openwrt/target/linux/layerscape/patches-5.4/819-uart-0009-MLK-17133-02-tty-serial-lpuart-add-runtime-pm-suppor.patch

From ff3d8063eed907bed728a14e1519dc659036315a Mon Sep 17 00:00:00 2001
From: Fugang Duan <fugang.duan@nxp.com>
Date: Wed, 11 Sep 2019 16:36:48 +0800
Subject: [PATCH] MLK-17133-02 tty: serial: lpuart: add runtime pm support

Add runtime pm support to manage lpuart clock and its power domain
to save power in system idle and system suspend stages.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Reviewed-by: Robin Gong <yibin.gong@nxp.com>
---
 drivers/tty/serial/fsl_lpuart.c | 80 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 72 insertions(+), 8 deletions(-)

--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -245,6 +245,7 @@
 
 /* Rx DMA timeout in ms, which is used to calculate Rx ring buffer size */
 #define DMA_RX_TIMEOUT		(10)
+#define UART_AUTOSUSPEND_TIMEOUT	3000
 
 #define DRIVER_NAME	"fsl-lpuart"
 #define DEV_NAME	"ttyLP"
@@ -846,6 +847,20 @@ static void lpuart32_start_tx(struct uar
 	}
 }
 
+static void
+lpuart_uart_pm(struct uart_port *port, unsigned int state, unsigned int oldstate)
+{
+	switch (state) {
+	case UART_PM_STATE_OFF:
+		pm_runtime_mark_last_busy(port->dev);
+		pm_runtime_put_autosuspend(port->dev);
+		break;
+	default:
+		pm_runtime_get_sync(port->dev);
+		break;
+	}
+}
+
 /* return TIOCSER_TEMT when transmitter is not busy */
 static unsigned int lpuart_tx_empty(struct uart_port *port)
 {
@@ -2259,6 +2274,7 @@ static const struct uart_ops lpuart_pops
 	.break_ctl	= lpuart_break_ctl,
 	.startup	= lpuart_startup,
 	.shutdown	= lpuart_shutdown,
+	.pm		= lpuart_uart_pm,
 	.set_termios	= lpuart_set_termios,
 	.type		= lpuart_type,
 	.request_port	= lpuart_request_port,
@@ -2283,6 +2299,7 @@ static const struct uart_ops lpuart32_po
 	.break_ctl	= lpuart32_break_ctl,
 	.startup	= lpuart32_startup,
 	.shutdown	= lpuart32_shutdown,
+	.pm		= lpuart_uart_pm,
 	.set_termios	= lpuart32_set_termios,
 	.type		= lpuart_type,
 	.request_port	= lpuart_request_port,
@@ -2742,6 +2759,11 @@ static int lpuart_probe(struct platform_
 	if (ret)
 		goto failed_irq_request;
 
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, UART_AUTOSUSPEND_TIMEOUT);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
 	ret = uart_add_one_port(&lpuart_reg, &sport->port);
 	if (ret)
 		goto failed_attach_port;
@@ -2776,6 +2798,9 @@ static int lpuart_probe(struct platform_
 failed_reset:
 	uart_remove_one_port(&lpuart_reg, &sport->port);
 failed_attach_port:
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
 failed_irq_request:
 	lpuart_disable_clks(sport);
 failed_clock_enable:
@@ -2802,15 +2827,41 @@ static int lpuart_remove(struct platform
 	if (sport->dma_rx_chan)
 		dma_release_channel(sport->dma_rx_chan);
 
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
 	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP
+static int lpuart_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct lpuart_port *sport = platform_get_drvdata(pdev);
+
+	lpuart_disable_clks(sport);
+
+	return 0;
+};
+
+static int lpuart_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct lpuart_port *sport = platform_get_drvdata(pdev);
+
+	return lpuart_enable_clks(sport);
+};
+
 static int lpuart_suspend(struct device *dev)
 {
 	struct lpuart_port *sport = dev_get_drvdata(dev);
 	unsigned long temp;
 	bool irq_wake;
+	int ret;
+
+	ret = clk_prepare_enable(sport->ipg_clk);
+	if (ret)
+		return ret;
 
 	if (lpuart_is_32(sport)) {
 		/* disable Rx/Tx and interrupts */
@@ -2824,10 +2875,14 @@ static int lpuart_suspend(struct device
 		writeb(temp, sport->port.membase + UARTCR2);
 	}
 
+	clk_disable_unprepare(sport->ipg_clk);
+
 	uart_suspend_port(&lpuart_reg, &sport->port);
 
 	/* uart_suspend_port() might set wakeup flag */
 	irq_wake = irqd_is_wakeup_set(irq_get_irq_data(sport->port.irq));
+	if (sport->port.suspended && !irq_wake)
+		return 0;
 
 	if (sport->lpuart_dma_rx_use) {
 		/*
@@ -2858,9 +2913,6 @@ static int lpuart_suspend(struct device
 		dmaengine_terminate_all(sport->dma_tx_chan);
 	}
 
-	if (sport->port.suspended && !irq_wake)
-		lpuart_disable_clks(sport);
-
 	return 0;
 }
 
@@ -2868,9 +2920,11 @@ static int lpuart_resume(struct device *
 {
 	struct lpuart_port *sport = dev_get_drvdata(dev);
 	bool irq_wake = irqd_is_wakeup_set(irq_get_irq_data(sport->port.irq));
+	int ret;
 
-	if (sport->port.suspended && !irq_wake)
-		lpuart_enable_clks(sport);
+	ret = clk_prepare_enable(sport->ipg_clk);
+	if (ret)
+		return ret;
 
 	if (lpuart_is_32(sport))
 		lpuart32_setup_watermark_enable(sport);
@@ -2891,13 +2945,23 @@ static int lpuart_resume(struct device *
 	if (lpuart_is_32(sport))
 		lpuart32_configure(sport);
 
+	clk_disable_unprepare(sport->ipg_clk);
+
 	uart_resume_port(&lpuart_reg, &sport->port);
 
 	return 0;
 }
-#endif
+static const struct dev_pm_ops lpuart_pm_ops = {
+	SET_RUNTIME_PM_OPS(lpuart_runtime_suspend,
+			   lpuart_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(lpuart_suspend, lpuart_resume)
+};
+#define SERIAL_LPUART_PM_OPS	(&lpuart_pm_ops)
 
-static SIMPLE_DEV_PM_OPS(lpuart_pm_ops, lpuart_suspend, lpuart_resume);
+#else /* !CONFIG_PM_SLEEP */
+
+#define SERIAL_LPUART_PM_OPS	NULL
+#endif
 
 static struct platform_driver lpuart_driver = {
 	.probe		= lpuart_probe,
@@ -2905,7 +2969,7 @@ static struct platform_driver lpuart_dri
 	.driver		= {
 		.name	= "fsl-lpuart",
 		.of_match_table = lpuart_dt_ids,
-		.pm	= &lpuart_pm_ops,
+		.pm	= SERIAL_LPUART_PM_OPS,
 	},
 };