hw/misc/pca9552.c - qemu - Git at Google

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

 #include "qemu/osdep.h"
 #include "qemu/log.h"
 #include "qemu/module.h"
 #include "qemu/bitops.h"
 #include "hw/qdev-properties.h"
 #include "hw/misc/pca9552.h"
 #include "hw/misc/pca9552_regs.h"
 #include "hw/irq.h"
 #include "migration/vmstate.h"
 #include "qapi/error.h"
 #include "qapi/visitor.h"
 #include "trace.h"
 #include "qom/object.h"

 struct PCA955xClass {
     /*< private >*/
     I2CSlaveClass parent_class;
     /*< public >*/

     uint8_t pin_count;
     uint8_t max_reg;
 };
 typedef struct PCA955xClass PCA955xClass;

 DECLARE_CLASS_CHECKERS(PCA955xClass, PCA955X,
                        TYPE_PCA955X)

 #define PCA9552_LED_ON   0x0
 #define PCA9552_LED_OFF  0x1
 #define PCA9552_LED_PWM0 0x2
 #define PCA9552_LED_PWM1 0x3

 static const char *led_state[] = {"on", "off", "pwm0", "pwm1"};

 static uint8_t pca955x_pin_get_config(PCA955xState *s, int pin)
 {
     uint8_t reg   = PCA9552_LS0 + (pin / 4);
     uint8_t shift = (pin % 4) << 1;

     return extract32(s->regs[reg], shift, 2);
 }

 /* Return INPUT status (bit #N belongs to GPIO #N) */
 static uint16_t pca955x_pins_get_status(PCA955xState *s)
 {
     return (s->regs[PCA9552_INPUT1] << 8) | s->regs[PCA9552_INPUT0];
 }

 static void pca955x_display_pins_status(PCA955xState *s,
                                         uint16_t previous_pins_status)
 {
     PCA955xClass *k = PCA955X_GET_CLASS(s);
     uint16_t pins_status, pins_changed;
     int i;

     pins_status = pca955x_pins_get_status(s);
     pins_changed = previous_pins_status ^ pins_status;
     if (!pins_changed) {
         return;
     }
     if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_STATUS)) {
         char *buf = g_newa(char, k->pin_count + 1);

         for (i = 0; i < k->pin_count; i++) {
             if (extract32(pins_status, i, 1)) {
                 buf[i] = '*';
             } else {
                 buf[i] = '.';
             }
         }
         buf[i] = '\0';
         trace_pca955x_gpio_status(s->description, buf);
     }
     if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_CHANGE)) {
         for (i = 0; i < k->pin_count; i++) {
             if (extract32(pins_changed, i, 1)) {
                 unsigned new_state = extract32(pins_status, i, 1);

                 /*
                  * We display the state using the PCA logic ("active-high").
                  * This is not the state of the LED, which signal might be
                  * wired "active-low" on the board.
                  */
                 trace_pca955x_gpio_change(s->description, i,
                                           !new_state, new_state);
             }
         }
     }
 }

 static void pca955x_update_pin_input(PCA955xState *s)
 {
     PCA955xClass *k = PCA955X_GET_CLASS(s);
     int i;

     for (i = 0; i < k->pin_count; i++) {
         uint8_t input_reg = PCA9552_INPUT0 + (i / 8);
         uint8_t input_shift = (i % 8);
         uint8_t config = pca955x_pin_get_config(s, i);

         switch (config) {
         case PCA9552_LED_ON:
             qemu_set_irq(s->gpio[i], 1);
             s->regs[input_reg] |= 1 << input_shift;
             break;
         case PCA9552_LED_OFF:
             qemu_set_irq(s->gpio[i], 0);
             s->regs[input_reg] &= ~(1 << input_shift);
             break;
         case PCA9552_LED_PWM0:
         case PCA9552_LED_PWM1:
             /* TODO */
         default:
             break;
         }
     }
 }

 static uint8_t pca955x_read(PCA955xState *s, uint8_t reg)
 {
     switch (reg) {
     case PCA9552_INPUT0:
     case PCA9552_INPUT1:
     case PCA9552_PSC0:
     case PCA9552_PWM0:
     case PCA9552_PSC1:
     case PCA9552_PWM1:
     case PCA9552_LS0:
     case PCA9552_LS1:
     case PCA9552_LS2:
     case PCA9552_LS3:
         return s->regs[reg];
     default:
         qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n",
                       __func__, reg);
         return 0xFF;
     }
 }

