linux-kernel - Re: [PATCH v8 2/3] Input: adp5588-keys

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Message-ID: <Zq17uABHdNENnwVq@google.com>
Date: Fri, 2 Aug 2024 17:37:12 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: utsav.agarwal@...log.com
Cc: Michael Hennerich <michael.hennerich@...log.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Nuno Sá <nuno.sa@...log.com>,
	linux-input@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Arturs Artamonovs <arturs.artamonovs@...log.com>,
	Vasileios Bimpikas <vasileios.bimpikas@...log.com>,
	Oliver Gaskell <oliver.gaskell@...log.com>
Subject: Re: [PATCH v8 2/3] Input: adp5588-keys - add support for pure gpio

Hi Utsav,

On Thu, Jul 04, 2024 at 03:26:31PM +0100, Utsav Agarwal via B4 Relay wrote:
> From: Utsav Agarwal <utsav.agarwal@...log.com>
> 
> Keypad specific setup is relaxed if no keypad rows/columns are specified,
> enabling a purely gpio operation.
> 
> Signed-off-by: Utsav Agarwal <utsav.agarwal@...log.com>
> ---
>  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.

Thanks.

-- 
Dmitry