On 07/01/15 18:24, Srinivas Pandruvada wrote:
> HID sensor hub exports several sensor which are fusion sensors, where
> data is interpreted from one or more sensors. Some of them can't be
> exported via IIO like sysfs as the user space download some firmware,
> which defines what sensor will look like. They can be a part of a
> collection.
This functionality is beginning to turn up on a number of devices.
I'd argue that where at all possible, we should try for standard
interfaces on the resulting 'fused sensors'. Still you do indeed
always need a means of uploading the firmware!
> Creating a MFD cell for a collection to write a standalone driver
> to manage collections. Most of the time they will be propritery drivers
> may not be even upstreamed. This patch allows framework to have
> capability to write such drivers.
>
> Signed-off-by: Srinivas Pandruvada <[email protected]>
>
A few comments inline...
How does userspace download a firmware?
---
> drivers/hid/hid-sensor-hub.c | 50
> ++++++++++++++++++++++++++++++++++++++----
> include/linux/hid-sensor-ids.h | 2 ++
> 2 files changed, 48 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
> index 865cd56..83b6e15 100644
> --- a/drivers/hid/hid-sensor-hub.c
> +++ b/drivers/hid/hid-sensor-hub.c
> @@ -119,11 +119,12 @@ static struct hid_sensor_hub_callbacks
> *sensor_hub_get_callback(
>
> spin_lock_irqsave(&pdata->dyn_callback_lock, flags);
> list_for_each_entry(callback, &pdata->dyn_callback_list, list)
> - if (callback->usage_id == usage_id &&
> + if (callback->usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION ||
> + (callback->usage_id == usage_id &&
> (collection_index >=
> callback->hsdev->start_collection_index) &&
> (collection_index <
> - callback->hsdev->end_collection_index)) {
> + callback->hsdev->end_collection_index))) {
> *priv = callback->priv;
> *hsdev = callback->hsdev;
> spin_unlock_irqrestore(&pdata->dyn_callback_lock,
> @@ -159,7 +160,12 @@ int sensor_hub_register_callback(struct
> hid_sensor_hub_device *hsdev,
> callback->usage_callback = usage_callback;
> callback->usage_id = usage_id;
> callback->priv = NULL;
> - list_add_tail(&callback->list, &pdata->dyn_callback_list);
> + /* Give higher priority to collection device, so add to front */
Comment should probably state why we want to give them higher priorities.
> + if (usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION)
> + list_add(&callback->list, &pdata->dyn_callback_list);
> + else
> + list_add_tail(&callback->list, &pdata->dyn_callback_list);
> +
> spin_unlock_irqrestore(&pdata->dyn_callback_lock, flags);
>
> return 0;
> @@ -547,6 +553,37 @@ static __u8 *sensor_hub_report_fixup(struct hid_device
> *hdev, __u8 *rdesc,
> return rdesc;
> }
>
> +static int sensor_hub_add_collection_device(struct hid_device *hdev,
> + struct sensor_hub_data *sd)
> +{
> + struct hid_sensor_hub_device *hsdev;
> + char *name;
> +
> + hsdev = devm_kzalloc(&hdev->dev, sizeof(*hsdev), GFP_KERNEL);
> + if (!hsdev)
> + return -ENOMEM;
> +
> + hsdev->hdev = hdev;
> + hsdev->vendor_id = hdev->vendor;
> + hsdev->product_id = hdev->product;
> + hsdev->usage = HID_USAGE_SENSOR_TYPE_COLLECTION;
> + mutex_init(&hsdev->mutex);
> + name = devm_kasprintf(&hdev->dev, GFP_KERNEL, "HID-SENSOR-%x",
> + HID_USAGE_SENSOR_TYPE_COLLECTION);
> + if (name == NULL) {
> + hid_err(hdev, "Failed MFD device name\n");
> + return -ENOMEM;
> + }
> + sd->hid_sensor_hub_client_devs[sd->hid_sensor_client_cnt].name = name;
> + sd->hid_sensor_hub_client_devs[
> + sd->hid_sensor_client_cnt].platform_data = hsdev;
Odd breaking up of the line... Perhaps break before .platform_data instead?
> + sd->hid_sensor_hub_client_devs[
> + sd->hid_sensor_client_cnt].pdata_size = sizeof(*hsdev);
> + sd->hid_sensor_client_cnt++;
> +
> + return 0;
> +}
> +
> static int sensor_hub_probe(struct hid_device *hdev,
> const struct hid_device_id *id)
> {
> @@ -591,7 +628,8 @@ static int sensor_hub_probe(struct hid_device *hdev,
> ret = -EINVAL;
> goto err_stop_hw;
> }
> - sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev, dev_cnt *
> + sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev,
> + (dev_cnt + 1) *
> sizeof(struct mfd_cell),
> GFP_KERNEL);
> if (sd->hid_sensor_hub_client_devs == NULL) {
> @@ -645,6 +683,10 @@ static int sensor_hub_probe(struct hid_device *hdev,
> if (last_hsdev)
> last_hsdev->end_collection_index = i;
>
> + ret = sensor_hub_add_collection_device(hdev, sd);
> + if (ret)
> + goto err_stop_hw;
> +
> ret = mfd_add_hotplug_devices(&hdev->dev,
> sd->hid_sensor_hub_client_devs,
> sd->hid_sensor_client_cnt);
> diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
> index 109f0e6..300ffea 100644
> --- a/include/linux/hid-sensor-ids.h
> +++ b/include/linux/hid-sensor-ids.h
> @@ -21,6 +21,8 @@
>
> #define HID_MAX_PHY_DEVICES 0xFF
>
> +#define HID_USAGE_SENSOR_TYPE_COLLECTION 0x200001
> +
> /* Accel 3D (200073) */
> #define HID_USAGE_SENSOR_ACCEL_3D 0x200073
> #define HID_USAGE_SENSOR_DATA_ACCELERATION 0x200452
>
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