 static void pca955x_write(PCA955xState *s, uint8_t reg, uint8_t data)
 {
     uint16_t pins_status;

     switch (reg) {
     case PCA9552_PSC0:
     case PCA9552_PWM0:
     case PCA9552_PSC1:
     case PCA9552_PWM1:
         s->regs[reg] = data;
         break;

     case PCA9552_LS0:
     case PCA9552_LS1:
     case PCA9552_LS2:
     case PCA9552_LS3:
         pins_status = pca955x_pins_get_status(s);
         s->regs[reg] = data;
         pca955x_update_pin_input(s);
         pca955x_display_pins_status(s, pins_status);
         break;

     case PCA9552_INPUT0:
     case PCA9552_INPUT1:
     default:
         qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n",
                       __func__, reg);
     }
 }

 /*
  * When Auto-Increment is on, the register address is incremented
  * after each byte is sent to or received by the device. The index
  * rollovers to 0 when the maximum register address is reached.
  */
 static void pca955x_autoinc(PCA955xState *s)
 {
     PCA955xClass *k = PCA955X_GET_CLASS(s);

     if (s->pointer != 0xFF && s->pointer & PCA9552_AUTOINC) {
         uint8_t reg = s->pointer & 0xf;

         reg = (reg + 1) % (k->max_reg + 1);
         s->pointer = reg | PCA9552_AUTOINC;
     }
 }

 static uint8_t pca955x_recv(I2CSlave *i2c)
 {
     PCA955xState *s = PCA955X(i2c);
     uint8_t ret;

     ret = pca955x_read(s, s->pointer & 0xf);

     /*
      * From the Specs:
      *
      *     Important Note: When a Read sequence is initiated and the
      *     AI bit is set to Logic Level 1, the Read Sequence MUST
      *     start by a register different from 0.
      *
      * I don't know what should be done in this case, so throw an
      * error.
      */
     if (s->pointer == PCA9552_AUTOINC) {
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: Autoincrement read starting with register 0\n",
                       __func__);
     }

     pca955x_autoinc(s);

     return ret;
 }

 static int pca955x_send(I2CSlave *i2c, uint8_t data)
 {
     PCA955xState *s = PCA955X(i2c);

     /* First byte sent by is the register address */
     if (s->len == 0) {
         s->pointer = data;
         s->len++;
     } else {
         pca955x_write(s, s->pointer & 0xf, data);

         pca955x_autoinc(s);
     }

     return 0;
 }

 static int pca955x_event(I2CSlave *i2c, enum i2c_event event)
 {
     PCA955xState *s = PCA955X(i2c);

     s->len = 0;
     return 0;
 }

 static void pca955x_get_led(Object *obj, Visitor *v, const char *name,
                             void *opaque, Error **errp)
 {
     PCA955xClass *k = PCA955X_GET_CLASS(obj);
     PCA955xState *s = PCA955X(obj);
     int led, rc, reg;
     uint8_t state;

     rc = sscanf(name, "led%2d", &led);
     if (rc != 1) {
         error_setg(errp, "%s: error reading %s", __func__, name);
         return;
     }
     if (led < 0 || led > k->pin_count) {
         error_setg(errp, "%s invalid led %s", __func__, name);
         return;
     }
     /*
      * Get the LSx register as the qom interface should expose the device
      * state, not the modeled 'input line' behaviour which would come from
      * reading the INPUTx reg
      */
     reg = PCA9552_LS0 + led / 4;
     state = (pca955x_read(s, reg) >> (led % 8)) & 0x3;
     visit_type_str(v, name, (char **)&led_state[state], errp);
 }

