i2c: imx-lpi2c: add VLLS mode support

When system enters VLLS mode, module power is turned off. As a result,
all registers are reset to HW default value. After exiting VLLS mode,
registers are still in default mode. As a result, the pinctrl settings
are incorrect, which will affect the module function.

The patch recovers the pinctrl setting when exit VLLS mode.

Signed-off-by: Gao Pan <pandy.gao@nxp.com>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
[wsa: added missing include]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-imx-lpi2c.c

@@ -28,6 +28,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
@@ -636,12 +637,31 @@ static int lpi2c_imx_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int lpi2c_imx_suspend(struct device *dev)
+{
+	pinctrl_pm_select_sleep_state(dev);
+
+	return 0;
+}
+
+static int lpi2c_imx_resume(struct device *dev)
+{
+	pinctrl_pm_select_default_state(dev);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(imx_lpi2c_pm, lpi2c_imx_suspend, lpi2c_imx_resume);
+
 static struct platform_driver lpi2c_imx_driver = {
 	.probe = lpi2c_imx_probe,
 	.remove = lpi2c_imx_remove,
 	.driver = {
 		.name = DRIVER_NAME,
 		.of_match_table = lpi2c_imx_of_match,
+		.pm = &imx_lpi2c_pm,
 	},
 };