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 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 36 static void pca9552_update_pin_input(PCA9552State *s) 37 { 38 int i; 39 40 for (i = 0; i < s->pin_count; 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 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 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 */ 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 } 122 123 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 } 150 151 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 } 167 168 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 } 175 176 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->pin_count) { 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 */ 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 } 211 212 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->pin_count) { 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 }; 264 265 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 } 283 284 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->pin_count = 16; 295 296 for (led = 0; led < s->pin_count; 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); 302 g_free(name); 303 } 304 } 305 306 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 }; 325 326 static void pca9552_register_types(void) 327 { 328 type_register_static(&pca9552_info); 329 } 330 331 type_init(pca9552_register_types) 332