Based on the cyapa core, add the gen3 trackpad device's basic functions
supported, so gen3 trackpad device can work with kernel input system.
The basic function is absolutely same as previous cyapa driver only
support gen3 trackpad device.
TEST=test on Chromebooks.

Signed-off-by: Dudley Du <redacted>
---
 drivers/input/mouse/Makefile     |    2 +-
 drivers/input/mouse/cyapa.c      |   96 ++++-
 drivers/input/mouse/cyapa.h      |    1 +
 drivers/input/mouse/cyapa_gen3.c |  784 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 881 insertions(+), 2 deletions(-)
 create mode 100644 drivers/input/mouse/cyapa_gen3.c

diff --git a/drivers/input/mouse/Makefile b/drivers/input/mouse/Makefile
index 8608eb7..63b42e0 100644
--- a/drivers/input/mouse/Makefile
+++ b/drivers/input/mouse/Makefile

@@ -35,4 +35,4 @@ psmouse-$(CONFIG_MOUSE_PS2_TRACKPOINT)	+= trackpoint.o
 psmouse-$(CONFIG_MOUSE_PS2_TOUCHKIT)	+= touchkit_ps2.o
 psmouse-$(CONFIG_MOUSE_PS2_CYPRESS)	+= cypress_ps2.o
 
-cyapatp-y := cyapa.o
+cyapatp-y := cyapa.o cyapa_gen3.o

diff --git a/drivers/input/mouse/cyapa.c b/drivers/input/mouse/cyapa.c
index ae24b02..5c62503 100644
--- a/drivers/input/mouse/cyapa.c
+++ b/drivers/input/mouse/cyapa.c

@@ -113,6 +113,15 @@ ssize_t cyapa_i2c_write(struct cyapa *cyapa, u8 reg,
 
 void cyapa_default_irq_handler(struct cyapa *cyapa)
 {
+	bool cont;
+
+	/* Interrupt triggerred by command response in detecting. */
+	cont = true;
+	if (cyapa_gen3_ops.irq_cmd_handler)
+		cont = cyapa_gen3_ops.irq_cmd_handler(cyapa);

+	if (!cont)
+		return;
+
 	/*
 	 * Do redetecting when device states is still unknown and
 	 * interrupt envent is received from device.

@@ -252,6 +261,9 @@ static int cyapa_check_is_operational(struct cyapa *cyapa)
 		return ret;
 
 	switch (cyapa->gen) {
+	case CYAPA_GEN3:
+		cyapa->ops = &cyapa_gen3_ops;
+		break;
 	default:
 		cyapa->ops = &cyapa_default_ops;
 		cyapa->gen = CYAPA_GEN_UNKNOWN;

@@ -314,9 +326,85 @@ out:
  */
 static int cyapa_get_state(struct cyapa *cyapa)
 {
+	int ret;
+	u8 status[BL_STATUS_SIZE];
+	u8 cmd[32];
+	/* The i2c address of gen4 and gen5 trackpad device must be even. */
+	bool even_addr = ((cyapa->client->addr & 0x0001) == 0);
+	bool smbus = false;
+	int retries = 2;
+
 	cyapa->state = CYAPA_STATE_NO_DEVICE;
 
-	return -ENODEV;
+	/*
+	 * Get trackpad status by reading 3 registers starting from 0.
+	 * If the device is in the bootloader, this will be BL_HEAD.
+	 * If the device is in operation mode, this will be the DATA regs.
+	 *
+	 */
+	ret = cyapa_i2c_reg_read_block(cyapa, BL_HEAD_OFFSET, BL_STATUS_SIZE,
+				       status);
+
+	/*
+	 * On smbus systems in OP mode, the i2c_reg_read will fail with
+	 * -ETIMEDOUT.  In this case, try again using the smbus equivalent
+	 * command.  This should return a BL_HEAD indicating CYAPA_STATE_OP.
+	 */
+	if (cyapa->smbus && (ret == -ETIMEDOUT || ret == -ENXIO)) {
+		if (!even_addr)
+			ret = cyapa_read_block(cyapa,
+					CYAPA_CMD_BL_STATUS, status);
+		smbus = true;
+	}
+	if (ret != BL_STATUS_SIZE)
+		goto error;
+
+	/*
+	 * Detect trackpad protocol based on characristic registers and bits.
+	 */
+	do {
+		cyapa->status[REG_OP_STATUS] = status[REG_OP_STATUS];
+		cyapa->status[REG_BL_STATUS] = status[REG_BL_STATUS];
+		cyapa->status[REG_BL_ERROR] = status[REG_BL_ERROR];
+
+		if (cyapa->gen == CYAPA_GEN_UNKNOWN ||
+				cyapa->gen == CYAPA_GEN3) {
+			ret = cyapa_gen3_ops.state_parse(cyapa,
+					status, BL_STATUS_SIZE);
+			if (ret == 0)
+				goto out_detected;
+		}
+
+		/*
+		 * Cannot detect communication protocol based on current
+		 * charateristic registers and bits.
+		 * So write error command to do further detection.
+		 * this method only valid on I2C bus.
+		 * for smbus interface, it won't have overwrite issue.
+		 */
+		if (!smbus) {
+			cmd[0] = 0x00;
+			cmd[1] = 0x00;
+			ret = cyapa_i2c_write(cyapa, 0, 2, cmd);
+			if (ret)
+				goto error;
+
+			msleep(50);
+
+			ret = cyapa_i2c_read(cyapa, BL_HEAD_OFFSET,
+					BL_STATUS_SIZE, status);
+			if (ret < 0)
+				goto error;
+		}
+	} while (--retries > 0 && !smbus);
+
+	goto error;
+
+out_detected:
+	return 0;
+
+error:
+	return (ret < 0) ? ret : -EAGAIN;
 }
 
 /*

@@ -994,11 +1082,17 @@ static void cyapa_detect_and_start(void *data, async_cookie_t cookie)
 
 static int cyapa_tp_modules_init(struct cyapa *cyapa)
 {
+	if (cyapa_gen3_ops.initialize)
+		return cyapa_gen3_ops.initialize(cyapa);