On Aug 04 2025, Jonathan Denose wrote:
> From: Angela Czubak <aczubak@xxxxxxxxxx>
>
> Add new option (MULTITOUCH_HAPTIC) to mark whether hid-multitouch
> should try and configure simple haptic device.
> Once this option is configured, and the device is recognized to have simple
> haptic capabilities, check input frames for pressure and handle it using
> hid_haptic_* API.
Why creating a new option? It seems it'll add unwanted work from
distributions when we should have something that "just works" no?
It makes sense to depend on FF, but adding a new option is probably
useless IMO.
>
> Signed-off-by: Angela Czubak <aczubak@xxxxxxxxxx>
> Co-developed-by: Jonathan Denose <jdenose@xxxxxxxxxx>
> Signed-off-by: Jonathan Denose <jdenose@xxxxxxxxxx>
> ---
> drivers/hid/Kconfig | 11 ++++
> drivers/hid/Makefile | 2 +-
> drivers/hid/hid-haptic.h | 52 +++++++++++++++++
> drivers/hid/hid-multitouch.c | 136 ++++++++++++++++++++++++++++++++++++++++++-
> 4 files changed, 199 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> index ad6bcc4248cc111705d7cfde2b1481b46353e2d7..b7452f11a4f914f92af582ed054d42ecbcd6cb9e 100644
> --- a/drivers/hid/Kconfig
> +++ b/drivers/hid/Kconfig
> @@ -817,6 +817,17 @@ config HID_MULTITOUCH
> To compile this driver as a module, choose M here: the
> module will be called hid-multitouch.
>
> +config MULTITOUCH_HAPTIC
> + bool "Simple haptic multitouch support"
> + depends on HID_MULTITOUCH
> + select HID_HAPTIC
> + default n
> + help
> + Support for simple multitouch haptic devices.
> + Adds extra parsing and FF device for the hid multitouch driver.
> + It can be used for Elan 2703 haptic touchpad.
> + To enable, say Y.
> +
> config HID_NINTENDO
> tristate "Nintendo Joy-Con, NSO, and Pro Controller support"
> depends on NEW_LEDS
> diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
> index 361a7daedeb85454114def8afb5f58caeab58a00..be09b4f13b2058a0a1d7eab79f35def758120fc4 100644
> --- a/drivers/hid/Makefile
> +++ b/drivers/hid/Makefile
> @@ -4,7 +4,7 @@
> #
> hid-y := hid-core.o hid-input.o hid-quirks.o
> hid-$(CONFIG_DEBUG_FS) += hid-debug.o
> -hid-$(CONFIG_HID_HAPTIC) += hid-haptic.o
> +hid-$(CONFIG_MULTITOUCH_HAPTIC) += hid-haptic.o
>
> obj-$(CONFIG_HID_BPF) += bpf/
>
> diff --git a/drivers/hid/hid-haptic.h b/drivers/hid/hid-haptic.h
> index 0a34b0c6d706a985630962acc41f7a8eb73cd343..808cec0b4e51eba1f58b839f3e552493655b7899 100644
> --- a/drivers/hid/hid-haptic.h
> +++ b/drivers/hid/hid-haptic.h
> @@ -58,6 +58,7 @@ struct hid_haptic_device {
> struct hid_haptic_effect stop_effect;
> };
>
> +#ifdef CONFIG_MULTITOUCH_HAPTIC
There is something wrong with your ifdef usages:
- here, you define the functions below conditionally to
CONFIG_MULTITOUCH_HAPTIC, which is fine
- but in hid-multitouch, you also check for CONFIG_MULTITOUCH_HAPTIC
before calling the same set of functions.
Either only define the haptic functions when CONFIG_MULTITOUCH_HAPTIC is
set, and in multitouch check for that define, or define it conditionally
and remove the checks in hid-multitouch (but probably add a comment).
