linux-kernel - Re: [PATCH 1/2] mfd: Use completion interrupt for WM835x AUXADC

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Date:	Mon, 1 Mar 2010 00:04:23 +0100
From:	Samuel Ortiz <sameo@...ux.intel.com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] mfd: Use completion interrupt for WM835x AUXADC

Hi Mark,

On Tue, Feb 23, 2010 at 11:08:05AM +0000, Mark Brown wrote:
> Use the completion interrupt generated by the device rather than
> polling for conversions to complete. As a backup we still check
> the state of the AUXADC if we don't get a completion, mostly for
> systems that don't have the WM8350 interrupt infrastructure hooked
> up.
Patch applied, many thanks.

Cheers,
Samuel.


> Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
> ---
>  drivers/mfd/wm8350-core.c       |   35 +++++++++++++++++++++++++++++------
>  include/linux/mfd/wm8350/core.h |    2 ++
>  2 files changed, 31 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mfd/wm8350-core.c b/drivers/mfd/wm8350-core.c
> index 9a970bd..bd75807 100644
> --- a/drivers/mfd/wm8350-core.c
> +++ b/drivers/mfd/wm8350-core.c
> @@ -339,7 +339,6 @@ EXPORT_SYMBOL_GPL(wm8350_reg_unlock);
>  int wm8350_read_auxadc(struct wm8350 *wm8350, int channel, int scale, int vref)
>  {
>  	u16 reg, result = 0;
> -	int tries = 5;
>  
>  	if (channel < WM8350_AUXADC_AUX1 || channel > WM8350_AUXADC_TEMP)
>  		return -EINVAL;
> @@ -363,12 +362,13 @@ int wm8350_read_auxadc(struct wm8350 *wm8350, int channel, int scale, int vref)
>  	reg |= 1 << channel | WM8350_AUXADC_POLL;
>  	wm8350_reg_write(wm8350, WM8350_DIGITISER_CONTROL_1, reg);
>  
> -	do {
> -		schedule_timeout_interruptible(1);
> -		reg = wm8350_reg_read(wm8350, WM8350_DIGITISER_CONTROL_1);
> -	} while ((reg & WM8350_AUXADC_POLL) && --tries);
> +	/* We ignore the result of the completion and just check for a
> +	 * conversion result, allowing us to soldier on if the IRQ
> +	 * infrastructure is not set up for the chip. */
> +	wait_for_completion_timeout(&wm8350->auxadc_done, msecs_to_jiffies(5));
>  
> -	if (!tries)
> +	reg = wm8350_reg_read(wm8350, WM8350_DIGITISER_CONTROL_1);
> +	if (reg & WM8350_AUXADC_POLL)
>  		dev_err(wm8350->dev, "adc chn %d read timeout\n", channel);
>  	else
>  		result = wm8350_reg_read(wm8350,
> @@ -385,6 +385,15 @@ int wm8350_read_auxadc(struct wm8350 *wm8350, int channel, int scale, int vref)
>  }
>  EXPORT_SYMBOL_GPL(wm8350_read_auxadc);
>  
> +static irqreturn_t wm8350_auxadc_irq(int irq, void *irq_data)
> +{
> +	struct wm8350 *wm8350 = irq_data;
> +
> +	complete(&wm8350->auxadc_done);
> +
> +	return IRQ_HANDLED;
> +}
> +
>  /*
>   * Cache is always host endian.
>   */
> @@ -682,11 +691,22 @@ int wm8350_device_init(struct wm8350 *wm8350, int irq,
>  	}
>  
>  	mutex_init(&wm8350->auxadc_mutex);
> +	init_completion(&wm8350->auxadc_done);
>  
>  	ret = wm8350_irq_init(wm8350, irq, pdata);
>  	if (ret < 0)
>  		goto err;
>  
> +	if (wm8350->irq_base) {
> +		ret = request_threaded_irq(wm8350->irq_base +
> +					   WM8350_IRQ_AUXADC_DATARDY,
> +					   NULL, wm8350_auxadc_irq, 0,
> +					   "auxadc", wm8350);
> +		if (ret < 0)
> +			dev_warn(wm8350->dev,
> +				 "Failed to request AUXADC IRQ: %d\n", ret);
> +	}
> +
>  	if (pdata && pdata->init) {
>  		ret = pdata->init(wm8350);
>  		if (ret != 0) {
> @@ -736,6 +756,9 @@ void wm8350_device_exit(struct wm8350 *wm8350)
>  	platform_device_unregister(wm8350->gpio.pdev);
>  	platform_device_unregister(wm8350->codec.pdev);
>  
> +	if (wm8350->irq_base)
> +		free_irq(wm8350->irq_base + WM8350_IRQ_AUXADC_DATARDY, wm8350);
> +
>  	wm8350_irq_exit(wm8350);
>  
>  	kfree(wm8350->reg_cache);
> diff --git a/include/linux/mfd/wm8350/core.h b/include/linux/mfd/wm8350/core.h
> index fae08aa..98fcc97 100644
> --- a/include/linux/mfd/wm8350/core.h
> +++ b/include/linux/mfd/wm8350/core.h
> @@ -16,6 +16,7 @@
>  #include <linux/kernel.h>
>  #include <linux/mutex.h>
>  #include <linux/interrupt.h>
> +#include <linux/completion.h>
>  
>  #include <linux/mfd/wm8350/audio.h>
>  #include <linux/mfd/wm8350/gpio.h>
> @@ -621,6 +622,7 @@ struct wm8350 {
>  	u16 *reg_cache;
>  
>  	struct mutex auxadc_mutex;
> +	struct completion auxadc_done;
>  
>  	/* Interrupt handling */
>  	struct mutex irq_lock;
> -- 
> 1.7.0
> 

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