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/module.h>
  17 #include <linux/of.h>
  18 #include <linux/of_gpio.h>
  19 #include <linux/i2c.h>
  20 #include <linux/gpio.h>
  21 #include <linux/delay.h>
  22
  23 #include "drmP.h"
  24 #include "drm_edid.h"
  25 #include "drm_crtc.h"
  26 #include "drm_crtc_helper.h"
  27
  28 #include "bridge/ptn3460.h"
  29
  30 #define PTN3460_EDID_ADDR                       0x0
  31 #define PTN3460_EDID_EMULATION_ADDR             0x84
  32 #define PTN3460_EDID_ENABLE_EMULATION           0
  33 #define PTN3460_EDID_EMULATION_SELECTION        1
  34 #define PTN3460_EDID_SRAM_LOAD_ADDR             0x85
  35
  36 struct ptn3460_bridge {
  37         struct drm_connector connector;
  38         struct i2c_client *client;
  39         struct drm_encoder *encoder;
  40         struct drm_bridge *bridge;
  41         struct edid *edid;
  42         int gpio_pd_n;
  43         int gpio_rst_n;
  44         u32 edid_emulation;
  45         bool enabled;
  46 };
  47
  48 static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
  49                 u8 *buf, int len)
  50 {
  51         int ret;
  52
  53         ret = i2c_master_send(ptn_bridge->client, &addr, 1);
  54         if (ret <= 0) {
  55                 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
  56                 return ret;
  57         }
  58
  59         ret = i2c_master_recv(ptn_bridge->client, buf, len);
  60         if (ret <= 0) {
  61                 DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
  62                 return ret;
  63         }
  64
  65         return 0;
  66 }
  67
  68 static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
  69                 char val)
  70 {
  71         int ret;
  72         char buf[2];
  73
  74         buf[0] = addr;
  75         buf[1] = val;
  76
  77         ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
  78         if (ret <= 0) {
  79                 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
  80                 return ret;
  81         }
  82
  83         return 0;
  84 }
  85
  86 static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
  87 {
  88         int ret;
  89         char val;
  90
  91         /* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
  92         ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
  93                         ptn_bridge->edid_emulation);
  94         if (ret) {
  95                 DRM_ERROR("Failed to transfer edid to sram, ret=%d\n", ret);
  96                 return ret;
  97         }
  98
  99         /* Enable EDID emulation and select the desired EDID */
 100         val = 1 << PTN3460_EDID_ENABLE_EMULATION |
 101                 ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;
 102
 103         ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
 104         if (ret) {
 105                 DRM_ERROR("Failed to write edid value, ret=%d\n", ret);
 106                 return ret;
 107         }
 108
 109         return 0;
 110 }
 111
 112 static void ptn3460_pre_enable(struct drm_bridge *bridge)
 113 {
 114         struct ptn3460_bridge *ptn_bridge = bridge->driver_private;
 115         int ret;
 116
 117         if (ptn_bridge->enabled)
 118                 return;
 119
 120         if (gpio_is_valid(ptn_bridge->gpio_pd_n))
 121                 gpio_set_value(ptn_bridge->gpio_pd_n, 1);
 122
 123         if (gpio_is_valid(ptn_bridge->gpio_rst_n)) {
 124                 gpio_set_value(ptn_bridge->gpio_rst_n, 0);
 125                 udelay(10);
 126                 gpio_set_value(ptn_bridge->gpio_rst_n, 1);
 127         }
 128
 129         /*
 130          * There's a bug in the PTN chip where it falsely asserts hotplug before
 131          * it is fully functional. We're forced to wait for the maximum start up
 132          * time specified in the chip's datasheet to make sure we're really up.
