kernel/drivers/gpu/drm/bridge/ptn3460.c

   1 /*
   2  * NXP PTN3460 DP/LVDS bridge driver
   3  *
   4  * Copyright (C) 2013 Google, Inc.
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/delay.h>
  17 #include <linux/gpio.h>
  18 #include <linux/gpio/consumer.h>
  19 #include <linux/i2c.h>
  20 #include <linux/module.h>
  21 #include <linux/of.h>
  22 #include <linux/of_gpio.h>
  23 #include <linux/of_graph.h>
  24
  25 #include <drm/drm_panel.h>
  26
  27 #include "bridge/ptn3460.h"
  28
  29 #include "drm_crtc.h"
  30 #include "drm_crtc_helper.h"
  31 #include "drm_edid.h"
  32 #include "drmP.h"
  33
  34 #define PTN3460_EDID_ADDR                       0x0
  35 #define PTN3460_EDID_EMULATION_ADDR             0x84
  36 #define PTN3460_EDID_ENABLE_EMULATION           0
  37 #define PTN3460_EDID_EMULATION_SELECTION        1
  38 #define PTN3460_EDID_SRAM_LOAD_ADDR             0x85
  39
  40 struct ptn3460_bridge {
  41         struct drm_connector connector;
  42         struct i2c_client *client;
  43         struct drm_bridge bridge;
  44         struct edid *edid;
  45         struct drm_panel *panel;
  46         struct gpio_desc *gpio_pd_n;
  47         struct gpio_desc *gpio_rst_n;
  48         u32 edid_emulation;
  49         bool enabled;
  50 };
  51
  52 static inline struct ptn3460_bridge *
  53                 bridge_to_ptn3460(struct drm_bridge *bridge)
  54 {
  55         return container_of(bridge, struct ptn3460_bridge, bridge);
  56 }
  57
  58 static inline struct ptn3460_bridge *
  59                 connector_to_ptn3460(struct drm_connector *connector)
  60 {
  61         return container_of(connector, struct ptn3460_bridge, connector);
  62 }
  63
  64 static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
  65                 u8 *buf, int len)
  66 {
  67         int ret;
  68
  69         ret = i2c_master_send(ptn_bridge->client, &addr, 1);
  70         if (ret <= 0) {
  71                 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
  72                 return ret;
  73         }
  74
  75         ret = i2c_master_recv(ptn_bridge->client, buf, len);
  76         if (ret <= 0) {
  77                 DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
  78                 return ret;
  79         }
  80
  81         return 0;
  82 }
  83
  84 static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
  85                 char val)
  86 {
  87         int ret;
  88         char buf[2];
  89
  90         buf[0] = addr;
  91         buf[1] = val;
  92
  93         ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
  94         if (ret <= 0) {
  95                 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
  96                 return ret;
  97         }
  98
  99         return 0;
 100 }
 101
 102 static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
 103 {
 104         int ret;
 105         char val;
 106
 107         /* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
 108         ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
 109                         ptn_bridge->edid_emulation);
 110         if (ret) {
 111                 DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
 112                 return ret;
 113         }
 114
 115         /* Enable EDID emulation and select the desired EDID */
 116         val = 1 << PTN3460_EDID_ENABLE_EMULATION |
 117                 ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;
 118
 119         ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
 120         if (ret) {
 121                 DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
 122                 return ret;
 123         }
 124
 125         return 0;
 126 }
 127
 128 static void ptn3460_pre_enable(struct drm_bridge *bridge)
 129 {
 130         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 131         int ret;
 132
 133         if (ptn_bridge->enabled)
 134                 return;
 135
 136         gpiod_set_value(ptn_bridge->gpio_pd_n, 1);
 137
 138         gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
 139         usleep_range(10, 20);
 140         gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
 141
 142         if (drm_panel_prepare(ptn_bridge->panel)) {
 143                 DRM_ERROR("failed to prepare panel\n");
 144                 return;
 145         }
 146
 147         /*
 148          * There's a bug in the PTN chip where it falsely asserts hotplug before
 149          * it is fully functional. We're forced to wait for the maximum start up
 150          * time specified in the chip's datasheet to make sure we're really up.
