linux-kernel - Re: [PATCH 01/10] spi: dw: Add support for polled operation via no IRQ specified in DT

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Date:   Wed, 13 May 2020 17:55:50 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Lars Povlsen <lars.povlsen@...rochip.com>
Cc:     Mark Brown <broonie@...nel.org>, SoC Team <soc@...nel.org>,
        Microchip Linux Driver Support <UNGLinuxDriver@...rochip.com>,
        linux-spi <linux-spi@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
Subject: Re: [PATCH 01/10] spi: dw: Add support for polled operation via no
 IRQ specified in DT

On Wed, May 13, 2020 at 5:03 PM Lars Povlsen <lars.povlsen@...rochip.com> wrote:
>
> With this change a SPI controller can be added without having a IRQ
> associated, and causing all transfers to be polled. For SPI controllers
> without DMA, this can significantly improve performance by less
> interrupt handling overhead.

...

> +#define VALID_IRQ(i) (i >= 0)

drivers/rtc/rtc-cmos.c:95:#define is_valid_irq(n)               ((n) > 0)

Candidate to be in include/linux/irq.h ?

...

> +       if (VALID_IRQ(dws->irq))
> +               free_irq(dws->irq, master);

Isn't free_irq() aware of invalid ones (not found IRQ in the tree or
any other backend container won't do anything)?


>  err_free_master:
>         spi_controller_put(master);
>         return ret;
> --
> 2.26.2



--
With Best Regards,
Andy Shevchenko