soundwire: qcom: add in-band wake up interrupt support

Some of the Qualcomm SoundWire Controller instances like the ones that are
connected to RX path along with Headset connections support Waking up
Controller from Low power clock stop state using SoundWire In-band interrupt.
SoundWire Slave on the bus would initiate this by pulling the data line high,
while the clock is stopped.

Add support to this wake up interrupt.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20220228172528.3489-4-srinivas.kandagatla@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: Srinivas-Kandagatla

drivers/soundwire/qcom.c

@@ -14,6 +14,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
+#include <linux/pm_wakeirq.h>
 #include <linux/slimbus.h>
 #include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_registers.h>
@@ -154,6 +155,7 @@ struct qcom_swrm_ctrl {
 	u8 rd_cmd_id;
 	int irq;
 	unsigned int version;
+	int wake_irq;
 	int num_din_ports;
 	int num_dout_ports;
 	int cols_index;
@@ -503,6 +505,30 @@ static int qcom_swrm_enumerate(struct sdw_bus *bus)
 	return 0;
 }
 
+static irqreturn_t qcom_swrm_wake_irq_handler(int irq, void *dev_id)
+{
+	struct qcom_swrm_ctrl *swrm = dev_id;
+	int ret;
+
+	ret = pm_runtime_get_sync(swrm->dev);
+	if (ret < 0 && ret != -EACCES) {
+		dev_err_ratelimited(swrm->dev,
+				    "pm_runtime_get_sync failed in %s, ret %d\n",
+				    __func__, ret);
+		pm_runtime_put_noidle(swrm->dev);
+	}
+
+	if (swrm->wake_irq > 0) {
+		if (!irqd_irq_disabled(irq_get_irq_data(swrm->wake_irq)))
+			disable_irq_nosync(swrm->wake_irq);
+	}
+
+	pm_runtime_mark_last_busy(swrm->dev);
+	pm_runtime_put_autosuspend(swrm->dev);
+
+	return IRQ_HANDLED;
+}
+
 static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id)
 {
 	struct qcom_swrm_ctrl *swrm = dev_id;
@@ -1340,6 +1366,18 @@ static int qcom_swrm_probe(struct platform_device *pdev)
 		goto err_clk;
 	}
 
+	ctrl->wake_irq = of_irq_get(dev->of_node, 1);
+	if (ctrl->wake_irq > 0) {
+		ret = devm_request_threaded_irq(dev, ctrl->wake_irq, NULL,
+						qcom_swrm_wake_irq_handler,
+						IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+						"swr_wake_irq", ctrl);
+		if (ret) {
+			dev_err(dev, "Failed to request soundwire wake irq\n");
+			goto err_init;
+		}
+	}
+
 	ret = sdw_bus_master_add(&ctrl->bus, dev, dev->fwnode);
 	if (ret) {
 		dev_err(dev, "Failed to register Soundwire controller (%d)\n",
@@ -1424,6 +1462,11 @@ static int swrm_runtime_resume(struct device *dev)
 	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev);
 	int ret;
 
+	if (ctrl->wake_irq > 0) {
+		if (!irqd_irq_disabled(irq_get_irq_data(ctrl->wake_irq)))
+			disable_irq_nosync(ctrl->wake_irq);
+	}
+
 	clk_prepare_enable(ctrl->hclk);
 
 	if (ctrl->clock_stop_not_supported) {
@@ -1491,6 +1534,11 @@ static int __maybe_unused swrm_runtime_suspend(struct device *dev)
 
 	usleep_range(300, 305);
 
+	if (ctrl->wake_irq > 0) {
+		if (irqd_irq_disabled(irq_get_irq_data(ctrl->wake_irq)))
+			enable_irq(ctrl->wake_irq);
+	}
+
 	return 0;
 }