iio / platform: cros_ec: Add cros-ec-sensorhub driver

Similar to HID sensor stack, the new driver sits between cros-ec-dev
and the IIO device drivers:

The EC based IIO device topology would be:

iio:device1 ->
   ...0/0000:00:1f.0/PNP0C09:00/GOOG0004:00/cros-ec-dev.6.auto/
                                            cros-ec-sensorhub.7.auto/
                                            cros-ec-accel.15.auto/
                                            iio:device1

It will be expanded to control EC sensor FIFO.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
[Fix "unknown type name 'uint32_t'" type errors]
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

1 files changed, 199 insertions, 0 deletions

diff --git a/drivers/platform/chrome/cros_ec_sensorhub.c b/drivers/platform/chrome/cros_ec_sensorhub.c
new file mode 100644
index 000000000000..04d8879689e9
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_sensorhub.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sensor HUB driver that discovers sensors behind a ChromeOS Embedded
+ * Controller.
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_data/cros_ec_sensorhub.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#define DRV_NAME		"cros-ec-sensorhub"
+
+static void cros_ec_sensorhub_free_sensor(void *arg)
+{
+	struct platform_device *pdev = arg;
+
+	platform_device_unregister(pdev);
+}
+
+static int cros_ec_sensorhub_allocate_sensor(struct device *parent,
+					     char *sensor_name,
+					     int sensor_num)
+{
+	struct cros_ec_sensor_platform sensor_platforms = {
+		.sensor_num = sensor_num,
+	};
+	struct platform_device *pdev;
+
+	pdev = platform_device_register_data(parent, sensor_name,
+					     PLATFORM_DEVID_AUTO,
+					     &sensor_platforms,
+					     sizeof(sensor_platforms));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	return devm_add_action_or_reset(parent,
+					cros_ec_sensorhub_free_sensor,
+					pdev);
+}
+
+static int cros_ec_sensorhub_register(struct device *dev,
+				      struct cros_ec_sensorhub *sensorhub)
+{
+	int sensor_type[MOTIONSENSE_TYPE_MAX] = { 0 };
+	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;
+
+	sensor_num = cros_ec_get_sensor_count(ec);
+	if (sensor_num < 0) {
+		dev_err(dev,
+			"Unable to retrieve sensor information (err:%d)\n",
+			sensor_num);
+		return sensor_num;
+	}
+
+	if (sensor_num == 0) {
+		dev_err(dev, "Zero sensors reported.\n");
+		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;
+
+	for (i = 0; i < sensor_num; i++) {
+		params->cmd = MOTIONSENSE_CMD_INFO;
+		params->info.sensor_num = i;
+
+		ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+		if (ret < 0) {
+			dev_warn(dev, "no info for EC sensor %d : %d/%d\n",
+				 i, ret, msg->result);
+			continue;
+		}
+
+		switch (resp->info.type) {
+		case MOTIONSENSE_TYPE_ACCEL:
+			name = "cros-ec-accel";
+			break;
+		case MOTIONSENSE_TYPE_BARO:
+			name = "cros-ec-baro";
+			break;
+		case MOTIONSENSE_TYPE_GYRO:
+			name = "cros-ec-gyro";
+			break;
+		case MOTIONSENSE_TYPE_MAG:
+			name = "cros-ec-mag";
+			break;
+		case MOTIONSENSE_TYPE_PROX:
+			name = "cros-ec-prox";
+			break;
+		case MOTIONSENSE_TYPE_LIGHT:
+			name = "cros-ec-light";
+			break;
+		case MOTIONSENSE_TYPE_ACTIVITY:
+			name = "cros-ec-activity";
+			break;
+		default:
+			dev_warn(dev, "unknown type %d\n", resp->info.type);
+			continue;
+		}
+
+		ret = cros_ec_sensorhub_allocate_sensor(dev, name, i);
+		if (ret)
+			goto error;
+
+		sensor_type[resp->info.type]++;
+	}
+
+	if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
+		ec->has_kb_wake_angle = true;
+
+	if (cros_ec_check_features(ec,
+				   EC_FEATURE_REFINED_TABLET_MODE_HYSTERESIS)) {
+		ret = cros_ec_sensorhub_allocate_sensor(dev,
+							"cros-ec-lid-angle",
+							0);
+		if (ret)
+			goto error;
+	}
+
+	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_sensorhub *data;
+	int ret;
+	int i;
+
+	data = devm_kzalloc(dev, sizeof(struct cros_ec_sensorhub), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->ec = dev_get_drvdata(dev->parent);
+	dev_set_drvdata(dev, data);
+
+	/* Check whether this EC is a sensor hub. */
+	if (cros_ec_check_features(data->ec, EC_FEATURE_MOTION_SENSE)) {
+		ret = cros_ec_sensorhub_register(dev, data);
+		if (ret)
+			return ret;
+	} else {
+		/*
+		 * If the device has sensors but does not claim to
+		 * be a sensor hub, we are in legacy mode.
+		 */
+		for (i = 0; i < 2; i++) {
+			ret = cros_ec_sensorhub_allocate_sensor(dev,
+						"cros-ec-accel-legacy", i);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static struct platform_driver cros_ec_sensorhub_driver = {
+	.driver = {
+		.name = DRV_NAME,
+	},
+	.probe = cros_ec_sensorhub_probe,
+};
+
+module_platform_driver(cros_ec_sensorhub_driver);
+
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>");
+MODULE_DESCRIPTION("ChromeOS EC MEMS Sensor Hub Driver");
+MODULE_LICENSE("GPL");