> void hid_haptic_feature_mapping(struct hid_device *hdev,
> struct hid_haptic_device *haptic,
> struct hid_field *field, struct hid_usage
> @@ -77,3 +78,54 @@ void hid_haptic_handle_press_release(struct hid_haptic_device *haptic);
> void hid_haptic_pressure_reset(struct hid_haptic_device *haptic);
> void hid_haptic_pressure_increase(struct hid_haptic_device *haptic,
> __s32 pressure);
> +#else
> +static inline
> +void hid_haptic_feature_mapping(struct hid_device *hdev,
> + struct hid_haptic_device *haptic,
> + struct hid_field *field, struct hid_usage
> + *usage)
> +{}
> +static inline
> +bool hid_haptic_check_pressure_unit(struct hid_haptic_device *haptic,
> + struct hid_input *hi, struct hid_field *field)
> +{
> + return false;
> +}
> +static inline
> +int hid_haptic_input_mapping(struct hid_device *hdev,
> + struct hid_haptic_device *haptic,
> + struct hid_input *hi,
> + struct hid_field *field, struct hid_usage *usage,
> + unsigned long **bit, int *max)
> +{
> + return 0;
> +}
> +static inline
> +int hid_haptic_input_configured(struct hid_device *hdev,
> + struct hid_haptic_device *haptic,
> + struct hid_input *hi)
> +{
> + return 0;
> +}
> +static inline
> +void hid_haptic_reset(struct hid_device *hdev, struct hid_haptic_device *haptic)
> +{}
> +static inline
> +int hid_haptic_init(struct hid_device *hdev, struct hid_haptic_device **haptic_ptr)
> +{
> + return 0;
> +}
> +static inline
> +void hid_haptic_handle_press_release(struct hid_haptic_device *haptic) {}
> +static inline
> +bool hid_haptic_handle_input(struct hid_haptic_device *haptic)
> +{
> + return false;
> +}
> +static inline
> +void hid_haptic_pressure_reset(struct hid_haptic_device *haptic) {}
> +static inline
> +void hid_haptic_pressure_increase(struct hid_haptic_device *haptic,
> + __s32 pressure)
> +{}
> +#endif
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index b41001e02da7e02d492bd85743b359ed7ec16e7f..4ff9ac5022b13a0739dbc7ae5f6ebd84f0114a73 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -49,6 +49,8 @@ MODULE_LICENSE("GPL");
>
> #include "hid-ids.h"
>
> +#include "hid-haptic.h"
> +
> /* quirks to control the device */
> #define MT_QUIRK_NOT_SEEN_MEANS_UP BIT(0)
> #define MT_QUIRK_SLOT_IS_CONTACTID BIT(1)
> @@ -167,11 +169,13 @@ struct mt_report_data {
> struct mt_device {
> struct mt_class mtclass; /* our mt device class */
> struct timer_list release_timer; /* to release sticky fingers */
> + struct hid_haptic_device *haptic; /* haptic related configuration */
> struct hid_device *hdev; /* hid_device we're attached to */
> unsigned long mt_io_flags; /* mt flags (MT_IO_FLAGS_*) */
> __u8 inputmode_value; /* InputMode HID feature value */
> __u8 maxcontacts;
> bool is_buttonpad; /* is this device a button pad? */
> + bool is_haptic_touchpad; /* is this device a haptic touchpad? */
> bool serial_maybe; /* need to check for serial protocol */
>
> struct list_head applications;
> @@ -490,6 +494,95 @@ static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
> kfree(buf);
> }
>
> +#if defined(CONFIG_MULTITOUCH_HAPTIC)
> +static int mt_haptic_init(struct hid_device *hdev,
> + struct hid_haptic_device **haptic_ptr)
> +{
> + return hid_haptic_init(hdev, haptic_ptr);
> +}
> +
> +static void mt_haptic_feature_mapping(struct hid_device *hdev,
> + struct hid_haptic_device *haptic,
> + struct hid_field *field, struct hid_usage *usage)
> +{
> + return hid_haptic_feature_mapping(hdev, haptic, field, usage);