 133          */
 134         msleep(90);
 135
 136         ret = ptn3460_select_edid(ptn_bridge);
 137         if (ret)
 138                 DRM_ERROR("Select edid failed ret=%d\n", ret);
 139
 140         ptn_bridge->enabled = true;
 141 }
 142
 143 static void ptn3460_enable(struct drm_bridge *bridge)
 144 {
 145 }
 146
 147 static void ptn3460_disable(struct drm_bridge *bridge)
 148 {
 149         struct ptn3460_bridge *ptn_bridge = bridge->driver_private;
 150
 151         if (!ptn_bridge->enabled)
 152                 return;
 153
 154         ptn_bridge->enabled = false;
 155
 156         if (gpio_is_valid(ptn_bridge->gpio_rst_n))
 157                 gpio_set_value(ptn_bridge->gpio_rst_n, 1);
 158
 159         if (gpio_is_valid(ptn_bridge->gpio_pd_n))
 160                 gpio_set_value(ptn_bridge->gpio_pd_n, 0);
 161 }
 162
 163 static void ptn3460_post_disable(struct drm_bridge *bridge)
 164 {
 165 }
 166
 167 void ptn3460_bridge_destroy(struct drm_bridge *bridge)
 168 {
 169         struct ptn3460_bridge *ptn_bridge = bridge->driver_private;
 170
 171         drm_bridge_cleanup(bridge);
 172         if (gpio_is_valid(ptn_bridge->gpio_pd_n))
 173                 gpio_free(ptn_bridge->gpio_pd_n);
 174         if (gpio_is_valid(ptn_bridge->gpio_rst_n))
 175                 gpio_free(ptn_bridge->gpio_rst_n);
 176         /* Nothing else to free, we've got devm allocated memory */
 177 }
 178
 179 struct drm_bridge_funcs ptn3460_bridge_funcs = {
 180         .pre_enable = ptn3460_pre_enable,
 181         .enable = ptn3460_enable,
 182         .disable = ptn3460_disable,
 183         .post_disable = ptn3460_post_disable,
 184         .destroy = ptn3460_bridge_destroy,
 185 };
 186
 187 int ptn3460_get_modes(struct drm_connector *connector)
 188 {
 189         struct ptn3460_bridge *ptn_bridge;
 190         u8 *edid;
 191         int ret, num_modes;
 192         bool power_off;
 193
 194         ptn_bridge = container_of(connector, struct ptn3460_bridge, connector);
 195
 196         if (ptn_bridge->edid)
 197                 return drm_add_edid_modes(connector, ptn_bridge->edid);
 198
 199         power_off = !ptn_bridge->enabled;
 200         ptn3460_pre_enable(ptn_bridge->bridge);
 201
 202         edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
 203         if (!edid) {
 204                 DRM_ERROR("Failed to allocate edid\n");
 205                 return 0;
 206         }
 207
 208         ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
 209                         EDID_LENGTH);
 210         if (ret) {
 211                 kfree(edid);
 212                 num_modes = 0;
 213                 goto out;
 214         }
 215
 216         ptn_bridge->edid = (struct edid *)edid;
 217         drm_mode_connector_update_edid_property(connector, ptn_bridge->edid);
 218
 219         num_modes = drm_add_edid_modes(connector, ptn_bridge->edid);
 220
 221 out:
 222         if (power_off)
 223                 ptn3460_disable(ptn_bridge->bridge);
 224
 225         return num_modes;
 226 }
 227
 228 struct drm_encoder *ptn3460_best_encoder(struct drm_connector *connector)
 229 {
 230         struct ptn3460_bridge *ptn_bridge;
 231
 232         ptn_bridge = container_of(connector, struct ptn3460_bridge, connector);
 233
 234         return ptn_bridge->encoder;
 235 }
 236
 237 struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
 238         .get_modes = ptn3460_get_modes,
 239         .best_encoder = ptn3460_best_encoder,
 240 };
 241
 242 enum drm_connector_status ptn3460_detect(struct drm_connector *connector,
 243                 bool force)
 244 {
 245         return connector_status_connected;
 246 }
 247
 248 void ptn3460_connector_destroy(struct drm_connector *connector)
 249 {
 250         drm_connector_cleanup(connector);
 251 }
