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Message-ID: <50752c1b-fea-af8b-6efd-ef0cd594cb@linux.intel.com>
Date: Wed, 9 Nov 2022 14:38:38 +0200 (EET)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Sherry Sun <sherry.sun@....com>
cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jirislaby@...nel.org>,
linux-serial <linux-serial@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>, linux-imx@....com
Subject: Re: [PATCH 2/2] tty: serial: fsl_lpuart: Add runtime pm support
On Wed, 9 Nov 2022, Sherry Sun wrote:
> Add runtime pm support to manage the lpuart clock.
>
> Signed-off-by: Sherry Sun <sherry.sun@....com>
> ---
> drivers/tty/serial/fsl_lpuart.c | 60 +++++++++++++++++++++++++++++++++
> 1 file changed, 60 insertions(+)
>
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
> index 474943cb06b2..e678a7aaf7e4 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -19,6 +19,7 @@
> #include <linux/of_device.h>
> #include <linux/of_dma.h>
> #include <linux/pinctrl/consumer.h>
> +#include <linux/pm_runtime.h>
> #include <linux/serial_core.h>
> #include <linux/slab.h>
> #include <linux/tty_flip.h>
> @@ -235,6 +236,7 @@
>
> /* 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"
> @@ -795,6 +797,20 @@ static void lpuart32_start_tx(struct uart_port *port)
> }
> }
>
> +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)
> {
> @@ -2243,6 +2259,7 @@ static const struct uart_ops lpuart_pops = {
> .startup = lpuart_startup,
> .shutdown = lpuart_shutdown,
> .set_termios = lpuart_set_termios,
> + .pm = lpuart_uart_pm,
> .type = lpuart_type,
> .request_port = lpuart_request_port,
> .release_port = lpuart_release_port,
> @@ -2267,6 +2284,7 @@ static const struct uart_ops lpuart32_pops = {
> .startup = lpuart32_startup,
> .shutdown = lpuart32_shutdown,
> .set_termios = lpuart32_set_termios,
> + .pm = lpuart_uart_pm,
> .type = lpuart_type,
> .request_port = lpuart_request_port,
> .release_port = lpuart_release_port,
> @@ -2747,6 +2765,11 @@ static int lpuart_probe(struct platform_device *pdev)
> handler = lpuart_int;
> }
>
> + 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 = lpuart_global_reset(sport);
> if (ret)
> goto failed_reset;
> @@ -2771,6 +2794,9 @@ static int lpuart_probe(struct platform_device *pdev)
> failed_attach_port:
> failed_get_rs485:
> failed_reset:
> + pm_runtime_disable(&pdev->dev);
> + pm_runtime_set_suspended(&pdev->dev);
> + pm_runtime_dont_use_autosuspend(&pdev->dev);
> lpuart_disable_clks(sport);
> return ret;
> }
> @@ -2789,9 +2815,30 @@ static int lpuart_remove(struct platform_device *pdev)
> 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;
> }
>
> +static int __maybe_unused lpuart_runtime_suspend(struct device *dev)
IIRC, the PM_OPS macros contain special logic to make __maybe_unused
unnecessary for these functions.
--
i.
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct lpuart_port *sport = platform_get_drvdata(pdev);
> +
> + lpuart_disable_clks(sport);
> +
> + return 0;
> +};
> +
> +static int __maybe_unused 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 void serial_lpuart_enable_wakeup(struct lpuart_port *sport, bool on)
> {
> unsigned int val, baud;
> @@ -2937,6 +2984,10 @@ static int __maybe_unused lpuart_suspend(struct device *dev)
> sport->dma_tx_in_progress = false;
> dmaengine_terminate_all(sport->dma_tx_chan);
> }
> + } else if (pm_runtime_active(sport->port.dev)) {
> + lpuart_disable_clks(sport);
> + pm_runtime_disable(sport->port.dev);
> + pm_runtime_set_suspended(sport->port.dev);
> }
>
> return 0;
> @@ -2971,12 +3022,19 @@ static void lpuart_console_fixup(struct lpuart_port *sport)
> static int __maybe_unused lpuart_resume(struct device *dev)
> {
> struct lpuart_port *sport = dev_get_drvdata(dev);
> + int ret;
>
> if (lpuart_uport_is_active(sport)) {
> if (lpuart_is_32(sport))
> lpuart32_hw_setup(sport);
> else
> lpuart_hw_setup(sport);
> + } else if (pm_runtime_active(sport->port.dev)) {
> + ret = lpuart_enable_clks(sport);
> + if (ret)
> + return ret;
> + pm_runtime_set_active(sport->port.dev);
> + pm_runtime_enable(sport->port.dev);
> }
>
> lpuart_console_fixup(sport);
> @@ -2986,6 +3044,8 @@ static int __maybe_unused lpuart_resume(struct device *dev)
> }
>
> static const struct dev_pm_ops lpuart_pm_ops = {
> + SET_RUNTIME_PM_OPS(lpuart_runtime_suspend,
> + lpuart_runtime_resume, NULL)
> SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(lpuart_suspend_noirq,
> lpuart_resume_noirq)
> SET_SYSTEM_SLEEP_PM_OPS(lpuart_suspend, lpuart_resume)
>
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