[PATCH v2 RESEND] i2c: cadence: Add system suspend and resume PM support

[Ji Sheng Teoh]

Enable device system suspend and resume PM support, and mark the device
state as suspended during system suspend to reject any data transfer.

Signed-off-by: Ji Sheng Teoh <jisheng.teoh at starfivetech.com>
---
Initial v2 was archived, previous discussion can be found in [1].
[1]: https://lore.kernel.org/all/20231209131516.1916550-1-jisheng.teoh@starfivetech.com/

Changes since v1:
- Add missing err assignment in cdns_i2c_resume().
---
 drivers/i2c/busses/i2c-cadence.c | 33 ++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index de3f58b60dce..4bb7d6756947 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -1176,6 +1176,18 @@ static int __maybe_unused cdns_i2c_runtime_suspend(struct device *dev)
 	return 0;
 }
 
+static int __maybe_unused cdns_i2c_suspend(struct device *dev)
+{
+	struct cdns_i2c *xi2c = dev_get_drvdata(dev);
+
+	i2c_mark_adapter_suspended(&xi2c->adap);
+
+	if (!pm_runtime_status_suspended(dev))
+		return cdns_i2c_runtime_suspend(dev);
+
+	return 0;
+}
+
 /**
  * cdns_i2c_init -  Controller initialisation
  * @id:		Device private data structure
@@ -1219,7 +1231,28 @@ static int __maybe_unused cdns_i2c_runtime_resume(struct device *dev)
 	return 0;
 }
 
+static int __maybe_unused cdns_i2c_resume(struct device *dev)
+{
+	struct cdns_i2c *xi2c = dev_get_drvdata(dev);
+	int err;
+
+	err = cdns_i2c_runtime_resume(dev);
+	if (err)
+		return err;
+
+	if (pm_runtime_status_suspended(dev)) {
+		err = cdns_i2c_runtime_suspend(dev);
+		if (err)
+			return err;
+	}
+
+	i2c_mark_adapter_resumed(&xi2c->adap);
+
+	return 0;
+}
+
 static const struct dev_pm_ops cdns_i2c_dev_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(cdns_i2c_suspend, cdns_i2c_resume)
 	SET_RUNTIME_PM_OPS(cdns_i2c_runtime_suspend,
 			   cdns_i2c_runtime_resume, NULL)
 };
-- 
2.43.0