linux-kernel - Re: [PATCH v2] spi: bcm2835: Enable shared interrupt support

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Message-ID: <20200605105100.kxe6wgh5itmhrgl2@wunner.de>
Date:   Fri, 5 Jun 2020 12:51:00 +0200
From:   Lukas Wunner <lukas@...ner.de>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        "maintainer:BROADCOM BCM281XX/BCM11XXX/BCM216XX ARM ARCHITE..." 
        <bcm-kernel-feedback-list@...adcom.com>,
        "open list:SPI SUBSYSTEM" <linux-spi@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-rpi-kernel@...ts.infradead.org>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        Martin Sperl <kernel@...tin.sperl.org>
Subject: Re: [PATCH v2] spi: bcm2835: Enable shared interrupt support

On Thu, Jun 04, 2020 at 02:28:19PM -0700, Florian Fainelli wrote:
> The 4 SPI controller instances added in BCM2711 and BCM7211 SoCs (SPI3,
> SPI4, SPI5 and SPI6) share the same interrupt line with SPI0.
> 
> For the BCM2835 case which is deemed performance critical, we would like
> to continue using an interrupt handler which does not have the extra
> comparison on BCM2835_SPI_CS_INTR.
> 
> To support that requirement the common interrupt handling code between
> the shared and non-shared interrupt paths is split into a
> bcm2835_spi_interrupt_common() and both bcm2835_spi_interrupt() as well
> as bcm2835_spi_shared_interrupt() make use of it.
> 
> During probe, we determine if there is at least another instance of this
> SPI controller, and if there is, then we install a shared interrupt
> handler.
> 
> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>

Reviewed-by: Lukas Wunner <lukas@...ner.de>