linux-kernel - Re: [PATCH 2/2] staging: iio: adc: ad7192: Add clock output option

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Date:   Sat, 8 Dec 2018 15:32:32 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Mircea Caprioru <mircea.caprioru@...log.com>
Cc:     <Michael.Hennerich@...log.com>, <knaack.h@....de>,
        <lars@...afoo.de>, <pmeerw@...erw.net>,
        <gregkh@...uxfoundation.org>, <linux-kernel@...r.kernel.org>,
        <linux-iio@...r.kernel.org>, <devel@...verdev.osuosl.org>
Subject: Re: [PATCH 2/2] staging: iio: adc: ad7192: Add clock output option

On Thu, 6 Dec 2018 11:10:52 +0200
Mircea Caprioru <mircea.caprioru@...log.com> wrote:

> When using the internal clock the device has an option in which the clock
> output is available on MCLK2 pin. This patch adds a dt binding for enabling
> this property.
> 
> Signed-off-by: Mircea Caprioru <mircea.caprioru@...log.com>
I'd rather we looked at getting this out of staging, with proper binding
docs before we add too many new features, but I suppose this is small
enough that it isn't too much of a problem other that we are defining
a binding that might not go down well long term.

If nothing else we should be supporting this as a clock source
to allow it for example to be looped into another identical device
as the input.

Here we are putting it out on a pin with no 'consumers'.

Jonathan


> ---
>  drivers/staging/iio/adc/ad7192.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
> index 8a4e6ede42b3..a11c8a82bb7c 100644
> --- a/drivers/staging/iio/adc/ad7192.c
> +++ b/drivers/staging/iio/adc/ad7192.c
> @@ -611,6 +611,10 @@ static const struct iio_chan_spec ad7193_channels[] = {
>  static int ad7192_clock_select(struct spi_device *spi, struct ad7192_state *st)
>  {
>  	int ret;
> +	bool clock_out_en;
> +
> +	clock_out_en = of_property_read_bool(spi->dev.of_node,
> +					     "adi,int-clock-output-enable");
>  
>  	st->clock_sel = AD7192_CLK_EXT_MCLK2;
>  	st->mclk = devm_clk_get(&spi->dev, "clk");
> @@ -626,7 +630,10 @@ static int ad7192_clock_select(struct spi_device *spi, struct ad7192_state *st)
>  				return PTR_ERR(st->mclk);
>  
>  			/* use internal clock */
> -			st->clock_sel = AD7192_CLK_INT;
> +			if (!clock_out_en)
> +				st->clock_sel = AD7192_CLK_INT;
> +			else
> +				st->clock_sel = AD7192_CLK_INT_CO;
>  			st->fclk = AD7192_INT_FREQ_MHZ;
>  		}
>  	}