linux-kernel - Re: [PATCH 2/2] i2c: Dynamically assign adapter id if it wasn't explictly specified

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Message-id: <4F6B4532.7090806@samsung.com>
Date:	Thu, 22 Mar 2012 16:28:50 +0100
From:	Karol Lewandowski <k.lewandowsk@...sung.com>
To:	w.sang@...gutronix.de, hskinnemoen@...il.com,
	linux@....linux.org.uk, Rade Bozic <rade.bozic.ext@....com>
Cc:	Karol Lewandowski <k.lewandowsk@...sung.com>, ben-linux@...ff.org,
	khali@...ux-fr.org, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org, dirk.brandewie@...il.com,
	bigeasy@...utronix.de, m.szyprowski@...sung.com,
	grant.likely@...retlab.ca, kyungmin.park@...sung.com,
	David Daney <ddaney@...iumnetworks.com>
Subject: Re: [PATCH 2/2] i2c: Dynamically assign adapter id if it wasn't
 explictly specified

On 16.03.2012 13:19, Karol Lewandowski wrote:

>> Commit 488bf314b ("i2c: Allow i2c_add_numbered_adapter() to assign a
>> bus id") reworked i2c_add_numbered_adapter() to call i2c_add_adapter()
>> if requested bus was -1.

>> This allows to simplify driver's initialization procedure as it allows

>> static and dynamic adapter id registration using one function.
>> 
>> This patch updates few more drivers (missed out in original patch) to
>> use this functionality.
>

> [ I must have lost actual problem description while rewording
>  message itself... ]
>
> Problem arises when multiple drivers (or multiple instances
> of one driver) try to assume the same fixed bus number (0).
>
> This simply causes i2c_add_numbered_bus() to fail.
> Leaving -1 works perfectly, as registration function switches
> to dynamic id registration.

>> Signed-off-by: Karol Lewandowski <k.lewandowsk@...sung.com>
>> Signed-off-by: Kyungmin Park <kyungmin.park@...sung.com>
>> ---
>>  drivers/i2c/busses/i2c-gpio.c         |    7 +------
>>  drivers/i2c/busses/i2c-octeon.c       |    2 +-
>>  drivers/i2c/busses/i2c-pca-platform.c |    2 +-
>>  drivers/i2c/busses/i2c-versatile.c    |    9 ++-------
>>  4 files changed, 5 insertions(+), 15 deletions(-)


Dear Haavard, Rade, Wolfram and Russel

Could you review following changes for gpio, octeon, pca-platform
and versatile i2c controller drivers (for which you are, or were,
maintainers)?

Grant requested explicit Ack to get this merged.

Thanks!

> 
> diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
> index a651779..50a2a94 100644
> --- a/drivers/i2c/busses/i2c-gpio.c
> +++ b/drivers/i2c/busses/i2c-gpio.c
> @@ -144,12 +144,7 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
>  	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
>  	adap->dev.parent = &pdev->dev;
>  
> -	/*
> -	 * If "dev->id" is negative we consider it as zero.
> -	 * The reason to do so is to avoid sysfs names that only make
> -	 * sense when there are multiple adapters.
> -	 */
> -	adap->nr = (pdev->id != -1) ? pdev->id : 0;
> +	adap->nr = pdev->id;
>  	ret = i2c_bit_add_numbered_bus(adap);
>  	if (ret)
>  		goto err_add_bus;
> diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
> index ee139a5..8470232 100644
> --- a/drivers/i2c/busses/i2c-octeon.c
> +++ b/drivers/i2c/busses/i2c-octeon.c
> @@ -581,7 +581,7 @@ static int __devinit octeon_i2c_probe(struct platform_device *pdev)
>  
>  	i2c->adap = octeon_i2c_ops;
>  	i2c->adap.dev.parent = &pdev->dev;
> -	i2c->adap.nr = pdev->id >= 0 ? pdev->id : 0;
> +	i2c->adap.nr = pdev->id;
>  	i2c_set_adapdata(&i2c->adap, i2c);
>  	platform_set_drvdata(pdev, i2c);
>  
> diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c
> index 2adbf1a..675878f 100644
> --- a/drivers/i2c/busses/i2c-pca-platform.c
> +++ b/drivers/i2c/busses/i2c-pca-platform.c
> @@ -171,7 +171,7 @@ static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
>  	i2c->io_size = resource_size(res);
>  	i2c->irq = irq;
>  
> -	i2c->adap.nr = pdev->id >= 0 ? pdev->id : 0;
> +	i2c->adap.nr = pdev->id;
>  	i2c->adap.owner = THIS_MODULE;
>  	snprintf(i2c->adap.name, sizeof(i2c->adap.name),
>  		 "PCA9564/PCA9665 at 0x%08lx",
> diff --git a/drivers/i2c/busses/i2c-versatile.c b/drivers/i2c/busses/i2c-versatile.c
> index 6055601..9458568 100644
> --- a/drivers/i2c/busses/i2c-versatile.c
> +++ b/drivers/i2c/busses/i2c-versatile.c
> @@ -102,13 +102,8 @@ static int i2c_versatile_probe(struct platform_device *dev)
>  	i2c->algo = i2c_versatile_algo;
>  	i2c->algo.data = i2c;
>  
> -	if (dev->id >= 0) {
> -		/* static bus numbering */
> -		i2c->adap.nr = dev->id;
> -		ret = i2c_bit_add_numbered_bus(&i2c->adap);
> -	} else
> -		/* dynamic bus numbering */
> -		ret = i2c_bit_add_bus(&i2c->adap);
> +	i2c->adap.nr = dev->id;
> +	ret = i2c_bit_add_numbered_bus(&i2c->adap);
>  	if (ret >= 0) {
>  		platform_set_drvdata(dev, i2c);
>  		return 0;



-- 
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform
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