linux-kernel - Re: [PATCH v4] Input: tsc2007 - enable cansleep pendown GPIO

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Message-ID: <ZCkXzQ38N44Y7H+I@google.com>
Date:   Sat, 1 Apr 2023 22:51:09 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Benjamin Bara <bbara93@...il.com>
Cc:     hns@...delico.com, richard.leitner@...ux.dev,
        christophe.jaillet@...adoo.fr, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Benjamin Bara <benjamin.bara@...data.com>
Subject: Re: [PATCH v4] Input: tsc2007 - enable cansleep pendown GPIO

Hi Benjamin,

On Thu, Mar 30, 2023 at 09:10:37PM +0200, Benjamin Bara wrote:
> From: Benjamin Bara <benjamin.bara@...data.com>
> 
> When a hard IRQ is triggered, the soft IRQ, which decides if an actual
> pen down happened, should always be triggered. This enables the usage of
> "can_sleep" GPIO chips as "pen down" GPIO, as the value is not read
> during the hard IRQ anymore. This might be the case if the GPIO chip is
> an expander behind i2c.
> 
> Signed-off-by: Benjamin Bara <benjamin.bara@...data.com>
> Signed-off-by: Richard Leitner <richard.leitner@...data.com>
> ---
> Hi!
> 
> I found a different approach to my problem:
> If the primary IRQ handler is set to NULL, the default primary IRQ
> handler simply triggers a soft IRQ handler wake up. As the hard IRQ is
> only triggered when a pen down is detected, the gpiod_get_value() inside
> tsc2007_is_pen_down() always returns true and therefore can be
> neglected.

Don't you need to switch to gpio_get_valued_cansleep() in
tsc2007_is_pen_down() to actually allow sleeping gpios?

Thanks.

-- 
Dmitry