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 * Copyright (c) 2020 Philippe Mathieu-Daudé
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or
10 * later. See the COPYING file in the top-level directory.
11 */
12
13 #include "qemu/osdep.h"
14 #include "qemu/log.h"
15 #include "qemu/module.h"
16 #include "qemu/bitops.h"
17 #include "hw/qdev-properties.h"
18 #include "hw/gpio/pca9552.h"
19 #include "hw/gpio/pca9552_regs.h"
20 #include "hw/irq.h"
21 #include "migration/vmstate.h"
22 #include "qapi/error.h"
23 #include "qapi/visitor.h"
24 #include "trace.h"
25 #include "qom/object.h"
26
27 struct PCA955xClass {
28 /*< private >*/
29 I2CSlaveClass parent_class;
30 /*< public >*/
31
32 uint8_t pin_count;
33 uint8_t max_reg;
34 };
35 typedef struct PCA955xClass PCA955xClass;
36
37 DECLARE_CLASS_CHECKERS(PCA955xClass, PCA955X,
38 TYPE_PCA955X)
39 /*
40 * Note: The LED_ON and LED_OFF configuration values for the PCA955X
41 * chips are the reverse of the PCA953X family of chips.
42 */
43 #define PCA9552_LED_ON 0x0
44 #define PCA9552_LED_OFF 0x1
45 #define PCA9552_LED_PWM0 0x2
46 #define PCA9552_LED_PWM1 0x3
47 #define PCA9552_PIN_LOW 0x0
48 #define PCA9552_PIN_HIZ 0x1
49
50 static const char *led_state[] = {"on", "off", "pwm0", "pwm1"};
51
pca955x_pin_get_config(PCA955xState * s,int pin)52 static uint8_t pca955x_pin_get_config(PCA955xState *s, int pin)
53 {
54 uint8_t reg = PCA9552_LS0 + (pin / 4);
55 uint8_t shift = (pin % 4) << 1;
56
57 return extract32(s->regs[reg], shift, 2);
58 }
59
60 /* Return INPUT status (bit #N belongs to GPIO #N) */
pca955x_pins_get_status(PCA955xState * s)61 static uint16_t pca955x_pins_get_status(PCA955xState *s)
62 {
63 return (s->regs[PCA9552_INPUT1] << 8) | s->regs[PCA9552_INPUT0];
64 }
65
pca955x_display_pins_status(PCA955xState * s,uint16_t previous_pins_status)66 static void pca955x_display_pins_status(PCA955xState *s,
67 uint16_t previous_pins_status)
68 {
69 PCA955xClass *k = PCA955X_GET_CLASS(s);
70 uint16_t pins_status, pins_changed;
71 int i;
72
73 pins_status = pca955x_pins_get_status(s);
74 pins_changed = previous_pins_status ^ pins_status;
75 if (!pins_changed) {
76 return;
77 }
78 if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_STATUS)) {
79 char *buf = g_newa(char, k->pin_count + 1);
80
81 for (i = 0; i < k->pin_count; i++) {
82 if (extract32(pins_status, i, 1)) {
83 buf[i] = '*';
84 } else {
85 buf[i] = '.';
86 }
87 }
88 buf[i] = '\0';
89 trace_pca955x_gpio_status(s->description, buf);
90 }
91 if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_CHANGE)) {
92 for (i = 0; i < k->pin_count; i++) {
93 if (extract32(pins_changed, i, 1)) {
94 unsigned new_state = extract32(pins_status, i, 1);
95
96 /*
97 * We display the state using the PCA logic ("active-high").
98 * This is not the state of the LED, which signal might be
99 * wired "active-low" on the board.
100 */
101 trace_pca955x_gpio_change(s->description, i,
102 !new_state, new_state);
103 }
104 }
105 }
106 }
107
pca955x_update_pin_input(PCA955xState * s)108 static void pca955x_update_pin_input(PCA955xState *s)
109 {
110 PCA955xClass *k = PCA955X_GET_CLASS(s);
111 int i;
112
113 for (i = 0; i < k->pin_count; i++) {
114 uint8_t input_reg = PCA9552_INPUT0 + (i / 8);
115 uint8_t bit_mask = 1 << (i % 8);
116 uint8_t config = pca955x_pin_get_config(s, i);
117 uint8_t old_value = s->regs[input_reg] & bit_mask;
118 uint8_t new_value;
119
120 switch (config) {
121 case PCA9552_LED_ON:
122 /* Pin is set to 0V to turn on LED */
123 s->regs[input_reg] &= ~bit_mask;
124 break;
125 case PCA9552_LED_OFF:
126 /*
127 * Pin is set to Hi-Z to turn off LED and
128 * pullup sets it to a logical 1 unless
129 * external device drives it low.
