Re: [PATCH 2/2] pwm: hibvt: Add hi3559v100 support

[Thierry Reding <thierry.reding@gmail.com>]

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On Tue, Feb 12, 2019 at 03:28:50PM +0100, Uwe Kleine-König wrote:
> On Tue, Feb 12, 2019 at 10:49:27AM +0100, Mathieu Othacehe wrote:
> > Add support for hi3559v100-shub-pwm and hisilicon,hi3559v100-pwm
> > platforms. They require a special quirk: pwm has to be enabled again
> > to force duty_cycle refresh.
> > 
> > Signed-off-by: Mathieu Othacehe <m.othacehe@gmail.com>
> > ---
> >  drivers/pwm/pwm-hibvt.c | 26 +++++++++++++++++++++++---
> >  1 file changed, 23 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/pwm/pwm-hibvt.c b/drivers/pwm/pwm-hibvt.c
> > index 27c107e78d59..bf33aa24433c 100644
> > --- a/drivers/pwm/pwm-hibvt.c
> > +++ b/drivers/pwm/pwm-hibvt.c
> > @@ -49,6 +49,7 @@ struct hibvt_pwm_chip {
> >  	struct clk *clk;
> >  	void __iomem *base;
> >  	struct reset_control *rstc;
> > +	bool quirk_force_enable;
> >  };
> >  
> >  struct hibvt_pwm_soc {
> > @@ -56,6 +57,7 @@ struct hibvt_pwm_soc {
> >  };
> >  
> >  static const struct hibvt_pwm_soc pwm_soc[2] = {
> > +	{ .num_pwms = 2 },
> >  	{ .num_pwms = 4 },
> >  	{ .num_pwms = 8 },
> 
> The members of this struct are used as of-data (in struct
> of_device_id::data below). When looking at the usage:
> 
> 	{ .compatible = "hisilicon,hi3516cv300-pwm", .data = &pwm_soc[1] },
> 	{ .compatible = "hisilicon,hi3519v100-pwm", .data = &pwm_soc[2] },
> 	{ .compatible = "hisilicon,hi3559v100-shub-pwm", .data = &pwm_soc[2] },
> 	{ .compatible = "hisilicon,hi3559v100-pwm", .data = &pwm_soc[0] },
> 
> this isn't exactly easy to understand. I would prefer to do it as
> follows:
> 
> 	static const struct hibvt_pwm_soc hi3516cv300_soc_info = {
> 		.num_pwms = 2,
> 	};
> 	...
> 
> 	static const struct of_device_id hibvt_pwm_of_match[] = {
> 		{ .compatible = "hisilicon,hi3516cv300-pwm", .data = &hi3516cv300_soc_info },
> 		...
> 	};
> 
> Then you could also add a member to hibvt_pwm_soc to signal if that
> force_enable quirk is necessary and would not need to use
> of_device_is_compatible() to determine this. The result is that you have
> a description of all relevant differences in a single place.
> 
> @Thierry: Also this is yet another driver instance where a num-pwms
> property would simplify the driver because up to before this patch this
> was the only difference between the different variants.

We don't need the num-pwms in device tree if it can be derived from the
compatible string.

Thierry

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