[PATCH v1 1/2] i2c: qcom-cci: Select pinctrl states during runtime PM

[Saikiran <bjsaikiran@gmail.com>]

The CCI runtime PM callbacks only gate the controller clocks, leaving the
bus pins in their default state while the controller is suspended. On the
Lenovo Yoga Slim 7x, this can back-power the camera sensor through SDA and
SCL after its supplies have been disabled, contributing to brownouts on
subsequent power cycles.

Select the sleep pinctrl state before disabling the clocks so that the
configured pull-downs can take effect. Restore the default state before
enabling the clocks on resume, and return to the sleep state if enabling
the clocks fails.

Tested-on: Lenovo Yoga Slim 7x (Snapdragon X Elite)
Signed-off-by: Saikiran <bjsaikiran@gmail.com>
---
 drivers/i2c/busses/i2c-qcom-cci.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-qcom-cci.c b/drivers/i2c/busses/i2c-qcom-cci.c
index 873e901a23d7..fba5f664eeaa 100644
--- a/drivers/i2c/busses/i2c-qcom-cci.c
+++ b/drivers/i2c/busses/i2c-qcom-cci.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/pm_runtime.h>
 
 #define CCI_HW_VERSION				0x0
@@ -474,6 +475,11 @@ static void cci_disable_clocks(struct cci *cci)
 static int __maybe_unused cci_suspend_runtime(struct device *dev)
 {
 	struct cci *cci = dev_get_drvdata(dev);
+	int ret;
+
+	ret = pinctrl_pm_select_sleep_state(dev);
+	if (ret)
+		return ret;
 
 	cci_disable_clocks(cci);
 	return 0;
@@ -484,10 +490,16 @@ static int __maybe_unused cci_resume_runtime(struct device *dev)
 	struct cci *cci = dev_get_drvdata(dev);
 	int ret;
 
-	ret = cci_enable_clocks(cci);
+	ret = pinctrl_pm_select_default_state(dev);
 	if (ret)
 		return ret;
 
+	ret = cci_enable_clocks(cci);
+	if (ret) {
+		pinctrl_pm_select_sleep_state(dev);
+		return ret;
+	}
+
 	cci_init(cci);
 	return 0;
 }
-- 
2.56.0