* [PATCH] Input: gpio-keys - add full support of EV_REL and EV_ABS
@ 2026-03-20 14:52 Xiong Nandi
2026-03-21 7:06 ` Dmitry Torokhov
0 siblings, 1 reply; 6+ messages in thread
From: Xiong Nandi @ 2026-03-20 14:52 UTC (permalink / raw)
To: dmitry.torokhov
Cc: linux-input, linux-kernel, Xiong Nandi, Gatien Chevallier,
Ingo Molnar, Thomas Gleixner, Marco Crivellari, Fabrice Gasnier
gpio_keys_gpio_report_event() handled EV_ABS but silently ignored EV_REL,
while the polled driver supports both. Extend the interrupt-driven driver
to fire an EV_REL event on button press.
For EV_ABS, use a shared atomic counter per (type, code) pair so that
a zero-value reset is sent only when the last active button on an axis
is released, avoiding premature axis resets when multiple buttons share
the same axis code.
Add gpio_keys_set_abs_params() to call input_set_abs_params() at setup
time, deriving the axis min/max from the configured button values.
Without this the input subsystem reports unbounded axis ranges.
Signed-off-by: Xiong Nandi <xndchn@gmail.com>
---
drivers/input/keyboard/gpio_keys.c | 65 +++++++++++++++++++++++++++++-
include/linux/gpio_keys.h | 4 +-
2 files changed, 65 insertions(+), 4 deletions(-)
diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
index e19617485679..652a6932c52f 100644
--- a/drivers/input/keyboard/gpio_keys.c
+++ b/drivers/input/keyboard/gpio_keys.c
@@ -51,8 +51,10 @@ struct gpio_button_data {
spinlock_t lock;
bool disabled;
bool key_pressed;
+ bool axis_active;
bool suspended;
bool debounce_use_hrtimer;
+ atomic_t *axis_count;
};
struct gpio_keys_drvdata {
@@ -373,9 +375,16 @@ static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
return;
}
- if (type == EV_ABS) {
- if (state)
+ if (type == EV_ABS || type == EV_REL) {
+ if (state && !bdata->axis_active) {
+ bdata->axis_active = true;
+ atomic_inc(bdata->axis_count);
input_event(input, type, button->code, button->value);
+ } else if (!state && bdata->axis_active) {
+ bdata->axis_active = false;
+ if (atomic_dec_and_test(bdata->axis_count))
+ input_event(input, type, button->code, 0);
+ }
} else {
input_event(input, type, *bdata->code, state);
}
@@ -493,6 +502,27 @@ static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static void gpio_keys_set_abs_params(struct input_dev *input,
+ struct gpio_keys_drvdata *ddata,
+ unsigned int code)
+{
+ int i, min = 0, max = 0;
+
+ for (i = 0; i < ddata->pdata->nbuttons; i++) {
+ const struct gpio_keys_button *button = &ddata->pdata->buttons[i];
+
+ if (button->type != EV_ABS || button->code != code)
+ continue;
+
+ if (button->value < min)
+ min = button->value;
+ if (button->value > max)
+ max = button->value;
+ }
+
+ input_set_abs_params(input, code, min, max, 0, 0);
+}
+
static int gpio_keys_setup_key(struct platform_device *pdev,
struct input_dev *input,
struct gpio_keys_drvdata *ddata,
@@ -651,6 +681,8 @@ static int gpio_keys_setup_key(struct platform_device *pdev,
bdata->code = &ddata->keymap[idx];
*bdata->code = button->code;
input_set_capability(input, button->type ?: EV_KEY, *bdata->code);
+ if ((button->type ?: EV_KEY) == EV_ABS)
+ gpio_keys_set_abs_params(input, ddata, button->code);
/*
* Install custom action to cancel release timer and
@@ -928,6 +960,35 @@ static int gpio_keys_probe(struct platform_device *pdev)
fwnode_handle_put(child);
+ /* Allocate shared axis counters for EV_ABS/EV_REL buttons */
+ for (i = 0; i < pdata->nbuttons; i++) {
+ struct gpio_button_data *bdata = &ddata->data[i];
+ unsigned int type = bdata->button->type ?: EV_KEY;
+ int j;
+
+ if (type != EV_ABS && type != EV_REL)
+ continue;
+
+ /* Reuse counter from an earlier button with same (type, code) */
+ for (j = 0; j < i; j++) {
+ struct gpio_button_data *prev = &ddata->data[j];
+ unsigned int prev_type = prev->button->type ?: EV_KEY;
+
+ if (prev_type == type &&
+ prev->button->code == bdata->button->code) {
+ bdata->axis_count = prev->axis_count;
+ break;
+ }
+ }
+
+ if (!bdata->axis_count) {
+ bdata->axis_count = devm_kzalloc(dev,
+ sizeof(*bdata->axis_count), GFP_KERNEL);
+ if (!bdata->axis_count)
+ return -ENOMEM;
+ }
+ }
+
error = input_register_device(input);
if (error) {
