395 lines
8.2 KiB
C
395 lines
8.2 KiB
C
/*
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* Filename: cfag12864b.c
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* Version: 0.1.0
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* Description: cfag12864b LCD driver
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* License: GPLv2
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* Depends: ks0108
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*
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* Author: Copyright (C) Miguel Ojeda Sandonis
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* Date: 2006-10-31
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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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/fs.h>
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#include <linux/slab.h>
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#include <linux/cdev.h>
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/jiffies.h>
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#include <linux/mutex.h>
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#include <linux/uaccess.h>
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#include <linux/vmalloc.h>
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#include <linux/workqueue.h>
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#include <linux/ks0108.h>
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#include <linux/cfag12864b.h>
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#define CFAG12864B_NAME "cfag12864b"
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/*
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* Module Parameters
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*/
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static unsigned int cfag12864b_rate = CONFIG_CFAG12864B_RATE;
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module_param(cfag12864b_rate, uint, S_IRUGO);
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MODULE_PARM_DESC(cfag12864b_rate,
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"Refresh rate (hertz)");
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unsigned int cfag12864b_getrate(void)
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{
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return cfag12864b_rate;
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}
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/*
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* cfag12864b Commands
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*
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* E = Enable signal
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* Every time E switch from low to high,
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* cfag12864b/ks0108 reads the command/data.
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*
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* CS1 = First ks0108controller.
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* If high, the first ks0108 controller receives commands/data.
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*
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* CS2 = Second ks0108 controller
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* If high, the second ks0108 controller receives commands/data.
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*
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* DI = Data/Instruction
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* If low, cfag12864b will expect commands.
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* If high, cfag12864b will expect data.
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*
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*/
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#define bit(n) (((unsigned char)1)<<(n))
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#define CFAG12864B_BIT_E (0)
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#define CFAG12864B_BIT_CS1 (2)
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#define CFAG12864B_BIT_CS2 (1)
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#define CFAG12864B_BIT_DI (3)
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static unsigned char cfag12864b_state;
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static void cfag12864b_set(void)
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{
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ks0108_writecontrol(cfag12864b_state);
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}
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static void cfag12864b_setbit(unsigned char state, unsigned char n)
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{
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if (state)
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cfag12864b_state |= bit(n);
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else
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cfag12864b_state &= ~bit(n);
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}
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static void cfag12864b_e(unsigned char state)
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{
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cfag12864b_setbit(state, CFAG12864B_BIT_E);
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cfag12864b_set();
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}
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static void cfag12864b_cs1(unsigned char state)
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{
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cfag12864b_setbit(state, CFAG12864B_BIT_CS1);
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}
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static void cfag12864b_cs2(unsigned char state)
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{
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cfag12864b_setbit(state, CFAG12864B_BIT_CS2);
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}
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static void cfag12864b_di(unsigned char state)
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{
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cfag12864b_setbit(state, CFAG12864B_BIT_DI);
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}
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static void cfag12864b_setcontrollers(unsigned char first,
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unsigned char second)
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{
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if (first)
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cfag12864b_cs1(0);
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else
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cfag12864b_cs1(1);
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if (second)
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cfag12864b_cs2(0);
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else
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cfag12864b_cs2(1);
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}
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static void cfag12864b_controller(unsigned char which)
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{
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if (which == 0)
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cfag12864b_setcontrollers(1, 0);
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else if (which == 1)
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cfag12864b_setcontrollers(0, 1);
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}
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static void cfag12864b_displaystate(unsigned char state)
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{
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cfag12864b_di(0);
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cfag12864b_e(1);
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ks0108_displaystate(state);
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cfag12864b_e(0);
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}
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static void cfag12864b_address(unsigned char address)
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{
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cfag12864b_di(0);
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cfag12864b_e(1);
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ks0108_address(address);
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cfag12864b_e(0);
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}
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static void cfag12864b_page(unsigned char page)
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{
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cfag12864b_di(0);
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cfag12864b_e(1);
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ks0108_page(page);
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cfag12864b_e(0);
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}
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static void cfag12864b_startline(unsigned char startline)
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{
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cfag12864b_di(0);
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cfag12864b_e(1);
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ks0108_startline(startline);
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cfag12864b_e(0);
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}
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static void cfag12864b_writebyte(unsigned char byte)
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{
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cfag12864b_di(1);
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cfag12864b_e(1);
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ks0108_writedata(byte);
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cfag12864b_e(0);
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}
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static void cfag12864b_nop(void)
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{
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cfag12864b_startline(0);
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}
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/*
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* cfag12864b Internal Commands
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*/
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static void cfag12864b_on(void)
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{
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cfag12864b_setcontrollers(1, 1);
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cfag12864b_displaystate(1);
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}
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static void cfag12864b_off(void)
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{
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cfag12864b_setcontrollers(1, 1);
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cfag12864b_displaystate(0);
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}
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static void cfag12864b_clear(void)
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{
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unsigned char i, j;
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cfag12864b_setcontrollers(1, 1);
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for (i = 0; i < CFAG12864B_PAGES; i++) {
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cfag12864b_page(i);
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cfag12864b_address(0);
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for (j = 0; j < CFAG12864B_ADDRESSES; j++)
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cfag12864b_writebyte(0);
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}
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}
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/*
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* Update work
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*/
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unsigned char *cfag12864b_buffer;
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static unsigned char *cfag12864b_cache;
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static DEFINE_MUTEX(cfag12864b_mutex);
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static unsigned char cfag12864b_updating;
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static void cfag12864b_update(struct work_struct *delayed_work);
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static struct workqueue_struct *cfag12864b_workqueue;
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static DECLARE_DELAYED_WORK(cfag12864b_work, cfag12864b_update);
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static void cfag12864b_queue(void)
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{
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queue_delayed_work(cfag12864b_workqueue, &cfag12864b_work,
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HZ / cfag12864b_rate);
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}
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unsigned char cfag12864b_enable(void)
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{
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unsigned char ret;
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mutex_lock(&cfag12864b_mutex);
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if (!cfag12864b_updating) {
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cfag12864b_updating = 1;
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cfag12864b_queue();
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ret = 0;
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} else
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ret = 1;
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mutex_unlock(&cfag12864b_mutex);
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return ret;
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}
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void cfag12864b_disable(void)
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{
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mutex_lock(&cfag12864b_mutex);
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if (cfag12864b_updating) {
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cfag12864b_updating = 0;
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cancel_delayed_work(&cfag12864b_work);
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flush_workqueue(cfag12864b_workqueue);
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}
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mutex_unlock(&cfag12864b_mutex);
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}
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unsigned char cfag12864b_isenabled(void)
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{
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return cfag12864b_updating;
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}
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static void cfag12864b_update(struct work_struct *work)
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{
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unsigned char c;
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unsigned short i, j, k, b;
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if (memcmp(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE)) {
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for (i = 0; i < CFAG12864B_CONTROLLERS; i++) {
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cfag12864b_controller(i);
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cfag12864b_nop();
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for (j = 0; j < CFAG12864B_PAGES; j++) {
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cfag12864b_page(j);
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cfag12864b_nop();
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cfag12864b_address(0);
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cfag12864b_nop();
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for (k = 0; k < CFAG12864B_ADDRESSES; k++) {
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for (c = 0, b = 0; b < 8; b++)
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if (cfag12864b_buffer
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[i * CFAG12864B_ADDRESSES / 8
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+ k / 8 + (j * 8 + b) *
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CFAG12864B_WIDTH / 8]
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& bit(k % 8))
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c |= bit(b);
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cfag12864b_writebyte(c);
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}
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}
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}
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memcpy(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE);
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}
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if (cfag12864b_updating)
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cfag12864b_queue();
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}
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/*
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* cfag12864b Exported Symbols
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*/
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EXPORT_SYMBOL_GPL(cfag12864b_buffer);
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EXPORT_SYMBOL_GPL(cfag12864b_getrate);
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EXPORT_SYMBOL_GPL(cfag12864b_enable);
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EXPORT_SYMBOL_GPL(cfag12864b_disable);
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EXPORT_SYMBOL_GPL(cfag12864b_isenabled);
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/*
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* Is the module inited?
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*/
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static unsigned char cfag12864b_inited;
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unsigned char cfag12864b_isinited(void)
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{
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return cfag12864b_inited;
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}
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EXPORT_SYMBOL_GPL(cfag12864b_isinited);
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/*
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* Module Init & Exit
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*/
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static int __init cfag12864b_init(void)
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{
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int ret = -EINVAL;
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/* ks0108_init() must be called first */
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if (!ks0108_isinited()) {
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printk(KERN_ERR CFAG12864B_NAME ": ERROR: "
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"ks0108 is not initialized\n");
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goto none;
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}
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BUILD_BUG_ON(PAGE_SIZE < CFAG12864B_SIZE);
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cfag12864b_buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
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if (cfag12864b_buffer == NULL) {
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printk(KERN_ERR CFAG12864B_NAME ": ERROR: "
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"can't get a free page\n");
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ret = -ENOMEM;
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goto none;
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}
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cfag12864b_cache = kmalloc(sizeof(unsigned char) *
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CFAG12864B_SIZE, GFP_KERNEL);
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if (cfag12864b_cache == NULL) {
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printk(KERN_ERR CFAG12864B_NAME ": ERROR: "
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"can't alloc cache buffer (%i bytes)\n",
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CFAG12864B_SIZE);
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ret = -ENOMEM;
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goto bufferalloced;
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}
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cfag12864b_workqueue = create_singlethread_workqueue(CFAG12864B_NAME);
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if (cfag12864b_workqueue == NULL)
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goto cachealloced;
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cfag12864b_clear();
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cfag12864b_on();
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cfag12864b_inited = 1;
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return 0;
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cachealloced:
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kfree(cfag12864b_cache);
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bufferalloced:
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free_page((unsigned long) cfag12864b_buffer);
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none:
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return ret;
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}
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static void __exit cfag12864b_exit(void)
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{
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cfag12864b_disable();
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cfag12864b_off();
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destroy_workqueue(cfag12864b_workqueue);
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kfree(cfag12864b_cache);
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free_page((unsigned long) cfag12864b_buffer);
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}
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module_init(cfag12864b_init);
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module_exit(cfag12864b_exit);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>");
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MODULE_DESCRIPTION("cfag12864b LCD driver");
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