From 09d8b2bdbc5c61dd6289d78ab4cb57d22dd5e0e6 Mon Sep 17 00:00:00 2001 From: Vignesh R Date: Mon, 2 Apr 2018 17:50:37 +0530 Subject: serial: 8250: omap: Provide ability to enable/disable UART as wakeup source Enable/Clear module level UART wakeup in UART_OMAP_WER register based on return value of device_may_wakeup() in .suspend(). This allows userspace to use sysfs to control the ability of UART to wakeup the system from deep sleep state. Register is restored back in .startup() call that happens as part of resume sequence. With this patch, userspace can control UART wakeup capability via sysfs: To enable wakeup capability: echo enabled > /sys/class/tty/ttyXX/device/power/wakeup For disabling wakeup capability: echo disabled > /sys/class/tty/ttyXX/device/power/wakeup Note that the UART wakeup events configured in the 8250 hardware only work for idle modes that do not cut off power for the UART. For deeper idle states, dedicated padconf wakeirqs must be used. Or in some cases the UART RX pin can be remuxed to GPIO input if the GPIO block stays powered. Signed-off-by: Vignesh R Tested-by: Tony Lindgren Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_omap.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index 624b501fd253..6aaa84355fd1 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -1310,8 +1310,17 @@ static void omap8250_complete(struct device *dev) static int omap8250_suspend(struct device *dev) { struct omap8250_priv *priv = dev_get_drvdata(dev); + struct uart_8250_port *up = serial8250_get_port(priv->line); serial8250_suspend_port(priv->line); + + pm_runtime_get_sync(dev); + if (!device_may_wakeup(dev)) + priv->wer = 0; + serial_out(up, UART_OMAP_WER, priv->wer); + pm_runtime_mark_last_busy(dev); + pm_runtime_put_autosuspend(dev); + flush_work(&priv->qos_work); return 0; } @@ -1403,6 +1412,8 @@ static int omap8250_runtime_suspend(struct device *dev) /* Restore to UART mode after reset (for wakeup) */ omap8250_update_mdr1(up, priv); + /* Restore wakeup enable register */ + serial_out(up, UART_OMAP_WER, priv->wer); } if (up->dma && up->dma->rxchan) -- cgit v1.2.3