linux-kernel - Re: [PATCH v2 1/4] regmap: provide regmap_field helpers for simple bit operations

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Date:   Sun, 22 May 2022 22:09:55 -0500
From:   Samuel Holland <samuel@...lland.org>
To:     Li Chen <lchen.firstlove@...omail.com>,
        Mark Brown <broonie@...nel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Patrice Chotard <patrice.chotard@...s.st.com>,
        linux-sunxi <linux-sunxi@...ts.linux.dev>,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>
Subject: Re: [PATCH v2 1/4] regmap: provide regmap_field helpers for simple
 bit operations

Hi,

On 5/22/22 9:23 PM, Li Chen wrote:
> From: Li Chen <lchen@...arella.com>
> 
> We have set/clear/test operations for regmap, but not for regmap_field yet.
> So let's introduce regmap_field helpers too.
> 
> In many instances regmap_field_update_bits() is used for simple bit setting
> and clearing. In these cases the last argument is redundant and we can
> hide it with a static inline function.
> 
> This adds three new helpers for simple bit operations: set_bits,
> clear_bits and test_bits (the last one defined as a regular function).
> 
> Signed-off-by: Li Chen <lchen@...arella.com>
> ---
>  drivers/base/regmap/regmap.c | 22 +++++++++++++++++++++
>  include/linux/regmap.h       | 37 ++++++++++++++++++++++++++++++++++++
>  2 files changed, 59 insertions(+)
> 
> diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
> index 5e12f7cb5147..a37d6041b7bd 100644
> --- a/drivers/base/regmap/regmap.c
> +++ b/drivers/base/regmap/regmap.c
> @@ -2208,6 +2208,28 @@ int regmap_field_update_bits_base(struct regmap_field *field,
>  }
>  EXPORT_SYMBOL_GPL(regmap_field_update_bits_base);
>  
> +/**
> + * regmap_field_test_bits() - Check if all specified bits are set in a
> + *                            register field.
> + *
> + * @field: Register field to operate on
> + * @bits: Bits to test
> + *
> + * Returns -1 if the underlying regmap_field_read() fails, 0 if at least one of the
> + * tested bits is not set and 1 if all tested bits are set.
> + */
> +int regmap_field_test_bits(struct regmap_field *field, unsigned int bits)
> +{
> +	unsigned int val, ret;
> +
> +	ret = regmap_field_read(field, &val);
> +	if (ret)
> +		return ret;
> +
> +	return (val & bits) == bits;
> +}
> +EXPORT_SYMBOL_GPL(regmap_field_test_bits);
> +
>  /**
>   * regmap_fields_update_bits_base() - Perform a read/modify/write cycle a
>   *                                    register field with port ID
> diff --git a/include/linux/regmap.h b/include/linux/regmap.h
> index de81a94d7b30..10b410734d9e 100644
> --- a/include/linux/regmap.h
> +++ b/include/linux/regmap.h
> @@ -1324,6 +1324,22 @@ static inline int regmap_field_update_bits(struct regmap_field *field,
>  					     NULL, false, false);
>  }
>  
> +static inline int regmap_field_set_bits(struct regmap_field *field,
> +					unsigned int bits)
> +{
> +	return regmap_field_update_bits_base(field, bits, 0, NULL, false,
> +					     false);
> +}
> +
> +static inline int regmap_field_clear_bits(struct regmap_field *field,
> +					  unsigned int bits)
> +{
> +	return regmap_field_update_bits_base(field, bits, bits, NULL, false,
> +					     false);

The contents of these two functions are swapped when compared to their names.

Regards,
Samuel

> +}
> +
> +int regmap_field_test_bits(struct regmap_field *field, unsigned int bits);
> +
>  static inline int
>  regmap_field_force_update_bits(struct regmap_field *field,
>  			       unsigned int mask, unsigned int val)
> @@ -1757,6 +1773,27 @@ regmap_field_force_update_bits(struct regmap_field *field,
>  	return -EINVAL;
>  }
>  
> +static inline int regmap_field_set_bits(struct regmap_field *field,
> +					unsigned int bits)
> +{
> +	WARN_ONCE(1, "regmap API is disabled");
> +	return -EINVAL;
> +}
> +
> +static inline int regmap_field_clear_bits(struct regmap_field *field,
> +					  unsigned int bits)
> +{
> +	WARN_ONCE(1, "regmap API is disabled");
> +	return -EINVAL;
> +}
> +
> +static inline int regmap_field_test_bits(struct regmap_field *field,
> +					 unsigned int bits)
> +{
> +	WARN_ONCE(1, "regmap API is disabled");
> +	return -EINVAL;
> +}
> +
>  static inline int regmap_fields_write(struct regmap_field *field,
>  				      unsigned int id, unsigned int val)
>  {
>