dev_err(dev, "Unable to register input device, error: %d\n",
diff --git a/include/linux/gpio_keys.h b/include/linux/gpio_keys.h
index 80fa930b04c6..75a745a32fe1 100644
--- a/include/linux/gpio_keys.h
+++ b/include/linux/gpio_keys.h
@@ -13,13 +13,13 @@ struct device;
* @active_low: %true indicates that button is considered
* depressed when gpio is low
* @desc: label that will be attached to button's gpio
- * @type: input event type (%EV_KEY, %EV_SW, %EV_ABS)
+ * @type: input event type (%EV_KEY, %EV_SW, %EV_ABS, %EV_REL)
* @wakeup: configure the button as a wake-up source
* @wakeup_event_action: event action to trigger wakeup
* @debounce_interval: debounce ticks interval in msecs
* @can_disable: %true indicates that userspace is allowed to
* disable button via sysfs
- * @value: axis value for %EV_ABS
+ * @value: axis value for %EV_ABS/%EV_REL
* @irq: Irq number in case of interrupt keys
* @wakeirq: Optional dedicated wake-up interrupt
*/
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] Input: gpio-keys - add full support of EV_REL and EV_ABS
2026-03-20 14:52 [PATCH] Input: gpio-keys - add full support of EV_REL and EV_ABS Xiong Nandi
@ 2026-03-21 7:06 ` Dmitry Torokhov
2026-03-22 11:35 ` [PATCH v2 0/3] " Xiong Nandi
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Dmitry Torokhov @ 2026-03-21 7:06 UTC (permalink / raw)
To: Xiong Nandi
Cc: linux-input, linux-kernel, Gatien Chevallier, Ingo Molnar,
Thomas Gleixner, Marco Crivellari, Fabrice Gasnier
Hi Xiong,
On Fri, Mar 20, 2026 at 10:52:14PM +0800, Xiong Nandi wrote:
> gpio_keys_gpio_report_event() handled EV_ABS but silently ignored EV_REL,
> while the polled driver supports both. Extend the interrupt-driven driver
> to fire an EV_REL event on button press.
>
> For EV_ABS, use a shared atomic counter per (type, code) pair so that
> a zero-value reset is sent only when the last active button on an axis
> is released, avoiding premature axis resets when multiple buttons share
> the same axis code.
>
> Add gpio_keys_set_abs_params() to call input_set_abs_params() at setup
> time, deriving the axis min/max from the configured button values.
> Without this the input subsystem reports unbounded axis ranges.
Could you please split this out? It looks like there are 2 or 3
logically separate changes.
Thanks.
--
Dmitry
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH v2 0/3] Input: gpio-keys - add full support of EV_REL and EV_ABS
2026-03-21 7:06 ` Dmitry Torokhov
@ 2026-03-22 11:35 ` Xiong Nandi
2026-03-22 11:35 ` [PATCH v2 1/3] Input: gpio-keys - set EV_ABS axis parameters at setup time Xiong Nandi
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Xiong Nandi @ 2026-03-22 11:35 UTC (permalink / raw)
To: dmitry.torokhov
Cc: linux-input, linux-kernel, Xiong Nandi, Fabrice Gasnier,
Gatien Chevallier, Ingo Molnar, Marco Crivellari, Thomas Gleixner
This series add full support of EV_REL and EV_ABS
v2: Split into 3 patches as requested. (In reply to ab5CXO6Fk7lhGazv@google.com)
Xiong Nandi (3):
Input: gpio-keys - set EV_ABS axis parameters at setup time
Input: gpio-keys - use shared axis counter for EV_ABS events
Input: gpio-keys - add EV_REL event type support
drivers/input/keyboard/gpio_keys.c | 65 +++++++++++++++++++++++++++++-
include/linux/gpio_keys.h | 4 +-
2 files changed, 65 insertions(+), 4 deletions(-)
--
2.25.1
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH v2 1/3] Input: gpio-keys - set EV_ABS axis parameters at setup time
2026-03-21 7:06 ` Dmitry Torokhov
2026-03-22 11:35 ` [PATCH v2 0/3] " Xiong Nandi
@ 2026-03-22 11:35 ` Xiong Nandi
2026-03-22 11:35 ` [PATCH v2 2/3] Input: gpio-keys - use shared axis counter for EV_ABS events Xiong Nandi
2026-03-22 11:35 ` [PATCH v2 3/3] Input: gpio-keys - add EV_REL event type support Xiong Nandi
3 siblings, 0 replies; 6+ messages in thread
From: Xiong Nandi @ 2026-03-22 11:35 UTC (permalink / raw)
To: dmitry.torokhov
Cc: linux-input, linux-kernel, Xiong Nandi, Gatien Chevallier,
Marco Crivellari, Thomas Gleixner, Fabrice Gasnier
The driver calls input_set_capability() for EV_ABS axes but never
sets the actual axis parameters, so the input subsystem sees
unbounded ranges.
