qemu

1
/*
2
 * PCA9552 I2C LED blinker
3
 *
4
 *     https://www.nxp.com/docs/en/application-note/AN264.pdf
5
 *
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 * Copyright (c) 2017-2018, IBM Corporation.
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 * Copyright (c) 2020 Philippe Mathieu-Daudé
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2 or
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 * later. See the COPYING file in the top-level directory.
11
 */
12

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#include "qemu/osdep.h"
14
#include "qemu/log.h"
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#include "qemu/module.h"
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#include "qemu/bitops.h"
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#include "hw/qdev-properties.h"
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#include "hw/gpio/pca9552.h"
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#include "hw/gpio/pca9552_regs.h"
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#include "hw/irq.h"
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#include "migration/vmstate.h"
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#include "qapi/error.h"
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#include "qapi/visitor.h"
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#include "trace.h"
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#include "qom/object.h"
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struct PCA955xClass {
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    /*< private >*/
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    I2CSlaveClass parent_class;
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    /*< public >*/
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    uint8_t pin_count;
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    uint8_t max_reg;
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};
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typedef struct PCA955xClass PCA955xClass;
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DECLARE_CLASS_CHECKERS(PCA955xClass, PCA955X,
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                       TYPE_PCA955X)
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/*
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 * Note:  The LED_ON and LED_OFF configuration values for the PCA955X
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 *        chips are the reverse of the PCA953X family of chips.
42
 */
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#define PCA9552_LED_ON   0x0
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#define PCA9552_LED_OFF  0x1
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#define PCA9552_LED_PWM0 0x2
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#define PCA9552_LED_PWM1 0x3
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#define PCA9552_PIN_LOW  0x0
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#define PCA9552_PIN_HIZ  0x1
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static const char *led_state[] = {"on", "off", "pwm0", "pwm1"};
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static uint8_t pca955x_pin_get_config(PCA955xState *s, int pin)
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{
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    uint8_t reg   = PCA9552_LS0 + (pin / 4);
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    uint8_t shift = (pin % 4) << 1;
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    return extract32(s->regs[reg], shift, 2);
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}
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/* Return INPUT status (bit #N belongs to GPIO #N) */
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static uint16_t pca955x_pins_get_status(PCA955xState *s)
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{
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    return (s->regs[PCA9552_INPUT1] << 8) | s->regs[PCA9552_INPUT0];
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}
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static void pca955x_display_pins_status(PCA955xState *s,
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                                        uint16_t previous_pins_status)
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{
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    PCA955xClass *k = PCA955X_GET_CLASS(s);
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    uint16_t pins_status, pins_changed;
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    int i;
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    pins_status = pca955x_pins_get_status(s);
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    pins_changed = previous_pins_status ^ pins_status;
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    if (!pins_changed) {
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        return;
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    }
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    if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_STATUS)) {
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        char *buf = g_newa(char, k->pin_count + 1);
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        for (i = 0; i < k->pin_count; i++) {
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            if (extract32(pins_status, i, 1)) {
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                buf[i] = '*';
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            } else {
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                buf[i] = '.';
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            }
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        }
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        buf[i] = '\0';
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        trace_pca955x_gpio_status(s->description, buf);
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    }
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    if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_CHANGE)) {
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        for (i = 0; i < k->pin_count; i++) {
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            if (extract32(pins_changed, i, 1)) {
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                unsigned new_state = extract32(pins_status, i, 1);
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                /*
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                 * We display the state using the PCA logic ("active-high").
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                 * This is not the state of the LED, which signal might be
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                 * wired "active-low" on the board.
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                 */
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                trace_pca955x_gpio_change(s->description, i,
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                                          !new_state, new_state);
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            }
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        }
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    }
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}
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static void pca955x_update_pin_input(PCA955xState *s)
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{
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    PCA955xClass *k = PCA955X_GET_CLASS(s);
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    int i;
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    for (i = 0; i < k->pin_count; i++) {
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        uint8_t input_reg = PCA9552_INPUT0 + (i / 8);
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        uint8_t bit_mask = 1 << (i % 8);
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        uint8_t config = pca955x_pin_get_config(s, i);
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        uint8_t old_value = s->regs[input_reg] & bit_mask;
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        uint8_t new_value;
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        switch (config) {
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        case PCA9552_LED_ON:
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            /* Pin is set to 0V to turn on LED */
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            s->regs[input_reg] &= ~bit_mask;
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            break;
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        case PCA9552_LED_OFF:
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            /*
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             * Pin is set to Hi-Z to turn off LED and
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             * pullup sets it to a logical 1 unless
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             * external device drives it low.
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             */
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            if (s->ext_state[i] == PCA9552_PIN_LOW) {
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                s->regs[input_reg] &= ~bit_mask;
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            } else {
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                s->regs[input_reg] |=  bit_mask;
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            }
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            break;
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        case PCA9552_LED_PWM0:
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        case PCA9552_LED_PWM1:
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            /* TODO */
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        default:
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            break;
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        }
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        /* update irq state only if pin state changed */
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        new_value = s->regs[input_reg] & bit_mask;
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        if (new_value != old_value) {
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            qemu_set_irq(s->gpio_out[i], !!new_value);
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        }
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    }
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}
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static uint8_t pca955x_read(PCA955xState *s, uint8_t reg)
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{
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    switch (reg) {
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    case PCA9552_INPUT0:
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    case PCA9552_INPUT1:
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    case PCA9552_PSC0:
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    case PCA9552_PWM0:
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    case PCA9552_PSC1:
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    case PCA9552_PWM1:
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    case PCA9552_LS0:
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    case PCA9552_LS1:
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    case PCA9552_LS2:
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    case PCA9552_LS3:
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        return s->regs[reg];
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    default:
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        qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n",
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                      __func__, reg);
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        return 0xFF;
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    }
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}
