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