drivers: input_gt911: Reinitialize interrupt GPIO on exit from PM

Certain power modes lose state of the GPIO, hence we need to
reconfigure the interrupt GPIO. This is managed using pm_notifiers

Signed-off-by: Mahesh Mahadevan <mahesh.mahadevan@nxp.com>

Author: mmahadevan108

drivers/input/input_gt911.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020 NXP
+ * Copyright (c) 2020, 2025 NXP
  * Copyright (c) 2020 Mark Olsson <mark@markolsson.se>
  * Copyright (c) 2020 Teslabs Engineering S.L.
  *
@@ -12,6 +12,7 @@
 #include <zephyr/drivers/i2c.h>
 #include <zephyr/input/input.h>
 #include <zephyr/sys/byteorder.h>
+#include <zephyr/pm/pm.h>
 
 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(gt911, CONFIG_INPUT_LOG_LEVEL);
@@ -64,6 +65,9 @@ struct gt911_data {
 	/** Timer (polling mode). */
 	struct k_timer timer;
 #endif
+#ifdef CONFIG_PM
+	struct pm_notifier pm_notifier_handle;
+#endif
 };
 
 /** gt911 point reg */
@@ -237,6 +241,37 @@ static bool gt911_verify_firmware(const uint8_t *firmware)
 		(gt911_get_firmware_checksum(firmware) == firmware[REG_CONFIG_SIZE - 2U]));
 }
 
+#if CONFIG_PM
+static void gt911_pm_state_exit(const struct device *dev, enum pm_state state)
+{
+	switch (state) {
+	case PM_STATE_STANDBY:
+		/* Reconfigure the GPIO interrupt pin on exit from
+		 * certain low power states as we might lose the GPIO state.
+		 */
+		const struct gt911_config *config = dev->config;
+		int r;
+
+		r = gpio_pin_configure_dt(&config->int_gpio, GPIO_INPUT);
+		if (r < 0) {
+			LOG_ERR("Could not configure interrupt GPIO pin");
+			return;
+		}
+
+#ifdef CONFIG_INPUT_GT911_INTERRUPT
+		r = gpio_pin_interrupt_configure_dt(&config->int_gpio, GPIO_INT_EDGE_TO_ACTIVE);
+		if (r < 0) {
+			LOG_ERR("Could not configure interrupt GPIO interrupt.");
+			return;
+		}
+#endif /* CONFIG_INPUT_GT911_INTERRUPT */
+		break;
+	default:
+		break;
+	}
+}
+#endif /* CONFIG_PM */
+
 static int gt911_init(const struct device *dev)
 {
 	const struct gt911_config *config = dev->config;
@@ -390,17 +425,42 @@ static int gt911_init(const struct device *dev)
 		      K_MSEC(CONFIG_INPUT_GT911_PERIOD_MS));
 #endif
 
+#if CONFIG_PM
+	/* We need to reconfigure the interrupt GPIO when waking up from
+	 * certain low power modes.
+	 */
+	pm_notifier_register(&data->pm_notifier_handle);
+#endif
 	return 0;
 }
 
+#if CONFIG_PM
+#define GT911_PM_NOTIFIER_FUNCS(n)                                                                 \
+static void gt911_##n##_pm_state_exit(enum pm_state state)                                         \
+{                                                                                                  \
+	gt911_pm_state_exit(DEVICE_DT_INST_GET(n), state);                                         \
+}
+
+#define GT911_PM_NOTIFIER(n)                                                                       \
+	.pm_notifier_handle = {                                                                    \
+		.state_exit = gt911_##n##_pm_state_exit,                                           \
+	},
+#else
+#define GT911_PM_NOTIFIER_FUNCS(n)
+#define GT911_PM_NOTIFIER(n)
+#endif /* CONFIG_PM */
+
 #define GT911_INIT(index)                                                                          \
 	static const struct gt911_config gt911_config_##index = {                                  \
 		.bus = I2C_DT_SPEC_INST_GET(index),                                                \
 		.rst_gpio = GPIO_DT_SPEC_INST_GET_OR(index, reset_gpios, {0}),                     \
 		.int_gpio = GPIO_DT_SPEC_INST_GET(index, irq_gpios),                               \
 		.alt_addr = DT_INST_PROP_OR(index, alt_addr, 0),                                   \
 	};                                                                                         \
-	static struct gt911_data gt911_data_##index;                                               \
+	GT911_PM_NOTIFIER_FUNCS(index)                                                             \
+	static struct gt911_data gt911_data_##index = {                                            \
+		GT911_PM_NOTIFIER(index)                                                           \
+	};                                                                                         \
 	DEVICE_DT_INST_DEFINE(index, gt911_init, NULL, &gt911_data_##index, &gt911_config_##index, \
 			      POST_KERNEL, CONFIG_INPUT_INIT_PRIORITY, NULL);