wlcore/wl18xx: Add invert-irq OF property for physically inverted IRQ
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Message ID 20190607172958.20745-1-erosca@de.adit-jv.com
State Under Review
Delegated to: Geert Uytterhoeven
Headers show
Series
  • wlcore/wl18xx: Add invert-irq OF property for physically inverted IRQ
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Commit Message

Eugeniu Rosca June 7, 2019, 5:29 p.m. UTC
The wl1837mod datasheet [1] says about the WL_IRQ pin:

 ---8<---
SDIO available, interrupt out. Active high. [..]
Set to rising edge (active high) on powerup.
 ---8<---

That's the reason of seeing the interrupt configured as:
 - IRQ_TYPE_EDGE_RISING on HiKey 960/970
 - IRQ_TYPE_LEVEL_HIGH on a number of i.MX6 platforms

We assert that all those platforms have the WL_IRQ pin connected
to the SoC _directly_ (confirmed on HiKey 970 [2]).

That's not the case for R-Car Kingfisher extension target, which carries
a WL1837MODGIMOCT IC. There is an SN74LV1T04DBVR inverter present
between the WLAN_IRQ pin of the WL18* chip and the SoC, effectively
reversing the requirement quoted from [1]. IOW, in Kingfisher DTS
configuration we would need to use IRQ_TYPE_EDGE_FALLING or
IRQ_TYPE_LEVEL_LOW.

Unfortunately, v4.2-rc1 commit bd763482c82ea2 ("wl18xx: wlan_irq:
support platform dependent interrupt types") made a special case out
of these interrupt types. After this commit, it is impossible to provide
an IRQ configuration via DTS which would describe an inverter present
between the WL18* chip and the SoC, generating the need for workarounds
like [3].

Create a boolean OF property, called "invert-irq" to specify that
the WLAN_IRQ pin of WL18* is connected to the SoC via an inverter.

This solution has been successfully tested on R-Car H3ULCB-KF-M06 using
the DTS configuration [4] combined with the "invert-irq" property.

[1] http://www.ti.com/lit/ds/symlink/wl1837mod.pdf
[2] https://www.96boards.org/documentation/consumer/hikey/hikey970/hardware-docs/
[3] https://github.com/CogentEmbedded/meta-rcar/blob/289fbd4f8354/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0024-wl18xx-do-not-invert-IRQ-on-WLxxxx-side.patch
[4] https://patchwork.kernel.org/patch/10895879/
    ("arm64: dts: ulcb-kf: Add support for TI WL1837")

Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
---
 drivers/net/wireless/ti/wl18xx/main.c     | 5 +++++
 drivers/net/wireless/ti/wlcore/sdio.c     | 2 ++
 drivers/net/wireless/ti/wlcore/wlcore_i.h | 4 ++++
 3 files changed, 11 insertions(+)

Comments

Kalle Valo June 10, 2019, 7:01 a.m. UTC | #1
Eugeniu Rosca <erosca@de.adit-jv.com> writes:

