Quoting Saravana Kannan (2021-01-28 09:01:41)

On Thu, Jan 28, 2021 at 2:45 AM Tudor Ambarus
[off-list ref] wrote:

quoted

The sama5d2 requires the clock provider initialized before timers.
We can't use a platform driver for the sama5d2-pmc driver, as the
platform_bus_init() is called later on, after time_init().

As fw_devlink considers only devices, it does not know that the
pmc is ready. Hence probing of devices that depend on it fail:
probe deferral - supplier f0014000.pmc not ready

Fix this by setting the OF_POPULATED flag for the sama5d2_pmc
device node after successful setup. This will make
of_link_to_phandle() ignore the sama5d2_pmc device node as a
dependency, and consumer devices will be probed again.

Fixes: e590474768f1cc04 ("driver core: Set fw_devlink=on by default")
Signed-off-by: Tudor Ambarus <redacted>
---
I'll be out of office, will check the rest of the at91 SoCs
at the begining of next week.

 drivers/clk/at91/sama5d2.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/clk/at91/sama5d2.c b/drivers/clk/at91/sama5d2.c
index 9a5cbc7cd55a..5eea2b4a63dd 100644
--- a/drivers/clk/at91/sama5d2.c
+++ b/drivers/clk/at91/sama5d2.c

@@ -367,6 +367,8 @@ static void __init sama5d2_pmc_setup(struct device_node *np)

        of_clk_add_hw_provider(np, of_clk_hw_pmc_get, sama5d2_pmc);

+       of_node_set_flag(np, OF_POPULATED);
+
        return;

Hi Tudor,

Thanks for looking into this.

I already accounted for early clocks like this when I designed
fw_devlink. Each driver shouldn't need to set OF_POPULATED.
drivers/clk/clk.c already does this for you.

I think the problem is that your driver is using
CLK_OF_DECLARE_DRIVER() instead of CLK_OF_DECLARE(). The comments for
CLK_OF_DECLARE_DRIVER() says:
/*
 * Use this macro when you have a driver that requires two initialization
 * routines, one at of_clk_init(), and one at platform device probe
 */

In your case, you are explicitly NOT having a driver bind to this
clock later. So you shouldn't be using CLK_OF_DECLARE() instead.

I see 

drivers/power/reset/at91-sama5d2_shdwc.c:       { .compatible = "atmel,sama5d2-pmc" },

so isn't that the driver that wants to bind to the same device node
again? First at of_clk_init() time here and then second for the reset
driver?

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel