[PATCH v5 2/3] tty: serial: qcom_geni_serial: Wakeup over UART RX

Akash Asthana
2019-11-13T10:49:13Z

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 V5:
- No change.

Changes in V4:
- As per Greg's comment, removed extra dev_err logging.
- As per Stephen's comment, using common code that manage wakeirq irqs for
devices. Using dev_pm_set_dedicated_wake_irq API that will take care of
requesting and attaching wakeup irqs for devices. Also, it sets wakeirq
status to WAKE_IRQ_DEDICATED_ALLOCATED as a result enabling/disabling of
wake irq will be managed by suspend/resume framework so, removed the code
for enabling and disabling of wake irq from the driver.

Changes in V3:
- As per Stephen's comment, using platform_get_irq_optional API to get wakeup
IRQ for device.

Changes in V2:
- As per Stephen's comment, splitted V1 patch into 2 seperate patch.
a) Clean up of core IRQ registration b) Add wakeup feature.

drivers/tty/serial/qcom_geni_serial.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 634054a..56dad67 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -14,6 +14,8 @@
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pm_wakeirq.h>
#include <linux/qcom-geni-se.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
@@ -116,6 +118,7 @@ struct qcom_geni_serial_port {
bool brk;

unsigned int tx_remaining;
+ int wakeup_irq;
};

static const struct uart_ops qcom_geni_console_pops;
@@ -1302,6 +1305,9 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
return irq;
uport->irq = irq;

+ if (!console)
+ port->wakeup_irq = platform_get_irq_optional(pdev, 1);
+
uport->private_data = drv;
platform_set_drvdata(pdev, port);
port->handle_rx = console ? handle_rx_console : handle_rx_uart;
@@ -1321,6 +1327,23 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
return ret;
}

+ if (port->wakeup_irq > 0) {
+ /*
+ * Set pm_runtime status as ACTIVE so that wakeup_irq gets
+ * enabled/disabled from dev_pm_arm_wake_irq during system
+ * suspend/resume respectively.
+ */
+ pm_runtime_set_active(&pdev->dev);
+ device_init_wakeup(&pdev->dev, true);
+ ret = dev_pm_set_dedicated_wake_irq(&pdev->dev,
+ port->wakeup_irq);
+ if (ret) {
+ device_init_wakeup(&pdev->dev, false);
+ uart_remove_one_port(drv, uport);
+ return ret;
+ }
+ }
+
return ret;
}

@@ -1330,6 +1353,10 @@ static int qcom_geni_serial_remove(struct platform_device *pdev)
struct uart_driver *drv = port->uport.private_data;

uart_remove_one_port(drv, &port->uport);
+
+ device_init_wakeup(&pdev->dev, false);
+ dev_pm_clear_wake_irq(&pdev->dev);
+
return 0;
}