130 */
131 if (s->ext_state[i] == PCA9552_PIN_LOW) {
132 s->regs[input_reg] &= ~bit_mask;
133 } else {
134 s->regs[input_reg] |= bit_mask;
135 }
136 break;
137 case PCA9552_LED_PWM0:
138 case PCA9552_LED_PWM1:
139 /* TODO */
140 default:
141 break;
142 }
143
144 /* update irq state only if pin state changed */
145 new_value = s->regs[input_reg] & bit_mask;
146 if (new_value != old_value) {
147 qemu_set_irq(s->gpio_out[i], !!new_value);
148 }
149 }
150 }
151
pca955x_read(PCA955xState * s,uint8_t reg)152 static uint8_t pca955x_read(PCA955xState *s, uint8_t reg)
153 {
154 switch (reg) {
155 case PCA9552_INPUT0:
156 case PCA9552_INPUT1:
157 case PCA9552_PSC0:
158 case PCA9552_PWM0:
159 case PCA9552_PSC1:
160 case PCA9552_PWM1:
161 case PCA9552_LS0:
162 case PCA9552_LS1:
163 case PCA9552_LS2:
164 case PCA9552_LS3:
165 return s->regs[reg];
166 default:
167 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n",
168 __func__, reg);
169 return 0xFF;
170 }
171 }
172
pca955x_write(PCA955xState * s,uint8_t reg,uint8_t data)173 static void pca955x_write(PCA955xState *s, uint8_t reg, uint8_t data)
174 {
175 uint16_t pins_status;
176
177 switch (reg) {
178 case PCA9552_PSC0:
179 case PCA9552_PWM0:
180 case PCA9552_PSC1:
181 case PCA9552_PWM1:
182 s->regs[reg] = data;
183 break;
184
185 case PCA9552_LS0:
186 case PCA9552_LS1:
187 case PCA9552_LS2:
188 case PCA9552_LS3:
189 pins_status = pca955x_pins_get_status(s);
190 s->regs[reg] = data;
191 pca955x_update_pin_input(s);
192 pca955x_display_pins_status(s, pins_status);
193 break;
194
195 case PCA9552_INPUT0:
196 case PCA9552_INPUT1:
197 default:
198 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n",
199 __func__, reg);
200 }
201 }
202
203 /*
204 * When Auto-Increment is on, the register address is incremented
205 * after each byte is sent to or received by the device. The index
206 * rollovers to 0 when the maximum register address is reached.
207 */
pca955x_autoinc(PCA955xState * s)208 static void pca955x_autoinc(PCA955xState *s)
209 {
210 PCA955xClass *k = PCA955X_GET_CLASS(s);
211
212 if (s->pointer != 0xFF && s->pointer & PCA9552_AUTOINC) {
213 uint8_t reg = s->pointer & 0xf;
214
215 reg = (reg + 1) % (k->max_reg + 1);
216 s->pointer = reg | PCA9552_AUTOINC;
217 }
218 }
219
pca955x_recv(I2CSlave * i2c)220 static uint8_t pca955x_recv(I2CSlave *i2c)
221 {
222 PCA955xState *s = PCA955X(i2c);
223 uint8_t ret;
224
225 ret = pca955x_read(s, s->pointer & 0xf);
226
227 /*
228 * From the Specs:
229 *
230 * Important Note: When a Read sequence is initiated and the
231 * AI bit is set to Logic Level 1, the Read Sequence MUST
232 * start by a register different from 0.
233 *
234 * I don't know what should be done in this case, so throw an
235 * error.
