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Date:   Sun, 15 Apr 2018 16:12:57 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     =?UTF-8?B?SGVybsOhbg==?= Gonzalez <hernan@vanguardiasur.com.ar>
Cc:     knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net,
        gregkh@linuxfoundation.org, Michael.Hennerich@analog.com,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 07/14] staging: iio: ad7746: Remove unused defines
Message-ID: <20180415161257.77769dc8@archlinux>
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        <1523637411-8531-8-git-send-email-hernan@vanguardiasur.com.ar>
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On Fri, 13 Apr 2018 13:36:44 -0300
Hernán Gonzalez <hernan@vanguardiasur.com.ar> wrote:

> Signed-off-by: Hernán Gonzalez <hernan@vanguardiasur.com.ar>
> ---
>  drivers/staging/iio/cdc/ad7746.c | 7 -------
>  drivers/staging/iio/cdc/ad7746.h | 5 -----
>  2 files changed, 12 deletions(-)
> 
> diff --git a/drivers/staging/iio/cdc/ad7746.c b/drivers/staging/iio/cdc/ad7746.c
> index f53612a..d39ab34 100644
> --- a/drivers/staging/iio/cdc/ad7746.c
> +++ b/drivers/staging/iio/cdc/ad7746.c
> @@ -25,7 +25,6 @@
>   * AD7746 Register Definition
>   */
>  
> -#define AD7746_REG_STATUS		0
>  #define AD7746_REG_CAP_DATA_HIGH	1
>  #define AD7746_REG_VT_DATA_HIGH		4
>  #define AD7746_REG_CAP_SETUP		7
> @@ -38,12 +37,6 @@
>  #define AD7746_REG_CAP_GAINH		15
>  #define AD7746_REG_VOLT_GAINH		17
>  
> -/* Status Register Bit Designations (AD7746_REG_STATUS) */
> -#define AD7746_STATUS_EXCERR		BIT(3)
> -#define AD7746_STATUS_RDY		BIT(2)
> -#define AD7746_STATUS_RDYVT		BIT(1)
> -#define AD7746_STATUS_RDYCAP		BIT(0)
> -
There is a pretty strong argument that the driver 'should' be
checking the status register...

I would leave it the defines here.  When they are acting
as 'documentation' of the register layout of a device, they
do little harm and can be very useful.

>  /* Capacitive Channel Setup Register Bit Designations (AD7746_REG_CAP_SETUP) */
>  #define AD7746_CAPSETUP_CAPEN		BIT(7)
>  #define AD7746_CAPSETUP_CIN2		BIT(6) /* AD7746 only */
> diff --git a/drivers/staging/iio/cdc/ad7746.h b/drivers/staging/iio/cdc/ad7746.h
> index ea8572d..2fbcee8 100644
> --- a/drivers/staging/iio/cdc/ad7746.h
> +++ b/drivers/staging/iio/cdc/ad7746.h
> @@ -13,11 +13,6 @@
>   * TODO: struct ad7746_platform_data needs to go into include/linux/iio
>   */
>  
> -#define AD7466_EXCLVL_0		0 /* +-VDD/8 */
> -#define AD7466_EXCLVL_1		1 /* +-VDD/4 */
> -#define AD7466_EXCLVL_2		2 /* +-VDD * 3/8 */
> -#define AD7466_EXCLVL_3		3 /* +-VDD/2 */
> -

Think about what these are for.... They aren't unused
if you are actually using platform data on a given oard.

>  struct ad7746_platform_data {
>  	unsigned char exclvl;	/*Excitation Voltage Level */
>  	bool exca_en;		/* enables EXCA pin as the excitation output */