305 lines
6.6 KiB
C
305 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* TQC PS/2 Multiplexer driver
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*
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* Copyright (C) 2010 Dmitry Eremin-Solenikov
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/serio.h>
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MODULE_AUTHOR("Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>");
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MODULE_DESCRIPTION("TQC PS/2 Multiplexer driver");
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MODULE_LICENSE("GPL");
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#define PS2MULT_KB_SELECTOR 0xA0
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#define PS2MULT_MS_SELECTOR 0xA1
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#define PS2MULT_ESCAPE 0x7D
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#define PS2MULT_BSYNC 0x7E
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#define PS2MULT_SESSION_START 0x55
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#define PS2MULT_SESSION_END 0x56
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struct ps2mult_port {
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struct serio *serio;
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unsigned char sel;
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bool registered;
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};
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#define PS2MULT_NUM_PORTS 2
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#define PS2MULT_KBD_PORT 0
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#define PS2MULT_MOUSE_PORT 1
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struct ps2mult {
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struct serio *mx_serio;
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struct ps2mult_port ports[PS2MULT_NUM_PORTS];
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spinlock_t lock;
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struct ps2mult_port *in_port;
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struct ps2mult_port *out_port;
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bool escape;
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};
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/* First MUST come PS2MULT_NUM_PORTS selectors */
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static const unsigned char ps2mult_controls[] = {
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PS2MULT_KB_SELECTOR, PS2MULT_MS_SELECTOR,
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PS2MULT_ESCAPE, PS2MULT_BSYNC,
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PS2MULT_SESSION_START, PS2MULT_SESSION_END,
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};
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static const struct serio_device_id ps2mult_serio_ids[] = {
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{
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.type = SERIO_RS232,
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.proto = SERIO_PS2MULT,
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.id = SERIO_ANY,
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.extra = SERIO_ANY,
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},
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{ 0 }
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};
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MODULE_DEVICE_TABLE(serio, ps2mult_serio_ids);
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static void ps2mult_select_port(struct ps2mult *psm, struct ps2mult_port *port)
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{
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struct serio *mx_serio = psm->mx_serio;
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serio_write(mx_serio, port->sel);
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psm->out_port = port;
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dev_dbg(&mx_serio->dev, "switched to sel %02x\n", port->sel);
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}
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static int ps2mult_serio_write(struct serio *serio, unsigned char data)
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{
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struct serio *mx_port = serio->parent;
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struct ps2mult *psm = serio_get_drvdata(mx_port);
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struct ps2mult_port *port = serio->port_data;
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bool need_escape;
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unsigned long flags;
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spin_lock_irqsave(&psm->lock, flags);
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if (psm->out_port != port)
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ps2mult_select_port(psm, port);
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need_escape = memchr(ps2mult_controls, data, sizeof(ps2mult_controls));
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dev_dbg(&serio->dev,
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"write: %s%02x\n", need_escape ? "ESC " : "", data);
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if (need_escape)
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serio_write(mx_port, PS2MULT_ESCAPE);
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serio_write(mx_port, data);
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spin_unlock_irqrestore(&psm->lock, flags);
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return 0;
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}
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static int ps2mult_serio_start(struct serio *serio)
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{
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struct ps2mult *psm = serio_get_drvdata(serio->parent);
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struct ps2mult_port *port = serio->port_data;
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unsigned long flags;
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spin_lock_irqsave(&psm->lock, flags);
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port->registered = true;
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spin_unlock_irqrestore(&psm->lock, flags);
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return 0;
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}
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static void ps2mult_serio_stop(struct serio *serio)
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{
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struct ps2mult *psm = serio_get_drvdata(serio->parent);
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struct ps2mult_port *port = serio->port_data;
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unsigned long flags;
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spin_lock_irqsave(&psm->lock, flags);
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port->registered = false;
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spin_unlock_irqrestore(&psm->lock, flags);
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}
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static int ps2mult_create_port(struct ps2mult *psm, int i)
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{
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struct serio *mx_serio = psm->mx_serio;
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struct serio *serio;
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serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
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if (!serio)
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return -ENOMEM;
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strscpy(serio->name, "TQC PS/2 Multiplexer", sizeof(serio->name));
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snprintf(serio->phys, sizeof(serio->phys),
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"%s/port%d", mx_serio->phys, i);
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serio->id.type = SERIO_8042;
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serio->write = ps2mult_serio_write;
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serio->start = ps2mult_serio_start;
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serio->stop = ps2mult_serio_stop;
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serio->parent = psm->mx_serio;
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serio->port_data = &psm->ports[i];
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psm->ports[i].serio = serio;
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return 0;
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}
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static void ps2mult_reset(struct ps2mult *psm)
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{
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unsigned long flags;
