linux-kernel - [PATCH 3/4] cpufreq: s5pv210: Defer probe if getting regulators fail

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Message-Id: <20190108200509.30494-4-pawel.mikolaj.chmiel@gmail.com>
Date:   Tue,  8 Jan 2019 21:05:08 +0100
From:   Paweł Chmiel <pawel.mikolaj.chmiel@...il.com>
To:     kgene@...nel.org
Cc:     krzk@...nel.org, robh+dt@...nel.org, mark.rutland@....com,
        linux@...linux.org.uk, viresh.kumar@...aro.org, rjw@...ysocki.net,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Paweł Chmiel <pawel.mikolaj.chmiel@...il.com>
Subject: [PATCH 3/4] cpufreq: s5pv210: Defer probe if getting regulators fail

There is possibility, that when probing driver, regulators are not yet
initialized. In this case we should return EPROBE_DEFER and wait till
they're initialized, since they're required currently for cpufreq driver
to work. Also move regulator initialization code at beginning of probe,
so we can defer as fast as posibble.

Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@...il.com>
---
 drivers/cpufreq/s5pv210-cpufreq.c | 33 +++++++++++++++++++------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/drivers/cpufreq/s5pv210-cpufreq.c b/drivers/cpufreq/s5pv210-cpufreq.c
index f51697f1e0b3..2d0e4dc7ede7 100644
--- a/drivers/cpufreq/s5pv210-cpufreq.c
+++ b/drivers/cpufreq/s5pv210-cpufreq.c
@@ -594,6 +594,26 @@ static int s5pv210_cpufreq_probe(struct platform_device *pdev)
 	 * this whole driver as soon as S5PV210 gets migrated to use
 	 * cpufreq-dt driver.
 	 */
+	arm_regulator = regulator_get(NULL, "vddarm");
+	if (PTR_ERR(arm_regulator) == -EPROBE_DEFER) {
+		pr_dbg("vddarm regulator not ready, defer\n");
+		return -EPROBE_DEFER;
+	} else if (IS_ERR(arm_regulator)) {
+		pr_err("failed to get regulator vddarm\n");
+		return PTR_ERR(arm_regulator);
+	}
+
+	int_regulator = regulator_get(NULL, "vddint");
+	if (PTR_ERR(int_regulator == -EPROBE_DEFER) {
+		regulator_put(arm_regulator);
+		pr_dbg("vddint regulator not ready, defer\n");
+		return -EPROBE_DEFER;
+	} else if (IS_ERR(int_regulator)) {
+		regulator_put(arm_regulator);
+		pr_err("failed to get regulator vddint\n");
+		return PTR_ERR(int_regulator);
+	}
+
 	np = of_find_compatible_node(NULL, NULL, "samsung,s5pv210-clock");
 	if (!np) {
 		pr_err("%s: failed to find clock controller DT node\n",
@@ -633,19 +653,6 @@ static int s5pv210_cpufreq_probe(struct platform_device *pdev)
 		}
 	}
 
-	arm_regulator = regulator_get(NULL, "vddarm");
-	if (IS_ERR(arm_regulator)) {
-		pr_err("failed to get regulator vddarm\n");
-		return PTR_ERR(arm_regulator);
-	}
-
-	int_regulator = regulator_get(NULL, "vddint");
-	if (IS_ERR(int_regulator)) {
-		pr_err("failed to get regulator vddint\n");
-		regulator_put(arm_regulator);
-		return PTR_ERR(int_regulator);
-	}
-
 	register_reboot_notifier(&s5pv210_cpufreq_reboot_notifier);
 
 	return cpufreq_register_driver(&s5pv210_driver);
-- 
2.17.1