1/*
2 * PCA9552 I2C LED blinker
3 *
4 * https://www.nxp.com/docs/en/application-note/AN264.pdf
5 *
6 * Copyright (c) 2017-2018, IBM Corporation.
7 *
8 * This work is licensed under the terms of the GNU GPL, version 2 or
9 * later. See the COPYING file in the top-level directory.
10 */
11
12#include "qemu/osdep.h"
13#include "qemu/log.h"
14#include "qemu/module.h"
15#include "hw/misc/pca9552.h"
16#include "hw/misc/pca9552_regs.h"
17#include "migration/vmstate.h"
18
19#define PCA9552_LED_ON 0x0
20#define PCA9552_LED_OFF 0x1
21#define PCA9552_LED_PWM0 0x2
22#define PCA9552_LED_PWM1 0x3
23
24static uint8_t pca9552_pin_get_config(PCA9552State *s, int pin)
25{
26 uint8_t reg = PCA9552_LS0 + (pin / 4);
27 uint8_t shift = (pin % 4) << 1;
28
29 return extract32(s->regs[reg], shift, 2);
30}
31
32static void pca9552_update_pin_input(PCA9552State *s)
33{
34 int i;
35
36 for (i = 0; i < s->nr_leds; i++) {
37 uint8_t input_reg = PCA9552_INPUT0 + (i / 8);
38 uint8_t input_shift = (i % 8);
39 uint8_t config = pca9552_pin_get_config(s, i);
40
41 switch (config) {
42 case PCA9552_LED_ON:
43 s->regs[input_reg] |= 1 << input_shift;
44 break;
45 case PCA9552_LED_OFF:
46 s->regs[input_reg] &= ~(1 << input_shift);
47 break;
48 case PCA9552_LED_PWM0:
49 case PCA9552_LED_PWM1:
50 /* TODO */
51 default:
52 break;
53 }
54 }
55}
56
57static uint8_t pca9552_read(PCA9552State *s, uint8_t reg)
58{
59 switch (reg) {
60 case PCA9552_INPUT0:
61 case PCA9552_INPUT1:
62 case PCA9552_PSC0:
63 case PCA9552_PWM0:
64 case PCA9552_PSC1:
65 case PCA9552_PWM1:
66 case PCA9552_LS0:
67 case PCA9552_LS1:
68 case PCA9552_LS2:
69 case PCA9552_LS3:
70 return s->regs[reg];
71 default:
72 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n",
73 __func__, reg);
74 return 0xFF;
75 }
76}
77
78static void pca9552_write(PCA9552State *s, uint8_t reg, uint8_t data)
79{
80 switch (reg) {
81 case PCA9552_PSC0:
82 case PCA9552_PWM0:
83 case PCA9552_PSC1:
84 case PCA9552_PWM1:
85 s->regs[reg] = data;
86 break;
87
88 case PCA9552_LS0:
89 case PCA9552_LS1:
90 case PCA9552_LS2:
91 case PCA9552_LS3:
92 s->regs[reg] = data;
93 pca9552_update_pin_input(s);
94 break;
95
96 case PCA9552_INPUT0:
97 case PCA9552_INPUT1:
98 default:
99 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n",
100 __func__, reg);
101 }
102}
103
104/*
105 * When Auto-Increment is on, the register address is incremented
106 * after each byte is sent to or received by the device. The index
107 * rollovers to 0 when the maximum register address is reached.
108 */
109static void pca9552_autoinc(PCA9552State *s)
110{
111 if (s->pointer != 0xFF && s->pointer & PCA9552_AUTOINC) {
112 uint8_t reg = s->pointer & 0xf;
113
114 reg = (reg + 1) % (s->max_reg + 1);
115 s->pointer = reg | PCA9552_AUTOINC;
116 }
117}
118
119static uint8_t pca9552_recv(I2CSlave *i2c)
120{
121 PCA9552State *s = PCA9552(i2c);
122 uint8_t ret;
123
124 ret = pca9552_read(s, s->pointer & 0xf);
125
126 /*
127 * From the Specs:
128 *
129 * Important Note: When a Read sequence is initiated and the
130 * AI bit is set to Logic Level 1, the Read Sequence MUST
131 * start by a register different from 0.
