linux-kernel - Re: [PATCH] regmap: regmap-irq/gpio-max77620: add level-irq support

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Date:   Tue, 11 Dec 2018 08:38:25 +0200
From:   Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
To:     Vladimir Zapolskiy <vladimir_zapolskiy@...tor.com>
Cc:     mazziesaccount@...il.com, broonie@...nel.org,
        gregkh@...uxfoundation.org, rafael@...nel.org,
        linus.walleij@...aro.org, linux-kernel@...r.kernel.org,
        linux-gpio@...r.kernel.org, heikki.haikola@...rohmeurope.com,
        mikko.mutanen@...rohmeurope.com
Subject: Re: [PATCH] regmap: regmap-irq/gpio-max77620: add level-irq support

Hello Vladimir,

Thanks for the review.

On Mon, Dec 10, 2018 at 05:16:28PM +0200, Vladimir Zapolskiy wrote:
> On 12/10/2018 10:14 AM, Matti Vaittinen wrote:
> > Add level active IRQ support to regmap-irq irqchip. Change breaks
> > existing regmap-irq type setting. Convert the existing drivers which
> > use regmap-irq with trigger type setting (gpio-max77620) to work
> > with this new approach. So we do not magically support level-active
> > IRQs on gpio-max77620 - but add support to the regmap-irq for chips
> > which support them =)
> > 
> > We do not support distinguishing situation where HW supports rising
> > and falling edge detection but not both. Separating this would require
> > inventing yet another flags for IRQ types.
> > 
> > Signed-off-by: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
> > ---
> > I did both the regmap-irq and max77620 changes in same commit because
> > I'd rather not cause spot where max77620 breaks. Besides the changes in
> > max77620 driver are trivial. Please let me know if this is not Ok.
> > 
> > Reason why I submit this patch now - even though my driver which would
> > use level active type setting with regmap-irq is not yet ready for
> > being submited - is that I'd like to minimize amount of existing drivers
> > we need to patch. And if we add level active irq support like this then
> > we must patch all existing drivers using type setting with regmap-irq.
> > So doing this now when only max77620 uses type setting may be easier
> > than postponing this to the future.
> > 
> > And finally - I don't have max77620 so I have only done _wery_ limited
> > testing. So I would really appreciate if someone had time to review this
> > thoroughly - and even happier if someone had possibility to try this out
> > with the max77620.
> > 
> 
> [snip]
> 
> > diff --git a/include/linux/regmap.h b/include/linux/regmap.h
> > index a367d59c301d..91c431ad98c3 100644
> > --- a/include/linux/regmap.h
> > +++ b/include/linux/regmap.h
> > @@ -1098,6 +1098,9 @@ int regmap_fields_update_bits_base(struct regmap_field *field,  unsigned int id,
> >   * @type_reg_offset: Offset register for the irq type setting.
> >   * @type_rising_mask: Mask bit to configure RISING type irq.
> >   * @type_falling_mask: Mask bit to configure FALLING type irq.
> > + * @type_level_low_mask: Mask bit to configure LEVEL_LOW type irq.
> > + * @type_level_high_mask: Mask bit to configure LEVEL_HIGH type irq.
> > + * @types_supported: logical OR of IRQ_TYPE_* flags indicating supported types.
> 
> While the existing interface is awful, you don't make it better.
> 
> .types_supported value is always derived from non-zero .type_*_mask values, so
> it is simply not needed, as well as the whole change to gpio-max77620.c driver.

Right. I didn't consider the "type_inverted" flag in the struct
regmap_irq_chip. I thought that "mask" is actually a register value -
which could be zero for some HWs. Thanks for pointing that out. It will
really make "types_supported" useless.

So please just drop this patch for now. There seems to be no need to
touch the existing regmap-irq users after all so I can submit this patch
together with the driver which needs to support the level active IRQs.

> 
> >   */
> >  struct regmap_irq {
> >  	unsigned int reg_offset;
> > @@ -1105,6 +1108,9 @@ struct regmap_irq {
> >  	unsigned int type_reg_offset;
> >  	unsigned int type_rising_mask;
> >  	unsigned int type_falling_mask;
> > +	unsigned int type_level_low_mask;
> > +	unsigned int type_level_high_mask;
> > +	unsigned int types_supported;
> >  };
> >  
> >  #define REGMAP_IRQ_REG(_irq, _off, _mask)		\
> > 
> 
> --
> Best wishes,
> Vladimir

-- 
Matti Vaittinen
ROHM Semiconductors

~~~ "I don't think so," said Rene Descartes.  Just then, he vanished ~~~