> The wl1837mod datasheet [1] says about the WL_IRQ pin:
>
>  ---8<---
> SDIO available, interrupt out. Active high. [..]
> Set to rising edge (active high) on powerup.
>  ---8<---
>
> That's the reason of seeing the interrupt configured as:
>  - IRQ_TYPE_EDGE_RISING on HiKey 960/970
>  - IRQ_TYPE_LEVEL_HIGH on a number of i.MX6 platforms
>
> We assert that all those platforms have the WL_IRQ pin connected
> to the SoC _directly_ (confirmed on HiKey 970 [2]).
>
> That's not the case for R-Car Kingfisher extension target, which carries
> a WL1837MODGIMOCT IC. There is an SN74LV1T04DBVR inverter present
> between the WLAN_IRQ pin of the WL18* chip and the SoC, effectively
> reversing the requirement quoted from [1]. IOW, in Kingfisher DTS
> configuration we would need to use IRQ_TYPE_EDGE_FALLING or
> IRQ_TYPE_LEVEL_LOW.
>
> Unfortunately, v4.2-rc1 commit bd763482c82ea2 ("wl18xx: wlan_irq:
> support platform dependent interrupt types") made a special case out
> of these interrupt types. After this commit, it is impossible to provide
> an IRQ configuration via DTS which would describe an inverter present
> between the WL18* chip and the SoC, generating the need for workarounds
> like [3].
>
> Create a boolean OF property, called "invert-irq" to specify that
> the WLAN_IRQ pin of WL18* is connected to the SoC via an inverter.
>
> This solution has been successfully tested on R-Car H3ULCB-KF-M06 using
> the DTS configuration [4] combined with the "invert-irq" property.
>
> [1] http://www.ti.com/lit/ds/symlink/wl1837mod.pdf
> [2] https://www.96boards.org/documentation/consumer/hikey/hikey970/hardware-docs/
> [3] https://github.com/CogentEmbedded/meta-rcar/blob/289fbd4f8354/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0024-wl18xx-do-not-invert-IRQ-on-WLxxxx-side.patch
> [4] https://patchwork.kernel.org/patch/10895879/
>     ("arm64: dts: ulcb-kf: Add support for TI WL1837")
>
> Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>

Tony&Eyal, do you agree with this?
Tony Lindgren June 10, 2019, 8:30 a.m. UTC | #2
Hi,

* Kalle Valo <kvalo@codeaurora.org> [190610 07:01]:
> Eugeniu Rosca <erosca@de.adit-jv.com> writes:
> 
> > The wl1837mod datasheet [1] says about the WL_IRQ pin:
> >
> >  ---8<---
> > SDIO available, interrupt out. Active high. [..]
> > Set to rising edge (active high) on powerup.
> >  ---8<---
> >
> > That's the reason of seeing the interrupt configured as:
> >  - IRQ_TYPE_EDGE_RISING on HiKey 960/970
> >  - IRQ_TYPE_LEVEL_HIGH on a number of i.MX6 platforms
> >
> > We assert that all those platforms have the WL_IRQ pin connected
> > to the SoC _directly_ (confirmed on HiKey 970 [2]).
> >
> > That's not the case for R-Car Kingfisher extension target, which carries
> > a WL1837MODGIMOCT IC. There is an SN74LV1T04DBVR inverter present
> > between the WLAN_IRQ pin of the WL18* chip and the SoC, effectively
> > reversing the requirement quoted from [1]. IOW, in Kingfisher DTS
> > configuration we would need to use IRQ_TYPE_EDGE_FALLING or
> > IRQ_TYPE_LEVEL_LOW.
> >
> > Unfortunately, v4.2-rc1 commit bd763482c82ea2 ("wl18xx: wlan_irq:
> > support platform dependent interrupt types") made a special case out
> > of these interrupt types. After this commit, it is impossible to provide
> > an IRQ configuration via DTS which would describe an inverter present
> > between the WL18* chip and the SoC, generating the need for workarounds
> > like [3].
> >
> > Create a boolean OF property, called "invert-irq" to specify that
> > the WLAN_IRQ pin of WL18* is connected to the SoC via an inverter.
> >
> > This solution has been successfully tested on R-Car H3ULCB-KF-M06 using
> > the DTS configuration [4] combined with the "invert-irq" property.
> >
> > [1] http://www.ti.com/lit/ds/symlink/wl1837mod.pdf
> > [2] https://www.96boards.org/documentation/consumer/hikey/hikey970/hardware-docs/
> > [3] https://github.com/CogentEmbedded/meta-rcar/blob/289fbd4f8354/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0024-wl18xx-do-not-invert-IRQ-on-WLxxxx-side.patch
> > [4] https://patchwork.kernel.org/patch/10895879/
> >     ("arm64: dts: ulcb-kf: Add support for TI WL1837")
> >
> > Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
> 
> Tony&Eyal, do you agree with this?

