linux-kernel - Re: [PATCH v2 07/13] i2c: acpi: Use ACPI wake capability bit to set wake

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Message-ID: <YyAxBtAD2wL91quT@shikoro>
Date:   Tue, 13 Sep 2022 08:28:06 +0100
From:   Wolfram Sang <wsa@...nel.org>
To:     Raul E Rangel <rrangel@...omium.org>
Cc:     linux-acpi@...r.kernel.org, linux-input@...r.kernel.org,
        andriy.shevchenko@...ux.intel.com, jingle.wu@....com.tw,
        mario.limonciello@....com, timvp@...gle.com,
        linus.walleij@...aro.org, hdegoede@...hat.com, rafael@...nel.org,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 07/13] i2c: acpi: Use ACPI wake capability bit to set
 wake_irq

On Mon, Sep 12, 2022 at 04:13:11PM -0600, Raul E Rangel wrote:
> Device tree already has a mechanism to pass the wake_irq. It does this
> by looking for the wakeup-source property and setting the
> I2C_CLIENT_WAKE flag. This CL adds the ACPI equivalent. It uses the
> ACPI interrupt wake flag to determine if the interrupt can be used to
> wake the system. Previously the i2c drivers had to make assumptions and
> blindly enable the wake IRQ. This can cause spurious wake events. e.g.,
> If there is a device with an Active Low interrupt and the device gets
> powered off while suspending, the interrupt line will go low since it's
> no longer powered and wakes the system. For this reason we should
> respect the board designers wishes and honor the wake bit defined on the
> interrupt.

I'll let the I2C ACPI maintainers deal with the technical details
because they are the experts here, yet one minor thing hits my eye:

> +		irq_ctx.irq = acpi_dev_gpio_irq_get_wake(
> +			adev, 0, &irq_ctx.wake_capable);

That line split looks weird with the open parens at the end of line 1.


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