Re: [PATCH v2] clk: keystone: sci-clk: Adding support for non contiguous clocks

[CHANDRU DHAVAMANI]

On 07/02/24 11:03, Kumar, Udit wrote:
> On 2/6/2024 9:24 PM, Kamlesh Gurudasani wrote:
> > "Kumar, Udit" <u-kumar1@xxxxxx> writes:
> >
> > > > > > > get_freq is a bit expensive as it has to walk the clock tree to 
> > > > > > > find
> > > > > > > the clock frequency (at least the first time?). just wondering if
> > > > > > > there is lighter alternative here?
> > > > > > How about get_clock? Doesn't read the registers at least.
> > > > > Said API needs, some flags to be passed,
> > > > >
> > > > > Can those flag be set to zero, Chandru ?
> > > >
> > > > get_clock doesn't require any flags to be passed.
> > >
> > > May be firmware does not need it but  I was referring to
> > >
> > > https://elixir.bootlin.com/linux/latest/source/drivers/clk/keystone/sci-clk.c#L78 
> > Just took a look,
> >
> > I now understand the reason for confusion,
> >
> > #define TI_SCI_MSG_SET_CLOCK_STATE    0x0100
> > #define TI_SCI_MSG_GET_CLOCK_STATE    0x0101
> >
> > cops->get_clock = ti_sci_cmd_get_clock;  --> refers to
> > TI_SCI_MSG_SET_CLOCK_STATE
> > That's why we are passing the flag from linux for get_clock
> >
> > Linux is using terminology of get/put.
> >
> > As Chandru pointed, we don't have to pass flags, cause he is refering
> > to TI_SCI_MSG_GET_CLOCK_STATE
> >
> > Below functions passes TI_SCI_MSG_GET_CLOCK_STATE to DM, which is what
> > we actually want.
> > cops->is_auto = ti_sci_cmd_clk_is_auto;
> > cops->is_on = ti_sci_cmd_clk_is_on;
> > cops->is_off = ti_sci_cmd_clk_is_off;
>
>
> I think calling ti_sci_cmd_clk_is_auto should be good . other 
> functions needs current state and requested state.
>
> Chandru ?

ti_sci_cmd_clk_is_auto is internal function to linux.
For TI_SCI_MSG_GET_CLOCK_STATE, linux only needs to pass pointers to the 
variables where result will be stored.


> > Which should be safe to call, Chandru can confirm.
> >
> > Regards,
> > Kamlesh
> > > > > > Regards,
> > > > > > Kamlesh