[PATCH v4 2/2] platform: Make platform_bus device a platform device

[Greg Kroah-Hartman]

On Wed, Jul 23, 2014 at 06:07:19PM +0100, Pawel Moll wrote:
> ... describing the root of the device tree, so one can write
> a platform driver initializing the platform.
> 
> Signed-off-by: Pawel Moll <pawel.moll at arm.com>
> ---
> Changes since v3:
> 
> * split the platform_bus->NULL changes into a separate patch
> * added #ifdef CONFIG_OF around of_allnodes
> 
> Changes since v2:
> 
> * replaced references to platform_bus.dev with NULL
>   in places where it shouldn't make any difference
> 
> Changes since v1:
> 
> * rebased on top of v3.16-rc6
> * fixed up all new explicit references to platform_bus,
>   with majority in mach-shmobile; 99% of them seem completely
>   useless and I was *very* tempted to replace them with
>   NULL - all reasons for and against this are welcomed
> 
> 
>  arch/arm/mach-imx/devices/devices.c |  4 ++--
>  drivers/base/platform.c             | 20 ++++++++++++++------
>  drivers/char/tile-srom.c            |  2 +-
>  drivers/mmc/host/sdhci-pltfm.c      |  2 +-
>  drivers/scsi/hosts.c                |  2 +-
>  include/linux/platform_device.h     |  2 +-
>  6 files changed, 20 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/devices/devices.c b/arch/arm/mach-imx/devices/devices.c
> index 1b4366a..48c3817 100644
> --- a/arch/arm/mach-imx/devices/devices.c
> +++ b/arch/arm/mach-imx/devices/devices.c
> @@ -24,12 +24,12 @@
>  
>  struct device mxc_aips_bus = {
>  	.init_name	= "mxc_aips",
> -	.parent		= &platform_bus,
> +	.parent		= &platform_bus.dev,
>  };
>  
>  struct device mxc_ahb_bus = {
>  	.init_name	= "mxc_ahb",
> -	.parent		= &platform_bus,
> +	.parent		= &platform_bus.dev,
>  };
>  

Again, not ok, these are real busses, don't hang them off the platform
bus, have them be at the root of the device tree so they aren't
"hidden".

> diff --git a/drivers/char/tile-srom.c b/drivers/char/tile-srom.c
> index bd37747..4e4b7a2 100644
> --- a/drivers/char/tile-srom.c
> +++ b/drivers/char/tile-srom.c
> @@ -350,7 +350,7 @@ static int srom_setup_minor(struct srom_dev *srom, int index)
>  		       SROM_PAGE_SIZE_OFF, sizeof(srom->page_size)) < 0)
>  		return -EIO;
>  
> -	dev = device_create(srom_class, &platform_bus,
> +	dev = device_create(srom_class, &platform_bus.dev,
>  			    MKDEV(srom_major, index), srom, "%d", index);
>  	return PTR_ERR_OR_ZERO(dev);
>  }

Why isn't this just NULL?  It's pretending to be a platform device by
doing this, which isn't ok.


> diff --git a/drivers/mmc/host/sdhci-pltfm.c b/drivers/mmc/host/sdhci-pltfm.c
> index 7e834fb..9a2b0d0 100644
> --- a/drivers/mmc/host/sdhci-pltfm.c
> +++ b/drivers/mmc/host/sdhci-pltfm.c
> @@ -137,7 +137,7 @@ struct sdhci_host *sdhci_pltfm_init(struct platform_device *pdev,
>  		dev_err(&pdev->dev, "Invalid iomem size!\n");
>  
>  	/* Some PCI-based MFD need the parent here */
> -	if (pdev->dev.parent != &platform_bus && !np)
> +	if (pdev->dev.parent != &platform_bus.dev && !np)
>  		host = sdhci_alloc_host(pdev->dev.parent,
>  			sizeof(struct sdhci_pltfm_host) + priv_size);
>  	else

Again, this isn't ok, check the type of the device if you really want to
"know" what it is, don't assume that it is going to be at one level deep
in the platform device hierarchy.

> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> index 3cbb57a..c14c36f 100644
> --- a/drivers/scsi/hosts.c
> +++ b/drivers/scsi/hosts.c
> @@ -218,7 +218,7 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
>  		goto fail;
>  
>  	if (!shost->shost_gendev.parent)
> -		shost->shost_gendev.parent = dev ? dev : &platform_bus;
> +		shost->shost_gendev.parent = dev ? dev : &platform_bus.dev;
>  	if (!dma_dev)
>  		dma_dev = shost->shost_gendev.parent;
>  

Again, no "pretending" to be a platform device if it really isn't.

> diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
> index 16f6654..a99032a 100644
> --- a/include/linux/platform_device.h
> +++ b/include/linux/platform_device.h
> @@ -44,7 +44,7 @@ extern int platform_device_register(struct platform_device *);
>  extern void platform_device_unregister(struct platform_device *);
>  
>  extern struct bus_type platform_bus_type;
> -extern struct device platform_bus;
> +extern struct platform_device platform_bus;

My end-goal is to just remove this external reference entirely, no one
outside of the platform file should be referencing it, just like all
other busses.

thanks,

greg k-h