Re: [PATCH] wlcore/wl18xx: Add invert-irq OF property for physically inverted IRQ

[Kalle Valo]

Eugeniu Rosca <erosca@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>

Tony&Eyal, do you agree with this?

-- 
Kalle Valo