Re: [PATCH v5] psmouse: Add some support for the FocalTech PS/2 protocol extensions.

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thu, Nov 13, 2014 at 12:00:33AM +0100, Mathias Gottschlag wrote:
> Most of the protocol for these touchpads has been reverse engineered. This
> commit adds a basic multitouch-capable driver.
> 
> A lot of the protocol is still unknown. Especially, we don't know how to
> identify the device yet apart from the PNP ID.
> 
> The previous workaround for these devices has been left in place in case
> the driver is not compiled into the kernel or in case some other device
> with the same PNP ID is not recognized by the driver yet still has the same
> problems with the device probing code.
> 
> Signed-off-by: Mathias Gottschlag <mgottschlag@gmail.com>
> Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Applied, sorry for the delay.

> ---
> 
> (Resent with the correct subject to prevent confusion, sorry, this is v5)
> Various smaller changes as requested. Also, accidentally pressing the touchpad
> disable button can cause really frustrating debugging sessions.
> 
>  drivers/input/mouse/Kconfig        |  10 ++
>  drivers/input/mouse/focaltech.c    | 313 ++++++++++++++++++++++++++++++++++++-
>  drivers/input/mouse/focaltech.h    |  60 +++++++
>  drivers/input/mouse/psmouse-base.c |  32 ++--
>  drivers/input/mouse/psmouse.h      |   1 +
>  5 files changed, 399 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/input/mouse/Kconfig b/drivers/input/mouse/Kconfig
> index 366fc7a..db973e5 100644
> --- a/drivers/input/mouse/Kconfig
> +++ b/drivers/input/mouse/Kconfig
> @@ -146,6 +146,16 @@ config MOUSE_PS2_OLPC
>  
>  	  If unsure, say N.
>  
> +config MOUSE_PS2_FOCALTECH
> +	bool "FocalTech PS/2 mouse protocol extension" if EXPERT
> +	default y
> +	depends on MOUSE_PS2
> +	help
> +	  Say Y here if you have a FocalTech PS/2 TouchPad connected to
> +	  your system.
> +
> +	  If unsure, say Y.
> +
>  config MOUSE_SERIAL
>  	tristate "Serial mouse"
>  	select SERIO
> diff --git a/drivers/input/mouse/focaltech.c b/drivers/input/mouse/focaltech.c
> index f4d657e..f838cab4 100644
> --- a/drivers/input/mouse/focaltech.c
> +++ b/drivers/input/mouse/focaltech.c
> @@ -2,6 +2,7 @@
>   * Focaltech TouchPad PS/2 mouse driver
>   *
>   * Copyright (c) 2014 Red Hat Inc.
> + * Copyright (c) 2014 Mathias Gottschlag <mgottschlag@gmail.com>
>   *
>   * This program is free software; you can redistribute it and/or modify
>   * it under the terms of the GNU General Public License as published by
> @@ -13,15 +14,14 @@
>   * Hans de Goede <hdegoede@redhat.com>
>   */
>  
> -/*
> - * The Focaltech PS/2 touchpad protocol is unknown. This drivers deals with
> - * detection only, to avoid further detection attempts confusing the touchpad
> - * this way it at least works in PS/2 mouse compatibility mode.
> - */
>  
>  #include <linux/device.h>
>  #include <linux/libps2.h>
> +#include <linux/input/mt.h>
> +#include <linux/serio.h>
> +#include <linux/slab.h>
>  #include "psmouse.h"
> +#include "focaltech.h"
>  
>  static const char * const focaltech_pnp_ids[] = {
>  	"FLT0101",
> @@ -30,6 +30,12 @@ static const char * const focaltech_pnp_ids[] = {
>  	NULL
>  };
>  
> +/*
> + * Even if the kernel is built without support for Focaltech PS/2 touchpads (or
> + * when the real driver fails to recognize the device), we still have to detect
> + * them in order to avoid further detection attempts confusing the touchpad.
> + * This way it at least works in PS/2 mouse compatibility mode.
