Add support for handling an Fn button and sending separate keycodes for
a subset of keys in the matrix defined in the upper half of the keymap.
Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
---
drivers/input/keyboard/cros_ec_keyb.c | 120 ++++++++++++++++++++++----
1 file changed, 104 insertions(+), 16 deletions(-)
diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
index 1c6b0461dc35..8b95b4f8a37d 100644
--- a/drivers/input/keyboard/cros_ec_keyb.c
+++ b/drivers/input/keyboard/cros_ec_keyb.c
@@ -29,6 +29,11 @@
#include <linux/unaligned.h>
+/* Maximum size of the normal key matrix, this is limited by the host command
+ * key_matrix field defined in ec_response_get_next_data_v3
+ */
+#define CROS_EC_KEYBOARD_COLS_MAX 18
+
/**
* struct cros_ec_keyb - Structure representing EC keyboard device
*
@@ -44,6 +49,11 @@
* @bs_idev: The input device for non-matrix buttons and switches (or NULL).
* @notifier: interrupt event notifier for transport devices
* @vdata: vivaldi function row data
+ * @use_fn_overlay: whether the driver use an fn function overlay
+ * @normal_key_status: active normal keys map
+ * @fn_key_status: active function keys map
+ * @fn_key_pressed: tracks the function key status
+ * @fn_key_triggered: tracks where any function key fired
*/
struct cros_ec_keyb {
unsigned int rows;
@@ -61,6 +71,12 @@ struct cros_ec_keyb {
struct notifier_block notifier;
struct vivaldi_data vdata;
+
+ bool use_fn_overlay;
+ u8 normal_key_status[CROS_EC_KEYBOARD_COLS_MAX];
+ u8 fn_key_status[CROS_EC_KEYBOARD_COLS_MAX];
+ bool fn_key_pressed;
+ bool fn_key_triggered;
};
/**
@@ -166,16 +182,83 @@ static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
return false;
}
+static void cros_ec_keyb_process_fn_key(struct cros_ec_keyb *ckdev,
+ int row, int col, bool state)
+{
+ struct input_dev *idev = ckdev->idev;
+ int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
+
+ ckdev->fn_key_pressed = state;
+
+ if (state) {
+ ckdev->fn_key_triggered = false;
+ } else if (!ckdev->fn_key_triggered) {
+ /*
+ * Send the original code if nothing else has been pressed
+ * together with Fn.
+ */
+ input_event(idev, EV_MSC, MSC_SCAN, pos);
+ input_report_key(idev, KEY_FN, true);
+ input_sync(idev);
+
+ input_event(idev, EV_MSC, MSC_SCAN, pos);
+ input_report_key(idev, KEY_FN, false);
+ }
+}
+
+static void cros_ec_keyb_process_one(struct cros_ec_keyb *ckdev,
+ int row, int col, bool state)
+{
+ struct input_dev *idev = ckdev->idev;
+ const unsigned short *keycodes = idev->keycode;
+ int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
+ unsigned int code = keycodes[pos];
+
+ dev_dbg(ckdev->dev, "changed: [r%d c%d]: byte %02x\n", row, col, state);
+
+ if (ckdev->use_fn_overlay) {
+ if (code == KEY_FN)
+ return cros_ec_keyb_process_fn_key(ckdev, row, col, state);
+
+ if (!state) {
+ if (ckdev->fn_key_status[col] & BIT(row)) {
+ pos = MATRIX_SCAN_CODE(row + ckdev->rows, col, ckdev->row_shift);
+ code = keycodes[pos];
+
+ ckdev->fn_key_status[col] &= ~BIT(row);
+ } else if (ckdev->normal_key_status[col] & BIT(row)) {
+ ckdev->normal_key_status[col] &= ~BIT(row);
+ } else {
+ /* Discard, key press code was not sent */
+ return;
+ }
+ } else if (ckdev->fn_key_pressed) {
+ pos = MATRIX_SCAN_CODE(row + ckdev->rows, col, ckdev->row_shift);
+ code = keycodes[pos];
+
+ ckdev->fn_key_triggered = true;
+
+ if (!code)
+ return;
+
+ ckdev->fn_key_status[col] |= BIT(row);
+ } else {
+ ckdev->normal_key_status[col] |= BIT(row);
+ }
+ }
+
+ input_event(idev, EV_MSC, MSC_SCAN, pos);
+ input_report_key(idev, code, state);
+}
/*
* Compares the new keyboard state to the old one and produces key
- * press/release events accordingly. The keyboard state is 13 bytes (one byte
- * per column)
+ * press/release events accordingly. The keyboard state is one byte
+ * per column.