 151          */
 152         msleep(90);
 153
 154         ret = ptn3460_select_edid(ptn_bridge);
 155         if (ret)
 156                 DRM_ERROR("Select EDID failed ret=%d\n", ret);
 157
 158         ptn_bridge->enabled = true;
 159 }
 160
 161 static void ptn3460_enable(struct drm_bridge *bridge)
 162 {
 163         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 164
 165         if (drm_panel_enable(ptn_bridge->panel)) {
 166                 DRM_ERROR("failed to enable panel\n");
 167                 return;
 168         }
 169 }
 170
 171 static void ptn3460_disable(struct drm_bridge *bridge)
 172 {
 173         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 174
 175         if (!ptn_bridge->enabled)
 176                 return;
 177
 178         ptn_bridge->enabled = false;
 179
 180         if (drm_panel_disable(ptn_bridge->panel)) {
 181                 DRM_ERROR("failed to disable panel\n");
 182                 return;
 183         }
 184
 185         gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
 186         gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
 187 }
 188
 189 static void ptn3460_post_disable(struct drm_bridge *bridge)
 190 {
 191         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 192
 193         if (drm_panel_unprepare(ptn_bridge->panel)) {
 194                 DRM_ERROR("failed to unprepare panel\n");
 195                 return;
 196         }
 197 }
 198
 199 static int ptn3460_get_modes(struct drm_connector *connector)
 200 {
 201         struct ptn3460_bridge *ptn_bridge;
 202         u8 *edid;
 203         int ret, num_modes = 0;
 204         bool power_off;
 205
 206         ptn_bridge = connector_to_ptn3460(connector);
 207
 208         if (ptn_bridge->edid)
 209                 return drm_add_edid_modes(connector, ptn_bridge->edid);
 210
 211         power_off = !ptn_bridge->enabled;
 212         ptn3460_pre_enable(&ptn_bridge->bridge);
 213
 214         edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
 215         if (!edid) {
 216                 DRM_ERROR("Failed to allocate EDID\n");
 217                 return 0;
 218         }
 219
 220         ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
 221                         EDID_LENGTH);
 222         if (ret) {
 223                 kfree(edid);
 224                 goto out;
 225         }
 226
 227         ptn_bridge->edid = (struct edid *)edid;
 228         drm_mode_connector_update_edid_property(connector, ptn_bridge->edid);
 229
 230         num_modes = drm_add_edid_modes(connector, ptn_bridge->edid);
 231
 232 out:
 233         if (power_off)
 234                 ptn3460_disable(&ptn_bridge->bridge);
 235
 236         return num_modes;
 237 }
 238
 239 static struct drm_encoder *ptn3460_best_encoder(struct drm_connector *connector)
 240 {
 241         struct ptn3460_bridge *ptn_bridge = connector_to_ptn3460(connector);
 242
 243         return ptn_bridge->bridge.encoder;
 244 }
 245
 246 static struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
 247         .get_modes = ptn3460_get_modes,
 248         .best_encoder = ptn3460_best_encoder,
 249 };
 250
 251 static enum drm_connector_status ptn3460_detect(struct drm_connector *connector,
 252                 bool force)
 253 {
 254         return connector_status_connected;
 255 }
 256
 257 static void ptn3460_connector_destroy(struct drm_connector *connector)
 258 {
 259         drm_connector_cleanup(connector);
 260 }
 261
 262 static struct drm_connector_funcs ptn3460_connector_funcs = {
 263         .dpms = drm_helper_connector_dpms,
 264         .fill_modes = drm_helper_probe_single_connector_modes,
 265         .detect = ptn3460_detect,
 266         .destroy = ptn3460_connector_destroy,
 267 };
 268
 269 static int ptn3460_bridge_attach(struct drm_bridge *bridge)
 270 {
 271         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 272         int ret;
 273
 274         if (!bridge->encoder) {
 275                 DRM_ERROR("Parent encoder object not found");
 276                 return -ENODEV;
 277         }
 278
 279         ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
 280         ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
 281                         &ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
 282         if (ret) {
 283                 DRM_ERROR("Failed to initialize connector with drm\n");
 284                 return ret;
 285         }
 286         drm_connector_helper_add(&ptn_bridge->connector,
 287                                         &ptn3460_connector_helper_funcs);
 288         drm_connector_register(&ptn_bridge->connector);
 289         drm_mode_connector_attach_encoder(&ptn_bridge->connector,
