Re: [PATCH] input: gpio_keys: Polling mode support.

[Paul Mundt <lethal@linux-sh.org>]

Ping.

On Wed, Nov 26, 2008 at 05:43:58AM +0900, Paul Mundt wrote:
> On Tue, Oct 28, 2008 at 11:51:23PM -0400, Dmitry Torokhov wrote:
> > On Tue, Oct 28, 2008 at 07:18:57PM +0900, Paul Mundt wrote:
> > > On Tue, Oct 21, 2008 at 05:38:16PM +0900, Paul Mundt wrote:
> > > > This implements an optional polling mode for the gpio_keys driver,
> > > > necessary for GPIOs that are not able to generate IRQs.
> > > > 
> > > > Polling mode is done device granular, and can not be toggled for
> > > > individual GPIOs in order to maintain simplicity. Platforms with both
> > > > IRQ capable and incapable GPIOs are required to register multiple
> > > > times, once for each case.
> > > > 
> > > >  
> > > > -	input_unregister_device(input);
> > > > +	if (pdata->polling)
> > > > +		input_unregister_polled_device(poll_dev);
> > 
> > You also need to do input_free_polled_device (but not input_free_device
> >  - yeah, I know, its confusing... The reason is that input_dev is
> >    refcounted while input_polled_dev is not).
> 
> Thanks, fixed.
> 
> > > > +	else
> > > > +		input_unregister_device(poll_dev->input);
> > > >  
> > 
> > I also concerned with unconditionally polling INPUT_POLLDEV for all
> > users of gpio-keys. Maybe we could make polling support optional?
> > 
> I thought that was what my patch was doing? I couldn't think of a clean
> way to do it on a per-gpio basis, so the cleanest way seemed to be to
> regster in polled and non-polled blocks. ie, polled devices will set
> pdata->polling and register those for gpio_keys to set up a polled dev.
> Devices that do not set pdata->polling will remain unaffected.
> 
> If you have some suggestions on how to toggle this on a per-gpio basis,
> I am quite happy to change the code. If your concern is the select of
> INPUT_POLLDEV, I can just select it from my platform code if you prefer.
> This does mean that we would need nopped definitions in
> linux/input-polldev.h though, or litter gpio_keys with ifdefs, which is
> what I was trying to avoid in the first place. Let me know what you
> prefer here, and I'll update accordingly.
> 
> For now, here is an updated version..
> 
> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
> 
> ---
> 
>  drivers/input/keyboard/Kconfig     |    1 
>  drivers/input/keyboard/gpio_keys.c |   92 ++++++++++++++++++++++++++++---------
>  include/linux/gpio_keys.h          |    1 
>  3 files changed, 73 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
> index efd70a9..a8cefe9 100644
> --- a/drivers/input/keyboard/Kconfig
> +++ b/drivers/input/keyboard/Kconfig
> @@ -283,6 +283,7 @@ config KEYBOARD_AAED2000
>  config KEYBOARD_GPIO
>  	tristate "GPIO Buttons"
>  	depends on GENERIC_GPIO
> +	select INPUT_POLLDEV
>  	help
>  	  This driver implements support for buttons connected
>  	  to GPIO pins of various CPUs (and some other chips).
> diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
> index 05f3f43..e7a46f8 100644
> --- a/drivers/input/keyboard/gpio_keys.c
> +++ b/drivers/input/keyboard/gpio_keys.c
> @@ -1,7 +1,8 @@
>  /*
> - * Driver for keys on GPIO lines capable of generating interrupts.
> + * Driver for keys on GPIO lines, either IRQ-driven or polled.
>   *
>   * Copyright 2005 Phil Blundell
> + * Copyright 2008 Paul Mundt
>   *
>   * This program is free software; you can redistribute it and/or modify
>   * it under the terms of the GNU General Public License version 2 as
> @@ -9,7 +10,6 @@
>   */
>  
>  #include <linux/module.h>
> -
>  #include <linux/init.h>
>  #include <linux/fs.h>
>  #include <linux/interrupt.h>
> @@ -22,7 +22,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/input.h>
>  #include <linux/gpio_keys.h>
> -
> +#include <linux/input-polldev.h>
>  #include <asm/gpio.h>
>  
>  struct gpio_button_data {
> @@ -32,7 +32,8 @@ struct gpio_button_data {
>  };
>  
>  struct gpio_keys_drvdata {
> -	struct input_dev *input;
> +	struct gpio_keys_platform_data *pdata;
> +	struct input_polled_dev *poll_dev;
>  	struct gpio_button_data data[0];
>  };
>  
> @@ -54,6 +55,33 @@ static void gpio_check_button(unsigned long _data)
>  	gpio_keys_report_event(data);
>  }
>  
> +static void gpio_handle_button_event(struct gpio_keys_button *button,
> +				     struct gpio_button_data *bdata)
> +{
> +	if (button->debounce_interval)
> +		mod_timer(&bdata->timer,
> +			jiffies + msecs_to_jiffies(button->debounce_interval));
> +	else
> +		gpio_keys_report_event(bdata);
> +}
> +
> +static void gpio_keys_poll(struct input_polled_dev *dev)
> +{
> +	struct gpio_keys_drvdata *ddata = dev->private;
> +	struct gpio_keys_platform_data *pdata = ddata->pdata;
> +	int i;
> +
> +	for (i = 0; i < pdata->nbuttons; i++) {
> +		struct gpio_keys_button *button = &pdata->buttons[i];