 /*
  * Return an LED selector register value based on an existing one, with
  * the appropriate 2-bit state value set for the given LED number (0-3).
  */
 static inline uint8_t pca955x_ledsel(uint8_t oldval, int led_num, int state)
 {
         return (oldval & (~(0x3 << (led_num << 1)))) |
                 ((state & 0x3) << (led_num << 1));
 }

 static void pca955x_set_led(Object *obj, Visitor *v, const char *name,
                             void *opaque, Error **errp)
 {
     PCA955xClass *k = PCA955X_GET_CLASS(obj);
     PCA955xState *s = PCA955X(obj);
     int led, rc, reg, val;
     uint8_t state;
     char *state_str;

     if (!visit_type_str(v, name, &state_str, errp)) {
         return;
     }
     rc = sscanf(name, "led%2d", &led);
     if (rc != 1) {
         error_setg(errp, "%s: error reading %s", __func__, name);
         return;
     }
     if (led < 0 || led > k->pin_count) {
         error_setg(errp, "%s invalid led %s", __func__, name);
         return;
     }

     for (state = 0; state < ARRAY_SIZE(led_state); state++) {
         if (!strcmp(state_str, led_state[state])) {
             break;
         }
     }
     if (state >= ARRAY_SIZE(led_state)) {
         error_setg(errp, "%s invalid led state %s", __func__, state_str);
         return;
     }

     reg = PCA9552_LS0 + led / 4;
     val = pca955x_read(s, reg);
     val = pca955x_ledsel(val, led % 4, state);
     pca955x_write(s, reg, val);
 }

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

 static void pca9552_reset(DeviceState *dev)
 {
     PCA955xState *s = PCA955X(dev);

     s->regs[PCA9552_PSC0] = 0xFF;
     s->regs[PCA9552_PWM0] = 0x80;
     s->regs[PCA9552_PSC1] = 0xFF;
     s->regs[PCA9552_PWM1] = 0x80;
     s->regs[PCA9552_LS0] = 0x55; /* all OFF */
     s->regs[PCA9552_LS1] = 0x55;
     s->regs[PCA9552_LS2] = 0x55;
     s->regs[PCA9552_LS3] = 0x55;

     pca955x_update_pin_input(s);

     s->pointer = 0xFF;
     s->len = 0;
 }

 static void pca955x_initfn(Object *obj)
 {
     PCA955xClass *k = PCA955X_GET_CLASS(obj);
     int led;

     assert(k->pin_count <= PCA955X_PIN_COUNT_MAX);
     for (led = 0; led < k->pin_count; led++) {
         char *name;

         name = g_strdup_printf("led%d", led);
         object_property_add(obj, name, "bool", pca955x_get_led, pca955x_set_led,
                             NULL, NULL);
         g_free(name);
     }
 }

 static void pca955x_realize(DeviceState *dev, Error **errp)
 {
     PCA955xClass *k = PCA955X_GET_CLASS(dev);
     PCA955xState *s = PCA955X(dev);

     if (!s->description) {
         s->description = g_strdup("pca-unspecified");
     }

     qdev_init_gpio_out(dev, s->gpio, k->pin_count);
 }

 static Property pca955x_properties[] = {
     DEFINE_PROP_STRING("description", PCA955xState, description),
     DEFINE_PROP_END_OF_LIST(),
 };

 static void pca955x_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);

     k->event = pca955x_event;
     k->recv = pca955x_recv;
     k->send = pca955x_send;
     dc->realize = pca955x_realize;
     device_class_set_props(dc, pca955x_properties);
 }

 static const TypeInfo pca955x_info = {
     .name          = TYPE_PCA955X,
     .parent        = TYPE_I2C_SLAVE,
     .instance_init = pca955x_initfn,
     .instance_size = sizeof(PCA955xState),
     .class_init    = pca955x_class_init,
     .class_size    = sizeof(PCA955xClass),
     .abstract      = true,
 };

 static void pca9552_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
     PCA955xClass *pc = PCA955X_CLASS(oc);

     dc->reset = pca9552_reset;
     dc->vmsd = &pca9552_vmstate;
     pc->max_reg = PCA9552_LS3;
     pc->pin_count = 16;
 }

 static const TypeInfo pca9552_info = {
     .name          = TYPE_PCA9552,
     .parent        = TYPE_PCA955X,
     .class_init    = pca9552_class_init,
 };

 static void pca955x_register_types(void)
 {
     type_register_static(&pca955x_info);
     type_register_static(&pca9552_info);
 }

 type_init(pca955x_register_types)
	/*
	* PCA9552 I2C LED blinker
	*
	* https://www.nxp.com/docs/en/application-note/AN264.pdf
	*
	* Copyright (c) 2017-2018, IBM Corporation.
	* Copyright (c) 2020 Philippe Mathieu-Daudé
	*
	* This work is licensed under the terms of the GNU GPL, version 2 or
	* later. See the COPYING file in the top-level directory.
	*/

