linux-kernel - Re: [PATCH 2/2] rv8803: add irq-gpio optional dts attribute

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Message-ID: <YYBuzqZD8/uK3d6Z@piout.net>
Date:   Mon, 1 Nov 2021 23:48:46 +0100
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Dominique Martinet <dominique.martinet@...ark-techno.com>
Cc:     Alessandro Zummo <a.zummo@...ertech.it>, linux-rtc@...r.kernel.org,
        linux-kernel@...r.kernel.org, Marek Vasut <marex@...x.de>,
        Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH 2/2] rv8803: add irq-gpio optional dts attribute

On 01/11/2021 10:34:00+0900, Dominique Martinet wrote:
> Some device cannot be woken up from i2c signal.
> Add a new irq-gpio attribute for devices which have a gpio connected to
> the rv8803 INT line so the rtc can be used for suspend to mem
> 

I don't think this is right, the interrupts property of the rtc node can
point to a gpio and this is expected to be the one connected on INT. You
don't need another property.

> Signed-off-by: Dominique Martinet <dominique.martinet@...ark-techno.com>
> ---
> 
> Our board does not have an upstream dts so I cannot provide a real
> example for it, but I've tested this on something close to the
> imx8mp-evk.
> 
> It should not break anything for people having no alarm at all or using
> the i2c irq.
> 
>  .../devicetree/bindings/rtc/epson,rx8900.yaml |  5 ++
>  drivers/rtc/rtc-rv8803.c                      | 73 +++++++++++++++++--
>  2 files changed, 73 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/rtc/epson,rx8900.yaml b/Documentation/devicetree/bindings/rtc/epson,rx8900.yaml
> index 29fe39bb08ad..0d7912b984c7 100644
> --- a/Documentation/devicetree/bindings/rtc/epson,rx8900.yaml
> +++ b/Documentation/devicetree/bindings/rtc/epson,rx8900.yaml
> @@ -28,6 +28,10 @@ properties:
>  
>    trickle-diode-disable: true
>  
> +  irq-gpio:
> +    description: |
> +      gpio for INT signal. Set up gpio for irq and device wakeup.
> +
>  required:
>    - compatible
>    - reg
> @@ -45,5 +49,6 @@ examples:
>              reg = <0x32>;
>              epson,vdet-disable;
>              trickle-diode-disable;
> +            irq-gpio = <&gpio1 11 GPIO_ACTIVE_LOW>;
>          };
>      };
> diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
> index 0d5ed38bf60c..1c4b96bc110e 100644
> --- a/drivers/rtc/rtc-rv8803.c
> +++ b/drivers/rtc/rtc-rv8803.c
> @@ -16,6 +16,7 @@
>  #include <linux/module.h>
>  #include <linux/of_device.h>
>  #include <linux/rtc.h>
> +#include <linux/pm_wakeirq.h>
>  
>  #define RV8803_I2C_TRY_COUNT		4
>  
> @@ -509,6 +510,61 @@ static int rx8900_trickle_charger_init(struct rv8803_data *rv8803)
>  					 flags);
>  }
>  
> +static int rv8803_setup_gpio_irq(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	int err;
> +	int irq;
> +	unsigned long irqflags;
> +	struct gpio_desc *gpiod;
> +
> +
> +	gpiod = devm_gpiod_get_from_of_node(dev, dev->of_node, "irq-gpio",
> +					    0, GPIOD_IN, "RTC irq pin");
> +	if (!gpiod || IS_ERR(gpiod)) {
> +		dev_dbg(dev, "no gpio for rtc: skipping\n");
> +		return -ENOENT;
> +	}
> +
> +	irq = gpiod_to_irq(gpiod);
> +	if (irq < 0) {
> +		dev_err(dev, "gpio found but no irq\n");
> +		err = irq;
> +		goto error_gpio;
> +	}
> +
> +	irqflags = IRQF_ONESHOT;
> +	irqflags |= gpiod_is_active_low(gpiod) ?
> +		    IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
> +
> +	err = devm_request_threaded_irq(dev, irq, NULL, rv8803_handle_irq,
> +					irqflags, "rtc-rv8803-gpio", client);
> +	if (err) {
> +		dev_warn(dev, "unable to request IRQ\n");
> +		goto error_gpio;
> +	}
> +
> +	err = device_init_wakeup(dev, true);
> +	if (err) {
> +		dev_warn(dev, "unable to set as wakeup source\n");
> +		goto error_irq;
> +	}
> +
> +	err = dev_pm_set_wake_irq(dev, irq);
> +	if (err) {
> +		dev_warn(dev, "unable to set wake irq\n");
> +		goto error_irq;
> +	}
> +
> +	return 0;
> +
> +error_irq:
> +	devm_free_irq(dev, irq, client);
> +error_gpio:
> +	devm_gpiod_put(dev, gpiod);
> +	return err;
> +}
> +
>  static int rv8803_probe(struct i2c_client *client,
>  			const struct i2c_device_id *id)
>  {
> @@ -524,6 +580,7 @@ static int rv8803_probe(struct i2c_client *client,
>  		.reg_write = rv8803_nvram_write,
>  		.priv = client,
>  	};
> +	bool irq_setup = false;
>  
>  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
>  				     I2C_FUNC_SMBUS_I2C_BLOCK)) {
> @@ -562,17 +619,23 @@ static int rv8803_probe(struct i2c_client *client,
>  	if (IS_ERR(rv8803->rtc))
>  		return PTR_ERR(rv8803->rtc);
>  
> -	if (client->irq > 0) {
> +	if (client->dev.of_node) {
> +		err = rv8803_setup_gpio_irq(client);
> +		if (!err)
> +			irq_setup = true;
> +	}
> +
> +	if (!irq_setup && client->irq > 0) {
>  		err = devm_request_threaded_irq(&client->dev, client->irq,
>  						NULL, rv8803_handle_irq,
>  						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
>  						"rv8803", client);
> -		if (err) {
> +		if (err)
>  			dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
> -			client->irq = 0;
> -		}
> +		else
> +			irq_setup = true;
>  	}
> -	if (!client->irq)
> +	if (!irq_setup)
>  		clear_bit(RTC_FEATURE_ALARM, rv8803->rtc->features);
>  
>  	err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA);
> -- 
> 2.30.2
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com