linux-kernel - [PATCH v1 2/2] cpuidle: tegra: Check whether PMC is ready

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Date:   Mon, 19 Jul 2021 00:27:06 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     linux-pm@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v1 2/2] cpuidle: tegra: Check whether PMC is ready

Check whether PMC is ready before proceeding with the cpuidle registration.
This fixes racing with the PMC driver probe order, which results in a
disabled deepest CC6 idling state if cpuidle driver is probed before the
PMC.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/cpuidle/cpuidle-tegra.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c
index 508bd9f23792..9845629aeb6d 100644
--- a/drivers/cpuidle/cpuidle-tegra.c
+++ b/drivers/cpuidle/cpuidle-tegra.c
@@ -337,6 +337,9 @@ static void tegra_cpuidle_setup_tegra114_c7_state(void)
 
 static int tegra_cpuidle_probe(struct platform_device *pdev)
 {
+	if (tegra_pmc_get_suspend_mode() == TEGRA_SUSPEND_NOT_READY)
+		return -EPROBE_DEFER;
+
 	/* LP2 could be disabled in device-tree */
 	if (tegra_pmc_get_suspend_mode() < TEGRA_SUSPEND_LP2)
 		tegra_cpuidle_disable_state(TEGRA_CC6);
-- 
2.32.0