On Wed, 9 Nov 2022, Sherry Sun wrote: > Add runtime pm support to manage the lpuart clock. > > Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx> > --- > 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) >