diff options
author | Daniel Baumann <mail@daniel-baumann.ch> | 2025-06-06 10:05:23 +0000 |
---|---|---|
committer | Daniel Baumann <mail@daniel-baumann.ch> | 2025-06-06 10:05:23 +0000 |
commit | 755cc582a2473d06f3a2131d506d0311cc70e9f9 (patch) | |
tree | 3efb1ddb8d57bbb4539ac0d229b384871c57820f /hw/display/i2c-ddc.c | |
parent | Initial commit. (diff) | |
download | qemu-upstream.tar.xz qemu-upstream.zip |
Adding upstream version 1:7.2+dfsg.upstream/1%7.2+dfsgupstream
Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>
Diffstat (limited to 'hw/display/i2c-ddc.c')
-rw-r--r-- | hw/display/i2c-ddc.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/hw/display/i2c-ddc.c b/hw/display/i2c-ddc.c new file mode 100644 index 00000000..14648951 --- /dev/null +++ b/hw/display/i2c-ddc.c @@ -0,0 +1,129 @@ +/* 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 const 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); |