	#include "qemu/osdep.h"
	#include "qemu/log.h"
	#include "qemu/module.h"
	#include "qemu/bitops.h"
	#include "hw/qdev-properties.h"
	#include "hw/misc/pca9552.h"
	#include "hw/misc/pca9552_regs.h"
	#include "hw/irq.h"
	#include "migration/vmstate.h"
	#include "qapi/error.h"
	#include "qapi/visitor.h"
	#include "trace.h"
	#include "qom/object.h"

	struct PCA955xClass {
	/< private >/
	I2CSlaveClass parent_class;
	/< public >/

	uint8_t pin_count;
	uint8_t max_reg;
	};
	typedef struct PCA955xClass PCA955xClass;

	DECLARE_CLASS_CHECKERS(PCA955xClass, PCA955X,
	TYPE_PCA955X)

	#define PCA9552_LED_ON 0x0
	#define PCA9552_LED_OFF 0x1
	#define PCA9552_LED_PWM0 0x2
	#define PCA9552_LED_PWM1 0x3

	static const char *led_state[] = {"on", "off", "pwm0", "pwm1"};

	static uint8_t pca955x_pin_get_config(PCA955xState *s, int pin)
	{
	uint8_t reg = PCA9552_LS0 + (pin / 4);
	uint8_t shift = (pin % 4) << 1;

	return extract32(s->regs[reg], shift, 2);
	}

	/* Return INPUT status (bit #N belongs to GPIO #N) */
	static uint16_t pca955x_pins_get_status(PCA955xState *s)
	{
	return (s->regs[PCA9552_INPUT1] << 8) \| s->regs[PCA9552_INPUT0];
	}

	static void pca955x_display_pins_status(PCA955xState *s,
	uint16_t previous_pins_status)
	{
	PCA955xClass *k = PCA955X_GET_CLASS(s);
	uint16_t pins_status, pins_changed;
	int i;

	pins_status = pca955x_pins_get_status(s);
	pins_changed = previous_pins_status ^ pins_status;
	if (!pins_changed) {
	return;
	}
	if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_STATUS)) {
	char *buf = g_newa(char, k->pin_count + 1);

	for (i = 0; i < k->pin_count; i++) {
	if (extract32(pins_status, i, 1)) {
	buf[i] = '*';
	} else {
	buf[i] = '.';
	}
	}
	buf[i] = '\0';
	trace_pca955x_gpio_status(s->description, buf);
	}
	if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_CHANGE)) {
	for (i = 0; i < k->pin_count; i++) {
	if (extract32(pins_changed, i, 1)) {
	unsigned new_state = extract32(pins_status, i, 1);

	/*
	* We display the state using the PCA logic ("active-high").
	* This is not the state of the LED, which signal might be
	* wired "active-low" on the board.
	*/
	trace_pca955x_gpio_change(s->description, i,
	!new_state, new_state);
	}
	}
	}
	}

	static void pca955x_update_pin_input(PCA955xState *s)
	{
	PCA955xClass *k = PCA955X_GET_CLASS(s);
	int i;

	for (i = 0; i < k->pin_count; i++) {
	uint8_t input_reg = PCA9552_INPUT0 + (i / 8);
	uint8_t input_shift = (i % 8);
	uint8_t config = pca955x_pin_get_config(s, i);

	switch (config) {
	case PCA9552_LED_ON:
	qemu_set_irq(s->gpio[i], 1);
	s->regs[input_reg] \|= 1 << input_shift;
	break;
	case PCA9552_LED_OFF:
	qemu_set_irq(s->gpio[i], 0);
	s->regs[input_reg] &= ~(1 << input_shift);
	break;
	case PCA9552_LED_PWM0:
	case PCA9552_LED_PWM1:
	/* TODO */
	default:
	break;
	}
	}
	}

