From 3dba54b92da8f1d68569c3929605ee0131e33f9f Mon Sep 17 00:00:00 2001
From: Nick Ward <nix.ward@gmail.com>
Date: Sat, 23 Sep 2023 01:34:09 +1000
Subject: [PATCH] drivers: current sense amp: add pm

Enable power management for current sense amp.

Signed-off-by: Nick Ward <nix.ward@gmail.com>
---
 drivers/sensor/current_amp/current_amp.c      | 59 ++++++++++++++++++-
 .../iio/afe/current-sense-amplifier.yaml      |  8 +++
 .../drivers/adc/current_sense_amplifier.h     |  3 +
 3 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/drivers/sensor/current_amp/current_amp.c b/drivers/sensor/current_amp/current_amp.c
index 8a62a1e61f5..d760e4b34b0 100644
--- a/drivers/sensor/current_amp/current_amp.c
+++ b/drivers/sensor/current_amp/current_amp.c
@@ -8,7 +8,9 @@
 
 #include <zephyr/drivers/adc.h>
 #include <zephyr/drivers/adc/current_sense_amplifier.h>
+#include <zephyr/drivers/gpio.h>
 #include <zephyr/drivers/sensor.h>
+#include <zephyr/pm/device.h>
 
 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(current_amp, CONFIG_SENSOR_LOG_LEVEL);
@@ -73,6 +75,40 @@ static const struct sensor_driver_api current_api = {
 	.channel_get = get,
 };
 
+#ifdef CONFIG_PM_DEVICE
+static int pm_action(const struct device *dev, enum pm_device_action action)
+{
+	const struct current_sense_amplifier_dt_spec *config = dev->config;
+	int ret;
+
+	if (config->power_gpio.port == NULL) {
+		LOG_ERR("PM not supported");
+		return -ENOTSUP;
+	}
+
+	switch (action) {
+	case PM_DEVICE_ACTION_RESUME:
+		ret = gpio_pin_set_dt(&config->power_gpio, 1);
+		if (ret != 0) {
+			LOG_ERR("failed to set GPIO for PM resume");
+			return ret;
+		}
+		break;
+	case PM_DEVICE_ACTION_SUSPEND:
+		ret = gpio_pin_set_dt(&config->power_gpio, 0);
+		if (ret != 0) {
+			LOG_ERR("failed to set GPIO for PM suspend");
+			return ret;
+		}
+		break;
+	default:
+		return -ENOTSUP;
+	}
+
+	return 0;
+}
+#endif
+
 static int current_init(const struct device *dev)
 {
 	const struct current_sense_amplifier_dt_spec *config = dev->config;
@@ -84,6 +120,21 @@ static int current_init(const struct device *dev)
 		return -ENODEV;
 	}
 
+#ifdef CONFIG_PM_DEVICE
+	if (config->power_gpio.port != NULL) {
+		if (!gpio_is_ready_dt(&config->power_gpio)) {
+			LOG_ERR("Power GPIO is not ready");
+			return -ENODEV;
+		}
+
+		ret = gpio_pin_configure_dt(&config->power_gpio, GPIO_OUTPUT_ACTIVE);
+		if (ret != 0) {
+			LOG_ERR("failed to config GPIO: %d", ret);
+			return ret;
+		}
+	}
+#endif
+
 	ret = adc_channel_setup_dt(&config->port);
 	if (ret != 0) {
 		LOG_ERR("setup: %d", ret);
@@ -108,8 +159,10 @@ static int current_init(const struct device *dev)
 	static const struct current_sense_amplifier_dt_spec current_amp_##inst##_config =          \
 		CURRENT_SENSE_AMPLIFIER_DT_SPEC_GET(DT_DRV_INST(inst));                            \
                                                                                                    \
-	SENSOR_DEVICE_DT_INST_DEFINE(inst, &current_init, NULL, &current_amp_##inst##_data,        \
-			      &current_amp_##inst##_config, POST_KERNEL,                           \
-			      CONFIG_SENSOR_INIT_PRIORITY, &current_api);
+	PM_DEVICE_DT_INST_DEFINE(inst, pm_action);                                                 \
+                                                                                                   \
+	SENSOR_DEVICE_DT_INST_DEFINE(inst, &current_init, PM_DEVICE_DT_INST_GET(inst),             \
+				     &current_amp_##inst##_data, &current_amp_##inst##_config,     \
+				     POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY, &current_api);
 
 DT_INST_FOREACH_STATUS_OKAY(CURRENT_SENSE_AMPLIFIER_INIT)
diff --git a/dts/bindings/iio/afe/current-sense-amplifier.yaml b/dts/bindings/iio/afe/current-sense-amplifier.yaml
index e50bda74fe4..777116d0cff 100644
--- a/dts/bindings/iio/afe/current-sense-amplifier.yaml
+++ b/dts/bindings/iio/afe/current-sense-amplifier.yaml
@@ -37,3 +37,11 @@ properties:
     default: 1
     description: |
       Amplifier gain divider. The default is <1>.
+
+  power-gpios:
+    type: phandle-array
+    description: |
+      Control power to the current amplifier.
+
+      If present the corresponding GPIO must be set to an active level
+      to enable the current amplifier.
diff --git a/include/zephyr/drivers/adc/current_sense_amplifier.h b/include/zephyr/drivers/adc/current_sense_amplifier.h
index 6035eeb4ed2..888167b1ae9 100644
--- a/include/zephyr/drivers/adc/current_sense_amplifier.h
+++ b/include/zephyr/drivers/adc/current_sense_amplifier.h
@@ -8,12 +8,14 @@
 #define ZEPHYR_INCLUDE_DRIVERS_ADC_CURRENT_SENSE_AMPLIFIER_H_
 
 #include <zephyr/drivers/adc.h>
+#include <zephyr/drivers/gpio.h>
 
 struct current_sense_amplifier_dt_spec {
 	const struct adc_dt_spec port;
 	uint32_t sense_micro_ohms;
 	uint32_t sense_gain_mult;
 	uint32_t sense_gain_div;
+	struct gpio_dt_spec power_gpio;
 };
 
 /**
@@ -32,6 +34,7 @@ struct current_sense_amplifier_dt_spec {
 		.sense_micro_ohms = DT_PROP(node_id, sense_resistor_micro_ohms),                   \
 		.sense_gain_mult = DT_PROP(node_id, sense_gain_mult),                              \
 		.sense_gain_div = DT_PROP(node_id, sense_gain_div),                                \
+		.power_gpio = GPIO_DT_SPEC_GET_OR(node_id, power_gpios, {0}),                      \
 	}
 
 /**