// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for MegaChips STDP4028 with GE B850v3 firmware (LVDS-DP)
* Driver for MegaChips STDP2690 with GE B850v3 firmware (DP-DP++)
* Copyright (c) 2017, Collabora Ltd.
* Copyright (c) 2017, General Electric Company
* This driver creates a drm_bridge and a drm_connector for the LVDS to DP++
* display bridge of the GE B850v3. There are two physical bridges on the video
* signal pipeline: a STDP4028(LVDS to DP) and a STDP2690(DP to DP++). The
* physical bridges are automatically configured by the input video signal, and
* the driver has no access to the video processing pipeline. The driver is
* only needed to read EDID from the STDP2690 and to handle HPD events from the
* STDP4028. The driver communicates with both bridges over i2c. The video
* signal pipeline is as follows:
*
* Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output
*/
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_edid.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>
#define EDID_EXT_BLOCK_CNT 0x7E
#define STDP4028_IRQ_OUT_CONF_REG 0x02
#define STDP4028_DPTX_IRQ_EN_REG 0x3C
#define STDP4028_DPTX_IRQ_STS_REG 0x3D
#define STDP4028_DPTX_STS_REG 0x3E
#define STDP4028_DPTX_DP_IRQ_EN 0x1000
#define STDP4028_DPTX_HOTPLUG_IRQ_EN 0x0400
#define STDP4028_DPTX_LINK_CH_IRQ_EN 0x2000
#define STDP4028_DPTX_IRQ_CONFIG \
(STDP4028_DPTX_LINK_CH_IRQ_EN | STDP4028_DPTX_HOTPLUG_IRQ_EN)
#define STDP4028_DPTX_HOTPLUG_STS 0x0200
#define STDP4028_DPTX_LINK_STS 0x1000
#define STDP4028_CON_STATE_CONNECTED \
(STDP4028_DPTX_HOTPLUG_STS | STDP4028_DPTX_LINK_STS)
#define STDP4028_DPTX_HOTPLUG_CH_STS 0x0400
#define STDP4028_DPTX_LINK_CH_STS 0x2000
#define STDP4028_DPTX_IRQ_CLEAR \
(STDP4028_DPTX_LINK_CH_STS | STDP4028_DPTX_HOTPLUG_CH_STS)
static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex);
struct ge_b850v3_lvds {
struct drm_connector connector;
struct drm_bridge bridge;
struct i2c_client *stdp4028_i2c;
struct i2c_client *stdp2690_i2c;
};
static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
static int stdp2690_read_block(void *context, u8 *buf, unsigned int block, size_t len)
{
struct i2c_client *client = context;
struct i2c_adapter *adapter = client->adapter;
unsigned char start = block * EDID_LENGTH;
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = 1,
.buf = &start,
}, {
.addr = client->addr,
.flags = I2C_M_RD,
.len = len,
.buf = buf,
}
};
if (i2c_transfer(adapter, msgs, 2) != 2)
return -1;
return 0;
}
static const struct drm_edid *ge_b850v3_lvds_edid_read(struct drm_bridge *bridge,
struct drm_connector *connector)
{
struct i2c_client *client;
client = ge_b850v3_lvds_ptr->stdp2690_i2c;
return drm_edid_read_custom(connector, stdp2690_read_block, client);
}
static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
{
const struct drm_edid *drm_edid;
int num_modes;
drm_edid = ge_b850v3_lvds_edid_read(&ge_b850v3_lvds_ptr->bridge, connector);
drm_edid_connector_update(connector, drm_edid);
num_modes = drm_edid_connector_add_modes(connector);
drm_edid_free(drm_edid);
return num_modes;
}
static enum drm_mode_status ge_b850v3_lvds_mode_valid(
struct drm_connector *connector, struct drm_display_mode *mode)
{
return MODE_OK;
}
static const struct
drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
.get_modes = ge_b850v3_lvds_get_modes,
.mode_valid = ge_b850v3_lvds_mode_valid,
};
static enum drm_connector_status ge_b850v3_lvds_bridge_detect(struct drm_bridge *bridge)
{
struct i2c_client *stdp4028_i2c =
ge_b850v3_lvds_ptr->stdp4028_i2c;
s32 link_state;
link_state = i2c_smbus_read_word_data(stdp4028_i2c,
STDP4028_DPTX_STS_REG);
if (link_state == STDP4028_CON_STATE_CONNECTED)
return connector_status_connected;
if (link_state == 0)
return connector_status_disconnected;
return connector_status_unknown;
}
static enum drm_connector_status ge_b850v3_lvds_detect(struct drm_connector *connector,
bool force)
{
return ge_b850v3_lvds_bridge_detect(&ge_b850v3_lvds_ptr->bridge);
}
static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
.fill_modes = drm_helper_probe_single_connector_modes,
.detect = ge_b850v3_lvds_detect,
.destroy = drm_connector_cleanup,
.reset = drm_atomic_helper_connector_reset,
.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
};
static int ge_b850v3_lvds_create_connector(struct drm_bridge *bridge)
{
struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
int ret;
connector->polled = DRM_CONNECTOR_POLL_HPD;
drm_connector_helper_add(connector,
&ge_b850v3_lvds_connector_helper_funcs);
ret = drm_connector_init(bridge->dev, connector,
&ge_b850v3_lvds_connector_funcs,
DRM_MODE_CONNECTOR_DisplayPort);
if (ret) {
DRM_ERROR("Failed to initialize connector with drm\n");
return ret;
}
return drm_connector_attach_encoder(connector, bridge->encoder);
}
static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
{
struct i2c_client *stdp4028_i2c
= ge_b850v3_lvds_ptr->stdp4028_i2c;
i2c_smbus_write_word_data(stdp4028_i2c,
STDP4028_DPTX_IRQ_STS_REG,
