linux-kernel - Re: [PATCH 2/2] mfd: anatop: permit adata be NULL when access register

Open Source and information security mailing list archives

Date:	Mon, 14 May 2012 11:51:38 +0800
From:	Shawn Guo <shawn.guo@...escale.com>
To:	Richard Zhao <richard.zhao@...aro.org>
CC:	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <paul.liu@...aro.org>,
	<broonie@...nsource.wolfsonmicro.com>,
	Richard Zhao <richard.zhao@...escale.com>,
	<sameo@...ux.intel.com>, <shawn.guo@...aro.org>
Subject: Re: [PATCH 2/2] mfd: anatop: permit adata be NULL when access
 register

On Sun, May 13, 2012 at 08:59:54AM +0800, Richard Zhao wrote:
> It makes anatop register access easier. Anatop has many misc registers,
> which may not be a specific driver.
> 
> There's only one anatop device for a running system, so we use a global
> variable to store struct anatop.
> 
>From what I see, it's reasonable.  Then the immediate question I have
is, should we remove "struct anatop *adata" from anatop_read_reg and
anatop_write_reg completely?

Regards,
Shawn

> Signed-off-by: Richard Zhao <richard.zhao@...escale.com>
> ---
>  drivers/mfd/anatop-mfd.c |   12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/mfd/anatop-mfd.c b/drivers/mfd/anatop-mfd.c
> index 3bb7c49..b0313210 100644
> --- a/drivers/mfd/anatop-mfd.c
> +++ b/drivers/mfd/anatop-mfd.c
> @@ -41,8 +41,15 @@
>  #include <linux/of_address.h>
>  #include <linux/mfd/anatop.h>
>  
> +/* For any running system, there's only one anatop device. */
> +static struct anatop *anatop_data;
> +
>  u32 anatop_read_reg(struct anatop *adata, u32 addr)
>  {
> +	BUG_ON(!anatop_data);
> +	if (!adata)
> +		adata = anatop_data;
> +
>  	return readl(adata->ioreg + addr);
>  }
>  EXPORT_SYMBOL_GPL(anatop_read_reg);
> @@ -51,6 +58,10 @@ void anatop_write_reg(struct anatop *adata, u32 addr, u32 data, u32 mask)
>  {
>  	u32 val;
>  
> +	BUG_ON(!anatop_data);
> +	if (!adata)
> +		adata = anatop_data;
> +
>  	data &= mask;
>  
>  	spin_lock(&adata->reglock);
> @@ -83,6 +94,7 @@ static int __devinit of_anatop_probe(struct platform_device *pdev)
>  	drvdata->ioreg = ioreg;
>  	spin_lock_init(&drvdata->reglock);
>  	platform_set_drvdata(pdev, drvdata);
> +	anatop_data = drvdata;
>  	of_platform_populate(np, of_anatop_match, NULL, dev);
>  
>  	return 0;
> -- 
> 1.7.9.5
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

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