Add a helper that scans buttons sharing the same axis code, works
out the min/max values, and calls input_set_abs_params().
Signed-off-by: Xiong Nandi <xndchn@gmail.com>
---
drivers/input/keyboard/gpio_keys.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
index e19617485679..f97ca8dd073a 100644
--- a/drivers/input/keyboard/gpio_keys.c
+++ b/drivers/input/keyboard/gpio_keys.c
@@ -493,6 +493,27 @@ static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static void gpio_keys_set_abs_params(struct input_dev *input,
+ struct gpio_keys_drvdata *ddata,
+ unsigned int code)
+{
+ int i, min = 0, max = 0;
+
+ for (i = 0; i < ddata->pdata->nbuttons; i++) {
+ const struct gpio_keys_button *button = &ddata->pdata->buttons[i];
+
+ if (button->type != EV_ABS || button->code != code)
+ continue;
+
+ if (button->value < min)
+ min = button->value;
+ if (button->value > max)
+ max = button->value;
+ }
+
+ input_set_abs_params(input, code, min, max, 0, 0);
+}
+
static int gpio_keys_setup_key(struct platform_device *pdev,
struct input_dev *input,
struct gpio_keys_drvdata *ddata,
@@ -651,6 +672,8 @@ static int gpio_keys_setup_key(struct platform_device *pdev,
bdata->code = &ddata->keymap[idx];
*bdata->code = button->code;
input_set_capability(input, button->type ?: EV_KEY, *bdata->code);
+ if ((button->type ?: EV_KEY) == EV_ABS)
+ gpio_keys_set_abs_params(input, ddata, button->code);
/*
* Install custom action to cancel release timer and
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 2/3] Input: gpio-keys - use shared axis counter for EV_ABS events
2026-03-21 7:06 ` Dmitry Torokhov
2026-03-22 11:35 ` [PATCH v2 0/3] " Xiong Nandi
2026-03-22 11:35 ` [PATCH v2 1/3] Input: gpio-keys - set EV_ABS axis parameters at setup time Xiong Nandi
@ 2026-03-22 11:35 ` Xiong Nandi
2026-03-22 11:35 ` [PATCH v2 3/3] Input: gpio-keys - add EV_REL event type support Xiong Nandi
3 siblings, 0 replies; 6+ messages in thread
From: Xiong Nandi @ 2026-03-22 11:35 UTC (permalink / raw)
To: dmitry.torokhov
Cc: linux-input, linux-kernel, Xiong Nandi, Gatien Chevallier,
Marco Crivellari, Ingo Molnar, Fabrice Gasnier, Thomas Gleixner
When two buttons share an EV_ABS axis code, releasing one button
zeroes the axis while the other is still held.
Add a shared atomic counter per (type, code) pair so the axis only
resets to zero when the last button on it is released.
Signed-off-by: Xiong Nandi <xndchn@gmail.com>
---
drivers/input/keyboard/gpio_keys.c | 40 +++++++++++++++++++++++++++++-
1 file changed, 39 insertions(+), 1 deletion(-)
diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
index f97ca8dd073a..4cbfd5a273bd 100644
--- a/drivers/input/keyboard/gpio_keys.c
+++ b/drivers/input/keyboard/gpio_keys.c
@@ -51,8 +51,10 @@ struct gpio_button_data {
spinlock_t lock;
bool disabled;
bool key_pressed;
+ bool axis_active;
bool suspended;
bool debounce_use_hrtimer;
+ atomic_t *axis_count;
};
struct gpio_keys_drvdata {
@@ -374,8 +376,15 @@ static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
}
if (type == EV_ABS) {
- if (state)
+ if (state && !bdata->axis_active) {
+ bdata->axis_active = true;
+ atomic_inc(bdata->axis_count);
input_event(input, type, button->code, button->value);
+ } else if (!state && bdata->axis_active) {
+ bdata->axis_active = false;
+ if (atomic_dec_and_test(bdata->axis_count))
+ input_event(input, type, button->code, 0);
+ }
} else {
input_event(input, type, *bdata->code, state);
}
@@ -951,6 +960,35 @@ static int gpio_keys_probe(struct platform_device *pdev)
fwnode_handle_put(child);
+ /* Allocate shared axis counters for EV_ABS buttons */
+ for (i = 0; i < pdata->nbuttons; i++) {
+ struct gpio_button_data *bdata = &ddata->data[i];
+ unsigned int type = bdata->button->type ?: EV_KEY;
+ int j;
+
+ if (type != EV_ABS)
+ continue;
+
+ /* Reuse counter from an earlier button with same (type, code) */
+ for (j = 0; j < i; j++) {
+ struct gpio_button_data *prev = &ddata->data[j];
+ unsigned int prev_type = prev->button->type ?: EV_KEY;
+
+ if (prev_type == type &&
+ prev->button->code == bdata->button->code) {
+ bdata->axis_count = prev->axis_count;
+ break;
+ }
+ }
+
+ if (!bdata->axis_count) {
+ bdata->axis_count = devm_kzalloc(dev,
+ sizeof(*bdata->axis_count), GFP_KERNEL);
+ if (!bdata->axis_count)
+ return -ENOMEM;
+ }
+ }
+
error = input_register_device(input);
if (error) {
dev_err(dev, "Unable to register input device, error: %d\n",
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 3/3] Input: gpio-keys - add EV_REL event type support
2026-03-21 7:06 ` Dmitry Torokhov
` (2 preceding siblings ...)