Yeah if there's some hardware between the WLAN device and the SoC
inverting the interrupt, I don't think we have clear a way to deal
with it short of setting up a separate irqchip that does the
translation.

But in some cases we also do not want to invert the interrupt, so
I think this property should take IRQ_TYPE_EDGE_RISING and
IRQ_TYPE_EDGE_RISING values to override the setting for
the WLAN end of the hardware?

Let's wait a bit longer for comments from Eyal too.

Regards,

Tony
Geert Uytterhoeven June 11, 2019, 8:45 a.m. UTC | #3
CC irqchip

Original thread at
https://lore.kernel.org/lkml/20190607172958.20745-1-erosca@de.adit-jv.com/

On Mon, Jun 10, 2019 at 10:30 AM Tony Lindgren <tony@atomide.com> wrote:
> * Kalle Valo <kvalo@codeaurora.org> [190610 07:01]:
> > Eugeniu Rosca <erosca@de.adit-jv.com> writes:
> >
> > > The wl1837mod datasheet [1] says about the WL_IRQ pin:
> > >
> > >  ---8<---
> > > SDIO available, interrupt out. Active high. [..]
> > > Set to rising edge (active high) on powerup.
> > >  ---8<---
> > >
> > > That's the reason of seeing the interrupt configured as:
> > >  - IRQ_TYPE_EDGE_RISING on HiKey 960/970
> > >  - IRQ_TYPE_LEVEL_HIGH on a number of i.MX6 platforms
> > >
> > > We assert that all those platforms have the WL_IRQ pin connected
> > > to the SoC _directly_ (confirmed on HiKey 970 [2]).
> > >
> > > That's not the case for R-Car Kingfisher extension target, which carries
> > > a WL1837MODGIMOCT IC. There is an SN74LV1T04DBVR inverter present
> > > between the WLAN_IRQ pin of the WL18* chip and the SoC, effectively
> > > reversing the requirement quoted from [1]. IOW, in Kingfisher DTS
> > > configuration we would need to use IRQ_TYPE_EDGE_FALLING or
> > > IRQ_TYPE_LEVEL_LOW.
> > >
> > > Unfortunately, v4.2-rc1 commit bd763482c82ea2 ("wl18xx: wlan_irq:
> > > support platform dependent interrupt types") made a special case out
> > > of these interrupt types. After this commit, it is impossible to provide
> > > an IRQ configuration via DTS which would describe an inverter present
> > > between the WL18* chip and the SoC, generating the need for workarounds
> > > like [3].
> > >
> > > Create a boolean OF property, called "invert-irq" to specify that
> > > the WLAN_IRQ pin of WL18* is connected to the SoC via an inverter.
> > >
> > > This solution has been successfully tested on R-Car H3ULCB-KF-M06 using
> > > the DTS configuration [4] combined with the "invert-irq" property.
> > >
> > > [1] http://www.ti.com/lit/ds/symlink/wl1837mod.pdf
> > > [2] https://www.96boards.org/documentation/consumer/hikey/hikey970/hardware-docs/
> > > [3] https://github.com/CogentEmbedded/meta-rcar/blob/289fbd4f8354/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0024-wl18xx-do-not-invert-IRQ-on-WLxxxx-side.patch
> > > [4] https://patchwork.kernel.org/patch/10895879/
> > >     ("arm64: dts: ulcb-kf: Add support for TI WL1837")
> > >
> > > Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
> >
> > Tony&Eyal, do you agree with this?
>
> Yeah if there's some hardware between the WLAN device and the SoC
> inverting the interrupt, I don't think we have clear a way to deal
> with it short of setting up a separate irqchip that does the
> translation.

Yeah, inverting the interrupt type in DT works only for simple devices,
that don't need configuration.
A simple irqchip driver that just inverts the type sounds like a good
solution to me. Does something like that already exists?

> But in some cases we also do not want to invert the interrupt, so
> I think this property should take IRQ_TYPE_EDGE_RISING and
> IRQ_TYPE_EDGE_RISING values to override the setting for
> the WLAN end of the hardware?
>
> Let's wait a bit longer for comments from Eyal too.

