From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [PATCH 2/6] extcon-gpio: If the gpio driver/chip supports debounce, use it Date: Tue, 10 Sep 2013 18:57:28 -0700 Message-ID: <522FCE08.5000704@roeck-us.net> References: <1377836978-24082-1-git-send-email-linux@roeck-us.net> <1377836978-24082-3-git-send-email-linux@roeck-us.net> <522FC476.7060100@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <522FC476.7060100@samsung.com> Sender: linux-kernel-owner@vger.kernel.org To: Chanwoo Choi Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Rob Herring , Pawel Moll , Mark Rutland , Stephen Warren , Ian Campbell , MyungJoo Ham , Grant Likely List-Id: devicetree@vger.kernel.org On 09/10/2013 06:16 PM, Chanwoo Choi wrote: > Hi Guenter > > I agree to use gpio_set_debounce() API but, I suggest following patch to code clean. > and I'd like you to use declarative sentence on patch name instead of 'If ...'. > > On 08/30/2013 01:29 PM, Guenter Roeck wrote: >> Signed-off-by: Guenter Roeck >> --- >> drivers/extcon/extcon-gpio.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c >> index 77d35a7..973600e 100644 >> --- a/drivers/extcon/extcon-gpio.c >> +++ b/drivers/extcon/extcon-gpio.c >> @@ -111,6 +111,11 @@ static int gpio_extcon_probe(struct platform_device *pdev) >> if (ret < 0) >> goto err; >> >> + /* Use gpio debounce if available. If so, don't debounce in software. */ >> + if (pdata->debounce && >> + !gpio_set_debounce(extcon_data->gpio, pdata->debounce * 1000)) >> + extcon_data->debounce_jiffies = 0; >> + >> INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work); >> >> extcon_data->irq = gpio_to_irq(extcon_data->gpio); >> > > diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c > index 3943ce2..0777e72 100644 > --- a/drivers/extcon/extcon-gpio.c > +++ b/drivers/extcon/extcon-gpio.c > @@ -56,8 +56,10 @@ static irqreturn_t gpio_irq_handler(int irq, void *dev_id) > { > struct gpio_extcon_data *extcon_data = dev_id; > > - queue_delayed_work(system_power_efficient_wq, &extcon_data->work, > - extcon_data->debounce_jiffies); > + if (extcon_data->debounce_jiffies) > + queue_delayed_work(system_power_efficient_wq, > + &extcon_data->work, > + extcon_data->debounce_jiffies); I am a bit lost about this one. The above means that the workqueue would not be executed at all if debounce_jiffies is 0 (and if pdata->debounce is 0), meaning an event would never be generated. With the original code, the workqueue will be executed immediately if debounce_jiffies is 0, which I think is exactly what we need. > return IRQ_HANDLED; > } > > @@ -100,7 +102,14 @@ static int gpio_extcon_probe(struct platform_device *pdev) > extcon_data->state_off = pdata->state_off; > if (pdata->state_on && pdata->state_off) > extcon_data->edev.print_state = extcon_gpio_print_state; > - extcon_data->debounce_jiffies = msecs_to_jiffies(pdata->debounce); > + extcon_data->debounce_jiffies = 0; > + if (pdata->debounce) { > + ret = gpio_set_debounce(extcon_data->gpio, > + pdata->debounce * 1000); > + if (ret < 0) > + extcon_data->debounce_jiffies = > + msecs_to_jiffies(pdata->debounce); > + } > Ok, though it is unnecessary to initialize debounce_jiffies (it is pre-initialized from the allocation), so I'll drop that line. > ret = extcon_dev_register(&extcon_data->edev, &pdev->dev); > if (ret < 0) > @@ -111,11 +120,6 @@ static int gpio_extcon_probe(struct platform_device *pdev) > if (ret < 0) > goto err; > > - /* Use gpio debounce if available. If so, don't debounce in software. */ > - if (pdata->debounce && > - !gpio_set_debounce(extcon_data->gpio, pdata->debounce * 1000)) > - extcon_data->debounce_jiffies = 0; > - > INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work); > > extcon_data->irq = gpio_to_irq(extcon_data->gpio); > @@ -146,7 +150,8 @@ static int gpio_extcon_remove(struct platform_device *pdev) > { > struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev); > > - cancel_delayed_work_sync(&extcon_data->work); > + if (extcon_data->debounce_jiffies) > + cancel_delayed_work_sync(&extcon_data->work); I think we would have to call cancel_work_sync() in the else case to make sure that no work is in the process of being executed - which just turns out to execute the same code as cancel_delayed_work_sync(). So the if/else would just add complexity with no real gain. Thanks, Guenter > free_irq(extcon_data->irq, extcon_data); > extcon_dev_unregister(&extcon_data->edev); > > > Thanks, > Chanwoo Choi > >