linux-kernel - Re: [PATCH] Convert the AB3100 driver to use threaded IRH

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Message-ID: <20100108093303.GA3734@sortiz.org>
Date:	Fri, 8 Jan 2010 10:33:04 +0100
From:	Samuel Ortiz <sameo@...ux.intel.com>
To:	Linus Walleij <linus.walleij@...ricsson.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Convert the AB3100 driver to use threaded IRH

Hi Linus,

On Fri, Jan 08, 2010 at 12:08:45AM +0100, Linus Walleij wrote:
> This converts the AB3100 core MFD driver to use a threaded
> interrupt handler instead of the explicit top/bottom-half
> construction with a workqueue. This saves some code and make it
> more similar to other modern MFD drivers.
patch applied, many thanks.

Cheers,
Samuel.


> Signed-off-by: Linus Walleij <linus.walleij@...ricsson.com>
> ---
>  drivers/mfd/ab3100-core.c  |   43 +++++++++++++------------------------------
>  include/linux/mfd/ab3100.h |    3 ---
>  2 files changed, 13 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/mfd/ab3100-core.c b/drivers/mfd/ab3100-core.c
> index fd42a80..93b2c14 100644
> --- a/drivers/mfd/ab3100-core.c
> +++ b/drivers/mfd/ab3100-core.c
> @@ -365,10 +365,13 @@ int ab3100_event_registers_startup_state_get(struct ab3100 *ab3100,
>  }
>  EXPORT_SYMBOL(ab3100_event_registers_startup_state_get);
>  
> -/* Interrupt handling worker */
> -static void ab3100_work(struct work_struct *work)
> +/*
> + * This is a threaded interrupt handler so we can make some
> + * I2C calls etc.
> + */
> +static irqreturn_t ab3100_irq_handler(int irq, void *data)
>  {
> -	struct ab3100 *ab3100 = container_of(work, struct ab3100, work);
> +	struct ab3100 *ab3100 = data;
>  	u8 event_regs[3];
>  	u32 fatevent;
>  	int err;
> @@ -376,7 +379,7 @@ static void ab3100_work(struct work_struct *work)
>  	err = ab3100_get_register_page_interruptible(ab3100, AB3100_EVENTA1,
>  				       event_regs, 3);
>  	if (err)
> -		goto err_event_wq;
> +		goto err_event;
>  
>  	fatevent = (event_regs[0] << 16) |
>  		(event_regs[1] << 8) |
> @@ -398,29 +401,11 @@ static void ab3100_work(struct work_struct *work)
>  	dev_dbg(ab3100->dev,
>  		"IRQ Event: 0x%08x\n", fatevent);
>  
> -	/* By now the IRQ should be acked and deasserted so enable it again */
> -	enable_irq(ab3100->i2c_client->irq);
> -	return;
> +	return IRQ_HANDLED;
>  
> - err_event_wq:
> + err_event:
>  	dev_dbg(ab3100->dev,
> -		"error in event workqueue\n");
> -	/* Enable the IRQ anyway, what choice do we have? */
> -	enable_irq(ab3100->i2c_client->irq);
> -	return;
> -}
> -
> -static irqreturn_t ab3100_irq_handler(int irq, void *data)
> -{
> -	struct ab3100 *ab3100 = data;
> -	/*
> -	 * Disable the IRQ and dispatch a worker to handle the
> -	 * event. Since the chip resides on I2C this is slow
> -	 * stuff and we will re-enable the interrupts once th
> -	 * worker has finished.
> -	 */
> -	disable_irq_nosync(irq);
> -	schedule_work(&ab3100->work);
> +		"error reading event status\n");
>  	return IRQ_HANDLED;
>  }
>  
> @@ -904,12 +889,10 @@ static int __init ab3100_probe(struct i2c_client *client,
>  	if (err)
>  		goto exit_no_setup;
>  
> -	INIT_WORK(&ab3100->work, ab3100_work);
> -
>  	/* This real unpredictable IRQ is of course sampled for entropy */
> -	err = request_irq(client->irq, ab3100_irq_handler,
> -			  IRQF_DISABLED | IRQF_SAMPLE_RANDOM,
> -			  "AB3100 IRQ", ab3100);
> +	err = request_threaded_irq(client->irq, NULL, ab3100_irq_handler,
> +			  IRQF_ONESHOT | IRQF_SAMPLE_RANDOM,
> +			  "ab3100-core", ab3100);
>  	if (err)
>  		goto exit_no_irq;
>  
> diff --git a/include/linux/mfd/ab3100.h b/include/linux/mfd/ab3100.h
> index e9aa4c9..9a881c3 100644
> --- a/include/linux/mfd/ab3100.h
> +++ b/include/linux/mfd/ab3100.h
> @@ -6,7 +6,6 @@
>   */
>  
>  #include <linux/device.h>
> -#include <linux/workqueue.h>
>  #include <linux/regulator/machine.h>
>  
>  #ifndef MFD_AB3100_H
> @@ -74,7 +73,6 @@
>   * @testreg_client: secondary client for test registers
>   * @chip_name: name of this chip variant
>   * @chip_id: 8 bit chip ID for this chip variant
> - * @work: an event handling worker
>   * @event_subscribers: event subscribers are listed here
>   * @startup_events: a copy of the first reading of the event registers
>   * @startup_events_read: whether the first events have been read
> @@ -90,7 +88,6 @@ struct ab3100 {
>  	struct i2c_client *testreg_client;
>  	char chip_name[32];
>  	u8 chip_id;
> -	struct work_struct work;
>  	struct blocking_notifier_head event_subscribers;
>  	u32 startup_events;
>  	bool startup_events_read;
> -- 
> 1.6.3.3
> 

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