xref: /openbmc/linux/drivers/video/fbdev/n411.c (revision c729203d)
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 
41 static unsigned long dio_addr;
42 static unsigned long cio_addr;
43 static unsigned long c2io_addr;
44 static unsigned long splashval;
45 static unsigned int nosplash;
46 static unsigned char ctl;
47 
n411_set_ctl(struct hecubafb_par * par,unsigned char bit,unsigned char state)48 static 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 
n411_get_ctl(struct hecubafb_par * par)68 static unsigned char n411_get_ctl(struct hecubafb_par *par)
69 {
70 	return inb(c2io_addr);
71 }
72 
n411_set_data(struct hecubafb_par * par,unsigned char value)73 static void n411_set_data(struct hecubafb_par *par, unsigned char value)
74 {
75 	outb(value, dio_addr);
76 }
77 
n411_wait_for_ack(struct hecubafb_par * par,int clear)78 static 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 
n411_init_control(struct hecubafb_par * par)95 static 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 
n411_init_board(struct hecubafb_par * par)121 static 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 
144 static 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 
152 static struct platform_device *n411_device;
n411_init(void)153 static 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 	ret = platform_device_add_data(n411_device, &n411_board,
169 				       sizeof(n411_board));
170 	if (ret)
171 		goto put_plat_device;
172 
173 	/* this _add binds hecubafb to n411. hecubafb refcounts n411 */
174 	ret = platform_device_add(n411_device);
175 
176 	if (ret)
177 		goto put_plat_device;
178 
179 	return 0;
180 
181 put_plat_device:
182 	platform_device_put(n411_device);
183 	return ret;
184 }
185 
n411_exit(void)186 static void __exit n411_exit(void)
187 {
188 	platform_device_unregister(n411_device);
189 }
190 
191 module_init(n411_init);
192 module_exit(n411_exit);
193 
194 module_param(nosplash, uint, 0);
195 MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
196 module_param_hw(dio_addr, ulong, ioport, 0);
197 MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
198 module_param_hw(cio_addr, ulong, ioport, 0);
199 MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
200 module_param_hw(c2io_addr, ulong, ioport, 0);
201 MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
202 module_param(splashval, ulong, 0);
203 MODULE_PARM_DESC(splashval, "Splash pattern: 0x00 is black, 0x01 is white");
204 
205 MODULE_DESCRIPTION("board driver for n411 hecuba/apollo epd kit");
206 MODULE_AUTHOR("Jaya Kumar");
207 MODULE_LICENSE("GPL");
208 
209