soc: imx: gpcv2: fix regulator deferred probe

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 <fabio.estevam@nxp.com>
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Fixes: 03aa12629fc4 ("soc: imx: Add GPCv2 power gating driver")
Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Tested-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
index 3039072..afc7ecc 100644 (file)
--- 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) {