linux-kernel - RE: [PATCH 07/16] iio: adc: max1027: Create a helper to configure the trigger

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Date:   Fri, 20 Aug 2021 07:16:28 +0000
From:   "Sa, Nuno" <Nuno.Sa@...log.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>
CC:     Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 07/16] iio: adc: max1027: Create a helper to configure the
 trigger



> -----Original Message-----
> From: Miquel Raynal <miquel.raynal@...tlin.com>
> Sent: Wednesday, August 18, 2021 1:12 PM
> To: Jonathan Cameron <jic23@...nel.org>; Lars-Peter Clausen
> <lars@...afoo.de>
> Cc: Thomas Petazzoni <thomas.petazzoni@...tlin.com>; linux-
> iio@...r.kernel.org; linux-kernel@...r.kernel.org; Miquel Raynal
> <miquel.raynal@...tlin.com>
> Subject: [PATCH 07/16] iio: adc: max1027: Create a helper to configure
> the trigger
> 
> [External]
> 
> There are two ways to physically trigger a conversion:
> - A falling edge on the cnvst pin
> - A write operation on the conversion register
> 
> Let's create a helper for this.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
> ---
>  drivers/iio/adc/max1027.c | 52 ++++++++++++++++++++++++++------
> -------
>  1 file changed, 35 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
> index a6ebc951c09a..59914fcfd320 100644
> --- a/drivers/iio/adc/max1027.c
> +++ b/drivers/iio/adc/max1027.c
> @@ -232,10 +232,37 @@ struct max1027_state {
>  	struct iio_trigger		*trig;
>  	__be16				*buffer;
>  	struct mutex			lock;
> -
> +	bool				cnvst_trigger;
>  	u8				reg ____cacheline_aligned;
>  };
> 
> +static int max1027_configure_trigger(struct iio_dev *indio_dev)
> +{
> +	struct max1027_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	st->reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2;
> +
> +	/*
> +	 * Start acquisition on:
> +	 * MODE0: external hardware trigger wired to the cnvst input
> pin
> +	 * MODE2: conversion register write
> +	 */
> +	if (st->cnvst_trigger)
> +		st->reg |= MAX1027_CKS_MODE0;
> +	else
> +		st->reg |= MAX1027_CKS_MODE2;
> +
> +	ret = spi_write(st->spi, &st->reg, 1);
> +	if (ret < 0) {
> +		dev_err(&indio_dev->dev,
> +			"Failed to configure register (%d)\n", ret);
> +		return ret;
> +	}

I do not think the error message is so important here that we cannot
make this more simple and just do:

return spi_write(st->spi, &st->reg, 1);

Anyways, not that important so:

Reviewed-by: Nuno Sá <nuno.sa@...log.com>

> +	return 0;
> +}
> +
>  static int max1027_read_single_value(struct iio_dev *indio_dev,
>  				     struct iio_chan_spec const *chan,
>  				     int *val)
> @@ -248,14 +275,9 @@ static int max1027_read_single_value(struct
> iio_dev *indio_dev,
>  		return -EBUSY;
>  	}
> 
> -	/* Start acquisition on conversion register write */
> -	st->reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2 |
> MAX1027_CKS_MODE2;
> -	ret = spi_write(st->spi, &st->reg, 1);
> -	if (ret < 0) {
> -		dev_err(&indio_dev->dev,
> -			"Failed to configure setup register\n");
> +	ret = max1027_configure_trigger(indio_dev);
> +	if (ret)
>  		return ret;
> -	}
> 
>  	/* Configure conversion register with the requested chan */
>  	st->reg = MAX1027_CONV_REG | MAX1027_CHAN(chan-
> >channel) |
> @@ -363,12 +385,10 @@ static int
> max1027_set_cnvst_trigger_state(struct iio_trigger *trig, bool state)
>  	if (bitmap_empty(indio_dev->active_scan_mask, indio_dev-
> >masklength))
>  		return -EINVAL;
> 
> +	st->cnvst_trigger = state;
>  	if (state) {
> -		/* Start acquisition on cnvst */
> -		st->reg = MAX1027_SETUP_REG |
> MAX1027_CKS_MODE0 |
> -			  MAX1027_REF_MODE2;
> -		ret = spi_write(st->spi, &st->reg, 1);
> -		if (ret < 0)
> +		ret = max1027_configure_trigger(indio_dev);
> +		if (ret)
>  			return ret;
> 
>  		/*
> @@ -382,10 +402,8 @@ static int
> max1027_set_cnvst_trigger_state(struct iio_trigger *trig, bool state)
>  			return ret;
>  	} else {
>  		/* Start acquisition on conversion register write */
> -		st->reg = MAX1027_SETUP_REG |
> MAX1027_CKS_MODE2	|
> -			  MAX1027_REF_MODE2;
> -		ret = spi_write(st->spi, &st->reg, 1);
> -		if (ret < 0)
> +		ret = max1027_configure_trigger(indio_dev);
> +		if (ret)
>  			return ret;
>  	}
> 
> --
> 2.27.0