linux-kernel - RE: [PATCH v2 1/3] regulator: ad5398: change enable bit name to improve readibility

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Message-ID:
 <PH0PR03MB6512C7E1E8CE8304778CC20E8EEE2@PH0PR03MB6512.namprd03.prod.outlook.com>
Date: Wed, 29 Jan 2025 08:31:35 +0000
From: "Hennerich, Michael" <Michael.Hennerich@...log.com>
To: Isaac Scott <isaac.scott@...asonboard.com>
CC: "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "broonie@...nel.org"
	<broonie@...nel.org>,
        "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2 1/3] regulator: ad5398: change enable bit name to
 improve readibility



> -----Original Message-----
> From: Isaac Scott <isaac.scott@...asonboard.com>
> Sent: Tuesday, January 28, 2025 6:32 PM
> To: Hennerich, Michael <Michael.Hennerich@...log.com>
> Cc: lgirdwood@...il.com; broonie@...nel.org; linux-kernel@...r.kernel.org;
> Isaac Scott <isaac.scott@...asonboard.com>
> Subject: [PATCH v2 1/3] regulator: ad5398: change enable bit name to
> improve readibility
> 
> 
> The mask name AD5398_CURRENT_EN_MASK is misleading, as it implies that
> setting bit 16 of the AD5398 enables current flow. In fact, setting this bit
> prevents current flow, due to this bit being a software power down control.
> This bit is referred to as "soft power down" in the datasheet.
> As such, change the name of the bit and modify its use in the driver to make
> the regulator more intuitively usable.
> 
> (When calling ad5398_enable, current will start flowing, and vice versa).
> 
> Signed-off-by: Isaac Scott <isaac.scott@...asonboard.com>

Acked-by: Michael Hennerich <michael.hennerich@...log.com>

> ---
>  drivers/regulator/ad5398.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/regulator/ad5398.c b/drivers/regulator/ad5398.c index
> 40f7dba42b5a..e6f45c6e750c 100644
> --- a/drivers/regulator/ad5398.c
> +++ b/drivers/regulator/ad5398.c
> @@ -15,7 +15,7 @@
>  #include <linux/regulator/driver.h>
>  #include <linux/regulator/machine.h>
> 
> -#define AD5398_CURRENT_EN_MASK	0x8000
> +#define AD5398_SW_POWER_DOWN	BIT(16)
> 
>  struct ad5398_chip_info {
>  	struct i2c_client *client;
> @@ -113,7 +113,7 @@ static int ad5398_set_current_limit(struct
> regulator_dev *rdev, int min_uA, int
> 
>  	/* prepare register data */
>  	selector = (selector << chip->current_offset) & chip->current_mask;
> -	data = (unsigned short)selector | (data &
> AD5398_CURRENT_EN_MASK);
> +	data = (unsigned short)selector | (data &
> AD5398_SW_POWER_DOWN);
> 
>  	/* write the new current value back as well as enable bit */
>  	ret = ad5398_write_reg(client, data);
> @@ -132,10 +132,10 @@ static int ad5398_is_enabled(struct regulator_dev
> *rdev)
>  	if (ret < 0)
>  		return ret;
> 
> -	if (data & AD5398_CURRENT_EN_MASK)
> -		return 1;
> -	else
> +	if (data & AD5398_SW_POWER_DOWN)
>  		return 0;
> +	else
> +		return 1;
>  }
> 
>  static int ad5398_enable(struct regulator_dev *rdev) @@ -149,10 +149,10
> @@ static int ad5398_enable(struct regulator_dev *rdev)
>  	if (ret < 0)
>  		return ret;
> 
> -	if (data & AD5398_CURRENT_EN_MASK)
> +	if (!(data & AD5398_SW_POWER_DOWN))
>  		return 0;
> 
> -	data |= AD5398_CURRENT_EN_MASK;
> +	data &= ~AD5398_SW_POWER_DOWN;
> 
>  	ret = ad5398_write_reg(client, data);
> 
> @@ -170,10 +170,10 @@ static int ad5398_disable(struct regulator_dev
> *rdev)
>  	if (ret < 0)
>  		return ret;
> 
> -	if (!(data & AD5398_CURRENT_EN_MASK))
> +	if (data & AD5398_SW_POWER_DOWN)
>  		return 0;
> 
> -	data &= ~AD5398_CURRENT_EN_MASK;
> +	data |= AD5398_SW_POWER_DOWN;
> 
>  	ret = ad5398_write_reg(client, data);
> 
> --
> 2.43.0