> + */
>  int focaltech_detect(struct psmouse *psmouse, bool set_properties)
>  {
>  	if (!psmouse_matches_pnp_id(psmouse, focaltech_pnp_ids))
> @@ -37,16 +43,309 @@ int focaltech_detect(struct psmouse *psmouse, bool set_properties)
>  
>  	if (set_properties) {
>  		psmouse->vendor = "FocalTech";
> -		psmouse->name = "FocalTech Touchpad in mouse emulation mode";
> +		psmouse->name = "FocalTech Touchpad";
>  	}
>  
>  	return 0;
>  }
>  
> -int focaltech_init(struct psmouse *psmouse)
> +static void focaltech_reset(struct psmouse *psmouse)
>  {
>  	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
>  	psmouse_reset(psmouse);
> +}
> +
> +#ifdef CONFIG_MOUSE_PS2_FOCALTECH
> +
> +static void focaltech_report_state(struct psmouse *psmouse)
> +{
> +	int i;
> +	struct focaltech_data *priv = psmouse->private;
> +	struct focaltech_hw_state *state = &priv->state;
> +	struct input_dev *dev = psmouse->dev;
> +
> +	for (i = 0; i < FOC_MAX_FINGERS; i++) {
> +		struct focaltech_finger_state *finger = &state->fingers[i];
> +		bool active = finger->active && finger->valid;
> +		input_mt_slot(dev, i);
> +		input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
> +		if (active) {
> +			input_report_abs(dev, ABS_MT_POSITION_X, finger->x);
> +			input_report_abs(dev, ABS_MT_POSITION_Y,
> +					focaltech_invert_y(finger->y));
> +		}
> +	}
> +	input_mt_report_pointer_emulation(dev, true);
> +
> +	input_report_key(psmouse->dev, BTN_LEFT, state->pressed);
> +	input_sync(psmouse->dev);
> +}
> +
> +static void process_touch_packet(struct focaltech_hw_state *state,
> +		unsigned char *packet)
> +{
> +	int i;
> +	unsigned char fingers = packet[1];
> +
> +	state->pressed = (packet[0] >> 4) & 1;
> +	/* the second byte contains a bitmap of all fingers touching the pad */
> +	for (i = 0; i < FOC_MAX_FINGERS; i++) {
> +		state->fingers[i].active = fingers & 0x1;
> +		if (!state->fingers[i].active) {
> +			/* even when the finger becomes active again, we still
> +			 * will have to wait for the first valid position */
> +			state->fingers[i].valid = false;
> +		}
> +		fingers >>= 1;
> +	}
> +}
> +
> +static void process_abs_packet(struct psmouse *psmouse,
> +		unsigned char *packet)
> +{
> +	struct focaltech_data *priv = psmouse->private;
> +	struct focaltech_hw_state *state = &priv->state;
> +	unsigned int finger;
> +
> +	finger = (packet[1] >> 4) - 1;
> +	if (finger >= FOC_MAX_FINGERS) {
> +		psmouse_err(psmouse, "Invalid finger in abs packet: %d",
> +				finger);
> +		return;
> +	}
> +
> +	state->pressed = (packet[0] >> 4) & 1;
> +	/*
> +	 * packet[5] contains some kind of tool size in the most significant
> +	 * nibble. 0xff is a special value (latching) that signals a large
> +	 * contact area.
> +	 */
> +	if (packet[5] == 0xff) {
> +		state->fingers[finger].valid = false;
> +		return;
> +	}
> +	state->fingers[finger].x = ((packet[1] & 0xf) << 8) | packet[2];
> +	state->fingers[finger].y = (packet[3] << 8) | packet[4];
> +	state->fingers[finger].valid = true;
> +}
> +
> +static void process_rel_packet(struct psmouse *psmouse,
> +		unsigned char *packet)
> +{
> +	struct focaltech_data *priv = psmouse->private;
> +	struct focaltech_hw_state *state = &priv->state;
> +	int finger1, finger2;
> +
> +	state->pressed = packet[0] >> 7;
> +	finger1 = ((packet[0] >> 4) & 0x7) - 1;
> +	if (finger1 < FOC_MAX_FINGERS) {
> +		state->fingers[finger1].x += (char)packet[1];
> +		state->fingers[finger1].y += (char)packet[2];
> +	} else {
> +		psmouse_err(psmouse, "First finger in rel packet invalid: %d",
> +				finger1);
> +	}
> +	/*
> +	 * If there is an odd number of fingers, the last relative packet only
> +	 * contains one finger. In this case, the second finger index in the
> +	 * packet is 0 (we subtract 1 in the lines above to create array
> +	 * indices, so the finger will overflow and be above FOC_MAX_FINGERS).
