platform/chrome: cros_ec_sensorhub: Add FIFO support

cros_ec_sensorhub registers a listener and query motion sense FIFO,
spread to iio sensors registers.

To test, we can use libiio:
  iiod&
  iio_readdev -u ip:localhost -T 10000 -s 25 -b 16 cros-ec-gyro | od -x
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

drivers/platform/chrome/Makefile

@@ -20,7 +20,8 @@ obj-$(CONFIG_CROS_EC_CHARDEV)		+= cros_ec_chardev.o
 obj-$(CONFIG_CROS_EC_LIGHTBAR)		+= cros_ec_lightbar.o
 obj-$(CONFIG_CROS_EC_VBC)		+= cros_ec_vbc.o
 obj-$(CONFIG_CROS_EC_DEBUGFS)		+= cros_ec_debugfs.o
-obj-$(CONFIG_CROS_EC_SENSORHUB)		+= cros_ec_sensorhub.o
+cros-ec-sensorhub-objs			:= cros_ec_sensorhub.o cros_ec_sensorhub_ring.o
+obj-$(CONFIG_CROS_EC_SENSORHUB)		+= cros-ec-sensorhub.o
 obj-$(CONFIG_CROS_EC_SYSFS)		+= cros_ec_sysfs.o
 obj-$(CONFIG_CROS_USBPD_LOGGER)		+= cros_usbpd_logger.o
 obj-$(CONFIG_CROS_USBPD_NOTIFY)		+= cros_usbpd_notify.o

drivers/platform/chrome/cros_ec_sensorhub.c

@@ -50,10 +50,8 @@ static int cros_ec_sensorhub_register(struct device *dev,
 				      struct cros_ec_sensorhub *sensorhub)
 {
 	int sensor_type[MOTIONSENSE_TYPE_MAX] = { 0 };
+	struct cros_ec_command *msg = sensorhub->msg;
 	struct cros_ec_dev *ec = sensorhub->ec;
-	struct ec_params_motion_sense *params;
-	struct ec_response_motion_sense *resp;
-	struct cros_ec_command *msg;
 	int ret, i, sensor_num;
 	char *name;
 
@@ -71,22 +69,13 @@ static int cros_ec_sensorhub_register(struct device *dev,
 		return -EINVAL;
 	}
 
-	/* Prepare a message to send INFO command to each sensor. */
-	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*resp)),
-		      GFP_KERNEL);
-	if (!msg)
-		return -ENOMEM;
-
 	msg->version = 1;
-	msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
-	msg->outsize = sizeof(*params);
-	msg->insize = sizeof(*resp);
-	params = (struct ec_params_motion_sense *)msg->data;
-	resp = (struct ec_response_motion_sense *)msg->data;
+	msg->insize = sizeof(struct ec_response_motion_sense);
+	msg->outsize = sizeof(struct ec_params_motion_sense);
 
 	for (i = 0; i < sensor_num; i++) {
-		params->cmd = MOTIONSENSE_CMD_INFO;
-		params->info.sensor_num = i;
+		sensorhub->params->cmd = MOTIONSENSE_CMD_INFO;
+		sensorhub->params->info.sensor_num = i;
 
 		ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 		if (ret < 0) {
@@ -95,7 +84,7 @@ static int cros_ec_sensorhub_register(struct device *dev,
 			continue;
 		}
 
-		switch (resp->info.type) {
+		switch (sensorhub->resp->info.type) {
 		case MOTIONSENSE_TYPE_ACCEL:
 			name = "cros-ec-accel";
 			break;
@@ -118,15 +107,16 @@ static int cros_ec_sensorhub_register(struct device *dev,
 			name = "cros-ec-activity";
 			break;
 		default:
-			dev_warn(dev, "unknown type %d\n", resp->info.type);
+			dev_warn(dev, "unknown type %d\n",
+				 sensorhub->resp->info.type);
 			continue;
 		}
 
 		ret = cros_ec_sensorhub_allocate_sensor(dev, name, i);
 		if (ret)
-			goto error;
+			return ret;
 
-		sensor_type[resp->info.type]++;
+		sensor_type[sensorhub->resp->info.type]++;
 	}
 
 	if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
@@ -138,29 +128,41 @@ static int cros_ec_sensorhub_register(struct device *dev,
 							"cros-ec-lid-angle",
 							0);
 		if (ret)
-			goto error;
+			return ret;
 	}
 
-	kfree(msg);
 	return 0;
-
-error:
-	kfree(msg);
-	return ret;
 }
 
 static int cros_ec_sensorhub_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
 	struct cros_ec_sensorhub *data;
+	struct cros_ec_command *msg;
 	int ret;
 	int i;
 
+	msg = devm_kzalloc(dev, sizeof(struct cros_ec_command) +
+			   max((u16)sizeof(struct ec_params_motion_sense),
+			       ec->ec_dev->max_response), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
+
 	data = devm_kzalloc(dev, sizeof(struct cros_ec_sensorhub), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 
-	data->ec = dev_get_drvdata(dev->parent);
+	mutex_init(&data->cmd_lock);
+
+	data->dev = dev;
+	data->ec = ec;
+	data->msg = msg;
+	data->params = (struct ec_params_motion_sense *)msg->data;
+	data->resp = (struct ec_response_motion_sense *)msg->data;
+
 	dev_set_drvdata(dev, data);
 
 	/* Check whether this EC is a sensor hub. */
@@ -182,12 +184,63 @@ static int cros_ec_sensorhub_probe(struct platform_device *pdev)
 		}
 	}
 
