On 08/06/2012 11:06 AM, Srinivas KANDAGATLA wrote:
> From: Srinivas Kandagatla <[email protected]>
>
> In the existing code, platform drivers probed via device trees get a
> pdev->id instance id as -1, which is Ok if the actual devices don't want
> to pass an Id. But some of the platform devices do pass an id and driver
> depends on this value to some extent.
> So, Every driver using pdev->id adds some extra code to cope up with the
> above behavior if it extends support to device tress.
>
> This patch adds code to look for "linux,pdev-id" property in the device
> node which is then used while creating platform device instance to
> correctly populate pdev->id. This patch also adds some checks in
> of_device_add not to override pdev->id if it is already set by the
> caller.
>
> After this patch, device nodes look like:
>
> usb@c5000000 {
> compatible = "nvidia,tegra20-ehci", "usb-ehci";
> reg = <0xc5000000 0x4000>;
> interrupts = < 0 20 0x04 >;
> linux,pdev-id = <0>;
> phy_type = "utmi";
> };
>
> and some of the ugly hacks in the drivers like ehci-tegra.c can be
> totally removed.
>
> Without this patch the driver have to modifed with some ugly hacks to
> get device trees working with that driver.
>
> Signed-off-by: Srinivas Kandagatla <[email protected]>
> ---
> Hi All,
> I noticed that platform drivers probed via device trees populates platform
> device structure with id = -1.
> Drivers tend to use this ID to some extent.
> Adding some hacks in to the driver can solve this problem, but I think the
> orignal source of the issue can be address neatly with my patch.
> The patch adds new property linux,pdev->id which can be used to pass id from
> device trees.
>
> Comments?
NAK. Most drivers can avoid relying on id. Putting linuxisms into DT is
also rarely the right thing to do.
The hack in ehci-tegra.c is because the usb phy is not described in DT.
Rob
>
> srini
>
> drivers/of/device.c | 2 +-
> drivers/of/platform.c | 5 ++++-
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index 4c74e4f..4333ec4 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -54,7 +54,7 @@ int of_device_add(struct platform_device *ofdev)
> /* name and id have to be set so that the platform bus doesn't get
> * confused on matching */
> ofdev->name = dev_name(&ofdev->dev);
> - ofdev->id = -1;
> + ofdev->id = (ofdev->id >= 0) ? ofdev->id : -1;
>
> /* device_add will assume that this device is on the same node as
> * the parent. If there is no parent defined, set the node
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index e44f8c2..ca12e0e 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -133,9 +133,12 @@ struct platform_device *of_device_alloc(struct
> device_node *np,
> {
> struct platform_device *dev;
> int rc, i, num_reg = 0, num_irq;
> + int id = -1;
> struct resource *res, temp_res;
>
> - dev = platform_device_alloc("", -1);
> + of_property_read_u32(np, "linux,pdev-id", &id);
> +
> + dev = platform_device_alloc("", id);
> if (!dev)
> return NULL;
>
>
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