Re: [PATCH 2/2] mfd: Use completion interrupt for WM831x AUXADC

[Samuel Ortiz <sameo@linux.intel.com>]

On Tue, Feb 23, 2010 at 11:08:06AM +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 status of the AUXADC if we don't get a completion, mostly for
> systems that don't have the WM831x interrupt infrastructure hooked
> up.
Patch applied to my for-next branch, thanks a lot.

Cheers,
Samuel.

 
> Also reduce the timeout for completion of conversions to 5ms from
> the previous 10ms, the lower timeout should be sufficient.
> 
> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
> ---
>  drivers/mfd/wm831x-core.c       |   36 +++++++++++++++++++++++++++++-------
>  include/linux/mfd/wm831x/core.h |    2 ++
>  2 files changed, 31 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/mfd/wm831x-core.c b/drivers/mfd/wm831x-core.c
> index c428d9f..07101e9 100644
> --- a/drivers/mfd/wm831x-core.c
> +++ b/drivers/mfd/wm831x-core.c
> @@ -321,7 +321,6 @@ EXPORT_SYMBOL_GPL(wm831x_set_bits);
>   */
>  int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
>  {
> -	int tries = 10;
>  	int ret, src;
>  
>  	mutex_lock(&wm831x->auxadc_lock);
> @@ -349,13 +348,14 @@ int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
>  		goto disable;
>  	}
>  
> -	do {
> -		msleep(1);
> +	/* Ignore the result to allow us to soldier on without IRQ hookup */
> +	wait_for_completion_timeout(&wm831x->auxadc_done, msecs_to_jiffies(5));
>  
> -		ret = wm831x_reg_read(wm831x, WM831X_AUXADC_CONTROL);
> -		if (ret < 0)
> -			ret = WM831X_AUX_CVT_ENA;
> -	} while ((ret & WM831X_AUX_CVT_ENA) && --tries);
> +	ret = wm831x_reg_read(wm831x, WM831X_AUXADC_CONTROL);
> +	if (ret < 0) {
> +		dev_err(wm831x->dev, "AUXADC status read failed: %d\n", ret);
> +		goto disable;
> +	}
>  
>  	if (ret & WM831X_AUX_CVT_ENA) {
>  		dev_err(wm831x->dev, "Timed out reading AUXADC\n");
> @@ -390,6 +390,15 @@ out:
>  }
>  EXPORT_SYMBOL_GPL(wm831x_auxadc_read);
>  
> +static irqreturn_t wm831x_auxadc_irq(int irq, void *irq_data)
> +{
> +	struct wm831x *wm831x = irq_data;
> +
> +	complete(&wm831x->auxadc_done);
> +
> +	return IRQ_HANDLED;
> +}
> +
>  /**
>   * wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC
>   *
> @@ -1411,6 +1420,7 @@ static int wm831x_device_init(struct wm831x *wm831x, unsigned long id, int irq)
>  	mutex_init(&wm831x->io_lock);
>  	mutex_init(&wm831x->key_lock);
>  	mutex_init(&wm831x->auxadc_lock);
> +	init_completion(&wm831x->auxadc_done);
>  	dev_set_drvdata(wm831x->dev, wm831x);
>  
>  	ret = wm831x_reg_read(wm831x, WM831X_PARENT_ID);
> @@ -1523,6 +1533,16 @@ static int wm831x_device_init(struct wm831x *wm831x, unsigned long id, int irq)
>  	if (ret != 0)
>  		goto err;
>  
> +	if (wm831x->irq_base) {
> +		ret = request_threaded_irq(wm831x->irq_base +
> +					   WM831X_IRQ_AUXADC_DATA,
> +					   NULL, wm831x_auxadc_irq, 0,
> +					   "auxadc", wm831x);
> +		if (ret < 0)
> +			dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n",
> +				ret);
> +	}
> +
>  	/* The core device is up, instantiate the subdevices. */
>  	switch (parent) {
>  	case WM8310:
> @@ -1593,6 +1613,8 @@ static void wm831x_device_exit(struct wm831x *wm831x)
>  {
>  	wm831x_otp_exit(wm831x);
>  	mfd_remove_devices(wm831x->dev);
> +	if (wm831x->irq_base)
> +		free_irq(wm831x->irq_base + WM831X_IRQ_AUXADC_DATA, wm831x);
>  	wm831x_irq_exit(wm831x);
>  	kfree(wm831x);
>  }
> diff --git a/include/linux/mfd/wm831x/core.h b/include/linux/mfd/wm831x/core.h
> index 53580b5..5915f6e 100644
> --- a/include/linux/mfd/wm831x/core.h
> +++ b/include/linux/mfd/wm831x/core.h
> @@ -15,6 +15,7 @@
>  #ifndef __MFD_WM831X_CORE_H__
>  #define __MFD_WM831X_CORE_H__
>  
> +#include <linux/completion.h>
>  #include <linux/interrupt.h>
>  
>  /*
> @@ -261,6 +262,7 @@ struct wm831x {
>  	int num_gpio;
>  
>  	struct mutex auxadc_lock;
> +	struct completion auxadc_done;
>  
>  	/* The WM831x has a security key blocking access to certain
>  	 * registers.  The mutex is taken by the accessors for locking
> -- 
> 1.7.0
> 

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