1 /*
2 * PCA9554 I/O port
3 *
4 * Copyright (c) 2023, IBM Corporation.
5 *
6 * SPDX-License-Identifier: GPL-2.0-or-later
7 */
8
9 #include "qemu/osdep.h"
10 #include "qemu/log.h"
11 #include "qemu/module.h"
12 #include "qemu/bitops.h"
13 #include "hw/qdev-properties.h"
14 #include "hw/gpio/pca9554.h"
15 #include "hw/gpio/pca9554_regs.h"
16 #include "hw/irq.h"
17 #include "migration/vmstate.h"
18 #include "qapi/error.h"
19 #include "qapi/visitor.h"
20 #include "trace.h"
21 #include "qom/object.h"
22
23 struct PCA9554Class {
24 /*< private >*/
25 I2CSlaveClass parent_class;
26 /*< public >*/
27 };
28 typedef struct PCA9554Class PCA9554Class;
29
30 DECLARE_CLASS_CHECKERS(PCA9554Class, PCA9554,
31 TYPE_PCA9554)
32
33 #define PCA9554_PIN_LOW 0x0
34 #define PCA9554_PIN_HIZ 0x1
35
36 static const char *pin_state[] = {"low", "high"};
37
pca9554_update_pin_input(PCA9554State * s)38 static void pca9554_update_pin_input(PCA9554State *s)
39 {
40 int i;
41 uint8_t config = s->regs[PCA9554_CONFIG];
42 uint8_t output = s->regs[PCA9554_OUTPUT];
43 uint8_t internal_state = config | output;
44
45 for (i = 0; i < PCA9554_PIN_COUNT; i++) {
46 uint8_t bit_mask = 1 << i;
47 uint8_t internal_pin_state = (internal_state >> i) & 0x1;
48 uint8_t old_value = s->regs[PCA9554_INPUT] & bit_mask;
49 uint8_t new_value;
50
51 switch (internal_pin_state) {
52 case PCA9554_PIN_LOW:
53 s->regs[PCA9554_INPUT] &= ~bit_mask;
54 break;
55 case PCA9554_PIN_HIZ:
56 /*
57 * pullup sets it to a logical 1 unless
58 * external device drives it low.
59 */
60 if (s->ext_state[i] == PCA9554_PIN_LOW) {
61 s->regs[PCA9554_INPUT] &= ~bit_mask;
62 } else {
63 s->regs[PCA9554_INPUT] |= bit_mask;
64 }
65 break;
66 default:
67 break;
68 }
69
70 /* update irq state only if pin state changed */
71 new_value = s->regs[PCA9554_INPUT] & bit_mask;
72 if (new_value != old_value) {
73 if (new_value) {
74 /* changed from 0 to 1 */
75 qemu_set_irq(s->gpio_out[i], 1);
76 } else {
77 /* changed from 1 to 0 */
78 qemu_set_irq(s->gpio_out[i], 0);
79 }
80 }
81 }
82 }
83
pca9554_read(PCA9554State * s,uint8_t reg)84 static uint8_t pca9554_read(PCA9554State *s, uint8_t reg)
85 {
86 switch (reg) {
87 case PCA9554_INPUT:
88 return s->regs[PCA9554_INPUT] ^ s->regs[PCA9554_POLARITY];
89 case PCA9554_OUTPUT:
90 case PCA9554_POLARITY:
91 case PCA9554_CONFIG:
92 return s->regs[reg];
93 default:
94 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n",
95 __func__, reg);
96 return 0xFF;
97 }
98 }
99
pca9554_write(PCA9554State * s,uint8_t reg,uint8_t data)100 static void pca9554_write(PCA9554State *s, uint8_t reg, uint8_t data)
101 {
102 switch (reg) {
103 case PCA9554_OUTPUT:
104 case PCA9554_CONFIG:
105 s->regs[reg] = data;
106 pca9554_update_pin_input(s);
107 break;
108 case PCA9554_POLARITY:
109 s->regs[reg] = data;
110 break;
111 case PCA9554_INPUT:
112 default:
113 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n",
114 __func__, reg);
115 }
116 }
117
pca9554_recv(I2CSlave * i2c)118 static uint8_t pca9554_recv(I2CSlave *i2c)
119 {