Gr{oetje,eeting}s,

                        Geert
Marc Zyngier June 11, 2019, 9 a.m. UTC | #4
On 11/06/2019 09:45, Geert Uytterhoeven wrote:
> CC irqchip
> 
> Original thread at
> https://lore.kernel.org/lkml/20190607172958.20745-1-erosca@de.adit-jv.com/
> 
> On Mon, Jun 10, 2019 at 10:30 AM Tony Lindgren <tony@atomide.com> wrote:
>> * Kalle Valo <kvalo@codeaurora.org> [190610 07:01]:
>>> Eugeniu Rosca <erosca@de.adit-jv.com> writes:
>>>
>>>> The wl1837mod datasheet [1] says about the WL_IRQ pin:
>>>>
>>>>  ---8<---
>>>> SDIO available, interrupt out. Active high. [..]
>>>> Set to rising edge (active high) on powerup.
>>>>  ---8<---
>>>>
>>>> That's the reason of seeing the interrupt configured as:
>>>>  - IRQ_TYPE_EDGE_RISING on HiKey 960/970
>>>>  - IRQ_TYPE_LEVEL_HIGH on a number of i.MX6 platforms
>>>>
>>>> We assert that all those platforms have the WL_IRQ pin connected
>>>> to the SoC _directly_ (confirmed on HiKey 970 [2]).
>>>>
>>>> That's not the case for R-Car Kingfisher extension target, which carries
>>>> a WL1837MODGIMOCT IC. There is an SN74LV1T04DBVR inverter present
>>>> between the WLAN_IRQ pin of the WL18* chip and the SoC, effectively
>>>> reversing the requirement quoted from [1]. IOW, in Kingfisher DTS
>>>> configuration we would need to use IRQ_TYPE_EDGE_FALLING or
>>>> IRQ_TYPE_LEVEL_LOW.
>>>>
>>>> Unfortunately, v4.2-rc1 commit bd763482c82ea2 ("wl18xx: wlan_irq:
>>>> support platform dependent interrupt types") made a special case out
>>>> of these interrupt types. After this commit, it is impossible to provide
>>>> an IRQ configuration via DTS which would describe an inverter present
>>>> between the WL18* chip and the SoC, generating the need for workarounds
>>>> like [3].
>>>>
>>>> Create a boolean OF property, called "invert-irq" to specify that
>>>> the WLAN_IRQ pin of WL18* is connected to the SoC via an inverter.
>>>>
>>>> This solution has been successfully tested on R-Car H3ULCB-KF-M06 using
>>>> the DTS configuration [4] combined with the "invert-irq" property.
>>>>
>>>> [1] http://www.ti.com/lit/ds/symlink/wl1837mod.pdf
>>>> [2] https://www.96boards.org/documentation/consumer/hikey/hikey970/hardware-docs/
>>>> [3] https://github.com/CogentEmbedded/meta-rcar/blob/289fbd4f8354/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0024-wl18xx-do-not-invert-IRQ-on-WLxxxx-side.patch
>>>> [4] https://patchwork.kernel.org/patch/10895879/
>>>>     ("arm64: dts: ulcb-kf: Add support for TI WL1837")
>>>>
>>>> Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
>>>
>>> Tony&Eyal, do you agree with this?
>>
>> Yeah if there's some hardware between the WLAN device and the SoC
>> inverting the interrupt, I don't think we have clear a way to deal
>> with it short of setting up a separate irqchip that does the
>> translation.
> 
> Yeah, inverting the interrupt type in DT works only for simple devices,
> that don't need configuration.
> A simple irqchip driver that just inverts the type sounds like a good
> solution to me. Does something like that already exists?

We already have plenty of that in the tree, the canonical example
probably being drivers/irqchip/irq-mtk-sysirq.c. It should be pretty
easy to turn this driver into something more generic.

