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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Driver for MegaChips STDP4028 with GE B850v3 firmware (LVDS-DP)4 * Driver for MegaChips STDP2690 with GE B850v3 firmware (DP-DP++)5 6 * Copyright (c) 2017, Collabora Ltd.7 * Copyright (c) 2017, General Electric Company8 9 10 * This driver creates a drm_bridge and a drm_connector for the LVDS to DP++11 * display bridge of the GE B850v3. There are two physical bridges on the video12 * signal pipeline: a STDP4028(LVDS to DP) and a STDP2690(DP to DP++). The13 * physical bridges are automatically configured by the input video signal, and14 * the driver has no access to the video processing pipeline. The driver is15 * only needed to read EDID from the STDP2690 and to handle HPD events from the16 * STDP4028. The driver communicates with both bridges over i2c. The video17 * signal pipeline is as follows:18 *19 * Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output20 */21 22#include <linux/i2c.h>23#include <linux/module.h>24#include <linux/of.h>25 26#include <drm/drm_atomic.h>27#include <drm/drm_atomic_helper.h>28#include <drm/drm_bridge.h>29#include <drm/drm_edid.h>30#include <drm/drm_print.h>31#include <drm/drm_probe_helper.h>32 33#define EDID_EXT_BLOCK_CNT 0x7E34 35#define STDP4028_IRQ_OUT_CONF_REG 0x0236#define STDP4028_DPTX_IRQ_EN_REG 0x3C37#define STDP4028_DPTX_IRQ_STS_REG 0x3D38#define STDP4028_DPTX_STS_REG 0x3E39 40#define STDP4028_DPTX_DP_IRQ_EN 0x100041 42#define STDP4028_DPTX_HOTPLUG_IRQ_EN 0x040043#define STDP4028_DPTX_LINK_CH_IRQ_EN 0x200044#define STDP4028_DPTX_IRQ_CONFIG \45 (STDP4028_DPTX_LINK_CH_IRQ_EN | STDP4028_DPTX_HOTPLUG_IRQ_EN)46 47#define STDP4028_DPTX_HOTPLUG_STS 0x020048#define STDP4028_DPTX_LINK_STS 0x100049#define STDP4028_CON_STATE_CONNECTED \50 (STDP4028_DPTX_HOTPLUG_STS | STDP4028_DPTX_LINK_STS)51 52#define STDP4028_DPTX_HOTPLUG_CH_STS 0x040053#define STDP4028_DPTX_LINK_CH_STS 0x200054#define STDP4028_DPTX_IRQ_CLEAR \55 (STDP4028_DPTX_LINK_CH_STS | STDP4028_DPTX_HOTPLUG_CH_STS)56 57static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex);58 59struct ge_b850v3_lvds {60 struct drm_connector connector;61 struct drm_bridge bridge;62 struct i2c_client *stdp4028_i2c;63 struct i2c_client *stdp2690_i2c;64};65 66static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;67 68static int stdp2690_read_block(void *context, u8 *buf, unsigned int block, size_t len)69{70 struct i2c_client *client = context;71 struct i2c_adapter *adapter = client->adapter;72 unsigned char start = block * EDID_LENGTH;73 74 struct i2c_msg msgs[] = {75 {76 .addr = client->addr,77 .flags = 0,78 .len = 1,79 .buf = &start,80 }, {81 .addr = client->addr,82 .flags = I2C_M_RD,83 .len = len,84 .buf = buf,85 }86 };87 88 if (i2c_transfer(adapter, msgs, 2) != 2)89 return -1;90 91 return 0;92}93 94static const struct drm_edid *ge_b850v3_lvds_edid_read(struct drm_bridge *bridge,95 struct drm_connector *connector)96{97 struct i2c_client *client;98 99 client = ge_b850v3_lvds_ptr->stdp2690_i2c;100 101 return drm_edid_read_custom(connector, stdp2690_read_block, client);102}103 104static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)105{106 const struct drm_edid *drm_edid;107 int num_modes;108 109 drm_edid = ge_b850v3_lvds_edid_read(&ge_b850v3_lvds_ptr->bridge, connector);110 111 drm_edid_connector_update(connector, drm_edid);112 num_modes = drm_edid_connector_add_modes(connector);113 drm_edid_free(drm_edid);114 115 return num_modes;116}117 118static enum drm_mode_status ge_b850v3_lvds_mode_valid(119 struct drm_connector *connector, struct drm_display_mode *mode)120{121 return MODE_OK;122}123 124static const struct125drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {126 .get_modes = ge_b850v3_lvds_get_modes,127 .mode_valid = ge_b850v3_lvds_mode_valid,128};129 130static enum drm_connector_status ge_b850v3_lvds_bridge_detect(struct drm_bridge *bridge)131{132 struct i2c_client *stdp4028_i2c =133 ge_b850v3_lvds_ptr->stdp4028_i2c;134 s32 link_state;135 136 link_state = i2c_smbus_read_word_data(stdp4028_i2c,137 STDP4028_DPTX_STS_REG);138 139 if (link_state == STDP4028_CON_STATE_CONNECTED)140 return connector_status_connected;141 142 if (link_state == 0)143 return connector_status_disconnected;144 145 return connector_status_unknown;146}147 148static enum drm_connector_status ge_b850v3_lvds_detect(struct drm_connector *connector,149 bool force)150{151 return ge_b850v3_lvds_bridge_detect(&ge_b850v3_lvds_ptr->bridge);152}153 154static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {155 .fill_modes = drm_helper_probe_single_connector_modes,156 .detect = ge_b850v3_lvds_detect,157 .destroy = drm_connector_cleanup,158 .reset = drm_atomic_helper_connector_reset,159 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,160 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,161};162 163static int ge_b850v3_lvds_create_connector(struct drm_bridge *bridge)164{165 struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;166 int ret;167 168 connector->polled = DRM_CONNECTOR_POLL_HPD;169 170 drm_connector_helper_add(connector,171 &ge_b850v3_lvds_connector_helper_funcs);172 173 ret = drm_connector_init(bridge->dev, connector,174 &ge_b850v3_lvds_connector_funcs,175 DRM_MODE_CONNECTOR_DisplayPort);176 if (ret) {177 DRM_ERROR("Failed to initialize connector with drm\n");178 return ret;179 }180 181 return drm_connector_attach_encoder(connector, bridge->encoder);182}183 184static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)185{186 struct i2c_client *stdp4028_i2c187 = ge_b850v3_lvds_ptr->stdp4028_i2c;188 189 i2c_smbus_write_word_data(stdp4028_i2c,190 STDP4028_DPTX_IRQ_STS_REG,191 STDP4028_DPTX_IRQ_CLEAR);192 193 if (ge_b850v3_lvds_ptr->bridge.dev)194 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->bridge.dev);195 196 return IRQ_HANDLED;197}198 199static int ge_b850v3_lvds_attach(struct drm_bridge *bridge,200 enum drm_bridge_attach_flags flags)201{202 struct i2c_client *stdp4028_i2c203 = ge_b850v3_lvds_ptr->stdp4028_i2c;204 205 /* Configures the bridge to re-enable interrupts after each ack. */206 i2c_smbus_write_word_data(stdp4028_i2c,207 STDP4028_IRQ_OUT_CONF_REG,208 STDP4028_DPTX_DP_IRQ_EN);209 210 /* Enable interrupts */211 i2c_smbus_write_word_data(stdp4028_i2c,212 STDP4028_DPTX_IRQ_EN_REG,213 STDP4028_DPTX_IRQ_CONFIG);214 215 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)216 return 0;217 218 return ge_b850v3_lvds_create_connector(bridge);219}220 221static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {222 .attach = ge_b850v3_lvds_attach,223 .detect = ge_b850v3_lvds_bridge_detect,224 .edid_read = ge_b850v3_lvds_edid_read,225};226 227static int ge_b850v3_lvds_init(struct device *dev)228{229 mutex_lock(&ge_b850v3_lvds_dev_mutex);230 231 if (ge_b850v3_lvds_ptr)232 goto success;233 234 ge_b850v3_lvds_ptr = devm_kzalloc(dev,235 sizeof(*ge_b850v3_lvds_ptr),236 GFP_KERNEL);237 238 if (!ge_b850v3_lvds_ptr) {239 mutex_unlock(&ge_b850v3_lvds_dev_mutex);240 return -ENOMEM;241 }242 243success:244 mutex_unlock(&ge_b850v3_lvds_dev_mutex);245 return 0;246}247 248static void ge_b850v3_lvds_remove(void)249{250 mutex_lock(&ge_b850v3_lvds_dev_mutex);251 /*252 * This check is to avoid both the drivers253 * removing the bridge in their remove() function254 */255 if (!ge_b850v3_lvds_ptr ||256 !ge_b850v3_lvds_ptr->stdp2690_i2c ||257 !ge_b850v3_lvds_ptr->stdp4028_i2c)258 goto out;259 260 drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);261 262 ge_b850v3_lvds_ptr = NULL;263out:264 mutex_unlock(&ge_b850v3_lvds_dev_mutex);265}266 267static int ge_b850v3_register(void)268{269 struct i2c_client *stdp4028_i2c = ge_b850v3_lvds_ptr->stdp4028_i2c;270 struct device *dev = &stdp4028_i2c->dev;271 272 /* drm bridge initialization */273 ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;274 ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT |275 