> +	 */
> +	finger2 = ((packet[3] >> 4) & 0x7) - 1;
> +	if (finger2 < FOC_MAX_FINGERS) {
> +		state->fingers[finger2].x += (char)packet[4];
> +		state->fingers[finger2].y += (char)packet[5];
> +	}
> +}
> +
> +static void focaltech_process_packet(struct psmouse *psmouse)
> +{
> +	struct focaltech_data *priv = psmouse->private;
> +	unsigned char *packet = psmouse->packet;
> +
> +	switch (packet[0] & 0xf) {
> +	case FOC_TOUCH:
> +		process_touch_packet(&priv->state, packet);
> +		break;
> +	case FOC_ABS:
> +		process_abs_packet(psmouse, packet);
> +		break;
> +	case FOC_REL:
> +		process_rel_packet(psmouse, packet);
> +		break;
> +	default:
> +		psmouse_err(psmouse, "Unknown packet type: %02x", packet[0]);
> +		break;
> +	}
> +
> +	focaltech_report_state(psmouse);
> +}
> +
> +static psmouse_ret_t focaltech_process_byte(struct psmouse *psmouse)
> +{
> +	if (psmouse->pktcnt >= 6) { /* Full packet received */
> +		focaltech_process_packet(psmouse);
> +		return PSMOUSE_FULL_PACKET;
> +	}
> +	/*
> +	 * we might want to do some validation of the data here, but we do not
> +	 * know the protocoll well enough
> +	 */
> +	return PSMOUSE_GOOD_DATA;
> +}
> +
> +static int focaltech_switch_protocol(struct psmouse *psmouse)
> +{
> +	struct ps2dev *ps2dev = &psmouse->ps2dev;
> +	unsigned char param[3];
> +
> +	param[0] = 0;
> +	if (ps2_command(ps2dev, param, 0x10f8))
> +		return -EIO;
> +	if (ps2_command(ps2dev, param, 0x10f8))
> +		return -EIO;
> +	if (ps2_command(ps2dev, param, 0x10f8))
> +		return -EIO;
> +	param[0] = 1;
> +	if (ps2_command(ps2dev, param, 0x10f8))
> +		return -EIO;
> +	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
> +		return -EIO;
> +
> +	if (ps2_command(ps2dev, param, PSMOUSE_CMD_ENABLE))
> +		return -EIO;
> +
> +	return 0;
> +}
> +
> +static void focaltech_disconnect(struct psmouse *psmouse)
> +{
> +	focaltech_reset(psmouse);
> +	kfree(psmouse->private);
> +	psmouse->private = NULL;
> +}
> +
> +static int focaltech_reconnect(struct psmouse *psmouse)
> +{
> +	focaltech_reset(psmouse);
> +	if (focaltech_switch_protocol(psmouse)) {
> +		psmouse_err(psmouse,
> +			    "Unable to initialize the device.");
> +		return -1;
> +	}
> +	return 0;
> +}
> +
> +static void set_input_params(struct psmouse *psmouse)
> +{
> +	struct input_dev *dev = psmouse->dev;
> +	struct focaltech_data *priv = psmouse->private;
> +
> +	__set_bit(EV_ABS, dev->evbit);
> +	input_set_abs_params(dev, ABS_MT_POSITION_X, 0, priv->x_max, 0, 0);
> +	input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, priv->y_max, 0, 0);
> +	input_mt_init_slots(dev, 5, INPUT_MT_POINTER);
> +	__clear_bit(EV_REL, dev->evbit);
> +	__clear_bit(REL_X, dev->relbit);
> +	__clear_bit(REL_Y, dev->relbit);
> +	__clear_bit(BTN_RIGHT, dev->keybit);
> +	__clear_bit(BTN_MIDDLE, dev->keybit);
> +	__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
> +}
> +
> +static int focaltech_read_register(struct ps2dev *ps2dev, int reg,
> +		unsigned char *param)
> +{
> +	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
> +		return -EIO;
> +	param[0] = 0;
> +	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
> +		return -EIO;
> +	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
> +		return -EIO;