Thanks,

	M.
Eugeniu Rosca June 12, 2019, 9:45 a.m. UTC | #5
Hi,

cc: Linus Walleij

On Tue, Jun 11, 2019 at 10:00:41AM +0100, Marc Zyngier wrote:
> On 11/06/2019 09:45, Geert Uytterhoeven wrote:
> > CC irqchip
> > 
> > Original thread at
> > https://lore.kernel.org/lkml/20190607172958.20745-1-erosca@de.adit-jv.com/
> > 
> > On Mon, Jun 10, 2019 at 10:30 AM Tony Lindgren <tony@atomide.com> wrote:
> >> * Kalle Valo <kvalo@codeaurora.org> [190610 07:01]:
> >>> Eugeniu Rosca <erosca@de.adit-jv.com> writes:
> >>>
> >>>> The wl1837mod datasheet [1] says about the WL_IRQ pin:
> >>>>
> >>>>  ---8<---
> >>>> SDIO available, interrupt out. Active high. [..]
> >>>> Set to rising edge (active high) on powerup.
> >>>>  ---8<---
> >>>>
> >>>> That's the reason of seeing the interrupt configured as:
> >>>>  - IRQ_TYPE_EDGE_RISING on HiKey 960/970
> >>>>  - IRQ_TYPE_LEVEL_HIGH on a number of i.MX6 platforms
> >>>>
> >>>> We assert that all those platforms have the WL_IRQ pin connected
> >>>> to the SoC _directly_ (confirmed on HiKey 970 [2]).
> >>>>
> >>>> That's not the case for R-Car Kingfisher extension target, which carries
> >>>> a WL1837MODGIMOCT IC. There is an SN74LV1T04DBVR inverter present
> >>>> between the WLAN_IRQ pin of the WL18* chip and the SoC, effectively
> >>>> reversing the requirement quoted from [1]. IOW, in Kingfisher DTS
> >>>> configuration we would need to use IRQ_TYPE_EDGE_FALLING or
> >>>> IRQ_TYPE_LEVEL_LOW.
> >>>>
> >>>> Unfortunately, v4.2-rc1 commit bd763482c82ea2 ("wl18xx: wlan_irq:
> >>>> support platform dependent interrupt types") made a special case out
> >>>> of these interrupt types. After this commit, it is impossible to provide
> >>>> an IRQ configuration via DTS which would describe an inverter present
> >>>> between the WL18* chip and the SoC, generating the need for workarounds
> >>>> like [3].
> >>>>
> >>>> Create a boolean OF property, called "invert-irq" to specify that
> >>>> the WLAN_IRQ pin of WL18* is connected to the SoC via an inverter.
> >>>>
> >>>> This solution has been successfully tested on R-Car H3ULCB-KF-M06 using
> >>>> the DTS configuration [4] combined with the "invert-irq" property.
> >>>>
> >>>> [1] http://www.ti.com/lit/ds/symlink/wl1837mod.pdf
> >>>> [2] https://www.96boards.org/documentation/consumer/hikey/hikey970/hardware-docs/
> >>>> [3] https://github.com/CogentEmbedded/meta-rcar/blob/289fbd4f8354/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0024-wl18xx-do-not-invert-IRQ-on-WLxxxx-side.patch
> >>>> [4] https://patchwork.kernel.org/patch/10895879/
> >>>>     ("arm64: dts: ulcb-kf: Add support for TI WL1837")
> >>>>
> >>>> Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
> >>>
> >>> Tony&Eyal, do you agree with this?
> >>
> >> Yeah if there's some hardware between the WLAN device and the SoC
> >> inverting the interrupt, I don't think we have clear a way to deal
> >> with it short of setting up a separate irqchip that does the
> >> translation.
> > 
> > Yeah, inverting the interrupt type in DT works only for simple devices,
> > that don't need configuration.
> > A simple irqchip driver that just inverts the type sounds like a good
> > solution to me. Does something like that already exists?
> 
> We already have plenty of that in the tree, the canonical example
> probably being drivers/irqchip/irq-mtk-sysirq.c. It should be pretty
> easy to turn this driver into something more generic.

