linux-kernel - RE: [PATCH v2] adp5588-keys: Support for dedicated gpio operation

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Date: Fri, 28 Jun 2024 13:38:08 +0000
From: "Agarwal, Utsav" <Utsav.Agarwal@...log.com>
To: Nuno Sá <noname.nuno@...il.com>,
        "Hennerich, Michael"
	<Michael.Hennerich@...log.com>,
        "dmitry.torokhov@...il.com"
	<dmitry.torokhov@...il.com>,
        "linux-input@...r.kernel.org"
	<linux-input@...r.kernel.org>,
        "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
CC: "Artamonovs, Arturs" <Arturs.Artamonovs@...log.com>,
        "Bimpikas, Vasileios"
	<Vasileios.Bimpikas@...log.com>,
        "Gaskell, Oliver"
	<Oliver.Gaskell@...log.com>
Subject: RE: [PATCH v2] adp5588-keys: Support for dedicated gpio operation

Hi Nuno,

Thank you for the feedback.

> -----Original Message-----
> From: Nuno Sá <noname.nuno@...il.com>
> Sent: Friday, June 28, 2024 2:16 PM
> To: Agarwal, Utsav <Utsav.Agarwal@...log.com>; Hennerich, Michael
> <Michael.Hennerich@...log.com>; dmitry.torokhov@...il.com; linux-
> input@...r.kernel.org; linux-kernel@...r.kernel.org
> Cc: Artamonovs, Arturs <Arturs.Artamonovs@...log.com>; Bimpikas,
> Vasileios <Vasileios.Bimpikas@...log.com>; Gaskell, Oliver
> <Oliver.Gaskell@...log.com>
> Subject: Re: [PATCH v2] adp5588-keys: Support for dedicated gpio operation
> 
> [External]
> 
> Hi Utsav,
> 
> On Fri, 2024-06-28 at 12:57 +0000, Agarwal, Utsav wrote:
> > From: Utsav Agarwal <utsav.agarwal@...log.com>
> >
> > Current state of the driver for the ADP5588/87 only allows partial
> > I/O to be used as GPIO. This support was previously present as a
> > separate gpio driver, which was dropped with the commit
> > 5ddc896088b0 ("gpio: gpio-adp5588: drop the driver") since the
> > functionality was deemed to have been merged with adp5588-keys.
> >
> > To restore this, keypad specific checks in the probe
> > function are relaxed if the following conditions are met:
> > 	1) "gpio-only" property has been specified for the node
> > 	2) No keypad rows/columns are specified
> >
> > The "gpio-only" property is introduced to simplify usage since it
> > serves as a clear indication of the user's intention as opposed to being
> > inferred from the number of rows and columns specified. This
> > also adds simplicity for the accompanying dt binding update as well
> > as interpretation of the same.
> >
> > In such a case, additional checks are also introduced to make sure
> > that keypad and pure GPIO operation are mutually exclusive by
> > checking for keypad specific properties (keypad,num-rows and
> > keypad,num-columns).
> >
> > Signed-off-by: Utsav Agarwal <utsav.agarwal@...log.com>
> > ---
> >  drivers/input/keyboard/adp5588-keys.c | 33
> +++++++++++++++++++++++++++
> >  1 file changed, 33 insertions(+)
> >
> > diff --git a/drivers/input/keyboard/adp5588-keys.c
> > b/drivers/input/keyboard/adp5588-keys.c
> > index 1b0279393df4..6bfe748797df 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;
> > @@ -647,6 +648,25 @@ 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. If
> > +	 * so, confirm that no keypad rows or columns have been specified,
> > since
> > +	 * all GPINS should be configured as GPIO.
> > +	 */
> > +	if (kpad->gpio_only) {
> > +		ret = device_property_present(&client->dev,
> > +				"keypad,num-rows");
> 
> Should align with open parenthesis...
> 
> > +		if (ret)
> > +			return -EINVAL;
> > +
> 
> dev_err_probe() with a message should be helpful...

I will add an error message in the next version.
> 
> > +		ret = device_property_present(&client->dev,
> > +				"keypad,num-columns");
> > +		if (ret)
> > +			return -EINVAL;
> 
> Alternatively, you could just:
> 
> if (kpad->gpio_only)
> 	return 0;
> 
> And ignore the other properties...
> 
> > +
> > +		return 0;
> > +	}
> > +
> >  	ret = matrix_keypad_parse_properties(&client->dev, &kpad->rows,
> >  					     &kpad->cols);
> >  	if (ret)
> > @@ -739,6 +759,7 @@ static int adp5588_probe(struct i2c_client *client)
> >  	kpad->client = client;
> >  	kpad->input = input;
> >
> > +	kpad->gpio_only = device_property_present(&client->dev, "gpio-
> only");
> 
> Since the above is also FW properties it could go inside adp5588_fw_parse().
> It's also missing the bindings patch.

Yes, I agree, on revaluation it makes sense to do so.

> 
> >  	error = adp5588_fw_parse(kpad);
> >  	if (error)
> >  		return error;
> > @@ -790,6 +811,11 @@ static int adp5588_probe(struct i2c_client *client)
> >  	if (error)
> >  		return error;
> >
> > +	if (!client->irq && kpad->gpio_only) {
> > +		dev_info(&client->dev, "Rev.%d, started as GPIO only\n",
> > revid);
> > +		return 0;
> > +	}
> > +
> 
> Note that in case there are no IRQ, you should not make the gpiochip an
> irqchip
> capable:
> 
> https://urldefense.com/v3/__https://elixir.bootlin.com/linux/v6.10-
> rc5/source/drivers/input/keyboard/adp5588-
> keys.c*L449__;Iw!!A3Ni8CS0y2Y!5V_cLrmVT4t1wmVNsUbaGelR4BAMJDj3l35C
> IIOfGIXDiCVEY7qu8Zc5u_r7322sJQsUTRNWzehxZ8q9fsJGo6Hz$
> 
> 
Understood, I'll make the revisions accordingly.
> - Nuno Sá
>