> +	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
> +		return -EIO;
> +	param[0] = reg;
> +	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
> +		return -EIO;
> +	if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
> +		return -EIO;
> +	return 0;
> +}
> +
> +static int focaltech_read_size(struct psmouse *psmouse)
> +{
> +	struct ps2dev *ps2dev = &psmouse->ps2dev;
> +	struct focaltech_data *priv = psmouse->private;
> +	char param[3];
> +
> +	if (focaltech_read_register(ps2dev, 2, param))
> +		return -EIO;
> +	/* not sure whether this is 100% correct */
> +	priv->x_max = (unsigned char)param[1] * 128;
> +	priv->y_max = (unsigned char)param[2] * 128;
> +
> +	return 0;
> +}
> +int focaltech_init(struct psmouse *psmouse)
> +{
> +	struct focaltech_data *priv;
> +	int err;
> +
> +	psmouse->private = priv = kzalloc(sizeof(struct focaltech_data), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	focaltech_reset(psmouse);
> +	err = focaltech_read_size(psmouse);
> +	if (err) {
> +		focaltech_reset(psmouse);
> +		psmouse_err(psmouse,
> +			    "Unable to read the size of the touchpad.");
> +		goto fail;
> +	}
> +	if (focaltech_switch_protocol(psmouse)) {
> +		focaltech_reset(psmouse);
> +		psmouse_err(psmouse,
> +			    "Unable to initialize the device.");
> +		err = -ENOSYS;
> +		goto fail;
> +	}
> +
> +	set_input_params(psmouse);
> +
> +	psmouse->protocol_handler = focaltech_process_byte;
> +	psmouse->pktsize = 6;
> +	psmouse->disconnect = focaltech_disconnect;
> +	psmouse->reconnect = focaltech_reconnect;
> +	psmouse->cleanup = focaltech_reset;
> +	/* resync is not supported yet */
> +	psmouse->resync_time = 0;
>  
>  	return 0;
> +fail:
> +	focaltech_reset(psmouse);
> +	kfree(priv);
> +	return err;
> +}
> +
> +bool focaltech_supported(void)
> +{
> +	return true;
>  }
> +
> +#else /* CONFIG_MOUSE_PS2_FOCALTECH */
> +
> +int focaltech_init(struct psmouse *psmouse)
> +{
> +	focaltech_reset(psmouse);
> +
> +	return 0;
> +}
> +
> +bool focaltech_supported(void)
> +{
> +	return false;
> +}
> +
> +#endif /* CONFIG_MOUSE_PS2_FOCALTECH */
> diff --git a/drivers/input/mouse/focaltech.h b/drivers/input/mouse/focaltech.h
> index 498650c..bda3241 100644
> --- a/drivers/input/mouse/focaltech.h
> +++ b/drivers/input/mouse/focaltech.h
> @@ -2,6 +2,7 @@
>   * Focaltech TouchPad PS/2 mouse driver
>   *
>   * Copyright (c) 2014 Red Hat Inc.
> + * Copyright (c) 2014 Mathias Gottschlag <mgottschlag@gmail.com>
>   *
>   * This program is free software; you can redistribute it and/or modify
>   * it under the terms of the GNU General Public License as published by
> @@ -16,7 +17,66 @@
>  #ifndef _FOCALTECH_H
>  #define _FOCALTECH_H
>  
> +/*
> + * Packet types - the numbers are not consecutive, so we might be missing
> + * something here.
> + */
> +#define FOC_TOUCH 0x3 /* bitmap of active fingers */
> +#define FOC_ABS 0x6 /* absolute position of one finger */
> +#define FOC_REL 0x9 /* relative position of 1-2 fingers */
> +
> +#define FOC_MAX_FINGERS 5
> +
> +#define FOC_MAX_X 2431
> +#define FOC_MAX_Y 1663
> +
> +static inline int focaltech_invert_y(int y)
> +{
> +	return FOC_MAX_Y - y;
> +}
> +
> +/*
> + * Current state of a single finger on the touchpad.