I don't think drivers/irqchip/irq-mtk-sysirq.c can serve the
use-case/purpose of this patch. The MTK driver seems to be dealing with
the polarity inversion of on-SoC interrupts which are routed to GiC,
whereas in this patch we are talking about an off-chip interrupt
wired to R-Car GPIO controller.

It looks to me that the nice DTS sketch shared by Linus Walleij in [5]
might come closer to the concept proposed by Geert? FWIW, the
infrastructure/implementation to make this possible is still not ready.

One question to the wlcore/wl18xx maintainers: Why exactly do you give
freedom to users to set the interrupt as LEVEL_LOW/EDGE_FALLING [6]?
Apparently, this:
 - complicates the wl18xx driver, thus increasing the chance for bugs
 - is not supposed to reflect any HW differences between boards using
   LEVEL_LOW/EDGE_FALLING and the boards using LEVEL_HIGH/EDGE_RISING
 - doesn't bring any obvious advantage to the users, who are expected to
   sense the same behavior regardless of the IRQ type set in DTS
 - prevent the users to set IRQ type to LEVEL_LOW/EDGE_FALLING when
   there is an inverter present between WL_IRQ and SoC
 - seems to be not used almost at all, as 99% of mainline DTS set the
   IRQ type to the canonical/NLCP LEVEL_HIGH/EDGE_RISING

[5] https://patchwork.ozlabs.org/patch/1095690/#2167076
  ("[V1,1/2] gpio: make it possible to set active-state on GPIO lines")
 --------------------8<-------------------
 gpio0: gpio {
    compatible = "foo,chip";
    gpio-controller;
    (...)
 };

 inv0: inverter {
     compatible = "inverter";
     gpio-controller;
     gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
 };

 consumer {
    compatible = "bar";
    gpios = <&inv0 0 GPIO_ACTIVE_HIGH>;
 };
 --------------------8<-------------------

[6] bd763482c82ea2 ("wl18xx: wlan_irq: support platform dependent interrupt types")
Eugeniu Rosca June 12, 2019, 3:06 p.m. UTC | #6
Hi Marc,

Thanks for your comment.

On Wed, Jun 12, 2019 at 11:17:10AM +0100, Marc Zyngier wrote:
> Eugeniu Rosca <erosca@de.adit-jv.com> wrote:
> > On Tue, Jun 11, 2019 at 10:00:41AM +0100, Marc Zyngier wrote:
[..]
> > > We already have plenty of that in the tree, the canonical example
> > > probably being drivers/irqchip/irq-mtk-sysirq.c. It should be pretty
> > > easy to turn this driver into something more generic.
> > 
> > I don't think drivers/irqchip/irq-mtk-sysirq.c can serve the
> > use-case/purpose of this patch. The MTK driver seems to be dealing with
> > the polarity inversion of on-SoC interrupts which are routed to GiC,
> > whereas in this patch we are talking about an off-chip interrupt
> > wired to R-Car GPIO controller.
> 
> And how different is that? The location of the interrupt source is
> pretty irrelevant here.

The main difference which I sense is that a driver like irq-mtk-sysirq
mostly (if not exclusively) deals with internal kernel implementation
detail (tuned via DT) whilst adding an inverter for GPIO IRQs raises
a whole bunch of new questions (e.g. how to arbitrate between
kernel-space and user-space IRQ polarity configuration?).

> The point is that there is already a general
> scheme to deal with these "signal altering widgets", and that we
> should try to reuse at least the concept, if not the code.

Since Harish Jenny K N might be working on a new driver doing GPIO IRQ
inversion, I have CC-ed him as well to avoid any overlapping work.

> 
> > It looks to me that the nice DTS sketch shared by Linus Walleij in [5]
> > might come closer to the concept proposed by Geert? FWIW, the
> > infrastructure/implementation to make this possible is still not
> > ready.
> 
> Which looks like what I'm suggesting.

