[RFC PATCH v2 2/3] power: sequencing: qcom-wcn: support SW_CTRL wake IRQ

[Linghui Wu <linghui.wu@oss.qualcomm.com>]

Some WCN3990-family devices use SW_CTRL to signal that resources must
remain available while the application processor is suspended.

When the PMU is marked as a wakeup source, request the existing SW_CTRL
GPIO as an input, map it to an IRQ and register it as a dedicated wake
IRQ. The PM core then keeps the IRQ disabled during normal operation and
arms it for system suspend.

Signed-off-by: Linghui Wu <linghui.wu@oss.qualcomm.com>
---
 drivers/power/sequencing/pwrseq-qcom-wcn.c | 36 ++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/power/sequencing/pwrseq-qcom-wcn.c b/drivers/power/sequencing/pwrseq-qcom-wcn.c
index 636dd7e63891..69b7eb565996 100644
--- a/drivers/power/sequencing/pwrseq-qcom-wcn.c
+++ b/drivers/power/sequencing/pwrseq-qcom-wcn.c
@@ -11,6 +11,8 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/pm_wakeup.h>
 #include <linux/property.h>
 #include <linux/regulator/consumer.h>
 #include <linux/pwrseq/provider.h>
@@ -484,11 +486,18 @@ static int pwrseq_qcom_wcn3990_match(struct pwrseq_device *pwrseq,
 	return pwrseq_qcom_wcn_match_regulator(pwrseq, dev, "vdd-1.8-xo-supply");
 }
 
+static void pwrseq_qcom_wcn_clear_wake_irq(void *data)
+{
+	dev_pm_clear_wake_irq(data);
+}
+
 static int pwrseq_qcom_wcn_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct pwrseq_qcom_wcn_ctx *ctx;
+	struct gpio_desc *swctrl_gpio;
 	struct pwrseq_config config;
+	int wake_irq;
 	int i, ret;
 
 	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
@@ -526,6 +535,33 @@ static int pwrseq_qcom_wcn_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, PTR_ERR(ctx->bt_gpio),
 				     "Failed to get the Bluetooth enable GPIO\n");
 
+	if (device_property_read_bool(dev, "wakeup-source")) {
+		swctrl_gpio = devm_gpiod_get(dev, "swctrl", GPIOD_IN);
+		if (IS_ERR(swctrl_gpio))
+			return dev_err_probe(dev, PTR_ERR(swctrl_gpio),
+					     "Failed to get the SW_CTRL GPIO\n");
+
+		wake_irq = gpiod_to_irq(swctrl_gpio);
+		if (wake_irq < 0)
+			return dev_err_probe(dev, wake_irq,
+					     "Failed to get the SW_CTRL wake IRQ\n");
+
+		ret = devm_device_init_wakeup(dev);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "Failed to enable wakeup\n");
+
+		ret = dev_pm_set_dedicated_wake_irq(dev, wake_irq);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "Failed to set the SW_CTRL wake IRQ\n");
+
+		ret = devm_add_action_or_reset(dev,
+					       pwrseq_qcom_wcn_clear_wake_irq, dev);
+		if (ret)
+			return ret;
+	}
+
 	ctx->wlan_gpio = devm_gpiod_get_optional(dev, "wlan-enable",
 						 GPIOD_OUT_LOW);
 	if (IS_ERR(ctx->wlan_gpio))
-- 
2.43.0