1/*
2 * linux/drivers/video/n411.c -- Platform device for N411 EPD kit
3 *
4 * Copyright (C) 2008, Jaya Kumar
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file COPYING in the main directory of this archive for
8 * more details.
9 *
10 * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
11 *
12 * This driver is written to be used with the Hecuba display controller
13 * board, and tested with the EInk 800x600 display in 1 bit mode.
14 * The interface between Hecuba and the host is TTL based GPIO. The
15 * GPIO requirements are 8 writable data lines and 6 lines for control.
16 * Only 4 of the controls are actually used here but 6 for future use.
17 * The driver requires the IO addresses for data and control GPIO at
18 * load time. It is also possible to use this display with a standard
19 * PC parallel port.
20 *
21 * General notes:
22 * - User must set dio_addr=0xIOADDR cio_addr=0xIOADDR c2io_addr=0xIOADDR
23 *
24 */
25
26#include <linux/module.h>
27#include <linux/kernel.h>
28#include <linux/errno.h>
29#include <linux/string.h>
30#include <linux/delay.h>
31#include <linux/interrupt.h>
32#include <linux/fb.h>
33#include <linux/init.h>
34#include <linux/platform_device.h>
35#include <linux/list.h>
36#include <linux/uaccess.h>
37#include <linux/irq.h>
38
39#include <video/hecubafb.h>
40
41static unsigned long dio_addr;
42static unsigned long cio_addr;
43static unsigned long c2io_addr;
44static unsigned long splashval;
45static unsigned int nosplash;
46static unsigned char ctl;
47
48static void n411_set_ctl(struct hecubafb_par *par, unsigned char bit, unsigned
49							char state)
50{
51	switch (bit) {
52	case HCB_CD_BIT:
53		if (state)
54			ctl &= ~(HCB_CD_BIT);
55		else
56			ctl |= HCB_CD_BIT;
57		break;
58	case HCB_DS_BIT:
59		if (state)
60			ctl &= ~(HCB_DS_BIT);
61		else
62			ctl |= HCB_DS_BIT;
63		break;
64	}
65	outb(ctl, cio_addr);
66}
67
68static unsigned char n411_get_ctl(struct hecubafb_par *par)
69{
70	return inb(c2io_addr);
71}
72
73static void n411_set_data(struct hecubafb_par *par, unsigned char value)
74{
75	outb(value, dio_addr);
76}
77
78static void n411_wait_for_ack(struct hecubafb_par *par, int clear)
79{
80	int timeout;
81	unsigned char tmp;
82
83	timeout = 500;
84	do {
85		tmp = n411_get_ctl(par);
86		if ((tmp & HCB_ACK_BIT) && (!clear))
87			return;
88		else if (!(tmp & HCB_ACK_BIT) && (clear))
89			return;
90		udelay(1);
91	} while (timeout--);
92	printk(KERN_ERR "timed out waiting for ack\n");
93}
94
95static int n411_init_control(struct hecubafb_par *par)
96{
97	unsigned char tmp;
98	/* for init, we want the following setup to be set:
99	WUP = lo
100	ACK = hi
101	DS = hi
102	RW = hi
103	CD = lo
104	*/
105
106	/* write WUP to lo, DS to hi, RW to hi, CD to lo */
107	ctl = HCB_WUP_BIT | HCB_RW_BIT | HCB_CD_BIT ;
108	n411_set_ctl(par, HCB_DS_BIT, 1);
109
110	/* check ACK is not lo */
111	tmp = n411_get_ctl(par);
112	if (tmp & HCB_ACK_BIT) {
113		printk(KERN_ERR "Fail because ACK is already low\n");
114		return -ENXIO;
115	}
116
117	return 0;
118}
119
120
121static int n411_init_board(struct hecubafb_par *par)
122{
123	int retval;
124
125	retval = n411_init_control(par);
126	if (retval)
127		return retval;
128
129	par->send_command(par, APOLLO_INIT_DISPLAY);
130	par->send_data(par, 0x81);
131
132	/* have to wait while display resets */
133	udelay(1000);
134
135	/* if we were told to splash the screen, we just clear it */
136	if (!nosplash) {
137		par->send_command(par, APOLLO_ERASE_DISPLAY);
138		par->send_data(par, splashval);
139	}
140
141	return 0;
142}
143
144static struct hecuba_board n411_board = {
145	.owner			= THIS_MODULE,
146	.init			= n411_init_board,
147	.set_ctl		= n411_set_ctl,
148	.set_data		= n411_set_data,
149	.wait_for_ack		= n411_wait_for_ack,
150};
151
152static struct platform_device *n411_device;
153static int __init n411_init(void)
154{
155	int ret;
156	if (!dio_addr || !cio_addr || !c2io_addr) {
157		printk(KERN_WARNING "no IO addresses supplied\n");
158		return -EINVAL;
159	}
160
161	/* request our platform independent driver */
162	request_module("hecubafb");
163
164	n411_device = platform_device_alloc("hecubafb", -1);
165	if (!n411_device)
166		return -ENOMEM;
167
168	platform_device_add_data(n411_device, &n411_board, sizeof(n411_board));
169
170	/* this _add binds hecubafb to n411. hecubafb refcounts n411 */
171	ret = platform_device_add(n411_device);
172
173	if (ret)
174		platform_device_put(n411_device);
175
176	return ret;
177
178}
179
180static void __exit n411_exit(void)
181{
182	platform_device_unregister(n411_device);
183}
184
185module_init(n411_init);
186module_exit(n411_exit);
187
188module_param(nosplash, uint, 0);
189MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
190module_param(dio_addr, ulong, 0);
191MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
192module_param(cio_addr, ulong, 0);
193MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
194module_param(c2io_addr, ulong, 0);
195MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
196module_param(splashval, ulong, 0);
197MODULE_PARM_DESC(splashval, "Splash pattern: 0x00 is black, 0x01 is white");
198
199MODULE_DESCRIPTION("board driver for n411 hecuba/apollo epd kit");
200MODULE_AUTHOR("Jaya Kumar");
201MODULE_LICENSE("GPL");
202
203