DRM_BRIDGE_OP_EDID;276 ge_b850v3_lvds_ptr->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;277 ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;278 drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);279 280 /* Clear pending interrupts since power up. */281 i2c_smbus_write_word_data(stdp4028_i2c,282 STDP4028_DPTX_IRQ_STS_REG,283 STDP4028_DPTX_IRQ_CLEAR);284 285 if (!stdp4028_i2c->irq)286 return 0;287 288 return devm_request_threaded_irq(&stdp4028_i2c->dev,289 stdp4028_i2c->irq, NULL,290 ge_b850v3_lvds_irq_handler,291 IRQF_TRIGGER_HIGH | IRQF_ONESHOT,292 "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);293}294 295static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c)296{297 struct device *dev = &stdp4028_i2c->dev;298 int ret;299 300 ret = ge_b850v3_lvds_init(dev);301 302 if (ret)303 return ret;304 305 ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;306 i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);307 308 /* Only register after both bridges are probed */309 if (!ge_b850v3_lvds_ptr->stdp2690_i2c)310 return 0;311 312 return ge_b850v3_register();313}314 315static void stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)316{317 ge_b850v3_lvds_remove();318}319 320static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {321 {"stdp4028_ge_fw", 0},322 {},323};324MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);325 326static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {327 { .compatible = "megachips,stdp4028-ge-b850v3-fw" },328 {},329};330MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);331 332static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {333 .id_table = stdp4028_ge_b850v3_fw_i2c_table,334 .probe = stdp4028_ge_b850v3_fw_probe,335 .remove = stdp4028_ge_b850v3_fw_remove,336 .driver = {337 .name = "stdp4028-ge-b850v3-fw",338 .of_match_table = stdp4028_ge_b850v3_fw_match,339 },340};341 342static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c)343{344 struct device *dev = &stdp2690_i2c->dev;345 int ret;346 347 ret = ge_b850v3_lvds_init(dev);348 349 if (ret)350 return ret;351 352 ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;353 i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);354 355 /* Only register after both bridges are probed */356 if (!ge_b850v3_lvds_ptr->stdp4028_i2c)357 return 0;358 359 return ge_b850v3_register();360}361 362static void stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)363{364 ge_b850v3_lvds_remove();365}366 367static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {368 {"stdp2690_ge_fw", 0},369 {},370};371MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);372 373static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {374 { .compatible = "megachips,stdp2690-ge-b850v3-fw" },375 {},376};377MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);378 379static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {380 .id_table = stdp2690_ge_b850v3_fw_i2c_table,381 .probe = stdp2690_ge_b850v3_fw_probe,382 .remove = stdp2690_ge_b850v3_fw_remove,383 .driver = {384 .name = "stdp2690-ge-b850v3-fw",385 .of_match_table = stdp2690_ge_b850v3_fw_match,386 },387};388 389static int __init stdpxxxx_ge_b850v3_init(void)390{391 int ret;392 393 ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);394 if (ret)395 return ret;396 397 ret = i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);398 if (ret)399 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);400 401 return ret;402}403module_init(stdpxxxx_ge_b850v3_init);404 405static void __exit stdpxxxx_ge_b850v3_exit(void)406{407 i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);408 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);409}410module_exit(stdpxxxx_ge_b850v3_exit);411 412MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");413MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");414MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");415MODULE_LICENSE("GPL v2");416