Re: [PATCH v2 03/10] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation

Sascha Hauer
2016-11-01T08:59:47Z

On Mon, Oct 31, 2016 at 10:29:37AM +0100, Sascha Hauer wrote:
> > accesses. This is true for the ->config() callback, but not for the
> > ->set_enable() callback. Given that the ipg clock is not consistently
> > enabled for all register accesses we can assume that either it is not
> > required at all or that the current code does not work.
> > Remove the ipg clock code for now so that it's no longer in the way of
> > refactoring the driver.
>
> For reference:
>
> I verified on i.MX53 and i.MX25 that the ipg clock provided to the pwm
> driver is not needed when accessing registers. I would have to verify
> that on i.MX27 aswell, but I do not have a board handy at the moment.

Also on i.MX27 disabling the PWMs ipg_clk does not disable register
accesses.

Sascha

>
> The current assumption as discussed by Philipp and me is that the ipg
> clk is only needed when the pwm output is driven by the ipg clk
> (MX3_PWMCR[16:17] = MX3_PWMCR_CLKSRC_IPG)
>
> Sascha
>
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>

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Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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