132 *
133 * I don't know what should be done in this case, so throw an
134 * error.
135 */
136 if (s->pointer == PCA9552_AUTOINC) {
137 qemu_log_mask(LOG_GUEST_ERROR,
138 "%s: Autoincrement read starting with register 0\n",
139 __func__);
140 }
141
142 pca9552_autoinc(s);
143
144 return ret;
145}
146
147static int pca9552_send(I2CSlave *i2c, uint8_t data)
148{
149 PCA9552State *s = PCA9552(i2c);
150
151 /* First byte sent by is the register address */
152 if (s->len == 0) {
153 s->pointer = data;
154 s->len++;
155 } else {
156 pca9552_write(s, s->pointer & 0xf, data);
157
158 pca9552_autoinc(s);
159 }
160
161 return 0;
162}
163
164static int pca9552_event(I2CSlave *i2c, enum i2c_event event)
165{
166 PCA9552State *s = PCA9552(i2c);
167
168 s->len = 0;
169 return 0;
170}
171
172static const VMStateDescription pca9552_vmstate = {
173 .name = "PCA9552",
174 .version_id = 0,
175 .minimum_version_id = 0,
176 .fields = (VMStateField[]) {
177 VMSTATE_UINT8(len, PCA9552State),
178 VMSTATE_UINT8(pointer, PCA9552State),
179 VMSTATE_UINT8_ARRAY(regs, PCA9552State, PCA9552_NR_REGS),
180 VMSTATE_I2C_SLAVE(i2c, PCA9552State),
181 VMSTATE_END_OF_LIST()
182 }
183};
184
185static void pca9552_reset(DeviceState *dev)
186{
187 PCA9552State *s = PCA9552(dev);
188
189 s->regs[PCA9552_PSC0] = 0xFF;
190 s->regs[PCA9552_PWM0] = 0x80;
191 s->regs[PCA9552_PSC1] = 0xFF;
192 s->regs[PCA9552_PWM1] = 0x80;
193 s->regs[PCA9552_LS0] = 0x55; /* all OFF */
194 s->regs[PCA9552_LS1] = 0x55;
195 s->regs[PCA9552_LS2] = 0x55;
196 s->regs[PCA9552_LS3] = 0x55;
197
198 pca9552_update_pin_input(s);
199
200 s->pointer = 0xFF;
201 s->len = 0;
202}
203
204static void pca9552_initfn(Object *obj)
205{
206 PCA9552State *s = PCA9552(obj);
207
208 /* If support for the other PCA955X devices are implemented, these
209 * constant values might be part of class structure describing the
210 * PCA955X device
211 */
212 s->max_reg = PCA9552_LS3;
213 s->nr_leds = 16;
214}
215
216static void pca9552_class_init(ObjectClass *klass, void *data)
217{
218 DeviceClass *dc = DEVICE_CLASS(klass);
219 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
220
221 k->event = pca9552_event;
222 k->recv = pca9552_recv;
223 k->send = pca9552_send;
224 dc->reset = pca9552_reset;
225 dc->vmsd = &pca9552_vmstate;
226}
227
228static const TypeInfo pca9552_info = {
229 .name = TYPE_PCA9552,
230 .parent = TYPE_I2C_SLAVE,
231 .instance_init = pca9552_initfn,
232 .instance_size = sizeof(PCA9552State),
233 .class_init = pca9552_class_init,
234};
235
236static void pca9552_register_types(void)
237{
238 type_register_static(&pca9552_info);
239}
240
241type_init(pca9552_register_types)
242