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static void pca955x_write(PCA955xState *s, uint8_t reg, uint8_t data)
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{
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    uint16_t pins_status;
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    switch (reg) {
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    case PCA9552_PSC0:
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    case PCA9552_PWM0:
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    case PCA9552_PSC1:
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    case PCA9552_PWM1:
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        s->regs[reg] = data;
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        break;
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    case PCA9552_LS0:
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    case PCA9552_LS1:
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    case PCA9552_LS2:
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    case PCA9552_LS3:
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        pins_status = pca955x_pins_get_status(s);
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        s->regs[reg] = data;
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        pca955x_update_pin_input(s);
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        pca955x_display_pins_status(s, pins_status);
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        break;
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    case PCA9552_INPUT0:
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    case PCA9552_INPUT1:
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    default:
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        qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n",
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                      __func__, reg);
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    }
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}
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/*
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 * When Auto-Increment is on, the register address is incremented
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 * after each byte is sent to or received by the device. The index
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 * rollovers to 0 when the maximum register address is reached.
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 */
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static void pca955x_autoinc(PCA955xState *s)
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{
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    PCA955xClass *k = PCA955X_GET_CLASS(s);
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    if (s->pointer != 0xFF && s->pointer & PCA9552_AUTOINC) {
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        uint8_t reg = s->pointer & 0xf;
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        reg = (reg + 1) % (k->max_reg + 1);
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        s->pointer = reg | PCA9552_AUTOINC;
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    }
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}
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static uint8_t pca955x_recv(I2CSlave *i2c)
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{
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    PCA955xState *s = PCA955X(i2c);
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    uint8_t ret;
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    ret = pca955x_read(s, s->pointer & 0xf);
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    /*
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     * From the Specs:
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     *
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     *     Important Note: When a Read sequence is initiated and the
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     *     AI bit is set to Logic Level 1, the Read Sequence MUST
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     *     start by a register different from 0.
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     *
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     * I don't know what should be done in this case, so throw an
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     * error.
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     */
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    if (s->pointer == PCA9552_AUTOINC) {
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        qemu_log_mask(LOG_GUEST_ERROR,
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                      "%s: Autoincrement read starting with register 0\n",
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                      __func__);
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    }
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    pca955x_autoinc(s);
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    return ret;
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}
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static int pca955x_send(I2CSlave *i2c, uint8_t data)
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{
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    PCA955xState *s = PCA955X(i2c);
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    /* First byte sent by is the register address */
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    if (s->len == 0) {
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        s->pointer = data;
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        s->len++;
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    } else {
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        pca955x_write(s, s->pointer & 0xf, data);
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        pca955x_autoinc(s);
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    }
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    return 0;
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}
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static int pca955x_event(I2CSlave *i2c, enum i2c_event event)
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{
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    PCA955xState *s = PCA955X(i2c);
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    s->len = 0;
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    return 0;
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}
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static void pca955x_get_led(Object *obj, Visitor *v, const char *name,
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                            void *opaque, Error **errp)
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{
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    PCA955xClass *k = PCA955X_GET_CLASS(obj);
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    PCA955xState *s = PCA955X(obj);
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    int led, rc, reg;
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    uint8_t state;
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    rc = sscanf(name, "led%2d", &led);
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    if (rc != 1) {
283
        error_setg(errp, "%s: error reading %s", __func__, name);
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        return;
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    }
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    if (led < 0 || led > k->pin_count) {
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        error_setg(errp, "%s invalid led %s", __func__, name);
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        return;
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    }
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    /*
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     * Get the LSx register as the qom interface should expose the device
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     * state, not the modeled 'input line' behaviour which would come from
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     * reading the INPUTx reg
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     */
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    reg = PCA9552_LS0 + led / 4;
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    state = (pca955x_read(s, reg) >> ((led % 4) * 2)) & 0x3;
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    visit_type_str(v, name, (char **)&led_state[state], errp);
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}
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/*
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 * Return an LED selector register value based on an existing one, with
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 * the appropriate 2-bit state value set for the given LED number (0-3).
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 */
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static inline uint8_t pca955x_ledsel(uint8_t oldval, int led_num, int state)
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{
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        return (oldval & (~(0x3 << (led_num << 1)))) |
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                ((state & 0x3) << (led_num << 1));
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}
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static void pca955x_set_led(Object *obj, Visitor *v, const char *name,
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                            void *opaque, Error **errp)
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{
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    PCA955xClass *k = PCA955X_GET_CLASS(obj);
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    PCA955xState *s = PCA955X(obj);
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    int led, rc, reg, val;
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    uint8_t state;
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    char *state_str;
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    if (!visit_type_str(v, name, &state_str, errp)) {
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        return;
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    }
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    rc = sscanf(name, "led%2d", &led);
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    if (rc != 1) {
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        error_setg(errp, "%s: error reading %s", __func__, name);
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        return;
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    }
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    if (led < 0 || led > k->pin_count) {
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        error_setg(errp, "%s invalid led %s", __func__, name);
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        return;
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    }
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    for (state = 0; state < ARRAY_SIZE(led_state); state++) {
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        if (!strcmp(state_str, led_state[state])) {
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            break;
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        }
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    }
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    if (state >= ARRAY_SIZE(led_state)) {
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        error_setg(errp, "%s invalid led state %s", __func__, state_str);
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        return;
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    }
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    reg = PCA9552_LS0 + led / 4;
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    val = pca955x_read(s, reg);
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    val = pca955x_ledsel(val, led % 4, state);
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    pca955x_write(s, reg, val);
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}
347

