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// SPDX-License-Identifier: GPL-2.0
/*
* Filename: ks0108.c
* Version: 0.1.0
* Description: ks0108 LCD Controller driver
* Depends: parport
*
* Author: Copyright (C) Miguel Ojeda <ojeda@kernel.org>
* Date: 2006-10-31
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/parport.h>
#include <linux/ks0108.h>
#define KS0108_NAME "ks0108"
/*
* Module Parameters
*/
static unsigned int ks0108_port = CONFIG_KS0108_PORT;
module_param(ks0108_port, uint, 0444);
MODULE_PARM_DESC(ks0108_port, "Parallel port where the LCD is connected");
static unsigned int ks0108_delay = CONFIG_KS0108_DELAY;
module_param(ks0108_delay, uint, 0444);
MODULE_PARM_DESC(ks0108_delay, "Delay between each control writing (microseconds)");
/*
* Device
*/
static struct parport *ks0108_parport;
static struct pardevice *ks0108_pardevice;
/*
* ks0108 Exported Commands (don't lock)
*
* You _should_ lock in the top driver: This functions _should not_
* get race conditions in any way. Locking for each byte here would be
* so slow and useless.
*
* There are not bit definitions because they are not flags,
* just arbitrary combinations defined by the documentation for each
* function in the ks0108 LCD controller. If you want to know what means
* a specific combination, look at the function's name.
*
* The ks0108_writecontrol bits need to be reverted ^(0,1,3) because
* the parallel port also revert them using a "not" logic gate.
*/
#define bit(n) (((unsigned char)1)<<(n))
void ks0108_writedata(unsigned char byte)
{
parport_write_data(ks0108_parport, byte);
}
void ks0108_writecontrol(unsigned char byte)
{
udelay(ks0108_delay);
parport_write_control(ks0108_parport, byte ^ (bit(0) | bit(1) | bit(3)));
}
void ks0108_displaystate(unsigned char state)
{
ks0108_writedata((state ? bit(0) : 0) | bit(1) | bit(2) | bit(3) | bit(4) | bit(5));
}
void ks0108_startline(unsigned char startline)
{
ks0108_writedata(min_t(unsigned char, startline, 63) | bit(6) |
bit(7));
}
void ks0108_address(unsigned char address)
{
ks0108_writedata(min_t(unsigned char, address, 63) | bit(6));
}
void ks0108_page(unsigned char page)
{
ks0108_writedata(min_t(unsigned char, page, 7) | bit(3) | bit(4) |
bit(5) | bit(7));
}
EXPORT_SYMBOL_GPL(ks0108_writedata);
EXPORT_SYMBOL_GPL(ks0108_writecontrol);
EXPORT_SYMBOL_GPL(ks0108_displaystate);
EXPORT_SYMBOL_GPL(ks0108_startline);
EXPORT_SYMBOL_GPL(ks0108_address);
EXPORT_SYMBOL_GPL(ks0108_page);
/*
* Is the module inited?
*/
static unsigned char ks0108_inited;
unsigned char ks0108_isinited(void)
{
return ks0108_inited;
}
EXPORT_SYMBOL_GPL(ks0108_isinited);
static void ks0108_parport_attach(struct parport *port)
{
struct pardev_cb ks0108_cb;
if (port->base != ks0108_port)
return;
memset(&ks0108_cb, 0, sizeof(ks0108_cb));
ks0108_cb.flags = PARPORT_DEV_EXCL;
ks0108_pardevice = parport_register_dev_model(port, KS0108_NAME,
&ks0108_cb, 0);
if (!ks0108_pardevice) {
pr_err("ERROR: parport didn't register new device\n");
return;
}
if (parport_claim(ks0108_pardevice)) {
pr_err("could not claim access to parport %i. Aborting.\n",
ks0108_port);
goto err_unreg_device;
}
ks0108_parport = port;
ks0108_inited = 1;
return;
err_unreg_device:
parport_unregister_device(ks0108_pardevice);
ks0108_pardevice = NULL;
}
static void ks0108_parport_detach(struct parport *port)
{
if (port->base != ks0108_port)
return;
if (!ks0108_pardevice) {
pr_err("%s: already unregistered.\n", KS0108_NAME);
return;
}
parport_release(ks0108_pardevice);
parport_unregister_device(ks0108_pardevice);
ks0108_pardevice = NULL;
ks0108_parport = NULL;
}
/*
* Module Init & Exit
*/
static struct parport_driver ks0108_parport_driver = {
.name = "ks0108",
.match_port = ks0108_parport_attach,
.detach = ks0108_parport_detach,
};
module_parport_driver(ks0108_parport_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Miguel Ojeda <ojeda@kernel.org>");
MODULE_DESCRIPTION("ks0108 LCD Controller driver");
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