> + */
> +struct focaltech_finger_state {
> +	/* the touchpad has generated a touch event for the finger */
> +	bool active;
> +	/*
> +	 * The touchpad has sent position data for the finger. The flag is 0
> +	 * when the finger is not active, and there is a time between the first
> +	 * touch event for the finger and the following absolute position
> +	 * packet for the finger where the touchpad has declared the finger to
> +	 * be valid, but we do not have any valid position yet.
> +	 */
> +	bool valid;
> +	/* absolute position (from the bottom left corner) of the finger */
> +	unsigned int x;
> +	unsigned int y;
> +};
> +
> +/*
> + * Description of the current state of the touchpad hardware.
> + */
> +struct focaltech_hw_state {
> +	/*
> +	 * The touchpad tracks the positions of the fingers for us, the array
> +	 * indices correspond to the finger indices returned in the report
> +	 * packages.
> +	 */
> +	struct focaltech_finger_state fingers[FOC_MAX_FINGERS];
> +	/*
> +	 * True if the clickpad has been pressed.
> +	 */
> +	bool pressed;
> +};
> +
> +struct focaltech_data {
> +	unsigned int x_max, y_max;
> +	struct focaltech_hw_state state;
> +};
> +
>  int focaltech_detect(struct psmouse *psmouse, bool set_properties);
>  int focaltech_init(struct psmouse *psmouse);
> +bool focaltech_supported(void);
>  
>  #endif
> diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
> index 95a3a6e..68469fe 100644
> --- a/drivers/input/mouse/psmouse-base.c
> +++ b/drivers/input/mouse/psmouse-base.c
> @@ -725,16 +725,19 @@ static int psmouse_extensions(struct psmouse *psmouse,
>  
>  /* Always check for focaltech, this is safe as it uses pnp-id matching */
>  	if (psmouse_do_detect(focaltech_detect, psmouse, set_properties) == 0) {
> -		if (!set_properties || focaltech_init(psmouse) == 0) {
> -			/*
> -			 * Not supported yet, use bare protocol.
> -			 * Note that we need to also restrict
> -			 * psmouse_max_proto so that psmouse_initialize()
> -			 * does not try to reset rate and resolution,
> -			 * because even that upsets the device.
> -			 */
> -			psmouse_max_proto = PSMOUSE_PS2;
> -			return PSMOUSE_PS2;
> +		if (max_proto > PSMOUSE_IMEX) {
> +			if (!set_properties || focaltech_init(psmouse) == 0) {
> +				if (focaltech_supported())
> +					return PSMOUSE_FOCALTECH;
> +				/*
> +				 * Note that we need to also restrict
> +				 * psmouse_max_proto so that psmouse_initialize()
> +				 * does not try to reset rate and resolution,
> +				 * because even that upsets the device.
> +				 */
> +				psmouse_max_proto = PSMOUSE_PS2;
> +				return PSMOUSE_PS2;
> +			}
>  		}
>  	}
>  
> @@ -1063,6 +1066,15 @@ static const struct psmouse_protocol psmouse_protocols[] = {
>  		.alias		= "cortps",
>  		.detect		= cortron_detect,
>  	},
> +#ifdef CONFIG_MOUSE_PS2_FOCALTECH
> +	{
> +		.type		= PSMOUSE_FOCALTECH,
> +		.name		= "FocalTechPS/2",
> +		.alias		= "focaltech",
> +		.detect		= focaltech_detect,
> +		.init		= focaltech_init,
> +	},
> +#endif
>  	{
>  		.type		= PSMOUSE_AUTO,
>  		.name		= "auto",
> diff --git a/drivers/input/mouse/psmouse.h b/drivers/input/mouse/psmouse.h
> index f4cf664..c2ff137 100644
> --- a/drivers/input/mouse/psmouse.h
> +++ b/drivers/input/mouse/psmouse.h
> @@ -96,6 +96,7 @@ enum psmouse_type {
>  	PSMOUSE_FSP,
>  	PSMOUSE_SYNAPTICS_RELATIVE,
>  	PSMOUSE_CYPRESS,
> +	PSMOUSE_FOCALTECH,
>  	PSMOUSE_AUTO		/* This one should always be last */
>  };
>  
> -- 
> 1.9.1
> 

-- 
Dmitry