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    SubjectRe: [PATCH] clk: add strict of_clk_init dependency check
    Hi Boris,

    On 05/02/2014 10:48, Boris BREZILLON wrote:
    > The parent dependency check is only available on the first parent of a given
    > clk.
    >
    > Add support for strict dependency check: all parents of a given clk must be
    > initialized.
    >
    > Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
    > ---
    >
    > Hello Gregory,
    >
    > This patch adds support for strict check on clk dependencies (check if all
    > parents specified by an DT clk node are initialized).
    >
    > I'm not sure this is what you were expecting (maybe testing the first parent
    > is what you really want), so please feel free to tell me if I'm wrong.
    >
    > Best Regards,
    >
    > Boris
    >
    > drivers/clk/clk.c | 27 +++++++++++++++++++++------
    > 1 file changed, 21 insertions(+), 6 deletions(-)
    >
    > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
    > index beb0f8b..6849769 100644
    > --- a/drivers/clk/clk.c
    > +++ b/drivers/clk/clk.c
    > @@ -2543,22 +2543,37 @@ static int parent_ready(struct device_node *np)
    > {
    > struct of_phandle_args clkspec;
    > struct of_clk_provider *provider;
    > + int num_parents;
    > + bool found;
    > + int i;
    >
    > /*
    > * If there is no clock parent, no need to wait for them, then
    > * we can consider their absence as being ready
    > */
    > - if (of_parse_phandle_with_args(np, "clocks", "#clock-cells", 0,
    > - &clkspec))
    > + num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
    > + if (num_parents <= 0)
    > return 1;
    >
    > - /* Check if we have such a provider in our array */
    > - list_for_each_entry(provider, &of_clk_providers, link) {
    > - if (provider->node == clkspec.np)
    > + for (i = 0; i < num_parents; i++) {
    > + if (of_parse_phandle_with_args(np, "clocks", "#clock-cells", i,
    > + &clkspec))
    > return 1;
    > +
    > + /* Check if we have such a provider in our array */
    > + found = false;
    > + list_for_each_entry(provider, &of_clk_providers, link) {
    > + if (provider->node == clkspec.np) {
    > + found = true;
    > + break;

    Hum this means that as soon as you have one parent then you consider it
    as ready. It is better of what I have done because I only test the 1st
    parent. However I wondered if we should go further by ensuring all the
    parents are ready.

    If I am right, there is more than one parent only for the muxer. In this
    case is it really expected that all the parent are ready?

    Thanks,

    Gregory

    > + }
    > + }
    > +
    > + if (!found)
    > + return 0;
    > }
    >
    > - return 0;
    > + return 1;
    > }
    >
    > /**
    >


    --
    Gregory Clement, Free Electrons
    Kernel, drivers, real-time and embedded Linux
    development, consulting, training and support.
    http://free-electrons.com


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