linux-kernel - Re: [PATCH v4 6/9] iio: adc: mcp3911: add support for interrupts

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Message-ID: <20220731175221.4adbbfa6@jic23-huawei>
Date:   Sun, 31 Jul 2022 17:52:21 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Marcus Folkesson <marcus.folkesson@...il.com>
Cc:     Kent Gustavsson <kent@...oris.se>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 6/9] iio: adc: mcp3911: add support for interrupts

On Fri, 22 Jul 2022 15:07:23 +0200
Marcus Folkesson <marcus.folkesson@...il.com> wrote:

> Make it possible to read values upon interrupts.
> Configure Data Ready Signal Output Pin to either HiZ or push-pull and
> use it as interrupt source.
> 
> Signed-off-by: Marcus Folkesson <marcus.folkesson@...il.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Looks good to me.

J

> ---
>  drivers/iio/adc/mcp3911.c | 53 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
> index 96c0a2a50c7c..7db2c75da4ac 100644
> --- a/drivers/iio/adc/mcp3911.c
> +++ b/drivers/iio/adc/mcp3911.c
> @@ -29,6 +29,7 @@
>  #define MCP3911_REG_GAIN		0x09
>  
>  #define MCP3911_REG_STATUSCOM		0x0a
> +#define MCP3911_STATUSCOM_DRHIZ         BIT(12)
>  #define MCP3911_STATUSCOM_READ		GENMASK(7, 6)
>  #define MCP3911_STATUSCOM_CH1_24WIDTH	BIT(4)
>  #define MCP3911_STATUSCOM_CH0_24WIDTH	BIT(3)
> @@ -62,6 +63,7 @@ struct mcp3911 {
>  	struct regulator *vref;
>  	struct clk *clki;
>  	u32 dev_addr;
> +	struct iio_trigger *trig;
>  	struct {
>  		u32 channels[MCP3911_NUM_CHANNELS];
>  		s64 ts __aligned(8);
> @@ -346,6 +348,23 @@ static void mcp3911_cleanup_regulator(void *_adc)
>  	regulator_disable(adc->vref);
>  }
>  
> +static int mcp3911_set_trigger_state(struct iio_trigger *trig, bool enable)
> +{
> +	struct mcp3911 *adc = iio_trigger_get_drvdata(trig);
> +
> +	if (enable)
> +		enable_irq(adc->spi->irq);
> +	else
> +		disable_irq(adc->spi->irq);
> +
> +	return 0;
> +}
> +
> +static const struct iio_trigger_ops mcp3911_trigger_ops = {
> +	.validate_device = iio_trigger_validate_own_device,
> +	.set_trigger_state = mcp3911_set_trigger_state,
> +};
> +
>  static int mcp3911_probe(struct spi_device *spi)
>  {
>  	struct iio_dev *indio_dev;
> @@ -409,6 +428,15 @@ static int mcp3911_probe(struct spi_device *spi)
>  	if (ret)
>  		return ret;
>  
> +	if (device_property_read_bool(&adc->spi->dev, "microchip,data-ready-hiz"))
> +		ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM, MCP3911_STATUSCOM_DRHIZ,
> +				0, 2);
> +	else
> +		ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM, MCP3911_STATUSCOM_DRHIZ,
> +				MCP3911_STATUSCOM_DRHIZ, 2);
> +	if (ret)
> +		return ret;
> +
>  	indio_dev->name = spi_get_device_id(spi)->name;
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  	indio_dev->info = &mcp3911_info;
> @@ -419,6 +447,31 @@ static int mcp3911_probe(struct spi_device *spi)
>  
>  	mutex_init(&adc->lock);
>  
> +	if (spi->irq > 0) {
> +		adc->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
> +				indio_dev->name,
> +				iio_device_id(indio_dev));
> +		if (!adc->trig)
> +			return PTR_ERR(adc->trig);
> +
> +		adc->trig->ops = &mcp3911_trigger_ops;
> +		iio_trigger_set_drvdata(adc->trig, adc);
> +		ret = devm_iio_trigger_register(&spi->dev, adc->trig);
> +		if (ret)
> +			return ret;
> +
> +		/*
> +		 * The device generates interrupts as long as it is powered up.
> +		 * Some platforms might not allow the option to power it down so
> +		 * don't enable the interrupt to avoid extra load on the system.
> +		 */
> +		ret = devm_request_irq(&spi->dev, spi->irq,
> +				&iio_trigger_generic_data_rdy_poll, IRQF_NO_AUTOEN | IRQF_ONESHOT,
> +				indio_dev->name, adc->trig);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
>  			NULL,
>  			mcp3911_trigger_handler, NULL);