Re: [PATCH v1 2/2] of: Let of_for_each_phandle fallback to non-negative cell_count

From: Rob Herring
Date: Mon Sep 02 2019 - 10:26:45 EST


On Sat, Aug 24, 2019 at 03:28:46PM +0200, Uwe Kleine-König wrote:
> Referencing device tree nodes from a property allows to pass arguments.
> This is for example used for referencing gpios. This looks as follows:
>
> gpio_ctrl: gpio-controller {
> #gpio-cells = <2>
> ...
> }
>
> someothernode {
> gpios = <&gpio_ctrl 5 0 &gpio_ctrl 3 0>;
> ...
> }
>
> To know the number of arguments this must be either fixed, or the
> referenced node is checked for a $cells_name (here: "#gpio-cells")
> property and with this information the start of the second reference can
> be determined.
>
> Currently regulators are referenced with no additional arguments. To
> allow some optional arguments without having to change all referenced
> nodes this change introduces a way to specify a default cell_count. So
> when a phandle is parsed we check for the $cells_name property and use
> it as before if present. If it is not present we fall back to
> cells_count if non-negative and only fail if cells_count is smaller than
> zero.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> ---
> drivers/of/base.c | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)

Looks fine to me. I can apply with an ack from the iommu folks on patch
1.

Rob