Re: [PATCH 2/5] pwm: Add support for the MSTAR MSC313 PWM

From: Uwe Kleine-König
Date: Fri Aug 19 2022 - 10:47:25 EST


Hello Romain,

On Fri, Aug 19, 2022 at 03:12:56PM +0200, Romain Perier wrote:
> Le dim. 19 juin 2022 à 23:35, Uwe Kleine-König
> <u.kleine-koenig@xxxxxxxxxxxxxx> a écrit :
> > > +static void msc313e_pwm_writecounter(struct regmap_field *low, struct regmap_field *high, u32 value)
> > > +{
> > > + regmap_field_write(low, value);
> > > + regmap_field_write(high, value >> 16);
> >
> > Is this racy? E.g. if the hw is running and the low register overflows
> > before the high register is updated?
> >
>
> Ack, I am re-working most of the stuff you noticed. The problem with
> this IP blocks (and others...) is we have close registers
> but we only need to write or read 16 bits in each of these (it is
> mainly reverse engineered from vendor source or runtime most of the
> time) . You cannot really do a single read (except by doing an obscur
> thing via readq ? ...)

This is fine, but pleast document that in a comment.

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
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