236 */
237 if (s->pointer == PCA9552_AUTOINC) {
238 qemu_log_mask(LOG_GUEST_ERROR,
239 "%s: Autoincrement read starting with register 0\n",
240 __func__);
241 }
242
243 pca955x_autoinc(s);
244
245 return ret;
246 }
247
pca955x_send(I2CSlave * i2c,uint8_t data)248 static int pca955x_send(I2CSlave *i2c, uint8_t data)
249 {
250 PCA955xState *s = PCA955X(i2c);
251
252 /* First byte sent by is the register address */
253 if (s->len == 0) {
254 s->pointer = data;
255 s->len++;
256 } else {
257 pca955x_write(s, s->pointer & 0xf, data);
258
259 pca955x_autoinc(s);
260 }
261
262 return 0;
263 }
264
pca955x_event(I2CSlave * i2c,enum i2c_event event)265 static int pca955x_event(I2CSlave *i2c, enum i2c_event event)
266 {
267 PCA955xState *s = PCA955X(i2c);
268
269 s->len = 0;
270 return 0;
271 }
272
pca955x_get_led(Object * obj,Visitor * v,const char * name,void * opaque,Error ** errp)273 static void pca955x_get_led(Object *obj, Visitor *v, const char *name,
274 void *opaque, Error **errp)
275 {
276 PCA955xClass *k = PCA955X_GET_CLASS(obj);
277 PCA955xState *s = PCA955X(obj);
278 int led, rc, reg;
279 uint8_t state;
280
281 rc = sscanf(name, "led%2d", &led);
282 if (rc != 1) {
283 error_setg(errp, "%s: error reading %s", __func__, name);
284 return;
285 }
286 if (led < 0 || led > k->pin_count) {
287 error_setg(errp, "%s invalid led %s", __func__, name);
288 return;
289 }
290 /*
291 * Get the LSx register as the qom interface should expose the device
292 * state, not the modeled 'input line' behaviour which would come from
293 * reading the INPUTx reg
294 */
295 reg = PCA9552_LS0 + led / 4;
296 state = (pca955x_read(s, reg) >> ((led % 4) * 2)) & 0x3;
297 visit_type_str(v, name, (char **)&led_state[state], errp);
298 }
299
300 /*
301 * Return an LED selector register value based on an existing one, with
302 * the appropriate 2-bit state value set for the given LED number (0-3).
303 */
pca955x_ledsel(uint8_t oldval,int led_num,int state)304 static inline uint8_t pca955x_ledsel(uint8_t oldval, int led_num, int state)
305 {
306 return (oldval & (~(0x3 << (led_num << 1)))) |
307 ((state & 0x3) << (led_num << 1));
308 }
309
pca955x_set_led(Object * obj,Visitor * v,const char * name,void * opaque,Error ** errp)310 static void pca955x_set_led(Object *obj, Visitor *v, const char *name,
311 void *opaque, Error **errp)
312 {
313 PCA955xClass *k = PCA955X_GET_CLASS(obj);
314 PCA955xState *s = PCA955X(obj);
315 int led, rc, reg, val;
316 uint8_t state;
317 char *state_str;
318
319 if (!visit_type_str(v, name, &state_str, errp)) {
320 return;
321 }
322 rc = sscanf(name, "led%2d", &led);
323 if (rc != 1) {
324 error_setg(errp, "%s: error reading %s", __func__, name);
325 return;
326 }
327 if (led < 0 || led > k->pin_count) {
328 error_setg(errp, "%s invalid led %s", __func__, name);
329 return;
330 }
331
332 for (state = 0; state < ARRAY_SIZE(led_state); state++) {
333 if (!strcmp(state_str, led_state[state])) {
334 break;
335 }
336 }
337 if (state >= ARRAY_SIZE(led_state)) {
338 error_setg(errp, "%s invalid led state %s", __func__, state_str);
339 return;
340 }
341
342 reg = PCA9552_LS0 + led / 4;
343 val = pca955x_read(s, reg);
344 val = pca955x_ledsel(val, led % 4, state);
345 pca955x_write(s, reg, val);
346 }
347
348 static const VMStateDescription pca9552_vmstate = {
349 .name = "PCA9552",
350 .version_id = 0,
351 .minimum_version_id = 0,
352 .fields = (const VMStateField[]) {
353 VMSTATE_UINT8(len, PCA955xState),
354 VMSTATE_UINT8(pointer, PCA955xState),
355 VMSTATE_UINT8_ARRAY(regs, PCA955xState, PCA955X_NR_REGS),
356 VMSTATE_UINT8_ARRAY(ext_state, PCA955xState, PCA955X_PIN_COUNT_MAX),
357 VMSTATE_I2C_SLAVE(i2c, PCA955xState),
