qemu-e2k/hw/misc/pca9552.c

241 lines
5.7 KiB
C

/*
* PCA9552 I2C LED blinker
*
* https://www.nxp.com/docs/en/application-note/AN264.pdf
*
* Copyright (c) 2017-2018, IBM Corporation.
*
* 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 "hw/hw.h"
#include "hw/misc/pca9552.h"
#include "hw/misc/pca9552_regs.h"
#define PCA9552_LED_ON 0x0
#define PCA9552_LED_OFF 0x1
#define PCA9552_LED_PWM0 0x2
#define PCA9552_LED_PWM1 0x3
static uint8_t pca9552_pin_get_config(PCA9552State *s, int pin)
{
uint8_t reg = PCA9552_LS0 + (pin / 4);
uint8_t shift = (pin % 4) << 1;
return extract32(s->regs[reg], shift, 2);
}
static void pca9552_update_pin_input(PCA9552State *s)
{
int i;
for (i = 0; i < s->nr_leds; i++) {
uint8_t input_reg = PCA9552_INPUT0 + (i / 8);
uint8_t input_shift = (i % 8);
uint8_t config = pca9552_pin_get_config(s, i);
switch (config) {
case PCA9552_LED_ON:
s->regs[input_reg] |= 1 << input_shift;
break;
case PCA9552_LED_OFF:
s->regs[input_reg] &= ~(1 << input_shift);
break;
case PCA9552_LED_PWM0:
case PCA9552_LED_PWM1:
/* TODO */
default:
break;
}
}
}
static uint8_t pca9552_read(PCA9552State *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 pca9552_write(PCA9552State *s, uint8_t reg, uint8_t data)
{
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:
s->regs[reg] = data;
pca9552_update_pin_input(s);
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 pca9552_autoinc(PCA9552State *s)
{
if (s->pointer != 0xFF && s->pointer & PCA9552_AUTOINC) {
uint8_t reg = s->pointer & 0xf;
reg = (reg + 1) % (s->max_reg + 1);
s->pointer = reg | PCA9552_AUTOINC;
}
}
static int pca9552_recv(I2CSlave *i2c)
{
PCA9552State *s = PCA9552(i2c);
uint8_t ret;
ret = pca9552_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__);
}
pca9552_autoinc(s);
return ret;
}
static int pca9552_send(I2CSlave *i2c, uint8_t data)
{
PCA9552State *s = PCA9552(i2c);
/* First byte sent by is the register address */
if (s->len == 0) {
s->pointer = data;
s->len++;
} else {
pca9552_write(s, s->pointer & 0xf, data);
pca9552_autoinc(s);
}
return 0;
}
static int pca9552_event(I2CSlave *i2c, enum i2c_event event)
{
PCA9552State *s = PCA9552(i2c);
s->len = 0;
return 0;
}
static const VMStateDescription pca9552_vmstate = {
.name = "PCA9552",
.version_id = 0,
.minimum_version_id = 0,
.fields = (VMStateField[]) {
VMSTATE_UINT8(len, PCA9552State),
VMSTATE_UINT8(pointer, PCA9552State),
VMSTATE_UINT8_ARRAY(regs, PCA9552State, PCA9552_NR_REGS),
VMSTATE_I2C_SLAVE(i2c, PCA9552State),
VMSTATE_END_OF_LIST()
}
};
static void pca9552_reset(DeviceState *dev)
{
PCA9552State *s = PCA9552(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;
pca9552_update_pin_input(s);
s->pointer = 0xFF;
s->len = 0;
}
static void pca9552_initfn(Object *obj)
{
PCA9552State *s = PCA9552(obj);
/* If support for the other PCA955X devices are implemented, these
* constant values might be part of class structure describing the
* PCA955X device
*/
s->max_reg = PCA9552_LS3;
s->nr_leds = 16;
}
static void pca9552_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
k->event = pca9552_event;
k->recv = pca9552_recv;
k->send = pca9552_send;
dc->reset = pca9552_reset;
dc->vmsd = &pca9552_vmstate;
}
static const TypeInfo pca9552_info = {
.name = TYPE_PCA9552,
.parent = TYPE_I2C_SLAVE,
.instance_init = pca9552_initfn,
.instance_size = sizeof(PCA9552State),
.class_init = pca9552_class_init,
};
static void pca9552_register_types(void)
{
type_register_static(&pca9552_info);
}
type_init(pca9552_register_types)