blob: 13eb529fc14cc0675a2e636ca0e57553c5263643 [file] [log] [blame]
/* A simple I2C slave for returning monitor EDID data via DDC.
*
* Copyright (c) 2011 Linaro Limited
* Written by Peter Maydell
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "qemu/module.h"
#include "hw/i2c/i2c.h"
#include "hw/qdev-properties.h"
#include "migration/vmstate.h"
#include "hw/display/i2c-ddc.h"
#ifndef DEBUG_I2CDDC
#define DEBUG_I2CDDC 0
#endif
#define DPRINTF(fmt, ...) do { \
if (DEBUG_I2CDDC) { \
qemu_log("i2c-ddc: " fmt , ## __VA_ARGS__); \
} \
} while (0)
static void i2c_ddc_reset(DeviceState *ds)
{
I2CDDCState *s = I2CDDC(ds);
s->firstbyte = false;
s->reg = 0;
}
static int i2c_ddc_event(I2CSlave *i2c, enum i2c_event event)
{
I2CDDCState *s = I2CDDC(i2c);
if (event == I2C_START_SEND) {
s->firstbyte = true;
}
return 0;
}
static uint8_t i2c_ddc_rx(I2CSlave *i2c)
{
I2CDDCState *s = I2CDDC(i2c);
int value;
value = s->edid_blob[s->reg % sizeof(s->edid_blob)];
s->reg++;
return value;
}
static int i2c_ddc_tx(I2CSlave *i2c, uint8_t data)
{
I2CDDCState *s = I2CDDC(i2c);
if (s->firstbyte) {
s->reg = data;
s->firstbyte = false;
DPRINTF("[EDID] Written new pointer: %u\n", data);
return 0;
}
/* Ignore all writes */
s->reg++;
return 0;
}
static void i2c_ddc_init(Object *obj)
{
I2CDDCState *s = I2CDDC(obj);
qemu_edid_generate(s->edid_blob, sizeof(s->edid_blob), &s->edid_info);
}
static const VMStateDescription vmstate_i2c_ddc = {
.name = TYPE_I2CDDC,
.version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_BOOL(firstbyte, I2CDDCState),
VMSTATE_UINT8(reg, I2CDDCState),
VMSTATE_END_OF_LIST()
}
};
static Property i2c_ddc_properties[] = {
DEFINE_EDID_PROPERTIES(I2CDDCState, edid_info),
DEFINE_PROP_END_OF_LIST(),
};
static void i2c_ddc_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
I2CSlaveClass *isc = I2C_SLAVE_CLASS(oc);
dc->reset = i2c_ddc_reset;
dc->vmsd = &vmstate_i2c_ddc;
device_class_set_props(dc, i2c_ddc_properties);
isc->event = i2c_ddc_event;
isc->recv = i2c_ddc_rx;
isc->send = i2c_ddc_tx;
}
static TypeInfo i2c_ddc_info = {
.name = TYPE_I2CDDC,
.parent = TYPE_I2C_SLAVE,
.instance_size = sizeof(I2CDDCState),
.instance_init = i2c_ddc_init,
.class_init = i2c_ddc_class_init
};
static void ddc_register_devices(void)
{
type_register_static(&i2c_ddc_info);
}
type_init(ddc_register_devices);