linux-kernel - [PATCH v2 04/10] serial: stm32: add pm

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Date:   Tue, 11 Jun 2019 14:25:24 +0200
From:   Erwan Le Ray <erwan.leray@...com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        "Alexandre Torgue" <alexandre.torgue@...com>,
        Rob Herring <robh+dt@...nel.org>,
        "Mark Rutland" <mark.rutland@....com>
CC:     <linux-serial@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        Erwan Le Ray <erwan.leray@...com>,
        "Fabrice Gasnier" <fabrice.gasnier@...com>,
        Bich Hemon <bich.hemon@...com>
Subject: [PATCH v2 04/10] serial: stm32: add pm_runtime support

Use pm_runtime for clock management.

Signed-off-by: Bich Hemon <bich.hemon@...com>
Signed-off-by: Erwan Le Ray <erwan.leray@...com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 04eda75..60f3faf 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -809,13 +809,13 @@ static void stm32_pm(struct uart_port *port, unsigned int state,
 
 	switch (state) {
 	case UART_PM_STATE_ON:
-		clk_prepare_enable(stm32port->clk);
+		pm_runtime_get_sync(port->dev);
 		break;
 	case UART_PM_STATE_OFF:
 		spin_lock_irqsave(&port->lock, flags);
 		stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 		spin_unlock_irqrestore(&port->lock, flags);
-		clk_disable_unprepare(stm32port->clk);
+		pm_runtime_put_sync(port->dev);
 		break;
 	}
 }
@@ -1110,6 +1110,11 @@ static int stm32_serial_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, &stm32port->port);
 
+	pm_runtime_get_noresume(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
+
 	return 0;
 
 err_wirq:
@@ -1131,6 +1136,9 @@ static int stm32_serial_remove(struct platform_device *pdev)
 	struct uart_port *port = platform_get_drvdata(pdev);
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+	int err;
+
+	pm_runtime_get_sync(&pdev->dev);
 
 	stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
 
@@ -1159,7 +1167,12 @@ static int stm32_serial_remove(struct platform_device *pdev)
 
 	clk_disable_unprepare(stm32_port->clk);
 
-	return uart_remove_one_port(&stm32_usart_driver, port);
+	err = uart_remove_one_port(&stm32_usart_driver, port);
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
+	return err;
 }
 
 
@@ -1316,7 +1329,29 @@ static int stm32_serial_resume(struct device *dev)
 }
 #endif /* CONFIG_PM_SLEEP */
 
+static int __maybe_unused stm32_serial_runtime_suspend(struct device *dev)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct stm32_port *stm32port = container_of(port,
+			struct stm32_port, port);
+
+	clk_disable_unprepare(stm32port->clk);
+
+	return 0;
+}
+
+static int __maybe_unused stm32_serial_runtime_resume(struct device *dev)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct stm32_port *stm32port = container_of(port,
+			struct stm32_port, port);
+
+	return clk_prepare_enable(stm32port->clk);
+}
+
 static const struct dev_pm_ops stm32_serial_pm_ops = {
+	SET_RUNTIME_PM_OPS(stm32_serial_runtime_suspend,
+			   stm32_serial_runtime_resume, NULL)
 	SET_SYSTEM_SLEEP_PM_OPS(stm32_serial_suspend, stm32_serial_resume)
 };
 
-- 
1.9.1