[openwrt/staging/thess.git] /

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,
        },
 };