linux-kernel - Re: [PATCH V4 4/4] gpio: tegra: Add support for gpio debounce

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Date:	Mon, 25 Apr 2016 14:10:42 +0530
From:	Laxman Dewangan <ldewangan@...dia.com>
To:	Alexandre Courbot <gnurou@...il.com>
CC:	Stephen Warren <swarren@...dotorg.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Thierry Reding <thierry.reding@...il.com>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V4 4/4] gpio: tegra: Add support for gpio debounce


On Monday 25 April 2016 11:06 AM, Alexandre Courbot wrote:
> Sorry, just realized I commented on v3...
>
> On Fri, Apr 22, 2016 at 7:09 PM, Laxman Dewangan <ldewangan@...dia.com> wrote:
>> +       spinlock_t dbc_lock[4]; /* Lock for updating debounce count register */
> I'm nit'ing here, but maybe one spinlock shared by all ports would be
> enough? (the same would apply to lvl_lock, so feel free to do this as
> a separate patch) I don't think we expect *that* many concurrent
> accesses, do we?

Really no, but to make the stuff uniform, it should be fine here. If the 
registers are not conflicting then do not make under same lock.


>>   
>>
>>         spin_lock_irqsave(bank->dbc_lock[port], flags);
>>         if (bank->dbc_cnt[port] < debounce_ms) {
>>                 tegra_gpio_writel(tgi, debounce_ms, GPIO_DBC_CNT(tgi, offset));
>>                 bank->dbc_cnt[port] = debounce_ms;
>>         }
>>         spin_unlock_irqrestore(&bank->dbc_lock[port], flags);
>>
>> Which is nicer to the eyes.
>>


OK, this also looks fine. As I am goign to respin this for V5 (for gc as 
instance rather than pointer), I will take care of it.