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From: Erwan Le Ray <erwan.leray@st.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre Torgue <alexandre.torgue@st.com>,
	Sumit Semwal <sumit.semwal@linaro.org>
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linaro-mm-sig@lists.linaro.org, Erwan Le Ray <erwan.leray@st.com>,
	linux-serial@vger.kernel.org,
	Fabrice Gasnier <fabrice.gasnier@st.com>,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-kernel@lists.infradead.org,
	linux-media@vger.kernel.org
Subject: [PATCH 1/1] serial: stm32: add no_console_suspend support
Date: Tue, 19 May 2020 11:41:04 +0200	[thread overview]
Message-ID: <20200519094104.27082-1-erwan.leray@st.com> (raw)

In order to display console messages in low power mode, console pins
must be kept active after suspend call.

---
Initial patch "serial: stm32: add support for no_console_suspend" was part
of "STM32 usart power improvement" series, but as dependancy to
console_suspend pinctl state has been removed to fit with Rob comment [1],
this patch has no more dependancy with any other patch of this series.

[1] https://lkml.org/lkml/2019/7/9/451

Signed-off-by: Erwan Le Ray <erwan.leray@st.com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 9cfcf355567a..5afd29162f6c 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -1425,7 +1425,18 @@ static int __maybe_unused stm32_serial_suspend(struct device *dev)
 	else
 		stm32_serial_enable_wakeup(port, false);
 
-	pinctrl_pm_select_sleep_state(dev);
+	/*
+	 * When "no_console_suspend" is enabled, keep the pinctrl default state
+	 * and rely on bootloader stage to restore this state upon resume.
+	 * Otherwise, apply the idle or sleep states depending on wakeup
+	 * capabilities.
+	 */
+	if (console_suspend_enabled || !uart_console(port)) {
+		if (device_may_wakeup(dev))
+			pinctrl_pm_select_idle_state(dev);
+		else
+			pinctrl_pm_select_sleep_state(dev);
+	}
 
 	return 0;
 }
-- 
2.17.1


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                 reply	other threads:[~2020-05-19  9:41 UTC|newest]

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