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