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spin_lock_irqsave(&psm->lock, flags);
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serio_write(psm->mx_serio, PS2MULT_SESSION_END);
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serio_write(psm->mx_serio, PS2MULT_SESSION_START);
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ps2mult_select_port(psm, &psm->ports[PS2MULT_KBD_PORT]);
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spin_unlock_irqrestore(&psm->lock, flags);
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}
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static int ps2mult_connect(struct serio *serio, struct serio_driver *drv)
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{
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struct ps2mult *psm;
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int i;
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int error;
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if (!serio->write)
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return -EINVAL;
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psm = kzalloc(sizeof(*psm), GFP_KERNEL);
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if (!psm)
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return -ENOMEM;
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spin_lock_init(&psm->lock);
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psm->mx_serio = serio;
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for (i = 0; i < PS2MULT_NUM_PORTS; i++) {
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psm->ports[i].sel = ps2mult_controls[i];
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error = ps2mult_create_port(psm, i);
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if (error)
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goto err_out;
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}
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psm->in_port = psm->out_port = &psm->ports[PS2MULT_KBD_PORT];
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serio_set_drvdata(serio, psm);
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error = serio_open(serio, drv);
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if (error)
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goto err_out;
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ps2mult_reset(psm);
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for (i = 0; i < PS2MULT_NUM_PORTS; i++) {
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struct serio *s = psm->ports[i].serio;
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dev_info(&serio->dev, "%s port at %s\n", s->name, serio->phys);
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serio_register_port(s);
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}
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return 0;
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err_out:
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while (--i >= 0)
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kfree(psm->ports[i].serio);
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kfree(psm);
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return error;
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}
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static void ps2mult_disconnect(struct serio *serio)
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{
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struct ps2mult *psm = serio_get_drvdata(serio);
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/* Note that serio core already take care of children ports */
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serio_write(serio, PS2MULT_SESSION_END);
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serio_close(serio);
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kfree(psm);
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serio_set_drvdata(serio, NULL);
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}
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static int ps2mult_reconnect(struct serio *serio)
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{
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struct ps2mult *psm = serio_get_drvdata(serio);
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ps2mult_reset(psm);
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return 0;
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}
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static irqreturn_t ps2mult_interrupt(struct serio *serio,
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unsigned char data, unsigned int dfl)
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{
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struct ps2mult *psm = serio_get_drvdata(serio);
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struct ps2mult_port *in_port;
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unsigned long flags;
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dev_dbg(&serio->dev, "Received %02x flags %02x\n", data, dfl);
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spin_lock_irqsave(&psm->lock, flags);
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if (psm->escape) {
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psm->escape = false;
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in_port = psm->in_port;
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if (in_port->registered)
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serio_interrupt(in_port->serio, data, dfl);
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goto out;
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}
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switch (data) {
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case PS2MULT_ESCAPE:
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dev_dbg(&serio->dev, "ESCAPE\n");
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psm->escape = true;
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break;
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case PS2MULT_BSYNC:
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dev_dbg(&serio->dev, "BSYNC\n");
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psm->in_port = psm->out_port;
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break;
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case PS2MULT_SESSION_START:
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dev_dbg(&serio->dev, "SS\n");
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break;
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case PS2MULT_SESSION_END:
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dev_dbg(&serio->dev, "SE\n");
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break;
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case PS2MULT_KB_SELECTOR:
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dev_dbg(&serio->dev, "KB\n");
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psm->in_port = &psm->ports[PS2MULT_KBD_PORT];
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break;
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case PS2MULT_MS_SELECTOR:
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dev_dbg(&serio->dev, "MS\n");
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psm->in_port = &psm->ports[PS2MULT_MOUSE_PORT];
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break;
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default:
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in_port = psm->in_port;
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if (in_port->registered)
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serio_interrupt(in_port->serio, data, dfl);
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break;
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}
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out:
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spin_unlock_irqrestore(&psm->lock, flags);
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return IRQ_HANDLED;
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}
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static struct serio_driver ps2mult_drv = {
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.driver = {
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.name = "ps2mult",
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},
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.description = "TQC PS/2 Multiplexer driver",
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.id_table = ps2mult_serio_ids,
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.interrupt = ps2mult_interrupt,
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.connect = ps2mult_connect,
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.disconnect = ps2mult_disconnect,
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.reconnect = ps2mult_reconnect,
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};
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module_serio_driver(ps2mult_drv);
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