HID: hid-sensor-custom: Add custom sensor iio support

Currently custom sensors properties are not decoded and it is up to
user space to interpret.

Some manufacturers already standardized the meaning of some custom sensors.
They can be presented as a proper IIO sensor. We can identify these sensors
based on manufacturer and serial number property in the report.

This change is identifying hinge sensor when the manufacturer is "INTEL".
This creates a platform device so that a sensor driver can be loaded to
process these sensors.

Signed-off-by: Ye Xiang <xiang.ye@intel.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Link: https://lore.kernel.org/r/20201215054444.9324-2-xiang.ye@intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 143 insertions, 0 deletions

diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-sensor-custom.c
index 4d25577a8573..2628bc53ed80 100644
--- a/drivers/hid/hid-sensor-custom.c
+++ b/drivers/hid/hid-sensor-custom.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2015, Intel Corporation.
  */
 
+#include <linux/ctype.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -21,6 +22,7 @@
 #define HID_CUSTOM_TOTAL_ATTRS		(HID_CUSTOM_MAX_CORE_ATTRS + 1)
 #define HID_CUSTOM_FIFO_SIZE		4096
 #define HID_CUSTOM_MAX_FEATURE_BYTES	64
+#define HID_SENSOR_USAGE_LENGTH (4 + 1)
 
 struct hid_sensor_custom_field {
 	int report_id;
@@ -50,6 +52,7 @@ struct hid_sensor_custom {
 	struct kfifo data_fifo;
 	unsigned long misc_opened;
 	wait_queue_head_t wait;
+	struct platform_device *custom_pdev;
 };
 
 /* Header for each sample to user space via dev interface */
@@ -746,11 +749,130 @@ static void hid_sensor_custom_dev_if_remove(struct hid_sensor_custom
 
