Re: [PATCH] i2c: nomadik: allocate adapter number dynamically

[Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>]

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On Mon, Jun 10, 2013 at 12:15:53AM +0200, Linus Walleij wrote:
> The Nomadik I2C was using a local atomic counter to number
> the I2C adapters. This does not work on configurations where
> you also add, say a GPIO bit-banged adapter to the system.
> They will start to conflict about being adapter 0.
> 
> There is no reason to use the numbered adapter function, and
> the semantic effect on systems with only Nomadik I2C blocks
> will be none - instead of increasing the number atomically
> in the driver itself, it is done in the I2C core.
> 
> Signed-off-by: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

Basically fine...

> ---
>  drivers/i2c/busses/i2c-nomadik.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
> index 9f1423a..96c8515 100644
> --- a/drivers/i2c/busses/i2c-nomadik.c
> +++ b/drivers/i2c/busses/i2c-nomadik.c
> @@ -15,7 +15,6 @@
>  #include <linux/init.h>
>  #include <linux/module.h>
>  #include <linux/amba/bus.h>
> -#include <linux/atomic.h>
>  #include <linux/slab.h>
>  #include <linux/interrupt.h>
>  #include <linux/i2c.h>
> @@ -981,8 +980,6 @@ static void nmk_i2c_of_probe(struct device_node *np,
>  		pdata->sm = I2C_FREQ_MODE_FAST;
>  }
>  
> -static atomic_t adapter_id = ATOMIC_INIT(0);
> -
>  static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
>  {
>  	int ret = 0;
> @@ -1095,10 +1092,9 @@ static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
>  	adap->class	= I2C_CLASS_HWMON | I2C_CLASS_SPD;
>  	adap->algo	= &nmk_i2c_algo;
>  	adap->timeout	= msecs_to_jiffies(pdata->timeout);
> -	adap->nr = atomic_read(&adapter_id);
> +	adap->nr = -1;

... only that line can be removed since you now use i2c_add_adapter
instead of i2c_add_numbered_adapter.

>  	snprintf(adap->name, sizeof(adap->name),
> -		 "Nomadik I2C%d at %pR", adap->nr, &adev->res);
> -	atomic_inc(&adapter_id);
> +		 "Nomadik I2C at %pR", &adev->res);
>  
>  	/* fetch the controller configuration from machine */
>  	dev->cfg.clk_freq = pdata->clk_freq;
> @@ -1113,7 +1109,7 @@ static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
>  		 "initialize %s on virtual base %p\n",
>  		 adap->name, dev->virtbase);
>  
> -	ret = i2c_add_numbered_adapter(adap);
> +	ret = i2c_add_adapter(adap);
>  	if (ret) {
>  		dev_err(&adev->dev, "failed to add adapter\n");
>  		goto err_add_adap;
> -- 
> 1.8.1.4
> 

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