> +		struct gpio_button_data *bdata = &ddata->data[i];
> +
> +		bdata->input = dev->input;
> +		bdata->button = button;
> +
> +		gpio_handle_button_event(button, bdata);
> +	}
> +}
> +
>  static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
>  {
>  	struct gpio_button_data *bdata = dev_id;
> @@ -61,11 +89,7 @@ static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
>  
>  	BUG_ON(irq != gpio_to_irq(button->gpio));
>  
> -	if (button->debounce_interval)
> -		mod_timer(&bdata->timer,
> -			jiffies + msecs_to_jiffies(button->debounce_interval));
> -	else
> -		gpio_keys_report_event(bdata);
> +	gpio_handle_button_event(button, bdata);
>  
>  	return IRQ_HANDLED;
>  }
> @@ -74,6 +98,7 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
>  {
>  	struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
>  	struct gpio_keys_drvdata *ddata;
> +	struct input_polled_dev *poll_dev;
>  	struct input_dev *input;
>  	int i, error;
>  	int wakeup = 0;
> @@ -81,14 +106,19 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
>  	ddata = kzalloc(sizeof(struct gpio_keys_drvdata) +
>  			pdata->nbuttons * sizeof(struct gpio_button_data),
>  			GFP_KERNEL);
> -	input = input_allocate_device();
> -	if (!ddata || !input) {
> +	poll_dev = input_allocate_polled_device();
> +	if (!ddata || !poll_dev) {
>  		error = -ENOMEM;
>  		goto fail1;
>  	}
>  
>  	platform_set_drvdata(pdev, ddata);
>  
> +	poll_dev->private = ddata;
> +	poll_dev->poll = gpio_keys_poll;
> +	poll_dev->poll_interval = 50; /* msec */
> +
> +	input = poll_dev->input;
>  	input->name = pdev->name;
>  	input->phys = "gpio-keys/input0";
>  	input->dev.parent = &pdev->dev;
> @@ -98,7 +128,8 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
>  	input->id.product = 0x0001;
>  	input->id.version = 0x0100;
>  
> -	ddata->input = input;
> +	ddata->poll_dev = poll_dev;
> +	ddata->pdata = pdata;
>  
>  	for (i = 0; i < pdata->nbuttons; i++) {
>  		struct gpio_keys_button *button = &pdata->buttons[i];
> @@ -127,6 +158,15 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
>  			goto fail2;
>  		}
>  
> +		input_set_capability(input, type, button->code);
> +
> +		/*
> +		 * Skip the IRQ setup and wakeup source initialization if
> +		 * we are going to be polled.
> +		 */
> +		if (pdata->polling)
> +			continue;
> +
>  		irq = gpio_to_irq(button->gpio);
>  		if (irq < 0) {
>  			error = irq;
> @@ -151,11 +191,12 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
>  
>  		if (button->wakeup)
>  			wakeup = 1;
> -
> -		input_set_capability(input, type, button->code);
>  	}
>  
> -	error = input_register_device(input);
> +	if (pdata->polling)
> +		error = input_register_polled_device(poll_dev);
> +	else
> +		error = input_register_device(input);
>  	if (error) {
>  		pr_err("gpio-keys: Unable to register input device, "
>  			"error: %d\n", error);
> @@ -168,7 +209,9 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
>  
>   fail2:
>  	while (--i >= 0) {
> -		free_irq(gpio_to_irq(pdata->buttons[i].gpio), &ddata->data[i]);
> +		if (!pdata->polling)
> +			free_irq(gpio_to_irq(pdata->buttons[i].gpio),
> +				 &ddata->data[i]);
>  		if (pdata->buttons[i].debounce_interval)
>  			del_timer_sync(&ddata->data[i].timer);
>  		gpio_free(pdata->buttons[i].gpio);
> @@ -176,7 +219,7 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, NULL);
>   fail1:
> -	input_free_device(input);
> +	input_free_polled_device(poll_dev);
>  	kfree(ddata);
>  
>  	return error;
> @@ -186,20 +229,27 @@ static int __devexit gpio_keys_remove(struct platform_device *pdev)
>  {
>  	struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
>  	struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
> -	struct input_dev *input = ddata->input;
> +	struct input_polled_dev *poll_dev = ddata->poll_dev;
>  	int i;
>  
>  	device_init_wakeup(&pdev->dev, 0);
>  
>  	for (i = 0; i < pdata->nbuttons; i++) {
> -		int irq = gpio_to_irq(pdata->buttons[i].gpio);
> -		free_irq(irq, &ddata->data[i]);
> +		if (!pdata->polling) {
> +			int irq = gpio_to_irq(pdata->buttons[i].gpio);
> +			free_irq(irq, &ddata->data[i]);
> +		}
> +
>  		if (pdata->buttons[i].debounce_interval)
>  			del_timer_sync(&ddata->data[i].timer);
>  		gpio_free(pdata->buttons[i].gpio);
>  	}
>  
> -	input_unregister_device(input);
> +	if (pdata->polling) {
> +		input_unregister_polled_device(poll_dev);
> +		input_free_polled_device(poll_dev);
> +	} else
> +		input_unregister_device(poll_dev->input);
>  
>  	return 0;
>  }
> diff --git a/include/linux/gpio_keys.h b/include/linux/gpio_keys.h
> index ec6ecd7..e869752 100644
> --- a/include/linux/gpio_keys.h
> +++ b/include/linux/gpio_keys.h
> @@ -15,6 +15,7 @@ struct gpio_keys_button {
>  struct gpio_keys_platform_data {
>  	struct gpio_keys_button *buttons;
>  	int nbuttons;
> +	int polling;		/* force polling mode */
>  };
>  
>  #endif