If a regulator requests a deferred probe, the power domain gets
initialized twice. This leads to a list double add (without
list debugging the kernel hangs due to the double add later):

  WARNING: CPU: 0 PID: 19 at lib/list_debug.c:31 __list_add_valid+0xbc/0xc4
  list_add double add: new=c1229754, prev=c12383b4, next=c1229754.

Initialize the power domain after we get the regulator. Also do
not print an error in case the regulator defers probing.

Cc: Fabio Estevam <[email protected]>
Cc: Andrey Smirnov <[email protected]>
Cc: [email protected]
Cc: [email protected]
Fixes: 03aa12629fc4 ("soc: imx: Add GPCv2 power gating driver")
Signed-off-by: Stefan Agner <[email protected]>
---
Hi Shawn,

Since this leads to a Kernel hang in v4.13-rc3, can you get this
into v4.13 still?

--
Stefan

 drivers/soc/imx/gpcv2.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
index 3039072911a5..afc7ecc3c187 100644
--- a/drivers/soc/imx/gpcv2.c
+++ b/drivers/soc/imx/gpcv2.c
@@ -200,16 +200,11 @@ static int imx7_pgc_domain_probe(struct platform_device 
*pdev)
 
        domain->dev = &pdev->dev;
 
-       ret = pm_genpd_init(&domain->genpd, NULL, true);
-       if (ret) {
-               dev_err(domain->dev, "Failed to init power domain\n");
-               return ret;
-       }
-
        domain->regulator = devm_regulator_get_optional(domain->dev, "power");
        if (IS_ERR(domain->regulator)) {
                if (PTR_ERR(domain->regulator) != -ENODEV) {
-                       dev_err(domain->dev, "Failed to get domain's 
regulator\n");
+                       if (PTR_ERR(domain->regulator) != -EPROBE_DEFER)
+                               dev_err(domain->dev, "Failed to get domain's 
regulator\n");
                        return PTR_ERR(domain->regulator);
                }
        } else {
@@ -217,6 +212,12 @@ static int imx7_pgc_domain_probe(struct platform_device 
*pdev)
                                      domain->voltage, domain->voltage);
        }
 
+       ret = pm_genpd_init(&domain->genpd, NULL, true);
+       if (ret) {
+               dev_err(domain->dev, "Failed to init power domain\n");
+               return ret;
+       }
+
        ret = of_genpd_add_provider_simple(domain->dev->of_node,
                                           &domain->genpd);
        if (ret) {
-- 
2.13.3

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