STDP4028_DPTX_IRQ_CLEAR);
if (ge_b850v3_lvds_ptr->bridge.dev)
drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->bridge.dev);
return IRQ_HANDLED;
}
static int ge_b850v3_lvds_attach(struct drm_bridge *bridge,
enum drm_bridge_attach_flags flags)
{
struct i2c_client *stdp4028_i2c
= ge_b850v3_lvds_ptr->stdp4028_i2c;
/* Configures the bridge to re-enable interrupts after each ack. */
i2c_smbus_write_word_data(stdp4028_i2c,
STDP4028_IRQ_OUT_CONF_REG,
STDP4028_DPTX_DP_IRQ_EN);
/* Enable interrupts */
i2c_smbus_write_word_data(stdp4028_i2c,
STDP4028_DPTX_IRQ_EN_REG,
STDP4028_DPTX_IRQ_CONFIG);
if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
return 0;
return ge_b850v3_lvds_create_connector(bridge);
}
static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
.attach = ge_b850v3_lvds_attach,
.detect = ge_b850v3_lvds_bridge_detect,
.edid_read = ge_b850v3_lvds_edid_read,
};
static int ge_b850v3_lvds_init(struct device *dev)
{
mutex_lock(&ge_b850v3_lvds_dev_mutex);
if (ge_b850v3_lvds_ptr)
goto success;
ge_b850v3_lvds_ptr = devm_kzalloc(dev,
sizeof(*ge_b850v3_lvds_ptr),
GFP_KERNEL);
if (!ge_b850v3_lvds_ptr) {
mutex_unlock(&ge_b850v3_lvds_dev_mutex);
return -ENOMEM;
}
success:
mutex_unlock(&ge_b850v3_lvds_dev_mutex);
return 0;
}
static void ge_b850v3_lvds_remove(void)
{
mutex_lock(&ge_b850v3_lvds_dev_mutex);
/*
* This check is to avoid both the drivers
* removing the bridge in their remove() function
*/
if (!ge_b850v3_lvds_ptr ||
!ge_b850v3_lvds_ptr->stdp2690_i2c ||
!ge_b850v3_lvds_ptr->stdp4028_i2c)
goto out;
drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
ge_b850v3_lvds_ptr = NULL;
out:
mutex_unlock(&ge_b850v3_lvds_dev_mutex);
}
static int ge_b850v3_register(void)
{
struct i2c_client *stdp4028_i2c = ge_b850v3_lvds_ptr->stdp4028_i2c;
struct device *dev = &stdp4028_i2c->dev;
/* drm bridge initialization */
ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT |
DRM_BRIDGE_OP_EDID;
ge_b850v3_lvds_ptr->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
/* Clear pending interrupts since power up. */
i2c_smbus_write_word_data(stdp4028_i2c,
STDP4028_DPTX_IRQ_STS_REG,
STDP4028_DPTX_IRQ_CLEAR);
if (!stdp4028_i2c->irq)
return 0;
return devm_request_threaded_irq(&stdp4028_i2c->dev,
stdp4028_i2c->irq, NULL,
ge_b850v3_lvds_irq_handler,
IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
"ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
}
static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c)
{
struct device *dev = &stdp4028_i2c->dev;
int ret;
ret = ge_b850v3_lvds_init(dev);
if (ret)
return ret;
ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
/* Only register after both bridges are probed */
if (!ge_b850v3_lvds_ptr->stdp2690_i2c)
return 0;
return ge_b850v3_register();
}
static void stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
{
ge_b850v3_lvds_remove();
}
static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
{"stdp4028_ge_fw", 0},
{},
};
MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
{ .compatible = "megachips,stdp4028-ge-b850v3-fw" },
{},
};
MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
.id_table = stdp4028_ge_b850v3_fw_i2c_table,
.probe = stdp4028_ge_b850v3_fw_probe,
.remove = stdp4028_ge_b850v3_fw_remove,
.driver = {
.name = "stdp4028-ge-b850v3-fw",
.of_match_table = stdp4028_ge_b850v3_fw_match,
},
};
static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c)
{
struct device *dev = &stdp2690_i2c->dev;
int ret;
ret = ge_b850v3_lvds_init(dev);
if (ret)
return ret;
ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
/* Only register after both bridges are probed */
if (!ge_b850v3_lvds_ptr->stdp4028_i2c)
return 0;
return ge_b850v3_register();
}
static void stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
{
ge_b850v3_lvds_remove();
}
static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
{"stdp2690_ge_fw", 0},
{},
};
MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
{ .compatible = "megachips,stdp2690-ge-b850v3-fw" },
{},
};
MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
.id_table = stdp2690_ge_b850v3_fw_i2c_table,
.probe = stdp2690_ge_b850v3_fw_probe,
.remove = stdp2690_ge_b850v3_fw_remove,
.driver = {
.name = "stdp2690-ge-b850v3-fw",
.of_match_table = stdp2690_ge_b850v3_fw_match,
},
};
static int __init stdpxxxx_ge_b850v3_init(void)
{
int ret;
ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
if (ret)
return ret;
ret = i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
if (ret)
i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
return ret;
}
module_init(stdpxxxx_ge_b850v3_init);
static void __exit stdpxxxx_ge_b850v3_exit(void)
{
i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
}
module_exit(stdpxxxx_ge_b850v3_exit);
MODULE_AUTHOR("Peter Senna Tschudin <[email protected]>");
MODULE_AUTHOR("Martyn Welch <[email protected]>");
MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
MODULE_LICENSE("GPL v2");
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