358 VMSTATE_END_OF_LIST()
359 }
360 };
361
pca9552_reset(DeviceState * dev)362 static void pca9552_reset(DeviceState *dev)
363 {
364 PCA955xState *s = PCA955X(dev);
365
366 s->regs[PCA9552_PSC0] = 0xFF;
367 s->regs[PCA9552_PWM0] = 0x80;
368 s->regs[PCA9552_PSC1] = 0xFF;
369 s->regs[PCA9552_PWM1] = 0x80;
370 s->regs[PCA9552_LS0] = 0x55; /* all OFF */
371 s->regs[PCA9552_LS1] = 0x55;
372 s->regs[PCA9552_LS2] = 0x55;
373 s->regs[PCA9552_LS3] = 0x55;
374
375 memset(s->ext_state, PCA9552_PIN_HIZ, PCA955X_PIN_COUNT_MAX);
376 pca955x_update_pin_input(s);
377
378 s->pointer = 0xFF;
379 s->len = 0;
380 }
381
pca955x_initfn(Object * obj)382 static void pca955x_initfn(Object *obj)
383 {
384 PCA955xClass *k = PCA955X_GET_CLASS(obj);
385 int led;
386
387 assert(k->pin_count <= PCA955X_PIN_COUNT_MAX);
388 for (led = 0; led < k->pin_count; led++) {
389 char *name;
390
391 name = g_strdup_printf("led%d", led);
392 object_property_add(obj, name, "bool", pca955x_get_led, pca955x_set_led,
393 NULL, NULL);
394 g_free(name);
395 }
396 }
397
pca955x_set_ext_state(PCA955xState * s,int pin,int level)398 static void pca955x_set_ext_state(PCA955xState *s, int pin, int level)
399 {
400 if (s->ext_state[pin] != level) {
401 uint16_t pins_status = pca955x_pins_get_status(s);
402 s->ext_state[pin] = level;
403 pca955x_update_pin_input(s);
404 pca955x_display_pins_status(s, pins_status);
405 }
406 }
407
pca955x_gpio_in_handler(void * opaque,int pin,int level)408 static void pca955x_gpio_in_handler(void *opaque, int pin, int level)
409 {
410
411 PCA955xState *s = PCA955X(opaque);
412 PCA955xClass *k = PCA955X_GET_CLASS(s);
413
414 assert((pin >= 0) && (pin < k->pin_count));
415 pca955x_set_ext_state(s, pin, level);
416 }
417
pca955x_realize(DeviceState * dev,Error ** errp)418 static void pca955x_realize(DeviceState *dev, Error **errp)
419 {
420 PCA955xClass *k = PCA955X_GET_CLASS(dev);
421 PCA955xState *s = PCA955X(dev);
422
423 if (!s->description) {
424 s->description = g_strdup("pca-unspecified");
425 }
426
427 qdev_init_gpio_out(dev, s->gpio_out, k->pin_count);
428 qdev_init_gpio_in(dev, pca955x_gpio_in_handler, k->pin_count);
429 }
430
431 static Property pca955x_properties[] = {
432 DEFINE_PROP_STRING("description", PCA955xState, description),
433 DEFINE_PROP_END_OF_LIST(),
434 };
435
pca955x_class_init(ObjectClass * klass,void * data)436 static void pca955x_class_init(ObjectClass *klass, void *data)
437 {
438 DeviceClass *dc = DEVICE_CLASS(klass);
439 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
440
441 k->event = pca955x_event;
442 k->recv = pca955x_recv;
443 k->send = pca955x_send;
444 dc->realize = pca955x_realize;
445 device_class_set_props(dc, pca955x_properties);
446 }
447
448 static const TypeInfo pca955x_info = {
449 .name = TYPE_PCA955X,
450 .parent = TYPE_I2C_SLAVE,
451 .instance_init = pca955x_initfn,
452 .instance_size = sizeof(PCA955xState),
453 .class_init = pca955x_class_init,
454 .class_size = sizeof(PCA955xClass),
455 .abstract = true,
456 };
457
pca9552_class_init(ObjectClass * oc,void * data)458 static void pca9552_class_init(ObjectClass *oc, void *data)
459 {
460 DeviceClass *dc = DEVICE_CLASS(oc);
461 PCA955xClass *pc = PCA955X_CLASS(oc);
462
463 dc->reset = pca9552_reset;
464 dc->vmsd = &pca9552_vmstate;
465 pc->max_reg = PCA9552_LS3;
466 pc->pin_count = 16;
467 }
468
469 static const TypeInfo pca9552_info = {
470 .name = TYPE_PCA9552,
471 .parent = TYPE_PCA955X,
472 .class_init = pca9552_class_init,
473 };
474
pca955x_register_types(void)475 static void pca955x_register_types(void)
476 {
477 type_register_static(&pca955x_info);
478 type_register_static(&pca9552_info);
479 }
480
481 type_init(pca955x_register_types)
482