Then we are on the same page. Thanks.

> 
> 	M.
> 
> -- 
> Jazz is not dead, it just smells funny.
Harish Jenny K N June 13, 2019, 4:36 a.m. UTC | #7
On 12/06/19 8:36 PM, Eugeniu Rosca wrote:
> Hi Marc,
>
> Thanks for your comment.
>
> On Wed, Jun 12, 2019 at 11:17:10AM +0100, Marc Zyngier wrote:
>> Eugeniu Rosca <erosca@de.adit-jv.com> wrote:
>>> On Tue, Jun 11, 2019 at 10:00:41AM +0100, Marc Zyngier wrote:
> [..]
>>>> We already have plenty of that in the tree, the canonical example
>>>> probably being drivers/irqchip/irq-mtk-sysirq.c. It should be pretty
>>>> easy to turn this driver into something more generic.
>>> I don't think drivers/irqchip/irq-mtk-sysirq.c can serve the
>>> use-case/purpose of this patch. The MTK driver seems to be dealing with
>>> the polarity inversion of on-SoC interrupts which are routed to GiC,
>>> whereas in this patch we are talking about an off-chip interrupt
>>> wired to R-Car GPIO controller.
>> And how different is that? The location of the interrupt source is
>> pretty irrelevant here.
> The main difference which I sense is that a driver like irq-mtk-sysirq
> mostly (if not exclusively) deals with internal kernel implementation
> detail (tuned via DT) whilst adding an inverter for GPIO IRQs raises
> a whole bunch of new questions (e.g. how to arbitrate between
> kernel-space and user-space IRQ polarity configuration?).
>
>> The point is that there is already a general
>> scheme to deal with these "signal altering widgets", and that we
>> should try to reuse at least the concept, if not the code.
> Since Harish Jenny K N might be working on a new driver doing GPIO IRQ
> inversion, I have CC-ed him as well to avoid any overlapping work.


Sorry I am not completely aware of the background discussion.

But here is the link to my proposal for new consumer driver to provide a new virtual
gpio controller to configure the polarity of the gpio pins used by the userspace.

https://www.spinics.net/lists/linux-gpio/msg39681.html


>
>>> It looks to me that the nice DTS sketch shared by Linus Walleij in [5]
>>> might come closer to the concept proposed by Geert? FWIW, the
>>> infrastructure/implementation to make this possible is still not
>>> ready.
>> Which looks like what I'm suggesting.
> Then we are on the same page. Thanks.
>
>> 	M.
>>
>> -- 
>> Jazz is not dead, it just smells funny.
Kalle Valo July 24, 2019, 11:14 a.m. UTC | #8
Eugeniu Rosca <erosca@de.adit-jv.com> wrote:

> The wl1837mod datasheet [1] says about the WL_IRQ pin:
> 
>  ---8<---
> SDIO available, interrupt out. Active high. [..]
> Set to rising edge (active high) on powerup.
>  ---8<---
> 
> That's the reason of seeing the interrupt configured as:
>  - IRQ_TYPE_EDGE_RISING on HiKey 960/970
>  - IRQ_TYPE_LEVEL_HIGH on a number of i.MX6 platforms
> 
> We assert that all those platforms have the WL_IRQ pin connected
> to the SoC _directly_ (confirmed on HiKey 970 [2]).
> 
> That's not the case for R-Car Kingfisher extension target, which carries
> a WL1837MODGIMOCT IC. There is an SN74LV1T04DBVR inverter present
> between the WLAN_IRQ pin of the WL18* chip and the SoC, effectively
> reversing the requirement quoted from [1]. IOW, in Kingfisher DTS
> configuration we would need to use IRQ_TYPE_EDGE_FALLING or
> IRQ_TYPE_LEVEL_LOW.
> 
> Unfortunately, v4.2-rc1 commit bd763482c82ea2 ("wl18xx: wlan_irq:
> support platform dependent interrupt types") made a special case out
> of these interrupt types. After this commit, it is impossible to provide
> an IRQ configuration via DTS which would describe an inverter present
> between the WL18* chip and the SoC, generating the need for workarounds
> like [3].
> 
> Create a boolean OF property, called "invert-irq" to specify that
> the WLAN_IRQ pin of WL18* is connected to the SoC via an inverter.
> 
> This solution has been successfully tested on R-Car H3ULCB-KF-M06 using
> the DTS configuration [4] combined with the "invert-irq" property.
> 
> [1] http://www.ti.com/lit/ds/symlink/wl1837mod.pdf
> [2] https://www.96boards.org/documentation/consumer/hikey/hikey970/hardware-docs/
> [3] https://github.com/CogentEmbedded/meta-rcar/blob/289fbd4f8354/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0024-wl18xx-do-not-invert-IRQ-on-WLxxxx-side.patch
> [4] https://patchwork.kernel.org/patch/10895879/
>     ("arm64: dts: ulcb-kf: Add support for TI WL1837")
> 
> Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>