+	/*
+	 * If the EC does not have a FIFO, the sensors will query their data
+	 * themselves via sysfs or a software trigger.
+	 */
+	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
+		ret = cros_ec_sensorhub_ring_add(data);
+		if (ret)
+			return ret;
+		/*
+		 * The msg and its data is not under the control of the ring
+		 * handler.
+		 */
+		return devm_add_action_or_reset(dev,
+						cros_ec_sensorhub_ring_remove,
+						data);
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+/*
+ * When the EC is suspending, we must stop sending interrupt,
+ * we may use the same interrupt line for waking up the device.
+ * Tell the EC to stop sending non-interrupt event on the iio ring.
+ */
+static int cros_ec_sensorhub_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct cros_ec_sensorhub *sensorhub = platform_get_drvdata(pdev);
+	struct cros_ec_dev *ec = sensorhub->ec;
+
+	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO))
+		return cros_ec_sensorhub_ring_fifo_enable(sensorhub, false);
 	return 0;
 }
 
+static int cros_ec_sensorhub_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct cros_ec_sensorhub *sensorhub = platform_get_drvdata(pdev);
+	struct cros_ec_dev *ec = sensorhub->ec;
+
+	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO))
+		return cros_ec_sensorhub_ring_fifo_enable(sensorhub, true);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(cros_ec_sensorhub_pm_ops,
+		cros_ec_sensorhub_suspend,
+		cros_ec_sensorhub_resume);
+
 static struct platform_driver cros_ec_sensorhub_driver = {
 	.driver = {
 		.name = DRV_NAME,
+		.pm = &cros_ec_sensorhub_pm_ops,
 	},
 	.probe = cros_ec_sensorhub_probe,
 };

include/linux/platform_data/cros_ec_sensorhub.h

@@ -8,8 +8,13 @@
 #ifndef __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
 #define __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
 
+#include <linux/ktime.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
 #include <linux/platform_data/cros_ec_commands.h>
 
+struct iio_dev;
+
 /**
  * struct cros_ec_sensor_platform - ChromeOS EC sensor platform information.
  * @sensor_num: Id of the sensor, as reported by the EC.
@@ -18,15 +23,86 @@ struct cros_ec_sensor_platform {
 	u8 sensor_num;
 };
 
+/**
+ * typedef cros_ec_sensorhub_push_data_cb_t - Callback function to send datum
+ *					      to specific sensors.
+ *
+ * @indio_dev: The IIO device that will process the sample.
+ * @data: Vector array of the ring sample.
+ * @timestamp: Timestamp in host timespace when the sample was acquired by
+ *             the EC.
+ */
+typedef int (*cros_ec_sensorhub_push_data_cb_t)(struct iio_dev *indio_dev,
+						s16 *data,
+						s64 timestamp);
+
+struct cros_ec_sensorhub_sensor_push_data {
+	struct iio_dev *indio_dev;
+	cros_ec_sensorhub_push_data_cb_t push_data_cb;
+};
+
+enum {
+	CROS_EC_SENSOR_LAST_TS,
+	CROS_EC_SENSOR_NEW_TS,
+	CROS_EC_SENSOR_ALL_TS
+};
+
+struct cros_ec_sensors_ring_sample {
+	u8  sensor_id;
+	u8  flag;
+	s16 vector[3];
+	s64 timestamp;
+} __packed;
+
 /**
  * struct cros_ec_sensorhub - Sensor Hub device data.
  *
+ * @dev: Device object, mostly used for logging.
  * @ec: Embedded Controller where the hub is located.
  * @sensor_num: Number of MEMS sensors present in the EC.
+ * @msg: Structure to send FIFO requests.
+ * @params: Pointer to parameters in msg.
+ * @resp: Pointer to responses in msg.
+ * @cmd_lock : Lock for sending msg.
+ * @notifier: Notifier to kick the FIFO interrupt.
+ * @ring: Preprocessed ring to store events.
+ * @fifo_timestamp: array for event timestamp and spreading.
+ * @fifo_info: copy of FIFO information coming from the EC.
+ * @fifo_size: size of the ring.
+ * @push_data: array of callback to send datums to iio sensor object.
  */
 struct cros_ec_sensorhub {
+	struct device *dev;
 	struct cros_ec_dev *ec;
 	int sensor_num;
+
+	struct cros_ec_command *msg;
+	struct ec_params_motion_sense *params;
+	struct ec_response_motion_sense *resp;
+	struct mutex cmd_lock;  /* Lock for protecting msg structure. */
+
+	struct notifier_block notifier;
+
+	struct cros_ec_sensors_ring_sample *ring;
+
+	ktime_t fifo_timestamp[CROS_EC_SENSOR_ALL_TS];
+	struct ec_response_motion_sense_fifo_info *fifo_info;
+	int fifo_size;
+
+	struct cros_ec_sensorhub_sensor_push_data *push_data;
 };
 
+int cros_ec_sensorhub_register_push_data(struct cros_ec_sensorhub *sensorhub,
+					 u8 sensor_num,
+					 struct iio_dev *indio_dev,
+					 cros_ec_sensorhub_push_data_cb_t cb);
+
+void cros_ec_sensorhub_unregister_push_data(struct cros_ec_sensorhub *sensorhub,
+					    u8 sensor_num);
+
+int cros_ec_sensorhub_ring_add(struct cros_ec_sensorhub *sensorhub);
+void cros_ec_sensorhub_ring_remove(void *arg);
+int cros_ec_sensorhub_ring_fifo_enable(struct cros_ec_sensorhub *sensorhub,
+				       bool on);
+
 #endif   /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */