Input: synaptics-rmi4 - forward upper mechanical buttons to PS/2 guest

On the latest series of ThinkPads, the button events for the TrackPoint
are reported through the touchpad itself as opposed to the TrackPoint
device. In order to report these buttons properly, we need to forward
them to the TrackPoint device and notify psmouse to send the button
presses/releases.
Signed-off-by: Lyude Paul <thatslyude@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/rmi4/rmi_driver.h

@@ -107,6 +107,19 @@ int rmi_initial_reset(struct rmi_device *rmi_dev, void *ctx,
 
 const char *rmi_f01_get_product_ID(struct rmi_function *fn);
 
+#ifdef CONFIG_RMI4_F03
+int rmi_f03_overwrite_button(struct rmi_function *fn, unsigned int button,
+			     int value);
+void rmi_f03_commit_buttons(struct rmi_function *fn);
+#else
+static inline int rmi_f03_overwrite_button(struct rmi_function *fn,
+					   unsigned int button, int value)
+{
+	return 0;
+}
+static inline void rmi_f03_commit_buttons(struct rmi_function *fn) {}
+#endif
+
 #ifdef CONFIG_RMI4_F34
 int rmi_f34_create_sysfs(struct rmi_device *rmi_dev);
 void rmi_f34_remove_sysfs(struct rmi_device *rmi_dev);

drivers/input/rmi4/rmi_f03.c

@@ -26,15 +26,53 @@
 #define RMI_F03_BYTES_PER_DEVICE_SHIFT	4
 #define RMI_F03_QUEUE_LENGTH		0x0F
 
+#define PSMOUSE_OOB_EXTRA_BTNS		0x01
+
 struct f03_data {
 	struct rmi_function *fn;
 
 	struct serio *serio;
 
+	unsigned int overwrite_buttons;
+
 	u8 device_count;
 	u8 rx_queue_length;
 };
 
+int rmi_f03_overwrite_button(struct rmi_function *fn, unsigned int button,
+			     int value)
+{
+	struct f03_data *f03 = dev_get_drvdata(&fn->dev);
+	unsigned int bit;
+
+	if (button < BTN_LEFT || button > BTN_MIDDLE)
+		return -EINVAL;
+
+	bit = BIT(button - BTN_LEFT);
+
+	if (value)
+		f03->overwrite_buttons |= bit;
+	else
+		f03->overwrite_buttons &= ~bit;
+
+	return 0;
+}
+
+void rmi_f03_commit_buttons(struct rmi_function *fn)
+{
+	struct f03_data *f03 = dev_get_drvdata(&fn->dev);
+	struct serio *serio = f03->serio;
+
+	serio_pause_rx(serio);
+	if (serio->drv) {
+		serio->drv->interrupt(serio, PSMOUSE_OOB_EXTRA_BTNS,
+				      SERIO_OOB_DATA);
+		serio->drv->interrupt(serio, f03->overwrite_buttons,
+				      SERIO_OOB_DATA);
+	}
+	serio_continue_rx(serio);
+}
+
 static int rmi_f03_pt_write(struct serio *id, unsigned char val)
 {
 	struct f03_data *f03 = id->port_data;

drivers/input/rmi4/rmi_f30.c

@@ -48,6 +48,9 @@
 					+ 1				\
 					+ 1)
 
+#define TRACKSTICK_RANGE_START		3
+#define TRACKSTICK_RANGE_END		6
+
 struct rmi_f30_ctrl_data {
 	int address;
 	int length;
@@ -76,6 +79,9 @@ struct f30_data {
 	u16 *gpioled_key_map;
 
 	struct input_dev *input;
+
+	struct rmi_function *f03;
+	bool trackstick_buttons;
 };
 
 static int rmi_f30_read_control_parameters(struct rmi_function *fn,
@@ -100,13 +106,20 @@ static void rmi_f30_report_button(struct rmi_function *fn,
 {
 	unsigned int reg_num = button >> 3;
 	unsigned int bit_num = button & 0x07;
+	u16 key_code = f30->gpioled_key_map[button];
 	bool key_down = !(f30->data_regs[reg_num] & BIT(bit_num));
 
+	if (f30->trackstick_buttons &&
+	    button >= TRACKSTICK_RANGE_START &&
+	    button <= TRACKSTICK_RANGE_END) {
+		rmi_f03_overwrite_button(f30->f03, key_code, key_down);
+	} else {
 		rmi_dbg(RMI_DEBUG_FN, &fn->dev,
 			"%s: call input report key (0x%04x) value (0x%02x)",
-		__func__, f30->gpioled_key_map[button], key_down);
+			__func__, key_code, key_down);
 
-	input_report_key(f30->input, f30->gpioled_key_map[button], key_down);
+		input_report_key(f30->input, key_code, key_down);
+	}
 }
 
 static int rmi_f30_attention(struct rmi_function *fn, unsigned long *irq_bits)
@@ -138,10 +151,13 @@ static int rmi_f30_attention(struct rmi_function *fn, unsigned long *irq_bits)
 		}
 	}
 
-	if (f30->has_gpio)
+	if (f30->has_gpio) {
 		for (i = 0; i < f30->gpioled_count; i++)
 			if (f30->gpioled_key_map[i] != KEY_RESERVED)
 				rmi_f30_report_button(fn, f30, i);
+		if (f30->trackstick_buttons)
+			rmi_f03_commit_buttons(f30->f03);
+	}
 
 	return 0;
 }
@@ -154,6 +170,12 @@ static int rmi_f30_config(struct rmi_function *fn)
 				rmi_get_platform_data(fn->rmi_dev);
 	int error;
 
+	if (pdata->f30_data.trackstick_buttons) {
+		/* Try [re-]establish link to F03. */
+		f30->f03 = rmi_find_function(fn->rmi_dev, 0x03);
+		f30->trackstick_buttons = f30->f03 != NULL;
+	}
+
 	if (pdata->f30_data.disable) {
 		drv->clear_irq_bits(fn->rmi_dev, fn->irq_mask);
 	} else {
@@ -203,6 +225,8 @@ static int rmi_f30_map_gpios(struct rmi_function *fn,
 					rmi_get_platform_data(fn->rmi_dev);
 	struct input_dev *input = f30->input;
 	unsigned int button = BTN_LEFT;
+	unsigned int trackstick_button = BTN_LEFT;
+	bool button_mapped = false;
 	int i;
 
 	f30->gpioled_key_map = devm_kcalloc(&fn->dev,
@@ -215,19 +239,16 @@ static int rmi_f30_map_gpios(struct rmi_function *fn,
 	}
 
 	for (i = 0; i < f30->gpioled_count; i++) {
-		if (rmi_f30_is_valid_button(i, f30->ctrl)) {
+		if (!rmi_f30_is_valid_button(i, f30->ctrl))
+			continue;
+
+		if (pdata->f30_data.trackstick_buttons &&
+		    i >= TRACKSTICK_RANGE_START && i < TRACKSTICK_RANGE_END) {
+			f30->gpioled_key_map[i] = trackstick_button++;
+		} else if (!pdata->f30_data.buttonpad || !button_mapped) {
 			f30->gpioled_key_map[i] = button;
 			input_set_capability(input, EV_KEY, button++);
-
-			/*
-			 * buttonpad might be given by
-			 * f30->has_mech_mouse_btns, but I am
-			 * not sure, so use only the pdata info
-			 */
-			if (pdata->f30_data.buttonpad) {
-				__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
-				break;
-			}
+			button_mapped = true;
 		}
 	}
 
@@ -235,6 +256,13 @@ static int rmi_f30_map_gpios(struct rmi_function *fn,
 	input->keycodesize = sizeof(f30->gpioled_key_map[0]);
 	input->keycodemax = f30->gpioled_count;
 
+	/*
+	 * Buttonpad could be also inferred from f30->has_mech_mouse_btns,
+	 * but I am not sure, so use only the pdata info.
+	 */
+	if (pdata->f30_data.buttonpad)
+		__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
+
 	return 0;
 }