	static uint8_t pca955x_read(PCA955xState *s, uint8_t reg)
	{
	switch (reg) {
	case PCA9552_INPUT0:
	case PCA9552_INPUT1:
	case PCA9552_PSC0:
	case PCA9552_PWM0:
	case PCA9552_PSC1:
	case PCA9552_PWM1:
	case PCA9552_LS0:
	case PCA9552_LS1:
	case PCA9552_LS2:
	case PCA9552_LS3:
	return s->regs[reg];
	default:
	qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n",
	__func__, reg);
	return 0xFF;
	}
	}

	static void pca955x_write(PCA955xState *s, uint8_t reg, uint8_t data)
	{
	uint16_t pins_status;

	switch (reg) {
	case PCA9552_PSC0:
	case PCA9552_PWM0:
	case PCA9552_PSC1:
	case PCA9552_PWM1:
	s->regs[reg] = data;
	break;

	case PCA9552_LS0:
	case PCA9552_LS1:
	case PCA9552_LS2:
	case PCA9552_LS3:
	pins_status = pca955x_pins_get_status(s);
	s->regs[reg] = data;
	pca955x_update_pin_input(s);
	pca955x_display_pins_status(s, pins_status);
	break;

	case PCA9552_INPUT0:
	case PCA9552_INPUT1:
	default:
	qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n",
	__func__, reg);
	}
	}

	/*
	* When Auto-Increment is on, the register address is incremented
	* after each byte is sent to or received by the device. The index
	* rollovers to 0 when the maximum register address is reached.
	*/
	static void pca955x_autoinc(PCA955xState *s)
	{
	PCA955xClass *k = PCA955X_GET_CLASS(s);

	if (s->pointer != 0xFF && s->pointer & PCA9552_AUTOINC) {
	uint8_t reg = s->pointer & 0xf;

	reg = (reg + 1) % (k->max_reg + 1);
	s->pointer = reg \| PCA9552_AUTOINC;
	}
	}

	static uint8_t pca955x_recv(I2CSlave *i2c)
	{
	PCA955xState *s = PCA955X(i2c);
	uint8_t ret;

	ret = pca955x_read(s, s->pointer & 0xf);

	/*
	* From the Specs:
	*
	* Important Note: When a Read sequence is initiated and the
	* AI bit is set to Logic Level 1, the Read Sequence MUST
	* start by a register different from 0.
	*
	* I don't know what should be done in this case, so throw an
	* error.
	*/
	if (s->pointer == PCA9552_AUTOINC) {
	qemu_log_mask(LOG_GUEST_ERROR,
	"%s: Autoincrement read starting with register 0\n",
	__func__);
	}

	pca955x_autoinc(s);

	return ret;
	}

	static int pca955x_send(I2CSlave *i2c, uint8_t data)
	{
	PCA955xState *s = PCA955X(i2c);

	/* First byte sent by is the register address */
	if (s->len == 0) {
	s->pointer = data;
	s->len++;
	} else {
	pca955x_write(s, s->pointer & 0xf, data);

	pca955x_autoinc(s);
	}

	return 0;
	}

	static int pca955x_event(I2CSlave *i2c, enum i2c_event event)
	{
	PCA955xState *s = PCA955X(i2c);

	s->len = 0;
	return 0;
	}

	static void pca955x_get_led(Object obj, Visitor v, const char *name,
	void opaque, Error *errp)
	{
	PCA955xClass *k = PCA955X_GET_CLASS(obj);
	PCA955xState *s = PCA955X(obj);
	int led, rc, reg;
	uint8_t state;

	rc = sscanf(name, "led%2d", &led);
	if (rc != 1) {
	error_setg(errp, "%s: error reading %s", __func__, name);
	return;
	}
	if (led < 0 \|\| led > k->pin_count) {
	error_setg(errp, "%s invalid led %s", __func__, name);
	return;
	}
	/*
	* Get the LSx register as the qom interface should expose the device
	* state, not the modeled 'input line' behaviour which would come from
	* reading the INPUTx reg
	*/
	reg = PCA9552_LS0 + led / 4;
	state = (pca955x_read(s, reg) >> (led % 8)) & 0x3;
	visit_type_str(v, name, (char **)&led_state[state], errp);
	}

