linux-kernel - Re: [PATCH v3] Input - surface3_spi: add new driver for the Surface 3

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Message-ID: <20160517180428.GA9007@dtor-ws>
Date:	Tue, 17 May 2016 11:04:28 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
Cc:	Bastien Nocera <hadess@...ess.net>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] Input - surface3_spi: add new driver for the Surface 3

Hi Benjamin,

On Tue, May 17, 2016 at 12:16:19PM +0200, Benjamin Tissoires wrote:
> This is a basic driver for the Surface 3. I am not so sure it will work
> with any firmwares as most values are encoded, but given that I only have
> access to my current device with its firmware and I don't have the
> datasheet, it should be OK for now.
> 
> The Surface Pen is not supported (if it is supposed to be). I'll work on
> this when I get one.
> 
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
> ---
> Changes in v2:
> 
> - module renamed from ntrig_spi to surface3_spi
> - took into account Dmitry's remarks
> - kept the retrieval of the GPIO as mandatory as otherwise the device fails to work
> 
> Changes in v3:
> 
> - asm include put at the end
> - used proper types in struct surfacae3_ts_data_finger
> - dropped temps in surface3_spi_report_touch()
> - inlined surface3_spi_request_irq()
> - detect IRQ type (falling/rising) depending on the gpiod active low parameter

I do not think that this should be done in the driver. The device either
has interrupt descriptor or GpioInt decriptor in DSDT and SPI core/ACPI
should do the right thing and configure GPIO as input and set interrupt
polarity accordingly, so when you do request_threaded_irq() you only
need to specify IRQF_ONESHOT.

See drivers/spi/spi.c - in case there is no interrupt specified we call
acpi_dev_gpio_irq_get(). Do you see it called in your case? Or your DSDT
has interrupt for the touchscreen device and acpi_spi_add_resource() and
acpi_dev_resource_interrupt() are called? You need to trace it and
figure out if there is an issue there with setting up interrupt
properly.

Thanks.

-- 
Dmitry