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 #include "qapi/error.h"
19 #include "qapi/visitor.h"
20
21 #define PCA9552_LED_ON 0x0
22 #define PCA9552_LED_OFF 0x1
23 #define PCA9552_LED_PWM0 0x2
24 #define PCA9552_LED_PWM1 0x3
25
26 static const char *led_state[] = {"on", "off", "pwm0", "pwm1"};
27
pca9552_pin_get_config(PCA9552State * s,int pin)28 static uint8_t pca9552_pin_get_config(PCA9552State *s, int pin)
29 {
30 uint8_t reg = PCA9552_LS0 + (pin / 4);
31 uint8_t shift = (pin % 4) << 1;
32
33 return extract32(s->regs[reg], shift, 2);
34 }
35
pca9552_update_pin_input(PCA9552State * s)36 static void pca9552_update_pin_input(PCA9552State *s)
37 {
38 int i;
39
40 for (i = 0; i < s->nr_leds; i++) {
41 uint8_t input_reg = PCA9552_INPUT0 + (i / 8);
42 uint8_t input_shift = (i % 8);
43 uint8_t config = pca9552_pin_get_config(s, i);
44
45 switch (config) {
46 case PCA9552_LED_ON:
47 s->regs[input_reg] |= 1 << input_shift;
48 break;
49 case PCA9552_LED_OFF:
50 s->regs[input_reg] &= ~(1 << input_shift);
51 break;
52 case PCA9552_LED_PWM0:
53 case PCA9552_LED_PWM1:
54 /* TODO */
55 default:
56 break;
57 }
58 }
59 }
60
pca9552_read(PCA9552State * s,uint8_t reg)61 static uint8_t pca9552_read(PCA9552State *s, uint8_t reg)
62 {
63 switch (reg) {
64 case PCA9552_INPUT0:
65 case PCA9552_INPUT1:
66 case PCA9552_PSC0:
67 case PCA9552_PWM0:
68 case PCA9552_PSC1:
69 case PCA9552_PWM1:
70 case PCA9552_LS0:
71 case PCA9552_LS1:
72 case PCA9552_LS2:
73 case PCA9552_LS3:
74 return s->regs[reg];
75 default:
76 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n",
77 __func__, reg);
78 return 0xFF;
79 }
80 }
81
pca9552_write(PCA9552State * s,uint8_t reg,uint8_t data)82 static void pca9552_write(PCA9552State *s, uint8_t reg, uint8_t data)
83 {
84 switch (reg) {
85 case PCA9552_PSC0:
86 case PCA9552_PWM0:
87 case PCA9552_PSC1:
88 case PCA9552_PWM1:
89 s->regs[reg] = data;
90 break;
91
92 case PCA9552_LS0:
93 case PCA9552_LS1:
94 case PCA9552_LS2:
95 case PCA9552_LS3:
96 s->regs[reg] = data;
97 pca9552_update_pin_input(s);
98 break;
99
100 case PCA9552_INPUT0:
101 case PCA9552_INPUT1:
102 default:
103 qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n",
104 __func__, reg);
105 }
106 }
107
108 /*
109 * When Auto-Increment is on, the register address is incremented
110 * after each byte is sent to or received by the device. The index
111 * rollovers to 0 when the maximum register address is reached.
112 */
pca9552_autoinc(PCA9552State * s)113 static void pca9552_autoinc(PCA9552State *s)
114 {
115 if (s->pointer != 0xFF && s->pointer & PCA9552_AUTOINC) {
116 uint8_t reg = s->pointer & 0xf;
117
118 reg = (reg + 1) % (s->max_reg + 1);
119 s->pointer = reg | PCA9552_AUTOINC;
120 }
121 }
122
pca9552_recv(I2CSlave * i2c)123 static uint8_t pca9552_recv(I2CSlave *i2c)
124 {
125 PCA9552State *s = PCA9552(i2c);
126 uint8_t ret;
127
128 ret = pca9552_read(s, s->pointer & 0xf);
129
130 /*
131 * From the Specs:
132 *
133 * Important Note: When a Read sequence is initiated and the
134 * AI bit is set to Logic Level 1, the Read Sequence MUST
135 * start by a register different from 0.
136 *
137 * I don't know what should be done in this case, so throw an
138 * error.
139 */
140 if (s->pointer == PCA9552_AUTOINC) {
141 qemu_log_mask(LOG_GUEST_ERROR,
142 "%s: Autoincrement read starting with register 0\n",
143 __func__);
144 }
145
146 pca9552_autoinc(s);
147
148 return ret;
149 }
150
pca9552_send(I2CSlave * i2c,uint8_t data)151 static int pca9552_send(I2CSlave *i2c, uint8_t data)
152 {
153 PCA9552State *s = PCA9552(i2c);
154
155 /* First byte sent by is the register address */
156 if (s->len == 0) {
157 s->pointer = data;
158 s->len++;
159 } else {
160 pca9552_write(s, s->pointer & 0xf, data);
161
162 pca9552_autoinc(s);
163 }
164
165 return 0;
166 }
167
pca9552_event(I2CSlave * i2c,enum i2c_event event)168 static int pca9552_event(I2CSlave *i2c, enum i2c_event event)
169 {
170 PCA9552State *s = PCA9552(i2c);
171
172 s->len = 0;
173 return 0;
174 }
175
pca9552_get_led(Object * obj,Visitor * v,const char * name,void * opaque,Error ** errp)176 static void pca9552_get_led(Object *obj, Visitor *v, const char *name,
177 void *opaque, Error **errp)
178 {
179 PCA9552State *s = PCA9552(obj);
180 int led, rc, reg;
181 uint8_t state;
182
183 rc = sscanf(name, "led%2d", &led);
184 if (rc != 1) {
185 error_setg(errp, "%s: error reading %s", __func__, name);
186 return;
187 }
188 if (led < 0 || led > s->nr_leds) {
189 error_setg(errp, "%s invalid led %s", __func__, name);
190 return;
191 }
192 /*
193 * Get the LSx register as the qom interface should expose the device
194 * state, not the modeled 'input line' behaviour which would come from
195 * reading the INPUTx reg
196 */
197 reg = PCA9552_LS0 + led / 4;
198 state = (pca9552_read(s, reg) >> (led % 8)) & 0x3;
199 visit_type_str(v, name, (char **)&led_state[state], errp);
200 }
201
202 /*
203 * Return an LED selector register value based on an existing one, with
204 * the appropriate 2-bit state value set for the given LED number (0-3).
