Re: [patch 2.6.30-rc3] platform_bus: remove "whichplatform_data?" confusion

From: Greg KH
Date: Wed Apr 29 2009 - 00:15:37 EST


On Mon, Apr 27, 2009 at 07:43:40PM -0700, David Brownell wrote:
> From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
>
> Recent patches have caused platform_device_add_pdata() users
> to trigger confused "use which platform_data?" error messages
> from the kernel. ("The _only_ one you were given, dummy!" is
> the correct answer.)
>
> This patch fixes those messages so they only appear if there's
> reason to be confused. (The call should probably fail too...)
>
> Those patches seem to support what I think is a misguided
> notion: that somehow device.platform_data might move into
> the platform_device. The problem with that idea is that it's
> a general purpose hook, and is used by other busses to provide
> board-specific configuration data ... not just for platform_bus.
>
> Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
> ---

Ming, what do you think of this?

thanks,

greg k-h


> For 2.6.30, which recently acquired this confusion.
>
> drivers/base/platform.c | 22 +++++++++++++---------
> 1 file changed, 13 insertions(+), 9 deletions(-)
>
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -251,16 +251,20 @@ int platform_device_add(struct platform_
> * if all platform devices pass its platform specific data
> * from platform_device. The conversion is going to be a
> * long time, so we allow the two cases coexist to make
> - * this kind of fix more easily*/
> - if (pdev->platform_data && pdev->dev.platform_data) {
> - printk(KERN_ERR
> - "%s: use which platform_data?\n",
> - dev_name(&pdev->dev));
> - } else if (pdev->platform_data) {
> - pdev->dev.platform_data = pdev->platform_data;
> - } else if (pdev->dev.platform_data) {
> + * this kind of fix more easily
> + *
> + * REVISIT platform_data is used by more than "platform_bus".
> + * It's a generic hook for data that's specific to a given
> + * board. Removing it seems rather impractical...
> + */
> + if (!pdev->platform_data)
> pdev->platform_data = pdev->dev.platform_data;
> - }
> + else if (!pdev->dev.platform_data)
> + pdev->dev.platform_data = pdev->platform_data;
> +
> + if (pdev->platform_data != pdev->dev.platform_data)
> + pr_err("%s: use which platform_data?\n",
> + dev_name(&pdev->dev));
>
> for (i = 0; i < pdev->num_resources; i++) {
> struct resource *p, *r = &pdev->resource[i];
>
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