Re: [PATCH v3 1/3] dt-bindings: pwm: imx: Add optional clock '32k'

[Marek Vasut]

On 9/12/24 12:19 AM, Frank Li wrote:
> On Wed, Sep 11, 2024 at 11:14:15PM +0200, Marek Vasut wrote:
> > On 9/11/24 11:10 PM, Frank Li wrote:
> > > On Wed, Sep 11, 2024 at 10:28:52PM +0200, Marek Vasut wrote:
> > > > On 9/10/24 9:07 PM, Frank Li wrote:
> > > > > The pwm in imx8qxp mipi subsystem require one extra '32k' clock. So
> > > > > increase maxItems for clock and clock-names.
> > > >
> > > > This mentions MIPI subsystem, but the IP in question here is PWM.
> > >
> > > Here, mipi just name of subsystem, not related MIPI IP at all.
> > >
> > > There are many IP in i.MX8QXP mipi subsystem, such as i2c, PWM, MIPI PHY,
> > > MIPI controller, PLL, clock-gate, ...
> > >
> > > > Are you sure the clock are assigned to the correct IP ?
> > > >
> > > > Shouldn't the clock be assigned to some MIPI IP instead ?
> > >
> > > Are both question still validate if treat 'mipi' just name of subsystem.
> > >
> > > > Could you please clarify this in the commit message ?
> > >
> > > 'mipi' just name of subsystem because the major ip is for MIPI. is word
> > > 'mipi-subsystem' better?
> > Let's find out.
> >
> > What is the 32kHz clock used for in the PWM block ?
>
> After read document again, it is one option of input, CLKSRC in PWMCR.
Thank you for checking.

It seems PWMCR CLKSRC is currently hard-coded to IPG_HIGH in this PWM 
driver, so the 32kHz clock are currently not used ?

The question is, does it make sense to add them ? And if so, what would 
be the use case compared to current IPG_HIGH ?