 290                                                         bridge->encoder);
 291
 292         if (ptn_bridge->panel)
 293                 drm_panel_attach(ptn_bridge->panel, &ptn_bridge->connector);
 294
 295         drm_helper_hpd_irq_event(ptn_bridge->connector.dev);
 296
 297         return ret;
 298 }
 299
 300 static struct drm_bridge_funcs ptn3460_bridge_funcs = {
 301         .pre_enable = ptn3460_pre_enable,
 302         .enable = ptn3460_enable,
 303         .disable = ptn3460_disable,
 304         .post_disable = ptn3460_post_disable,
 305         .attach = ptn3460_bridge_attach,
 306 };
 307
 308 static int ptn3460_probe(struct i2c_client *client,
 309                                 const struct i2c_device_id *id)
 310 {
 311         struct device *dev = &client->dev;
 312         struct ptn3460_bridge *ptn_bridge;
 313         struct device_node *endpoint, *panel_node;
 314         int ret;
 315
 316         ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
 317         if (!ptn_bridge) {
 318                 return -ENOMEM;
 319         }
 320
 321         endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
 322         if (endpoint) {
 323                 panel_node = of_graph_get_remote_port_parent(endpoint);
 324                 if (panel_node) {
 325                         ptn_bridge->panel = of_drm_find_panel(panel_node);
 326                         of_node_put(panel_node);
 327                         if (!ptn_bridge->panel)
 328                                 return -EPROBE_DEFER;
 329                 }
 330         }
 331
 332         ptn_bridge->client = client;
 333
 334         ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown");
 335         if (IS_ERR(ptn_bridge->gpio_pd_n)) {
 336                 ret = PTR_ERR(ptn_bridge->gpio_pd_n);
 337                 dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
 338                 return ret;
 339         }
 340
 341         ret = gpiod_direction_output(ptn_bridge->gpio_pd_n, 1);
 342         if (ret) {
 343                 DRM_ERROR("cannot configure gpio_pd_n\n");
 344                 return ret;
 345         }
 346
 347         ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset");
 348         if (IS_ERR(ptn_bridge->gpio_rst_n)) {
 349                 ret = PTR_ERR(ptn_bridge->gpio_rst_n);
 350                 DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
 351                 return ret;
 352         }
 353         /*
 354          * Request the reset pin low to avoid the bridge being
 355          * initialized prematurely
 356          */
 357         ret = gpiod_direction_output(ptn_bridge->gpio_rst_n, 0);
 358         if (ret) {
 359                 DRM_ERROR("cannot configure gpio_rst_n\n");
 360                 return ret;
 361         }
 362
 363         ret = of_property_read_u32(dev->of_node, "edid-emulation",
 364                         &ptn_bridge->edid_emulation);
 365         if (ret) {
 366                 dev_err(dev, "Can't read EDID emulation value\n");
 367                 return ret;
 368         }
 369
 370         ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
 371         ptn_bridge->bridge.of_node = dev->of_node;
 372         ret = drm_bridge_add(&ptn_bridge->bridge);
 373         if (ret) {
 374                 DRM_ERROR("Failed to add bridge\n");
 375                 return ret;
 376         }
 377
 378         i2c_set_clientdata(client, ptn_bridge);
 379
 380         return 0;
 381 }
 382
 383 static int ptn3460_remove(struct i2c_client *client)
 384 {
 385         struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
 386
 387         drm_bridge_remove(&ptn_bridge->bridge);
 388
 389         return 0;
 390 }
 391
 392 static const struct i2c_device_id ptn3460_i2c_table[] = {
 393         {"nxp,ptn3460", 0},
 394         {},
 395 };
 396 MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
 397
 398 static const struct of_device_id ptn3460_match[] = {
 399         { .compatible = "nxp,ptn3460" },
 400         {},
 401 };
 402 MODULE_DEVICE_TABLE(of, ptn3460_match);
 403
 404 static struct i2c_driver ptn3460_driver = {
 405         .id_table       = ptn3460_i2c_table,
 406         .probe          = ptn3460_probe,
 407         .remove         = ptn3460_remove,
 408         .driver         = {
 409                 .name   = "nxp,ptn3460",
 410                 .owner  = THIS_MODULE,
 411                 .of_match_table = ptn3460_match,
 412         },
 413 };
 414 module_i2c_driver(ptn3460_driver);
 415
 416 MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
 417 MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
 418 MODULE_LICENSE("GPL v2");