linux-kernel - Re: [PATCH V3 3/4] gpio: tegra: Get rid of all file scoped global variables

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Date:	Thu, 21 Apr 2016 13:34:46 -0600
From:	Stephen Warren <swarren@...dotorg.org>
To:	Laxman Dewangan <ldewangan@...dia.com>
Cc:	linus.walleij@...aro.org, gnurou@...il.com,
	thierry.reding@...il.com, linux-gpio@...r.kernel.org,
	linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V3 3/4] gpio: tegra: Get rid of all file scoped global
 variables

On 04/21/2016 12:35 PM, Laxman Dewangan wrote:
>
> On Friday 22 April 2016 12:03 AM, Stephen Warren wrote:
>> On 04/20/2016 07:30 AM, Laxman Dewangan wrote:
>>> Move the file scoped multiple global variable from Tegra GPIO
>>> driver to the structure and make this as gpiochip data which
>>> can be referred from GPIO chip callbacks.
>>
>>> diff --git a/drivers/gpio/gpio-tegra.c b/drivers/gpio/gpio-tegra.c
>>
>>> +#define GPIO_MSK_CNF(t, x) (GPIO_REG(t, x) + t->soc->upper_offset +
>>> 0x00)
>>> +#define GPIO_MSK_OE(t, x)    (GPIO_REG(t, x) + t->soc->upper_offset
>>> + 0x10)
>>> +#define GPIO_MSK_OUT(t, x)    (GPIO_REG(t, x) + t->soc->upper_offset
>>> + 0X20)
>>> +#define GPIO_MSK_INT_STA(t, x)    (GPIO_REG(t, x) +
>>> t->soc->upper_offset + 0x40)
>>> +#define GPIO_MSK_INT_ENB(t, x)    (GPIO_REG(t, x) +
>>> t->soc->upper_offset + 0x50)
>>> +#define GPIO_MSK_INT_LVL(t, x)    (GPIO_REG(t, x) +
>>> t->soc->upper_offset + 0x60)
>>> +#define GPIO_MSK_DBC_EN(t, x)    (GPIO_REG(t, x) +
>>> t->soc->upper_offset + 0x30)
>>
>> DBC_EN/0x30 should be sorted correctly with the rest, and likely added
>> in patch 4 instead.
>>
>>> @@ -276,19 +307,25 @@ static void tegra_gpio_irq_handler(struct
>>> irq_desc *desc)
>>
>>> +    struct tegra_gpio_info *tgi = bank->tgi;
>>> +
>>>
>>>       chained_irq_enter(chip, desc);
>>
>> No need for 2 blank lines there.
>>
>>> @@ -410,7 +462,7 @@ static int dbg_gpio_show(struct seq_file *s, void
>>> *unused)
>>>
>>>   static int dbg_gpio_open(struct inode *inode, struct file *file)
>>>   {
>>> -    return single_open(file, dbg_gpio_show, &inode->i_private);
>>> +    return single_open(file, dbg_gpio_show, inode->i_private);
>>
>> Can you explain that change? I'm not sure it's correct, but don't know
>> why it was made.
>
> we have sysfs interface to dump register as /sys/kernel/debug/tega_gpio
> On this patch, I moved the tegra_gpio_info pointer as data for
> s->private so that we will not need the global variable.
> inode->i_private contains the pointer of the passed data. Hence we do
> not need to pass the pointe ro pointer of data. If we dont do then we
> will get wrong data pointer for tegra_gpio_info.

Oh I see. The old value wasn't ever used at all, so it wasn't set to 
anything in particular. This isn't so much a change as just using the 
data for the first time, and hence setting it correctly.

>> Once those are fixed,
>> Reviewed-by: Stephen Warren <swarren@...dia.com>
>
> Thanks for RB.