205 */
pca955x_ledsel(uint8_t oldval,int led_num,int state)206 static inline uint8_t pca955x_ledsel(uint8_t oldval, int led_num, int state)
207 {
208 return (oldval & (~(0x3 << (led_num << 1)))) |
209 ((state & 0x3) << (led_num << 1));
210 }
211
pca9552_set_led(Object * obj,Visitor * v,const char * name,void * opaque,Error ** errp)212 static void pca9552_set_led(Object *obj, Visitor *v, const char *name,
213 void *opaque, Error **errp)
214 {
215 PCA9552State *s = PCA9552(obj);
216 Error *local_err = NULL;
217 int led, rc, reg, val;
218 uint8_t state;
219 char *state_str;
220
221 visit_type_str(v, name, &state_str, &local_err);
222 if (local_err) {
223 error_propagate(errp, local_err);
224 return;
225 }
226 rc = sscanf(name, "led%2d", &led);
227 if (rc != 1) {
228 error_setg(errp, "%s: error reading %s", __func__, name);
229 return;
230 }
231 if (led < 0 || led > s->nr_leds) {
232 error_setg(errp, "%s invalid led %s", __func__, name);
233 return;
234 }
235
236 for (state = 0; state < ARRAY_SIZE(led_state); state++) {
237 if (!strcmp(state_str, led_state[state])) {
238 break;
239 }
240 }
241 if (state >= ARRAY_SIZE(led_state)) {
242 error_setg(errp, "%s invalid led state %s", __func__, state_str);
243 return;
244 }
245
246 reg = PCA9552_LS0 + led / 4;
247 val = pca9552_read(s, reg);
248 val = pca955x_ledsel(val, led % 4, state);
249 pca9552_write(s, reg, val);
250 }
251
252 static const VMStateDescription pca9552_vmstate = {
253 .name = "PCA9552",
254 .version_id = 0,
255 .minimum_version_id = 0,
256 .fields = (VMStateField[]) {
257 VMSTATE_UINT8(len, PCA9552State),
258 VMSTATE_UINT8(pointer, PCA9552State),
259 VMSTATE_UINT8_ARRAY(regs, PCA9552State, PCA9552_NR_REGS),
260 VMSTATE_I2C_SLAVE(i2c, PCA9552State),
261 VMSTATE_END_OF_LIST()
262 }
263 };
264
pca9552_reset(DeviceState * dev)265 static void pca9552_reset(DeviceState *dev)
266 {
267 PCA9552State *s = PCA9552(dev);
268
269 s->regs[PCA9552_PSC0] = 0xFF;
270 s->regs[PCA9552_PWM0] = 0x80;
271 s->regs[PCA9552_PSC1] = 0xFF;
272 s->regs[PCA9552_PWM1] = 0x80;
273 s->regs[PCA9552_LS0] = 0x55; /* all OFF */
274 s->regs[PCA9552_LS1] = 0x55;
275 s->regs[PCA9552_LS2] = 0x55;
276 s->regs[PCA9552_LS3] = 0x55;
277
278 pca9552_update_pin_input(s);
279
280 s->pointer = 0xFF;
281 s->len = 0;
282 }
283
pca9552_initfn(Object * obj)284 static void pca9552_initfn(Object *obj)
285 {
286 PCA9552State *s = PCA9552(obj);
287 int led;
288
289 /* If support for the other PCA955X devices are implemented, these
290 * constant values might be part of class structure describing the
291 * PCA955X device
292 */
293 s->max_reg = PCA9552_LS3;
294 s->nr_leds = 16;
295
296 for (led = 0; led < s->nr_leds; led++) {
297 char *name;
298
299 name = g_strdup_printf("led%d", led);
300 object_property_add(obj, name, "bool", pca9552_get_led, pca9552_set_led,
301 NULL, NULL, NULL);
302 g_free(name);
303 }
304 }
305
pca9552_class_init(ObjectClass * klass,void * data)306 static void pca9552_class_init(ObjectClass *klass, void *data)
307 {
308 DeviceClass *dc = DEVICE_CLASS(klass);
309 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
310
311 k->event = pca9552_event;
312 k->recv = pca9552_recv;
313 k->send = pca9552_send;
314 dc->reset = pca9552_reset;
315 dc->vmsd = &pca9552_vmstate;
316 }
317
318 static const TypeInfo pca9552_info = {
319 .name = TYPE_PCA9552,
320 .parent = TYPE_I2C_SLAVE,
321 .instance_init = pca9552_initfn,
322 .instance_size = sizeof(PCA9552State),
323 .class_init = pca9552_class_init,
324 };
325
pca9552_register_types(void)326 static void pca9552_register_types(void)
327 {
328 type_register_static(&pca9552_info);
329 }
330
331 type_init(pca9552_register_types)
332