 }
 
+/* luid defined in FW (e.g. ISH).  Maybe used to identify sensor. */
+static const char *const known_sensor_luid[] = { "020B000000000000" };
+
+static int get_luid_table_index(unsigned char *usage_str)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(known_sensor_luid); i++) {
+		if (!strncmp(usage_str, known_sensor_luid[i],
+			     strlen(known_sensor_luid[i])))
+			return i;
+	}
+
+	return -ENODEV;
+}
+
+static int get_known_custom_sensor_index(struct hid_sensor_hub_device *hsdev)
+{
+	struct hid_sensor_hub_attribute_info sensor_manufacturer = { 0 };
+	struct hid_sensor_hub_attribute_info sensor_luid_info = { 0 };
+	int report_size;
+	int ret;
+	static u16 w_buf[HID_CUSTOM_MAX_FEATURE_BYTES];
+	static char buf[HID_CUSTOM_MAX_FEATURE_BYTES];
+	int i;
+
+	memset(w_buf, 0, sizeof(w_buf));
+	memset(buf, 0, sizeof(buf));
+
+	/* get manufacturer info */
+	ret = sensor_hub_input_get_attribute_info(hsdev,
+			HID_FEATURE_REPORT, hsdev->usage,
+			HID_USAGE_SENSOR_PROP_MANUFACTURER, &sensor_manufacturer);
+	if (ret < 0)
+		return ret;
+
+	report_size =
+		sensor_hub_get_feature(hsdev, sensor_manufacturer.report_id,
+				       sensor_manufacturer.index, sizeof(w_buf),
+				       w_buf);
+	if (report_size <= 0) {
+		hid_err(hsdev->hdev,
+			"Failed to get sensor manufacturer info %d\n",
+			report_size);
+		return -ENODEV;
+	}
+
+	/* convert from wide char to char */
+	for (i = 0; i < ARRAY_SIZE(buf) - 1 && w_buf[i]; i++)
+		buf[i] = (char)w_buf[i];
+
+	/* ensure it's ISH sensor */
+	if (strncmp(buf, "INTEL", strlen("INTEL")))
+		return -ENODEV;
+
+	memset(w_buf, 0, sizeof(w_buf));
+	memset(buf, 0, sizeof(buf));
+
+	/* get real usage id */
+	ret = sensor_hub_input_get_attribute_info(hsdev,
+			HID_FEATURE_REPORT, hsdev->usage,
+			HID_USAGE_SENSOR_PROP_SERIAL_NUM, &sensor_luid_info);
+	if (ret < 0)
+		return ret;
+
+	report_size = sensor_hub_get_feature(hsdev, sensor_luid_info.report_id,
+					     sensor_luid_info.index, sizeof(w_buf),
+					     w_buf);
+	if (report_size <= 0) {
+		hid_err(hsdev->hdev, "Failed to get real usage info %d\n",
+			report_size);
+		return -ENODEV;
+	}
+
+	/* convert from wide char to char */
+	for (i = 0; i < ARRAY_SIZE(buf) - 1 && w_buf[i]; i++)
+		buf[i] = (char)w_buf[i];
+
+	if (strlen(buf) != strlen(known_sensor_luid[0]) + 5) {
+		hid_err(hsdev->hdev,
+			"%s luid length not match %zu != (%zu + 5)\n", __func__,
+			strlen(buf), strlen(known_sensor_luid[0]));
+		return -ENODEV;
+	}
+
+	/* get table index with luid (not matching 'LUID: ' in luid) */
+	return get_luid_table_index(&buf[5]);
+}
+
+static struct platform_device *
+hid_sensor_register_platform_device(struct platform_device *pdev,
+				    struct hid_sensor_hub_device *hsdev,
+				    int index)
+{
+	char real_usage[HID_SENSOR_USAGE_LENGTH] = { 0 };
+	struct platform_device *custom_pdev;
+	const char *dev_name;
+	char *c;
+
+	/* copy real usage id */
+	memcpy(real_usage, known_sensor_luid[index], 4);
+
+	/* usage id are all lowcase */
+	for (c = real_usage; *c != '\0'; c++)
+		*c = tolower(*c);
+
+	/* HID-SENSOR-INT-REAL_USAGE_ID */
+	dev_name = kasprintf(GFP_KERNEL, "HID-SENSOR-INT-%s", real_usage);
+	if (!dev_name)
+		return ERR_PTR(-ENOMEM);
+
+	custom_pdev = platform_device_register_data(pdev->dev.parent, dev_name,
+						    PLATFORM_DEVID_NONE, hsdev,
+						    sizeof(*hsdev));
+	kfree(dev_name);
+	return custom_pdev;
+}
+
 static int hid_sensor_custom_probe(struct platform_device *pdev)
 {
 	struct hid_sensor_custom *sensor_inst;
 	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
 	int ret;
+	int index;
 
 	sensor_inst = devm_kzalloc(&pdev->dev, sizeof(*sensor_inst),
 				   GFP_KERNEL);
@@ -764,6 +886,22 @@ static int hid_sensor_custom_probe(struct platform_device *pdev)
 	sensor_inst->pdev = pdev;
 	mutex_init(&sensor_inst->mutex);
 	platform_set_drvdata(pdev, sensor_inst);
+
+	index = get_known_custom_sensor_index(hsdev);
+	if (index >= 0 && index < ARRAY_SIZE(known_sensor_luid)) {
+		sensor_inst->custom_pdev =
+			hid_sensor_register_platform_device(pdev, hsdev, index);
+
+		ret = PTR_ERR_OR_ZERO(sensor_inst->custom_pdev);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"register_platform_device failed\n");
+			return ret;
+		}
+
+		return 0;
+	}
+
 	ret = sensor_hub_register_callback(hsdev, hsdev->usage,
 					   &sensor_inst->callbacks);
 	if (ret < 0) {
@@ -802,6 +940,11 @@ static int hid_sensor_custom_remove(struct platform_device *pdev)
 	struct hid_sensor_custom *sensor_inst = platform_get_drvdata(pdev);
 	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
 
+	if (sensor_inst->custom_pdev) {
+		platform_device_unregister(sensor_inst->custom_pdev);
+		return 0;
+	}
+
 	hid_sensor_custom_dev_if_remove(sensor_inst);
 	hid_sensor_custom_remove_attributes(sensor_inst);
 	sysfs_remove_group(&sensor_inst->pdev->dev.kobj,