diff options
Diffstat (limited to 'drivers/input/serio/ps2mult.c')
| -rw-r--r-- | drivers/input/serio/ps2mult.c | 304 |
1 files changed, 304 insertions, 0 deletions
diff --git a/drivers/input/serio/ps2mult.c b/drivers/input/serio/ps2mult.c new file mode 100644 index 000000000..902e81826 --- /dev/null +++ b/drivers/input/serio/ps2mult.c @@ -0,0 +1,304 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * TQC PS/2 Multiplexer driver + * + * Copyright (C) 2010 Dmitry Eremin-Solenikov + */ + + +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/serio.h> + +MODULE_AUTHOR("Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>"); +MODULE_DESCRIPTION("TQC PS/2 Multiplexer driver"); +MODULE_LICENSE("GPL"); + +#define PS2MULT_KB_SELECTOR 0xA0 +#define PS2MULT_MS_SELECTOR 0xA1 +#define PS2MULT_ESCAPE 0x7D +#define PS2MULT_BSYNC 0x7E +#define PS2MULT_SESSION_START 0x55 +#define PS2MULT_SESSION_END 0x56 + +struct ps2mult_port { + struct serio *serio; + unsigned char sel; + bool registered; +}; + +#define PS2MULT_NUM_PORTS 2 +#define PS2MULT_KBD_PORT 0 +#define PS2MULT_MOUSE_PORT 1 + +struct ps2mult { + struct serio *mx_serio; + struct ps2mult_port ports[PS2MULT_NUM_PORTS]; + + spinlock_t lock; + struct ps2mult_port *in_port; + struct ps2mult_port *out_port; + bool escape; +}; + +/* First MUST come PS2MULT_NUM_PORTS selectors */ +static const unsigned char ps2mult_controls[] = { + PS2MULT_KB_SELECTOR, PS2MULT_MS_SELECTOR, + PS2MULT_ESCAPE, PS2MULT_BSYNC, + PS2MULT_SESSION_START, PS2MULT_SESSION_END, +}; + +static const struct serio_device_id ps2mult_serio_ids[] = { + { + .type = SERIO_RS232, + .proto = SERIO_PS2MULT, + .id = SERIO_ANY, + .extra = SERIO_ANY, + }, + { 0 } +}; + +MODULE_DEVICE_TABLE(serio, ps2mult_serio_ids); + +static void ps2mult_select_port(struct ps2mult *psm, struct ps2mult_port *port) +{ + struct serio *mx_serio = psm->mx_serio; + + serio_write(mx_serio, port->sel); + psm->out_port = port; + dev_dbg(&mx_serio->dev, "switched to sel %02x\n", port->sel); +} + +static int ps2mult_serio_write(struct serio *serio, unsigned char data) +{ + struct serio *mx_port = serio->parent; + struct ps2mult *psm = serio_get_drvdata(mx_port); + struct ps2mult_port *port = serio->port_data; + bool need_escape; + unsigned long flags; + + spin_lock_irqsave(&psm->lock, flags); + + if (psm->out_port != port) + ps2mult_select_port(psm, port); + + need_escape = memchr(ps2mult_controls, data, sizeof(ps2mult_controls)); + + dev_dbg(&serio->dev, + "write: %s%02x\n", need_escape ? "ESC " : "", data); + + if (need_escape) + serio_write(mx_port, PS2MULT_ESCAPE); + + serio_write(mx_port, data); + + spin_unlock_irqrestore(&psm->lock, flags); + + return 0; +} + +static int ps2mult_serio_start(struct serio *serio) +{ + struct ps2mult *psm = serio_get_drvdata(serio->parent); + struct ps2mult_port *port = serio->port_data; + unsigned long flags; + + spin_lock_irqsave(&psm->lock, flags); + port->registered = true; + spin_unlock_irqrestore(&psm->lock, flags); + + return 0; +} + +static void ps2mult_serio_stop(struct serio *serio) +{ + struct ps2mult *psm = serio_get_drvdata(serio->parent); + struct ps2mult_port *port = serio->port_data; + unsigned long flags; + + spin_lock_irqsave(&psm->lock, flags); + port->registered = false; + spin_unlock_irqrestore(&psm->lock, flags); +} + +static int ps2mult_create_port(struct ps2mult *psm, int i) +{ + struct serio *mx_serio = psm->mx_serio; + struct serio *serio; + + serio = kzalloc(sizeof(struct serio), GFP_KERNEL); + if (!serio) + return -ENOMEM; + + strscpy(serio->name, "TQC PS/2 Multiplexer", sizeof(serio->name)); + snprintf(serio->phys, sizeof(serio->phys), + "%s/port%d", mx_serio->phys, i); + serio->id.type = SERIO_8042; + serio->write = ps2mult_serio_write; + serio->start = ps2mult_serio_start; + serio->stop = ps2mult_serio_stop; + serio->parent = psm->mx_serio; + serio->port_data = &psm->ports[i]; + + psm->ports[i].serio = serio; + + return 0; +} + +static void ps2mult_reset(struct ps2mult *psm) +{ + unsigned long flags; + + spin_lock_irqsave(&psm->lock, flags); + + serio_write(psm->mx_serio, PS2MULT_SESSION_END); + serio_write(psm->mx_serio, PS2MULT_SESSION_START); + + ps2mult_select_port(psm, &psm->ports[PS2MULT_KBD_PORT]); + + spin_unlock_irqrestore(&psm->lock, flags); +} + +static int ps2mult_connect(struct serio *serio, struct serio_driver *drv) +{ + struct ps2mult *psm; + int i; + int error; + + if (!serio->write) + return -EINVAL; + + psm = kzalloc(sizeof(*psm), GFP_KERNEL); + if (!psm) + return -ENOMEM; + + spin_lock_init(&psm->lock); + psm->mx_serio = serio; + + for (i = 0; i < PS2MULT_NUM_PORTS; i++) { + psm->ports[i].sel = ps2mult_controls[i]; + error = ps2mult_create_port(psm, i); + if (error) + goto err_out; + } + + psm->in_port = psm->out_port = &psm->ports[PS2MULT_KBD_PORT]; + + serio_set_drvdata(serio, psm); + error = serio_open(serio, drv); + if (error) + goto err_out; + + ps2mult_reset(psm); + + for (i = 0; i < PS2MULT_NUM_PORTS; i++) { + struct serio *s = psm->ports[i].serio; + + dev_info(&serio->dev, "%s port at %s\n", s->name, serio->phys); + serio_register_port(s); + } + + return 0; + +err_out: + while (--i >= 0) + kfree(psm->ports[i].serio); + kfree(psm); + return error; +} + +static void ps2mult_disconnect(struct serio *serio) +{ + struct ps2mult *psm = serio_get_drvdata(serio); + + /* Note that serio core already take care of children ports */ + serio_write(serio, PS2MULT_SESSION_END); + serio_close(serio); + kfree(psm); + + serio_set_drvdata(serio, NULL); +} + +static int ps2mult_reconnect(struct serio *serio) +{ + struct ps2mult *psm = serio_get_drvdata(serio); + + ps2mult_reset(psm); + + return 0; +} + +static irqreturn_t ps2mult_interrupt(struct serio *serio, + unsigned char data, unsigned int dfl) +{ + struct ps2mult *psm = serio_get_drvdata(serio); + struct ps2mult_port *in_port; + unsigned long flags; + + dev_dbg(&serio->dev, "Received %02x flags %02x\n", data, dfl); + + spin_lock_irqsave(&psm->lock, flags); + + if (psm->escape) { + psm->escape = false; + in_port = psm->in_port; + if (in_port->registered) + serio_interrupt(in_port->serio, data, dfl); + goto out; + } + + switch (data) { + case PS2MULT_ESCAPE: + dev_dbg(&serio->dev, "ESCAPE\n"); + psm->escape = true; + break; + + case PS2MULT_BSYNC: + dev_dbg(&serio->dev, "BSYNC\n"); + psm->in_port = psm->out_port; + break; + + case PS2MULT_SESSION_START: + dev_dbg(&serio->dev, "SS\n"); + break; + + case PS2MULT_SESSION_END: + dev_dbg(&serio->dev, "SE\n"); + break; + + case PS2MULT_KB_SELECTOR: + dev_dbg(&serio->dev, "KB\n"); + psm->in_port = &psm->ports[PS2MULT_KBD_PORT]; + break; + + case PS2MULT_MS_SELECTOR: + dev_dbg(&serio->dev, "MS\n"); + psm->in_port = &psm->ports[PS2MULT_MOUSE_PORT]; + break; + + default: + in_port = psm->in_port; + if (in_port->registered) + serio_interrupt(in_port->serio, data, dfl); + break; + } + + out: + spin_unlock_irqrestore(&psm->lock, flags); + return IRQ_HANDLED; +} + +static struct serio_driver ps2mult_drv = { + .driver = { + .name = "ps2mult", + }, + .description = "TQC PS/2 Multiplexer driver", + .id_table = ps2mult_serio_ids, + .interrupt = ps2mult_interrupt, + .connect = ps2mult_connect, + .disconnect = ps2mult_disconnect, + .reconnect = ps2mult_reconnect, +}; + +module_serio_driver(ps2mult_drv); |