> +}
> +
> +static bool mt_haptic_check_pressure_unit(struct hid_haptic_device *haptic,
> + struct hid_input *hi, struct hid_field *field)
> +{
> + return hid_haptic_check_pressure_unit(haptic, hi, field);
> +}
> +
> +static void mt_haptic_pressure_reset(struct hid_haptic_device *haptic)
> +{
> + return hid_haptic_pressure_reset(haptic);
> +}
> +
> +static void mt_haptic_pressure_increase(struct hid_haptic_device *haptic,
> + __s32 pressure)
> +{
> + return hid_haptic_pressure_increase(haptic, pressure);
> +}
> +
> +static int mt_haptic_input_mapping(struct hid_device *hdev,
> + struct hid_haptic_device *haptic,
> + struct hid_input *hi,
> + struct hid_field *field, struct hid_usage *usage,
> + unsigned long **bit, int *max)
> +{
> + return hid_haptic_input_mapping(hdev, haptic, hi, field, usage, bit, max);
> +}
> +
> +static int mt_haptic_input_configured(struct hid_device *hdev,
> + struct hid_haptic_device *haptic,
> + struct hid_input *hi)
> +{
> + return hid_haptic_input_configured(hdev, haptic, hi);
> +}
> +#else
> +static int mt_haptic_init(struct hid_device *hdev,
> + struct hid_haptic_device **haptic_ptr)
> +{
> + return 0;
> +}
> +
> +static void mt_haptic_feature_mapping(struct hid_device *hdev,
> + struct hid_haptic_device *haptic,
> + struct hid_field *field, struct hid_usage *usage)
> +{}
> +
> +static bool mt_haptic_check_pressure_unit(struct hid_haptic_device *haptic,
> + struct hid_input *hi, struct hid_field *field)
> +{
> + return 0;
> +}
> +
> +static void mt_haptic_pressure_reset(struct hid_haptic_device *haptic)
> +{}
> +
> +static void mt_haptic_pressure_increase(struct hid_haptic_device *haptic,
> + __s32 pressure)
> +{}
> +
> +static int mt_haptic_input_mapping(struct hid_device *hdev,
> + struct hid_haptic_device *haptic,
> + struct hid_input *hi,
> + struct hid_field *field, struct hid_usage *usage,
> + unsigned long **bit, int *max)
> +{
> + return 0;
> +}
> +
> +static int mt_haptic_input_configured(struct hid_device *hdev,
> + struct hid_haptic_device *haptic,
> + struct hid_input *hi)
> +{
> + return 0;
> +}
> +#endif
> +
> +
> static void mt_feature_mapping(struct hid_device *hdev,
> struct hid_field *field, struct hid_usage *usage)
> {
> @@ -525,6 +618,8 @@ static void mt_feature_mapping(struct hid_device *hdev,
> mt_get_feature(hdev, field->report);
> break;
> }
> +
> + mt_haptic_feature_mapping(hdev, td->haptic, field, usage);
> }
>
> static void set_abs(struct input_dev *input, unsigned int code,
> @@ -856,6 +951,9 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
> case HID_DG_TIPPRESSURE:
> set_abs(hi->input, ABS_MT_PRESSURE, field,
> cls->sn_pressure);
> + td->is_haptic_touchpad =
> + mt_haptic_check_pressure_unit(td->haptic,
> + hi, field);
> MT_STORE_FIELD(p);
> return 1;
> case HID_DG_SCANTIME:
> @@ -980,6 +1078,8 @@ static void mt_sync_frame(struct mt_device *td, struct mt_application *app,
>
> app->num_received = 0;
> app->left_button_state = 0;
> + if (td->is_haptic_touchpad)
> + mt_haptic_pressure_reset(td->haptic);
>
> if (test_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags))
> set_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags);
> @@ -1137,6 +1237,9 @@ static int mt_process_slot(struct mt_device *td, struct input_dev *input,
> minor = minor >> 1;
> }
>
> + if (td->is_haptic_touchpad)
> + mt_haptic_pressure_increase(td->haptic, *slot->p);
> +
> x = hdev->quirks & HID_QUIRK_X_INVERT ?