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static const VMStateDescription pca9552_vmstate = {
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    .name = "PCA9552",
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    .version_id = 0,
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    .minimum_version_id = 0,
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    .fields = (const VMStateField[]) {
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        VMSTATE_UINT8(len, PCA955xState),
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        VMSTATE_UINT8(pointer, PCA955xState),
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        VMSTATE_UINT8_ARRAY(regs, PCA955xState, PCA955X_NR_REGS),
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        VMSTATE_UINT8_ARRAY(ext_state, PCA955xState, PCA955X_PIN_COUNT_MAX),
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        VMSTATE_I2C_SLAVE(i2c, PCA955xState),
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        VMSTATE_END_OF_LIST()
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    }
360
};
361

362
static void pca9552_reset(DeviceState *dev)
363
{
364
    PCA955xState *s = PCA955X(dev);
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366
    s->regs[PCA9552_PSC0] = 0xFF;
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    s->regs[PCA9552_PWM0] = 0x80;
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    s->regs[PCA9552_PSC1] = 0xFF;
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    s->regs[PCA9552_PWM1] = 0x80;
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    s->regs[PCA9552_LS0] = 0x55; /* all OFF */
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    s->regs[PCA9552_LS1] = 0x55;
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    s->regs[PCA9552_LS2] = 0x55;
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    s->regs[PCA9552_LS3] = 0x55;
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    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

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

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

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

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

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

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

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