Based on the discussion I'm dropping this. Please resend once there's a
conclusion.

Patch set to Changes Requested.

Patch
diff mbox series

diff --git a/drivers/net/wireless/ti/wl18xx/main.c b/drivers/net/wireless/ti/wl18xx/main.c
index 496b9b63cea1..cea91d1aee98 100644
--- a/drivers/net/wireless/ti/wl18xx/main.c
+++ b/drivers/net/wireless/ti/wl18xx/main.c
@@ -877,6 +877,8 @@  static int wl18xx_pre_boot(struct wl1271 *wl)
 
 static int wl18xx_pre_upload(struct wl1271 *wl)
 {
+	struct platform_device *pdev = wl->pdev;
+	struct wlcore_platdev_data *pdata = dev_get_platdata(&pdev->dev);
 	u32 tmp;
 	int ret;
 	u16 irq_invert;
@@ -932,6 +934,9 @@  static int wl18xx_pre_upload(struct wl1271 *wl)
 	if (ret < 0)
 		goto out;
 
+	if (pdata->invert_irq)
+		goto out;
+
 	ret = irq_get_trigger_type(wl->irq);
 	if ((ret == IRQ_TYPE_LEVEL_LOW) || (ret == IRQ_TYPE_EDGE_FALLING)) {
 		wl1271_info("using inverted interrupt logic: %d", ret);
diff --git a/drivers/net/wireless/ti/wlcore/sdio.c b/drivers/net/wireless/ti/wlcore/sdio.c
index 4d4b07701149..581f56b0b6a2 100644
--- a/drivers/net/wireless/ti/wlcore/sdio.c
+++ b/drivers/net/wireless/ti/wlcore/sdio.c
@@ -266,6 +266,8 @@  static int wlcore_probe_of(struct device *dev, int *irq, int *wakeirq,
 	of_property_read_u32(np, "tcxo-clock-frequency",
 			     &pdev_data->tcxo_clock_freq);
 
+	pdev_data->invert_irq = of_property_read_bool(np, "invert-irq");
+
 	return 0;
 }
 #else
diff --git a/drivers/net/wireless/ti/wlcore/wlcore_i.h b/drivers/net/wireless/ti/wlcore/wlcore_i.h
index 32ec121ccac2..01679f9d7170 100644
--- a/drivers/net/wireless/ti/wlcore/wlcore_i.h
+++ b/drivers/net/wireless/ti/wlcore/wlcore_i.h
@@ -213,6 +213,10 @@  struct wlcore_platdev_data {
 	u32 ref_clock_freq;	/* in Hertz */
 	u32 tcxo_clock_freq;	/* in Hertz, tcxo is always XTAL */
 	bool pwr_in_suspend;
+	bool invert_irq;	/* specify if there is a physical IRQ inverter
+				 * between WL chip and SoC, like SN74LV1T04DBVR
+				 * in case of R-Car Kingfisher board
+				 */
 };
 
 #define MAX_NUM_KEYS 14