> input_abs_get_max(input, ABS_MT_POSITION_X) - *slot->x :
> *slot->x;
> @@ -1324,6 +1427,9 @@ static int mt_touch_input_configured(struct hid_device *hdev,
> if (cls->is_indirect)
> app->mt_flags |= INPUT_MT_POINTER;
>
> + if (td->is_haptic_touchpad)
> + app->mt_flags |= INPUT_MT_TOTAL_FORCE;
> +
> if (app->quirks & MT_QUIRK_NOT_SEEN_MEANS_UP)
> app->mt_flags |= INPUT_MT_DROP_UNUSED;
>
> @@ -1359,6 +1465,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
> struct mt_device *td = hid_get_drvdata(hdev);
> struct mt_application *application;
> struct mt_report_data *rdata;
> + int ret;
>
> rdata = mt_find_report_data(td, field->report);
> if (!rdata) {
> @@ -1421,6 +1528,11 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
> if (field->physical == HID_DG_STYLUS)
> hi->application = HID_DG_STYLUS;
>
> + ret = mt_haptic_input_mapping(hdev, td->haptic, hi, field, usage, bit,
> + max);
> + if (ret != 0)
> + return ret;
> +
> /* let hid-core decide for the others */
> return 0;
> }
> @@ -1635,6 +1747,14 @@ static int mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
> struct hid_report *report;
> int ret;
>
> + if (td->is_haptic_touchpad && (td->mtclass.name == MT_CLS_WIN_8 ||
> + td->mtclass.name == MT_CLS_WIN_8_FORCE_MULTI_INPUT)) {
> + if (mt_haptic_input_configured(hdev, td->haptic, hi) == 0)
> + td->is_haptic_touchpad = false;
> + } else {
> + td->is_haptic_touchpad = false;
> + }
> +
> list_for_each_entry(report, &hi->reports, hidinput_list) {
> rdata = mt_find_report_data(td, report);
> if (!rdata) {
> @@ -1764,7 +1884,6 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
> int ret, i;
> struct mt_device *td;
> const struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */
> -
unrelated change (line removed).
> for (i = 0; mt_classes[i].name ; i++) {
> if (id->driver_data == mt_classes[i].name) {
> mtclass = &(mt_classes[i]);
> @@ -1777,6 +1896,10 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
> dev_err(&hdev->dev, "cannot allocate multitouch data\n");
> return -ENOMEM;
> }
> + td->haptic = kzalloc(sizeof(*(td->haptic)), GFP_KERNEL);
Please make use of the devm api, you are leaking the allocated memory in
the regular case (AFAICT).
> + if (!td->haptic)
> + return -ENOMEM;
One extra blank line wouldn't hurt here :)
> + td->haptic->hdev = hdev;
> td->hdev = hdev;
> td->mtclass = *mtclass;
> td->inputmode_value = MT_INPUTMODE_TOUCHSCREEN;
> @@ -1840,6 +1963,17 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>
> mt_set_modes(hdev, HID_LATENCY_NORMAL, TOUCHPAD_REPORT_ALL);
>
> + if (td->is_haptic_touchpad) {
> + if (mt_haptic_init(hdev, &td->haptic)) {
> + dev_warn(&hdev->dev, "Cannot allocate haptic for %s\n",
> + hdev->name);
> + td->is_haptic_touchpad = false;
> + kfree(td->haptic);
> + }
> + } else {
> + kfree(td->haptic);
> + }
> +
> return 0;
> }
>
>
> --
> 2.50.1.565.gc32cd1483b-goog
>
Cheers,
Benjamin