*/
static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
uint8_t *kb_state, int len)
{
- struct input_dev *idev = ckdev->idev;
int col, row;
int new_state;
int old_state;
@@ -192,20 +275,13 @@ static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
for (col = 0; col < ckdev->cols; col++) {
for (row = 0; row < ckdev->rows; row++) {
- int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
- const unsigned short *keycodes = idev->keycode;
-
new_state = kb_state[col] & (1 << row);
old_state = ckdev->old_kb_state[col] & (1 << row);
- if (new_state != old_state) {
- dev_dbg(ckdev->dev,
- "changed: [r%d c%d]: byte %02x\n",
- row, col, new_state);
-
- input_event(idev, EV_MSC, MSC_SCAN, pos);
- input_report_key(idev, keycodes[pos],
- new_state);
- }
+
+ if (new_state == old_state)
+ continue;
+
+ cros_ec_keyb_process_one(ckdev, row, col, new_state);
}
ckdev->old_kb_state[col] = kb_state[col];
}
@@ -597,12 +673,19 @@ static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
struct device *dev = ckdev->dev;
struct input_dev *idev;
const char *phys;
+ unsigned int rows_keymap;
int err;
err = matrix_keypad_parse_properties(dev, &ckdev->rows, &ckdev->cols);
if (err)
return err;
+ if (ckdev->cols > CROS_EC_KEYBOARD_COLS_MAX) {
+ dev_err(dev, "keypad,num-columns too large: %d (max: %d)\n",
+ ckdev->cols, CROS_EC_KEYBOARD_COLS_MAX);
+ return -EINVAL;
+ }
+
ckdev->valid_keys = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
if (!ckdev->valid_keys)
return -ENOMEM;
@@ -635,7 +718,12 @@ static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
ckdev->ghost_filter = device_property_read_bool(dev,
"google,needs-ghost-filter");
- err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
+ ckdev->use_fn_overlay = device_property_read_bool(dev,
+ "google,use-fn-overlay");
+
+ rows_keymap = ckdev->use_fn_overlay ? ckdev->rows * 2 : ckdev->rows;
+
+ err = matrix_keypad_build_keymap(NULL, NULL, rows_keymap, ckdev->cols,
NULL, idev);
if (err) {
dev_err(dev, "cannot build key matrix\n");
--
2.52.0.351.gbe84eed79e-googHi Fabio,
On Wed, 24 Dec 2025 at 08:22, Fabio Baltieri <fabiobaltieri@chromium.org> wrote:
>
> Add support for handling an Fn button and sending separate keycodes for
> a subset of keys in the matrix defined in the upper half of the keymap.
>
> Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
> ---
> drivers/input/keyboard/cros_ec_keyb.c | 120 ++++++++++++++++++++++----
> 1 file changed, 104 insertions(+), 16 deletions(-)
>
Reviewed-by: Simon Glass <sjg@chromium.org>
I suggest a function comment for the two new functions you add.
> diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
> index 1c6b0461dc35..8b95b4f8a37d 100644
> --- a/drivers/input/keyboard/cros_ec_keyb.c
> +++ b/drivers/input/keyboard/cros_ec_keyb.c
> @@ -29,6 +29,11 @@
>
> #include <linux/unaligned.h>
>
> +/* Maximum size of the normal key matrix, this is limited by the host command
> + * key_matrix field defined in ec_response_get_next_data_v3
> + */
> +#define CROS_EC_KEYBOARD_COLS_MAX 18
> +
> /**
> * struct cros_ec_keyb - Structure representing EC keyboard device
> *
> @@ -44,6 +49,11 @@
> * @bs_idev: The input device for non-matrix buttons and switches (or NULL).
> * @notifier: interrupt event notifier for transport devices
> * @vdata: vivaldi function row data
> + * @use_fn_overlay: whether the driver use an fn function overlay
> + * @normal_key_status: active normal keys map
> + * @fn_key_status: active function keys map
> + * @fn_key_pressed: tracks the function key status
> + * @fn_key_triggered: tracks where any function key fired
> */
> struct cros_ec_keyb {
> unsigned int rows;
> @@ -61,6 +71,12 @@ struct cros_ec_keyb {
> struct notifier_block notifier;
>
> struct vivaldi_data vdata;
> +
> + bool use_fn_overlay;
> + u8 normal_key_status[CROS_EC_KEYBOARD_COLS_MAX];
> + u8 fn_key_status[CROS_EC_KEYBOARD_COLS_MAX];
> + bool fn_key_pressed;
> + bool fn_key_triggered;
> };
>
> /**
> @@ -166,16 +182,83 @@ static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
> return false;
> }
>
> +static void cros_ec_keyb_process_fn_key(struct cros_ec_keyb *ckdev,
> + int row, int col, bool state)
> +{
> + struct input_dev *idev = ckdev->idev;
> + int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
> +
> + ckdev->fn_key_pressed = state;
> +
> + if (state) {
> + ckdev->fn_key_triggered = false;
> + } else if (!ckdev->fn_key_triggered) {
> + /*
> + * Send the original code if nothing else has been pressed
> + * together with Fn.
> + */
> + input_event(idev, EV_MSC, MSC_SCAN, pos);
> + input_report_key(idev, KEY_FN, true);
> + input_sync(idev);
> +
> + input_event(idev, EV_MSC, MSC_SCAN, pos);
> + input_report_key(idev, KEY_FN, false);
> + }
> +}
> +
> +static void cros_ec_keyb_process_one(struct cros_ec_keyb *ckdev,
> + int row, int col, bool state)
> +{
> + struct input_dev *idev = ckdev->idev;
> + const unsigned short *keycodes = idev->keycode;
> + int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
> + unsigned int code = keycodes[pos];
> +
> + dev_dbg(ckdev->dev, "changed: [r%d c%d]: byte %02x\n", row, col, state);
> +
> + if (ckdev->use_fn_overlay) {
> + if (code == KEY_FN)
> + return cros_ec_keyb_process_fn_key(ckdev, row, col, state);
> +
> + if (!state) {
> + if (ckdev->fn_key_status[col] & BIT(row)) {
> + pos = MATRIX_SCAN_CODE(row + ckdev->rows, col, ckdev->row_shift);
> + code = keycodes[pos];
You might want a helper to do this as it is repeated below
> +
> + ckdev->fn_key_status[col] &= ~BIT(row);
> + } else if (ckdev->normal_key_status[col] & BIT(row)) {
> + ckdev->normal_key_status[col] &= ~BIT(row);
> + } else {
> + /* Discard, key press code was not sent */
> + return;
> + }
> + } else if (ckdev->fn_key_pressed) {
> + pos = MATRIX_SCAN_CODE(row + ckdev->rows, col, ckdev->row_shift);
> + code = keycodes[pos];
> +
> + ckdev->fn_key_triggered = true;
> +
> + if (!code)
> + return;
> +
> + ckdev->fn_key_status[col] |= BIT(row);
> + } else {
> + ckdev->normal_key_status[col] |= BIT(row);
> + }
> + }
> +
> + input_event(idev, EV_MSC, MSC_SCAN, pos);
> + input_report_key(idev, code, state);
> +}
>
> /*
> * Compares the new keyboard state to the old one and produces key
> - * press/release events accordingly. The keyboard state is 13 bytes (one byte
> - * per column)
> + * press/release events accordingly. The keyboard state is one byte
> + * per column.
