linux-kernel - Re: [RFC RFT PATCH v4 1/4] gpiolib: Pass bitmaps, not integer arrays, to get/set array

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Date:   Tue, 21 Aug 2018 08:52:33 +0200
From:   Peter Rosin <peda@...ntia.se>
To:     Janusz Krzysztofik <jmkrzyszt@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>
Cc:     Jonathan Corbet <corbet@....net>,
        Miguel Ojeda Sandonis <miguel.ojeda.sandonis@...il.com>,
        Peter Korsgaard <peter.korsgaard@...co.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Dominik Brodowski <linux@...inikbrodowski.net>,
        Kishon Vijay Abraham I <kishon@...com>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Michael Hennerich <Michael.Hennerich@...log.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>, linux-gpio@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-mmc@...r.kernel.org, netdev@...r.kernel.org,
        linux-iio@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC RFT PATCH v4 1/4] gpiolib: Pass bitmaps, not integer arrays,
 to get/set array

Sorry for replying to self...

On 2018-08-21 08:49, Peter Rosin wrote:
> On 2018-08-21 01:43, Janusz Krzysztofik wrote:
>> Most users of get/set array functions iterate consecutive bits of data,
>> usually a single integer, while or processing array of results obtained
>> from or building an array of values to be passed to those functions.
>> Save time wasted on those iterations by changing the functions' API to
>> accept bitmaps.
>>
>> All current users are updated as well.
>>
>> More benefits from the change are expected as soon as planned support
>> for accepting/passing those bitmaps directly from/to respective GPIO
>> chip callbacks if applicable is implemented.
>>
>> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@...il.com>
>> ---
>>  Documentation/driver-api/gpio/consumer.rst  | 22 ++++----
>>  drivers/auxdisplay/hd44780.c                | 52 +++++++++--------
>>  drivers/bus/ts-nbus.c                       | 19 ++-----
>>  drivers/gpio/gpio-max3191x.c                | 17 +++---
>>  drivers/gpio/gpiolib.c                      | 86 +++++++++++++++--------------
>>  drivers/gpio/gpiolib.h                      |  4 +-
>>  drivers/i2c/muxes/i2c-mux-gpio.c            |  3 +-
>>  drivers/mmc/core/pwrseq_simple.c            | 13 ++---
>>  drivers/mux/gpio.c                          |  4 +-
>>  drivers/net/phy/mdio-mux-gpio.c             |  3 +-
>>  drivers/pcmcia/soc_common.c                 | 11 ++--
>>  drivers/phy/motorola/phy-mapphone-mdm6600.c | 17 +++---
>>  drivers/staging/iio/adc/ad7606.c            |  9 +--
>>  drivers/tty/serial/serial_mctrl_gpio.c      |  7 ++-
>>  include/linux/gpio/consumer.h               | 18 +++---
>>  15 files changed, 138 insertions(+), 147 deletions(-)
>>
> 
> *snip*
> 
>> diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c
>> index 401308e3d036..d675e0ca2fa4 100644
>> --- a/drivers/i2c/muxes/i2c-mux-gpio.c
>> +++ b/drivers/i2c/muxes/i2c-mux-gpio.c
>> @@ -27,13 +27,14 @@ struct gpiomux {
>>  
>>  static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
>>  {
>> +	unsigned long value_bitmap[1] = { val, };
>>  	int i;
>>  
>>  	for (i = 0; i < mux->data.n_gpios; i++)
>>  		mux->values[i] = (val >> i) & 1;
>>  
>>  	gpiod_set_array_value_cansleep(mux->data.n_gpios,
>> -				       mux->gpios, mux->values);
>> +				       mux->gpios, value_bitmap);
>>  }
>>  
>>  static int i2c_mux_gpio_select(struct i2c_mux_core *muxc, u32 chan)
> 
> Please take the opportunity to completely get rid of the values member
> in struct mux_gpio. It no longer serves any purpose.

struct gpiomux

> 
> *snip*
> 
>> diff --git a/drivers/mux/gpio.c b/drivers/mux/gpio.c
>> index 6fdd9316db8b..cc2d5f50472a 100644
>> --- a/drivers/mux/gpio.c
>> +++ b/drivers/mux/gpio.c
>> @@ -23,14 +23,14 @@ struct mux_gpio {
>>  static int mux_gpio_set(struct mux_control *mux, int state)
>>  {
>>  	struct mux_gpio *mux_gpio = mux_chip_priv(mux->chip);
>> +	unsigned long value_bitmap[1] = { state, };
>>  	int i;
>>  
>>  	for (i = 0; i < mux_gpio->gpios->ndescs; i++)
>>  		mux_gpio->val[i] = (state >> i) & 1;
>>  
>>  	gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs,
>> -				       mux_gpio->gpios->desc,
>> -				       mux_gpio->val);
>> +				       mux_gpio->gpios->desc, value_bitmap);
>>  
>>  	return 0;
>>  }
> 
> Dito (but the member name is val).

Here is where struct mux_gpio fits.

Cheers,
Peter

> 
> *snip*
> 
> Cheers,
> Peter
>