120 PCA9554State *s = PCA9554(i2c);
121 uint8_t ret;
122
123 ret = pca9554_read(s, s->pointer & 0x3);
124
125 return ret;
126 }
127
pca9554_send(I2CSlave * i2c,uint8_t data)128 static int pca9554_send(I2CSlave *i2c, uint8_t data)
129 {
130 PCA9554State *s = PCA9554(i2c);
131
132 /* First byte sent by is the register address */
133 if (s->len == 0) {
134 s->pointer = data;
135 s->len++;
136 } else {
137 pca9554_write(s, s->pointer & 0x3, data);
138 }
139
140 return 0;
141 }
142
pca9554_event(I2CSlave * i2c,enum i2c_event event)143 static int pca9554_event(I2CSlave *i2c, enum i2c_event event)
144 {
145 PCA9554State *s = PCA9554(i2c);
146
147 s->len = 0;
148 return 0;
149 }
150
pca9554_get_pin(Object * obj,Visitor * v,const char * name,void * opaque,Error ** errp)151 static void pca9554_get_pin(Object *obj, Visitor *v, const char *name,
152 void *opaque, Error **errp)
153 {
154 PCA9554State *s = PCA9554(obj);
155 int pin, rc;
156 uint8_t state;
157
158 rc = sscanf(name, "pin%2d", &pin);
159 if (rc != 1) {
160 error_setg(errp, "%s: error reading %s", __func__, name);
161 return;
162 }
163 if (pin < 0 || pin >= PCA9554_PIN_COUNT) {
164 error_setg(errp, "%s invalid pin %s", __func__, name);
165 return;
166 }
167
168 state = pca9554_read(s, PCA9554_CONFIG);
169 state |= pca9554_read(s, PCA9554_OUTPUT);
170 state = (state >> pin) & 0x1;
171 visit_type_str(v, name, (char **)&pin_state[state], errp);
172 }
173
pca9554_set_pin(Object * obj,Visitor * v,const char * name,void * opaque,Error ** errp)174 static void pca9554_set_pin(Object *obj, Visitor *v, const char *name,
175 void *opaque, Error **errp)
176 {
177 PCA9554State *s = PCA9554(obj);
178 int pin, rc, val;
179 uint8_t state, mask;
180 char *state_str;
181
182 if (!visit_type_str(v, name, &state_str, errp)) {
183 return;
184 }
185 rc = sscanf(name, "pin%2d", &pin);
186 if (rc != 1) {
187 error_setg(errp, "%s: error reading %s", __func__, name);
188 return;
189 }
190 if (pin < 0 || pin >= PCA9554_PIN_COUNT) {
191 error_setg(errp, "%s invalid pin %s", __func__, name);
192 return;
193 }
194
195 for (state = 0; state < ARRAY_SIZE(pin_state); state++) {
196 if (!strcmp(state_str, pin_state[state])) {
197 break;
198 }
199 }
200 if (state >= ARRAY_SIZE(pin_state)) {
201 error_setg(errp, "%s invalid pin state %s", __func__, state_str);
202 return;
203 }
204
205 /* First, modify the output register bit */
206 val = pca9554_read(s, PCA9554_OUTPUT);
207 mask = 0x1 << pin;
208 if (state == PCA9554_PIN_LOW) {
209 val &= ~(mask);
210 } else {
211 val |= mask;
212 }
213 pca9554_write(s, PCA9554_OUTPUT, val);
214
215 /* Then, clear the config register bit for output mode */
216 val = pca9554_read(s, PCA9554_CONFIG);
217 val &= ~mask;
218 pca9554_write(s, PCA9554_CONFIG, val);
219 }
220
221 static const VMStateDescription pca9554_vmstate = {
222 .name = "PCA9554",
223 .version_id = 0,
224 .minimum_version_id = 0,
225 .fields = (VMStateField[]) {
226 VMSTATE_UINT8(len, PCA9554State),
227 VMSTATE_UINT8(pointer, PCA9554State),
