Re: [PATCH 2.6-git] SPI core refresh

[Vitaly Wool <vwool@ru.mvista.com>]

BTW:

David Brownell wrote:

> +How do I write an "SPI Master Controller Driver"?
> +-------------------------------------------------
> +An SPI controller will probably be registered on the platform_bus; write
> +a driver to bind to the device, whichever bus is involved.
> +
> +The main task of this type of driver is to provide an "spi_master".
> +Use spi_alloc_master() to allocate the master, and class_get_devdata()
> +to get the driver-private data allocated for that device.
> +
> +	struct spi_master	*master;
> +	struct CONTROLLER	*c;
> +
> +	master = spi_alloc_master(dev, sizeof *c);
> +	if (!master)
> +		return -ENODEV;
> +
> +	c = class_get_devdata(&master->cdev);
>  
Here's an example of a mixture of two approaches which leads to 
misleading code.
If you want to have abstract spi_master, then you have to disallow (or 
at least discourage) explicit usage of spi_master fields, otherwise 
'kzalloc is your friend' and you don't have toadd this spi_alloc_master 
API as it's basically useless IMHO.

As opposed to this, we use abstract handles where possible (i. e. for 
spi_message).
I'd have understood your dissatisfaction with that if you were 
consistently following the approach 'expose everything, forget the 
extensibility, viva lightwieghtness', but you're mixing things.

Vitaly
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