From ebf902ad6e444e2796ca789eb148edbbef67438d Mon Sep 17 00:00:00 2001
From: Ulf Hansson <ulf.hansson@linaro.org>
Date: Tue, 10 Mar 2020 11:40:23 +0100
Subject: [PATCH] PM / Domains: Allow no domain-idle-states DT property in
 genpd when parsing

commit 56cb26891ea4180121265dc6b596015772c4a4b8 upstream.

Commit 2c361684803e ("PM / Domains: Don't treat zero found compatible idle
states as an error"), moved of_genpd_parse_idle_states() towards allowing
none compatible idle state to be found for the device node, rather than
returning an error code.

However, it didn't consider that the "domain-idle-states" DT property may
be missing as it's optional, which makes of_count_phandle_with_args() to
return -ENOENT. Let's fix this to make the behaviour consistent.

Fixes: 2c361684803e ("PM / Domains: Don't treat zero found compatible idle states as an error")
Reported-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: 4.20+ <stable@vger.kernel.org> # 4.20+
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 33c30c1e6a30..dc135a7dfbe9 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2618,7 +2618,7 @@ static int genpd_iterate_idle_states(struct device_node *dn,
 
 	ret = of_count_phandle_with_args(dn, "domain-idle-states", NULL);
 	if (ret <= 0)
-		return ret;
+		return ret == -ENOENT ? 0 : ret;
 
 	/* Loop over the phandles until all the requested entry is found */
 	of_for_each_phandle(&it, ret, dn, "domain-idle-states", NULL, 0) {
-- 
2.7.4