RE: [PATCH v8 2/3] Input: adp5588-keys - add support for pure gpio

[Agarwal, Utsav]

> -----Original Message-----
> From: Nuno Sá <noname.nuno@xxxxxxxxx>
> Sent: Monday, August 5, 2024 7:44 AM
> To: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>; Agarwal, Utsav
> <Utsav.Agarwal@xxxxxxxxxx>
> Cc: Hennerich, Michael <Michael.Hennerich@xxxxxxxxxx>; Rob Herring
> <robh@xxxxxxxxxx>; Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx>; Conor Dooley
> <conor+dt@xxxxxxxxxx>; Sa, Nuno <Nuno.Sa@xxxxxxxxxx>; linux-
> input@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Artamonovs, Arturs
> <Arturs.Artamonovs@xxxxxxxxxx>; Bimpikas, Vasileios
> <Vasileios.Bimpikas@xxxxxxxxxx>; Gaskell, Oliver
> <Oliver.Gaskell@xxxxxxxxxx>
> Subject: Re: [PATCH v8 2/3] Input: adp5588-keys - add support for pure gpio
> 
> [External]
> 
> On Fri, 2024-08-02 at 17:37 -0700, Dmitry Torokhov wrote:
> > Hi Utsav,
> >
> > On Thu, Jul 04, 2024 at 03:26:31PM +0100, Utsav Agarwal via B4 Relay wrote:
> > > From: Utsav Agarwal <utsav.agarwal@xxxxxxxxxx>
> > >
> > > Keypad specific setup is relaxed if no keypad rows/columns are specified,
> > > enabling a purely gpio operation.
> > >
> > > Signed-off-by: Utsav Agarwal <utsav.agarwal@xxxxxxxxxx>
> > > ---
> > >  drivers/input/keyboard/adp5588-keys.c | 37
> +++++++++++++++++++++++++++++++-
> > > ---
> > >  1 file changed, 33 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/input/keyboard/adp5588-keys.c
> > > b/drivers/input/keyboard/adp5588-keys.c
> > > index 09bcfc6b9408..7c32f8b69a3e 100644
> > > --- a/drivers/input/keyboard/adp5588-keys.c
> > > +++ b/drivers/input/keyboard/adp5588-keys.c
> > > @@ -188,6 +188,7 @@ struct adp5588_kpad {
> > >  	u32 cols;
> > >  	u32 unlock_keys[2];
> > >  	int nkeys_unlock;
> > > +	bool gpio_only;
> > >  	unsigned short keycode[ADP5588_KEYMAPSIZE];
> > >  	unsigned char gpiomap[ADP5588_MAXGPIO];
> > >  	struct gpio_chip gc;
> > > @@ -431,10 +432,12 @@ static int adp5588_gpio_add(struct adp5588_kpad
> *kpad)
> > >  	kpad->gc.label = kpad->client->name;
> > >  	kpad->gc.owner = THIS_MODULE;
> > >
> > > -	girq = &kpad->gc.irq;
> > > -	gpio_irq_chip_set_chip(girq, &adp5588_irq_chip);
> > > -	girq->handler = handle_bad_irq;
> > > -	girq->threaded = true;
> > > +	if (kpad->client->irq) {
> > > +		girq = &kpad->gc.irq;
> > > +		gpio_irq_chip_set_chip(girq, &adp5588_irq_chip);
> > > +		girq->handler = handle_bad_irq;
> > > +		girq->threaded = true;
> > > +	}
> > >
> > >  	mutex_init(&kpad->gpio_lock);
> > >
> > > @@ -632,6 +635,21 @@ static int adp5588_fw_parse(struct adp5588_kpad
> *kpad)
> > >  	struct i2c_client *client = kpad->client;
> > >  	int ret, i;
> > >
> > > +	/*
> > > +	 * Check if the device is to be operated purely in GPIO mode. To do
> > > +	 * so, check that no keypad rows or columns have been specified,
> > > +	 * since all GPINS should be configured as GPIO.
> > > +	 */
> > > +	ret = device_property_present(&client->dev,
> > > +			"keypad,num-rows");
> > > +	ret |= device_property_present(&client->dev,
> > > +			"keypad,num-columns");
> > > +	/* If purely GPIO, skip keypad setup */
> > > +	if (!ret) {
> > > +		kpad->gpio_only = true;
> > > +		return 0;
> > > +	}
> > > +
> > >  	ret = matrix_keypad_parse_properties(&client->dev, &kpad->rows,
> > >  					     &kpad->cols);
> > >  	if (ret)
> > > @@ -775,6 +793,11 @@ static int adp5588_probe(struct i2c_client *client)
> > >  	if (error)
> > >  		return error;
> > >
> > > +	if (kpad->gpio_only && !client->irq) {
> > > +		dev_info(&client->dev, "Rev.%d, started as GPIO only\n",
> > > revid);
> > > +		return 0;
> >
> > I think we need more elaborate handling here (and probably more
> > elaborate binding yaml file): now that you are making interrupt optional
> > you should check if interrupt-controller functionality of the GPIO
> > block/gpiochip is requested. If it was, then we should not allow missing
> > interrupt. If only GPIO controller is needed, without interrupt
> > capabilities, tnen running without interrupt is fine.
> >
> Hi Dmitry,
> 
> I need to double check but I don't think we can act as an interrupt-controller
> without the interrupt line connected. So, I think the only thing we could likely
> add/improve is to express that dependency in the bindings.
> 
> - Nuno Sá

Hi Dmitry,

Thank you for pointing out the dependency, I will add the same in the bindings.

Utsav