other udevices (i.e. clk) bound. > > Yes, DM_FLAG_BOUND means the clk has a udevice binded. > > > > > - If it has bounded device then we use dev->driver_data to get it's > > struct clk (or clock IP - like mux). If not, then we just use this > > clk. > > Yes. > > > > > Considering the above - the commit message needs detailed > > explanation of the "binding" concept. > > > > > The mux/gate/divider inside a > > > composite clk should not bind a device, because they needs to be > > > hidden from dm tree or clk dumps. > > > > > > If bind the mux/gate/divider insides a composite clk, that will be > > > mess. > > > > But the composite clock itself would be printed in 'dm tree' ? > > Yes. > > > > > If yes, maybe we can add some kind of indication that it is a > > "container" and that it has some clocks "binded" ? > > Looking at clk summary from Linux /sys/kernel/debug/clk/clk_summary, > There is no flag shows that it is a composite clk or not. > > I think only add a flag to show the clk is a container does not make > much sense.
Ok. I see. > > Thanks, > Peng. > > > > > > The reason to introduce composite clk is to make clk tree > > > cleaner/simplier. > > > > Ok. No problem with this. > > > > > > > > Regards, > > > Peng. > > > > > > > > > > > > So add clk_dev_binded to let > > > > > choose the correct method. > > > > > > > > > > > > > [1] - http://patchwork.ozlabs.org/cover/1090669/ > > > > > > > > > Signed-off-by: Peng Fan <peng....@nxp.com> > > > > > --- > > > > > drivers/clk/clk.c | 8 ++++++++ > > > > > include/clk.h | 9 +++++++++ > > > > > 2 files changed, 17 insertions(+) > > > > > > > > > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index > > > > > 0a0fffb50b..025bb99ecc 100644 > > > > > --- a/drivers/clk/clk.c > > > > > +++ b/drivers/clk/clk.c > > > > > @@ -54,3 +54,11 @@ const char *clk_hw_get_name(const struct > > > > > clk *hw) { > > > > > return hw->dev->name; > > > > > } > > > > > + > > > > > +bool clk_dev_binded(struct clk *clk) { > > > > > + if (clk->dev && (clk->dev->flags & DM_FLAG_BOUND)) > > > > > + return true; > > > > > + > > > > > + return false; > > > > > +} > > > > > diff --git a/include/clk.h b/include/clk.h index > > > > > a4ecca9fbc..8199119d01 100644 > > > > > --- a/include/clk.h > > > > > +++ b/include/clk.h > > > > > @@ -337,4 +337,13 @@ static inline bool clk_valid(struct clk > > > > > *clk) > > > > > * @return zero on success, or -ENOENT on error > > > > > */ > > > > > int clk_get_by_id(ulong id, struct clk **clkp); > > > > > + > > > > > +/** > > > > > + * clk_dev_binded() - Check whether the clk has a device > > > > > binded > > > > > + * > > > > > + * @clk A pointer to the clk > > > > > + * > > > > > + * @return true on binded, or false on no */ bool > > > > > +clk_dev_binded(struct clk *clk); > > > > > #endif > > > > > > > > > > > > > > > > > > > > Best regards, > > > > > > > > Lukasz Majewski > > > > > > > > -- > > > > > > > > DENX Software Engineering GmbH, Managing Director: Wolfgang > > > > Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 > > > > Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: > > > > (+49)-8142-66989-80 Email: lu...@denx.de > > > > > > > > > > Best regards, > > > > Lukasz Majewski > > > > -- > > > > DENX Software Engineering GmbH, Managing Director: Wolfgang > > Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, > > Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: > > lu...@denx.de Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lu...@denx.de
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