1/*
2 * MAX7310 8-port GPIO expansion chip.
3 *
4 * Copyright (c) 2006 Openedhand Ltd.
5 * Written by Andrzej Zaborowski <balrog@zabor.org>
6 *
7 * This file is licensed under GNU GPL.
8 */
9
10#include "qemu/osdep.h"
11#include "hw/hw.h"
12#include "hw/i2c/i2c.h"
13#include "hw/hw.h"
14#include "hw/irq.h"
15#include "migration/vmstate.h"
16#include "qemu/module.h"
17
18#define TYPE_MAX7310 "max7310"
19#define MAX7310(obj) OBJECT_CHECK(MAX7310State, (obj), TYPE_MAX7310)
20
21typedef struct MAX7310State {
22 I2CSlave parent_obj;
23
24 int i2c_command_byte;
25 int len;
26
27 uint8_t level;
28 uint8_t direction;
29 uint8_t polarity;
30 uint8_t status;
31 uint8_t command;
32 qemu_irq handler[8];
33 qemu_irq *gpio_in;
34} MAX7310State;
35
36static void max7310_reset(DeviceState *dev)
37{
38 MAX7310State *s = MAX7310(dev);
39
40 s->level &= s->direction;
41 s->direction = 0xff;
42 s->polarity = 0xf0;
43 s->status = 0x01;
44 s->command = 0x00;
45}
46
47static uint8_t max7310_rx(I2CSlave *i2c)
48{
49 MAX7310State *s = MAX7310(i2c);
50
51 switch (s->command) {
52 case 0x00: /* Input port */
53 return s->level ^ s->polarity;
54 break;
55
56 case 0x01: /* Output port */
57 return s->level & ~s->direction;
58 break;
59
60 case 0x02: /* Polarity inversion */
61 return s->polarity;
62
63 case 0x03: /* Configuration */
64 return s->direction;
65
66 case 0x04: /* Timeout */
67 return s->status;
68 break;
69
70 case 0xff: /* Reserved */
71 return 0xff;
72
73 default:
74#ifdef VERBOSE
75 printf("%s: unknown register %02x\n", __func__, s->command);
76#endif
77 break;
78 }
79 return 0xff;
80}
81
82static int max7310_tx(I2CSlave *i2c, uint8_t data)
83{
84 MAX7310State *s = MAX7310(i2c);
85 uint8_t diff;
86 int line;
87
88 if (s->len ++ > 1) {
89#ifdef VERBOSE
90 printf("%s: message too long (%i bytes)\n", __func__, s->len);
91#endif
92 return 1;
93 }
94
95 if (s->i2c_command_byte) {
96 s->command = data;
97 s->i2c_command_byte = 0;
98 return 0;
99 }
100
101 switch (s->command) {
102 case 0x01: /* Output port */
103 for (diff = (data ^ s->level) & ~s->direction; diff;
104 diff &= ~(1 << line)) {
105 line = ctz32(diff);
106 if (s->handler[line])
107 qemu_set_irq(s->handler[line], (data >> line) & 1);
108 }
109 s->level = (s->level & s->direction) | (data & ~s->direction);
110 break;
111
112 case 0x02: /* Polarity inversion */
113 s->polarity = data;
114 break;
115
116 case 0x03: /* Configuration */
117 s->level &= ~(s->direction ^ data);
118 s->direction = data;
119 break;
120
121 case 0x04: /* Timeout */
122 s->status = data;
123 break;
124
125 case 0x00: /* Input port - ignore writes */
126 break;
127 default:
128#ifdef VERBOSE
129 printf("%s: unknown register %02x\n", __func__, s->command);
130#endif
131 return 1;
132 }
133
134 return 0;
135}
136
137static int max7310_event(I2CSlave *i2c, enum i2c_event event)
138{
139 MAX7310State *s = MAX7310(i2c);
140 s->len = 0;
141
142 switch (event) {
143 case I2C_START_SEND:
144 s->i2c_command_byte = 1;
145 break;
146 case I2C_FINISH:
147#ifdef VERBOSE
148 if (s->len == 1)
149 printf("%s: message too short (%i bytes)\n", __func__, s->len);
150#endif
151 break;
152 default:
153 break;
154 }
155
156 return 0;
157}
158
159static const VMStateDescription vmstate_max7310 = {
160 .name = "max7310",
161 .version_id = 0,
162 .minimum_version_id = 0,
163 .fields = (VMStateField[]) {
164 VMSTATE_INT32(i2c_command_byte, MAX7310State),
165 VMSTATE_INT32(len, MAX7310State),
166 VMSTATE_UINT8(level, MAX7310State),
167 VMSTATE_UINT8(direction, MAX7310State),
168 VMSTATE_UINT8(polarity, MAX7310State),
169 VMSTATE_UINT8(status, MAX7310State),
170 VMSTATE_UINT8(command, MAX7310State),
171 VMSTATE_I2C_SLAVE(parent_obj, MAX7310State),
172 VMSTATE_END_OF_LIST()
173 }
174};
175
176static void max7310_gpio_set(void *opaque, int line, int level)
177{
178 MAX7310State *s = (MAX7310State *) opaque;
179 if (line >= ARRAY_SIZE(s->handler) || line < 0)
180 hw_error("bad GPIO line");
181
182 if (level)
183 s->level |= s->direction & (1 << line);
184 else
185 s->level &= ~(s->direction & (1 << line));
186}
187
188/* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
189 * but also accepts sequences that are not SMBus so return an I2C device. */
190static void max7310_realize(DeviceState *dev, Error **errp)
191{
192 I2CSlave *i2c = I2C_SLAVE(dev);
193 MAX7310State *s = MAX7310(dev);
194
195 qdev_init_gpio_in(&i2c->qdev, max7310_gpio_set, 8);
196 qdev_init_gpio_out(&i2c->qdev, s->handler, 8);
197}
198
199static void max7310_class_init(ObjectClass *klass, void *data)
200{
201 DeviceClass *dc = DEVICE_CLASS(klass);
202 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
203
204 dc->realize = max7310_realize;
205 k->event = max7310_event;
206 k->recv = max7310_rx;
207 k->send = max7310_tx;
208 dc->reset = max7310_reset;
209 dc->vmsd = &vmstate_max7310;
210}
211
212static const TypeInfo max7310_info = {
213 .name = TYPE_MAX7310,
214 .parent = TYPE_I2C_SLAVE,
215 .instance_size = sizeof(MAX7310State),
216 .class_init = max7310_class_init,
217};
218
219static void max7310_register_types(void)
220{
221 type_register_static(&max7310_info);
222}
223
224type_init(max7310_register_types)
225