 252
 253 struct drm_connector_funcs ptn3460_connector_funcs = {
 254         .dpms = drm_helper_connector_dpms,
 255         .fill_modes = drm_helper_probe_single_connector_modes,
 256         .detect = ptn3460_detect,
 257         .destroy = ptn3460_connector_destroy,
 258 };
 259
 260 int ptn3460_init(struct drm_device *dev, struct drm_encoder *encoder,
 261                 struct i2c_client *client, struct device_node *node)
 262 {
 263         int ret;
 264         struct drm_bridge *bridge;
 265         struct ptn3460_bridge *ptn_bridge;
 266
 267         bridge = devm_kzalloc(dev->dev, sizeof(*bridge), GFP_KERNEL);
 268         if (!bridge) {
 269                 DRM_ERROR("Failed to allocate drm bridge\n");
 270                 return -ENOMEM;
 271         }
 272
 273         ptn_bridge = devm_kzalloc(dev->dev, sizeof(*ptn_bridge), GFP_KERNEL);
 274         if (!ptn_bridge) {
 275                 DRM_ERROR("Failed to allocate ptn bridge\n");
 276                 return -ENOMEM;
 277         }
 278
 279         ptn_bridge->client = client;
 280         ptn_bridge->encoder = encoder;
 281         ptn_bridge->bridge = bridge;
 282         ptn_bridge->gpio_pd_n = of_get_named_gpio(node, "powerdown-gpio", 0);
 283         if (gpio_is_valid(ptn_bridge->gpio_pd_n)) {
 284                 ret = gpio_request_one(ptn_bridge->gpio_pd_n,
 285                                 GPIOF_OUT_INIT_HIGH, "PTN3460_PD_N");
 286                 if (ret) {
 287                         DRM_ERROR("Request powerdown-gpio failed (%d)\n", ret);
 288                         return ret;
 289                 }
 290         }
 291
 292         ptn_bridge->gpio_rst_n = of_get_named_gpio(node, "reset-gpio", 0);
 293         if (gpio_is_valid(ptn_bridge->gpio_rst_n)) {
 294                 /*
 295                  * Request the reset pin low to avoid the bridge being
 296                  * initialized prematurely
 297                  */
 298                 ret = gpio_request_one(ptn_bridge->gpio_rst_n,
 299                                 GPIOF_OUT_INIT_LOW, "PTN3460_RST_N");
 300                 if (ret) {
 301                         DRM_ERROR("Request reset-gpio failed (%d)\n", ret);
 302                         gpio_free(ptn_bridge->gpio_pd_n);
 303                         return ret;
 304                 }
 305         }
 306
 307         ret = of_property_read_u32(node, "edid-emulation",
 308                         &ptn_bridge->edid_emulation);
 309         if (ret) {
 310                 DRM_ERROR("Can't read edid emulation value\n");
 311                 goto err;
 312         }
 313
 314         ret = drm_bridge_init(dev, bridge, &ptn3460_bridge_funcs);
 315         if (ret) {
 316                 DRM_ERROR("Failed to initialize bridge with drm\n");
 317                 goto err;
 318         }
 319
 320         bridge->driver_private = ptn_bridge;
 321         encoder->bridge = bridge;
 322
 323         ret = drm_connector_init(dev, &ptn_bridge->connector,
 324                         &ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
 325         if (ret) {
 326                 DRM_ERROR("Failed to initialize connector with drm\n");
 327                 goto err;
 328         }
 329         drm_connector_helper_add(&ptn_bridge->connector,
 330                         &ptn3460_connector_helper_funcs);
 331         drm_connector_register(&ptn_bridge->connector);
 332         drm_mode_connector_attach_encoder(&ptn_bridge->connector, encoder);
 333
 334         return 0;
 335
 336 err:
 337         if (gpio_is_valid(ptn_bridge->gpio_pd_n))
 338                 gpio_free(ptn_bridge->gpio_pd_n);
 339         if (gpio_is_valid(ptn_bridge->gpio_rst_n))
 340                 gpio_free(ptn_bridge->gpio_rst_n);
 341         return ret;
 342 }
 343 EXPORT_SYMBOL(ptn3460_init);