2026-03-22 11:35 ` [PATCH v2 2/3] Input: gpio-keys - use shared axis counter for EV_ABS events Xiong Nandi
@ 2026-03-22 11:35 ` Xiong Nandi
3 siblings, 0 replies; 6+ messages in thread
From: Xiong Nandi @ 2026-03-22 11:35 UTC (permalink / raw)
To: dmitry.torokhov
Cc: linux-input, linux-kernel, Xiong Nandi, Gatien Chevallier,
Thomas Gleixner, Fabrice Gasnier, Marco Crivellari
The polled path handles EV_REL but the interrupt path silently
ignores it. Widen the type check so EV_REL goes through the same
reporting and shared-counter logic as EV_ABS.
Signed-off-by: Xiong Nandi <xndchn@gmail.com>
---
drivers/input/keyboard/gpio_keys.c | 6 +++---
include/linux/gpio_keys.h | 4 ++--
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
index 4cbfd5a273bd..652a6932c52f 100644
--- a/drivers/input/keyboard/gpio_keys.c
+++ b/drivers/input/keyboard/gpio_keys.c
@@ -375,7 +375,7 @@ static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
return;
}
- if (type == EV_ABS) {
+ if (type == EV_ABS || type == EV_REL) {
if (state && !bdata->axis_active) {
bdata->axis_active = true;
atomic_inc(bdata->axis_count);
@@ -960,13 +960,13 @@ static int gpio_keys_probe(struct platform_device *pdev)
fwnode_handle_put(child);
- /* Allocate shared axis counters for EV_ABS buttons */
+ /* Allocate shared axis counters for EV_ABS/EV_REL buttons */
for (i = 0; i < pdata->nbuttons; i++) {
struct gpio_button_data *bdata = &ddata->data[i];
unsigned int type = bdata->button->type ?: EV_KEY;
int j;
- if (type != EV_ABS)
+ if (type != EV_ABS && type != EV_REL)
continue;
/* Reuse counter from an earlier button with same (type, code) */
diff --git a/include/linux/gpio_keys.h b/include/linux/gpio_keys.h
index 80fa930b04c6..75a745a32fe1 100644
--- a/include/linux/gpio_keys.h
+++ b/include/linux/gpio_keys.h
@@ -13,13 +13,13 @@ struct device;
* @active_low: %true indicates that button is considered
* depressed when gpio is low
* @desc: label that will be attached to button's gpio
- * @type: input event type (%EV_KEY, %EV_SW, %EV_ABS)
+ * @type: input event type (%EV_KEY, %EV_SW, %EV_ABS, %EV_REL)
* @wakeup: configure the button as a wake-up source
* @wakeup_event_action: event action to trigger wakeup
* @debounce_interval: debounce ticks interval in msecs
* @can_disable: %true indicates that userspace is allowed to
* disable button via sysfs
- * @value: axis value for %EV_ABS
+ * @value: axis value for %EV_ABS/%EV_REL
* @irq: Irq number in case of interrupt keys
* @wakeirq: Optional dedicated wake-up interrupt
*/
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-03-22 11:36 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-03-20 14:52 [PATCH] Input: gpio-keys - add full support of EV_REL and EV_ABS Xiong Nandi
2026-03-21 7:06 ` Dmitry Torokhov
2026-03-22 11:35 ` [PATCH v2 0/3] " Xiong Nandi
2026-03-22 11:35 ` [PATCH v2 1/3] Input: gpio-keys - set EV_ABS axis parameters at setup time Xiong Nandi
2026-03-22 11:35 ` [PATCH v2 2/3] Input: gpio-keys - use shared axis counter for EV_ABS events Xiong Nandi
2026-03-22 11:35 ` [PATCH v2 3/3] Input: gpio-keys - add EV_REL event type support Xiong Nandi
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