228 VMSTATE_UINT8_ARRAY(regs, PCA9554State, PCA9554_NR_REGS),
229 VMSTATE_UINT8_ARRAY(ext_state, PCA9554State, PCA9554_PIN_COUNT),
230 VMSTATE_I2C_SLAVE(i2c, PCA9554State),
231 VMSTATE_END_OF_LIST()
232 }
233 };
234
pca9554_reset(DeviceState * dev)235 static void pca9554_reset(DeviceState *dev)
236 {
237 PCA9554State *s = PCA9554(dev);
238
239 s->regs[PCA9554_INPUT] = 0xFF;
240 s->regs[PCA9554_OUTPUT] = 0xFF;
241 s->regs[PCA9554_POLARITY] = 0x0; /* No pins are inverted */
242 s->regs[PCA9554_CONFIG] = 0xFF; /* All pins are inputs */
243
244 memset(s->ext_state, PCA9554_PIN_HIZ, PCA9554_PIN_COUNT);
245 pca9554_update_pin_input(s);
246
247 s->pointer = 0x0;
248 s->len = 0;
249 }
250
pca9554_initfn(Object * obj)251 static void pca9554_initfn(Object *obj)
252 {
253 int pin;
254
255 for (pin = 0; pin < PCA9554_PIN_COUNT; pin++) {
256 char *name;
257
258 name = g_strdup_printf("pin%d", pin);
259 object_property_add(obj, name, "bool", pca9554_get_pin, pca9554_set_pin,
260 NULL, NULL);
261 g_free(name);
262 }
263 }
264
pca9554_set_ext_state(PCA9554State * s,int pin,int level)265 static void pca9554_set_ext_state(PCA9554State *s, int pin, int level)
266 {
267 if (s->ext_state[pin] != level) {
268 s->ext_state[pin] = level;
269 pca9554_update_pin_input(s);
270 }
271 }
272
pca9554_gpio_in_handler(void * opaque,int pin,int level)273 static void pca9554_gpio_in_handler(void *opaque, int pin, int level)
274 {
275
276 PCA9554State *s = PCA9554(opaque);
277
278 assert((pin >= 0) && (pin < PCA9554_PIN_COUNT));
279 pca9554_set_ext_state(s, pin, level);
280 }
281
pca9554_realize(DeviceState * dev,Error ** errp)282 static void pca9554_realize(DeviceState *dev, Error **errp)
283 {
284 PCA9554State *s = PCA9554(dev);
285
286 if (!s->description) {
287 s->description = g_strdup("pca9554");
288 }
289
290 qdev_init_gpio_out(dev, s->gpio_out, PCA9554_PIN_COUNT);
291 qdev_init_gpio_in(dev, pca9554_gpio_in_handler, PCA9554_PIN_COUNT);
292 }
293
294 static Property pca9554_properties[] = {
295 DEFINE_PROP_STRING("description", PCA9554State, description),
296 DEFINE_PROP_END_OF_LIST(),
297 };
298
pca9554_class_init(ObjectClass * klass,void * data)299 static void pca9554_class_init(ObjectClass *klass, void *data)
300 {
301 DeviceClass *dc = DEVICE_CLASS(klass);
302 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
303
304 k->event = pca9554_event;
305 k->recv = pca9554_recv;
306 k->send = pca9554_send;
307 dc->realize = pca9554_realize;
308 dc->reset = pca9554_reset;
309 dc->vmsd = &pca9554_vmstate;
310 device_class_set_props(dc, pca9554_properties);
311 }
312
313 static const TypeInfo pca9554_info = {
314 .name = TYPE_PCA9554,
315 .parent = TYPE_I2C_SLAVE,
316 .instance_init = pca9554_initfn,
317 .instance_size = sizeof(PCA9554State),
318 .class_init = pca9554_class_init,
319 .class_size = sizeof(PCA9554Class),
320 .abstract = false,
321 };
322
pca9554_register_types(void)323 static void pca9554_register_types(void)
324 {
325 type_register_static(&pca9554_info);
326 }
327
328 type_init(pca9554_register_types)
329