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* [PATCH v3 2/2] tty: serial: qcom_geni_serial: Wakeup over UART RX
@ 2019-10-15  6:11 Akash Asthana
  2019-10-15 18:59 ` Greg KH
  0 siblings, 1 reply; 3+ messages in thread
From: Akash Asthana @ 2019-10-15  6:11 UTC (permalink / raw)
  To: gregkh
  Cc: linux-arm-msm, linux-serial, mgautam, bjorn.andersson, swboyd,
	msavaliy, Akash Asthana

Add system wakeup capability over UART RX line for wakeup capable UART.
When system is suspended, RX line act as an interrupt to wakeup system
for any communication requests from peer.

Signed-off-by: Akash Asthana <akashast@codeaurora.org>
---
Changes in V3:
 - Address review comments on v2 patch.

 drivers/tty/serial/qcom_geni_serial.c | 44 ++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 12dc007..bc828e49 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -14,6 +14,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
 #include <linux/qcom-geni-se.h>
 #include <linux/serial.h>
 #include <linux/serial_core.h>
@@ -116,6 +117,7 @@ struct qcom_geni_serial_port {
 	bool brk;
 
 	unsigned int tx_remaining;
+	int wakeup_irq;
 };
 
 static const struct uart_ops qcom_geni_console_pops;
@@ -755,6 +757,15 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
 		uart_write_wakeup(uport);
 }
 
+static irqreturn_t qcom_geni_serial_wakeup_isr(int isr, void *dev)
+{
+	struct uart_port *uport = dev;
+
+	pm_wakeup_event(uport->dev, 2000);
+
+	return IRQ_HANDLED;
+}
+
 static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 {
 	u32 m_irq_en;
@@ -1310,6 +1321,29 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	if (!console) {
+		port->wakeup_irq = platform_get_irq_optional(pdev, 1);
+		if (port->wakeup_irq < 0) {
+			dev_err(&pdev->dev, "Failed to get wakeup IRQ %d\n",
+					port->wakeup_irq);
+		} else {
+			irq_set_status_flags(port->wakeup_irq, IRQ_NOAUTOEN);
+			ret = devm_request_irq(uport->dev, port->wakeup_irq,
+				qcom_geni_serial_wakeup_isr,
+				IRQF_TRIGGER_FALLING, "uart_wakeup", uport);
+			if (ret) {
+				dev_err(uport->dev, "Failed to register wakeup IRQ ret %d\n",
+						ret);
+				return ret;
+			}
+
+			device_init_wakeup(&pdev->dev, true);
+			ret = dev_pm_set_wake_irq(&pdev->dev, port->wakeup_irq);
+			if (unlikely(ret))
+				dev_err(uport->dev, "%s:Failed to set IRQ wake:%d\n",
+						__func__, ret);
+		}
+	}
 	uport->private_data = drv;
 	platform_set_drvdata(pdev, port);
 	port->handle_rx = console ? handle_rx_console : handle_rx_uart;
@@ -1332,7 +1366,12 @@ static int __maybe_unused qcom_geni_serial_sys_suspend(struct device *dev)
 	struct qcom_geni_serial_port *port = dev_get_drvdata(dev);
 	struct uart_port *uport = &port->uport;
 
-	return uart_suspend_port(uport->private_data, uport);
+	uart_suspend_port(uport->private_data, uport);
+
+	if (port->wakeup_irq > 0)
+		enable_irq(port->wakeup_irq);
+
+	return 0;
 }
 
 static int __maybe_unused qcom_geni_serial_sys_resume(struct device *dev)
@@ -1340,6 +1379,9 @@ static int __maybe_unused qcom_geni_serial_sys_resume(struct device *dev)
 	struct qcom_geni_serial_port *port = dev_get_drvdata(dev);
 	struct uart_port *uport = &port->uport;
 
+	if (port->wakeup_irq > 0)
+		disable_irq(port->wakeup_irq);
+
 	return uart_resume_port(uport->private_data, uport);
 }
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project


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2019-10-15  6:11 [PATCH v3 2/2] tty: serial: qcom_geni_serial: Wakeup over UART RX Akash Asthana
2019-10-15 18:59 ` Greg KH
2019-10-17 11:09   ` Akash Asthana

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