linux-kernel - Re: [PATCH v8 07/12] gpio: palmas: add in GPIO support for palmas charger

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Date:	Thu, 14 Mar 2013 11:58:10 +0000
From:	Ian Lartey <ian@...mlogic.co.uk>
To:	Linus Walleij <linus.walleij@...aro.org>
CC:	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-leds@...r.kernel.org,
	linux-watchdog@...r.kernel.org, swarren@...dotorg.org,
	grant.likely@...retlab.ca, broonie@...nsource.wolfsonmicro.com,
	rob.herring@...xeda.com, rob@...dley.net, mturquette@...aro.org,
	cooloney@...il.com, rpurdie@...ys.net, sameo@...ux.intel.com,
	wim@...ana.be, lgirdwood@...il.com, gg@...mlogic.co.uk,
	j-keerthy@...com, ldewangan@...dia.com, t-kristo@...com
Subject: Re: [PATCH v8 07/12] gpio: palmas: add in GPIO support for palmas
 charger

On 13/03/13 14:15, Linus Walleij wrote:
> Sorry for slow replies :-(
>
> On Thu, Mar 7, 2013 at 2:17 PM, Ian Lartey <ian@...mlogic.co.uk> wrote:
>
>> +static int palmas_gpio_read(struct palmas *palmas, unsigned int reg,
>> +               int gpio, unsigned int *dest)
>
> I don't like "int gpio" here, please use "int offset".
>
> This is not a global GPIO number, it is an offset in the local gpio_chip,
> right?

Correct.
>
>> +{
>> +       /* registers for second bank are identical and offset by 0x9 */
>> +       if (gpio > 7)
>> +               reg += PALMAS_GPIO_DATA_IN2;
>> +
>> +       return palmas_read(palmas, PALMAS_GPIO_BASE, reg, dest);
>> +}
>> +
>> +static int palmas_gpio_write(struct palmas *palmas, unsigned int reg,
>> +               int gpio, unsigned int data)
>> +{
>> +       /* registers for second bank are identical and offset by 0x9 */
>> +       if (gpio > 7)
>> +               reg += PALMAS_GPIO_DATA_IN2;
>> +
>> +       return palmas_write(palmas, PALMAS_GPIO_BASE, reg, data);
>> +}
>> +
>> +static int palmas_gpio_update_bits(struct palmas *palmas, unsigned int reg,
>> +               int gpio, unsigned int mask, unsigned int data)
>> +{
>> +       /* registers for second bank are identical and offset by 0x9 */
>> +       if (gpio > 7)
>> +               reg += PALMAS_GPIO_DATA_IN2;
>> +
>> +       return palmas_update_bits(palmas, PALMAS_GPIO_BASE, reg, mask, data);
>> +}
>
>
>> -       ret = palmas_read(palmas, PALMAS_GPIO_BASE, PALMAS_GPIO_DATA_IN, &val);
>> +       ret = palmas_gpio_read(palmas, PALMAS_GPIO_DATA_IN, offset, &val);
>
> (Obviously you are passing the offset.)
>
>> +               ret = palmas_gpio_write(palmas, PALMAS_GPIO_SET_DATA_OUT,
>> +                               offset, BIT(offset % 8));
> (..)
>> +               ret = palmas_gpio_write(palmas, PALMAS_GPIO_CLEAR_DATA_OUT,
>> +                               offset, BIT(offset % 8));
> (...)
>> +       ret = palmas_gpio_update_bits(palmas, PALMAS_GPIO_DATA_DIR,
>> +                       offset, 1 << (offset % 8), 1 << (offset % 8));
>
> Why aren't you using the BIT() macro here too?
>
> Further: if these functions are always used like this, with offset
> and some BIT() or (1 << (offset % 8)) why don't you move that
> latter part into the static helper and just pass offset into the
> helper?
>

Good points  - I missed the other bit shifts.


> Yours,
> Linus Walleij


Thanks

Ian
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