	/*
	* Return an LED selector register value based on an existing one, with
	* the appropriate 2-bit state value set for the given LED number (0-3).
	*/
	static inline uint8_t pca955x_ledsel(uint8_t oldval, int led_num, int state)
	{
	return (oldval & (~(0x3 << (led_num << 1)))) \|
	((state & 0x3) << (led_num << 1));
	}

	static void pca955x_set_led(Object obj, Visitor v, const char *name,
	void opaque, Error *errp)
	{
	PCA955xClass *k = PCA955X_GET_CLASS(obj);
	PCA955xState *s = PCA955X(obj);
	int led, rc, reg, val;
	uint8_t state;
	char *state_str;

	if (!visit_type_str(v, name, &state_str, errp)) {
	return;
	}
	rc = sscanf(name, "led%2d", &led);
	if (rc != 1) {
	error_setg(errp, "%s: error reading %s", __func__, name);
	return;
	}
	if (led < 0 \|\| led > k->pin_count) {
	error_setg(errp, "%s invalid led %s", __func__, name);
	return;
	}

	for (state = 0; state < ARRAY_SIZE(led_state); state++) {
	if (!strcmp(state_str, led_state[state])) {
	break;
	}
	}
	if (state >= ARRAY_SIZE(led_state)) {
	error_setg(errp, "%s invalid led state %s", __func__, state_str);
	return;
	}

	reg = PCA9552_LS0 + led / 4;
	val = pca955x_read(s, reg);
	val = pca955x_ledsel(val, led % 4, state);
	pca955x_write(s, reg, val);
	}

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

	static void pca9552_reset(DeviceState *dev)
	{
	PCA955xState *s = PCA955X(dev);

	s->regs[PCA9552_PSC0] = 0xFF;
	s->regs[PCA9552_PWM0] = 0x80;
	s->regs[PCA9552_PSC1] = 0xFF;
	s->regs[PCA9552_PWM1] = 0x80;
	s->regs[PCA9552_LS0] = 0x55; /* all OFF */
	s->regs[PCA9552_LS1] = 0x55;
	s->regs[PCA9552_LS2] = 0x55;
	s->regs[PCA9552_LS3] = 0x55;

	pca955x_update_pin_input(s);

	s->pointer = 0xFF;
	s->len = 0;
	}

	static void pca955x_initfn(Object *obj)
	{
	PCA955xClass *k = PCA955X_GET_CLASS(obj);
	int led;

	assert(k->pin_count <= PCA955X_PIN_COUNT_MAX);
	for (led = 0; led < k->pin_count; led++) {
	char *name;

	name = g_strdup_printf("led%d", led);
	object_property_add(obj, name, "bool", pca955x_get_led, pca955x_set_led,
	NULL, NULL);
	g_free(name);
	}
	}

	static void pca955x_realize(DeviceState dev, Error *errp)
	{
	PCA955xClass *k = PCA955X_GET_CLASS(dev);
	PCA955xState *s = PCA955X(dev);

	if (!s->description) {
	s->description = g_strdup("pca-unspecified");
	}

	qdev_init_gpio_out(dev, s->gpio, k->pin_count);
	}

	static Property pca955x_properties[] = {
	DEFINE_PROP_STRING("description", PCA955xState, description),
	DEFINE_PROP_END_OF_LIST(),
	};

	static void pca955x_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);
	I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);

	k->event = pca955x_event;
	k->recv = pca955x_recv;
	k->send = pca955x_send;
	dc->realize = pca955x_realize;
	device_class_set_props(dc, pca955x_properties);
	}

	static const TypeInfo pca955x_info = {
	.name = TYPE_PCA955X,
	.parent = TYPE_I2C_SLAVE,
	.instance_init = pca955x_initfn,
	.instance_size = sizeof(PCA955xState),
	.class_init = pca955x_class_init,
	.class_size = sizeof(PCA955xClass),
	.abstract = true,
	};

	static void pca9552_class_init(ObjectClass oc, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(oc);
	PCA955xClass *pc = PCA955X_CLASS(oc);

	dc->reset = pca9552_reset;
	dc->vmsd = &pca9552_vmstate;
	pc->max_reg = PCA9552_LS3;
	pc->pin_count = 16;
	}

	static const TypeInfo pca9552_info = {
	.name = TYPE_PCA9552,
	.parent = TYPE_PCA955X,
	.class_init = pca9552_class_init,
	};

	static void pca955x_register_types(void)
	{
	type_register_static(&pca955x_info);
	type_register_static(&pca9552_info);
	}

	type_init(pca955x_register_types)