> */
> static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
> uint8_t *kb_state, int len)
> {
> - struct input_dev *idev = ckdev->idev;
> int col, row;
> int new_state;
> int old_state;
> @@ -192,20 +275,13 @@ static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
>
> for (col = 0; col < ckdev->cols; col++) {
> for (row = 0; row < ckdev->rows; row++) {
> - int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
> - const unsigned short *keycodes = idev->keycode;
> -
> new_state = kb_state[col] & (1 << row);
> old_state = ckdev->old_kb_state[col] & (1 << row);
> - if (new_state != old_state) {
> - dev_dbg(ckdev->dev,
> - "changed: [r%d c%d]: byte %02x\n",
> - row, col, new_state);
> -
> - input_event(idev, EV_MSC, MSC_SCAN, pos);
> - input_report_key(idev, keycodes[pos],
> - new_state);
> - }
> +
> + if (new_state == old_state)
> + continue;
> +
> + cros_ec_keyb_process_one(ckdev, row, col, new_state);
> }
> ckdev->old_kb_state[col] = kb_state[col];
> }
> @@ -597,12 +673,19 @@ static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
> struct device *dev = ckdev->dev;
> struct input_dev *idev;
> const char *phys;
> + unsigned int rows_keymap;
> int err;
>
> err = matrix_keypad_parse_properties(dev, &ckdev->rows, &ckdev->cols);
> if (err)
> return err;
>
> + if (ckdev->cols > CROS_EC_KEYBOARD_COLS_MAX) {
> + dev_err(dev, "keypad,num-columns too large: %d (max: %d)\n",
> + ckdev->cols, CROS_EC_KEYBOARD_COLS_MAX);
> + return -EINVAL;
> + }
> +
> ckdev->valid_keys = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
> if (!ckdev->valid_keys)
> return -ENOMEM;
> @@ -635,7 +718,12 @@ static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
> ckdev->ghost_filter = device_property_read_bool(dev,
> "google,needs-ghost-filter");
>
> - err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
> + ckdev->use_fn_overlay = device_property_read_bool(dev,
> + "google,use-fn-overlay");
> +
> + rows_keymap = ckdev->use_fn_overlay ? ckdev->rows * 2 : ckdev->rows;
> +
> + err = matrix_keypad_build_keymap(NULL, NULL, rows_keymap, ckdev->cols,
> NULL, idev);
> if (err) {
> dev_err(dev, "cannot build key matrix\n");
> --
> 2.52.0.351.gbe84eed79e-goog
>
Regards,
Simon
On Sat, Dec 27, 2025 at 07:24:33AM -0700, Simon Glass wrote:
> Hi Fabio,
>
> On Wed, 24 Dec 2025 at 08:22, Fabio Baltieri <fabiobaltieri@chromium.org> wrote:
> >
> > Add support for handling an Fn button and sending separate keycodes for
> > a subset of keys in the matrix defined in the upper half of the keymap.
> >
> > Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
> > ---
> > drivers/input/keyboard/cros_ec_keyb.c | 120 ++++++++++++++++++++++----
> > 1 file changed, 104 insertions(+), 16 deletions(-)
> >
>
> Reviewed-by: Simon Glass <sjg@chromium.org>
>
> I suggest a function comment for the two new functions you add.
Sure, will do.
> > + if (code == KEY_FN)
> > + return cros_ec_keyb_process_fn_key(ckdev, row, col, state);
> > +
> > + if (!state) {
> > + if (ckdev->fn_key_status[col] & BIT(row)) {
> > + pos = MATRIX_SCAN_CODE(row + ckdev->rows, col, ckdev->row_shift);
> > + code = keycodes[pos];
>
> You might want a helper to do this as it is repeated below
Sounds good, adding one for v3
Thanks for the review,
Fabio
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