drivers/gpu/drm/zte/zx_vga.c

   1 /*
   2  * Copyright (C) 2017 Sanechips Technology Co., Ltd.
   3  * Copyright 2017 Linaro Ltd.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/clk.h>
  11 #include <linux/component.h>
  12 #include <linux/mfd/syscon.h>
  13 #include <linux/regmap.h>
  14
  15 #include <drm/drm_atomic_helper.h>
  16 #include <drm/drm_crtc_helper.h>
  17 #include <drm/drmP.h>
  18
  19 #include "zx_drm_drv.h"
  20 #include "zx_vga_regs.h"
  21 #include "zx_vou.h"
  22
  23 struct zx_vga_pwrctrl {
  24         struct regmap *regmap;
  25         u32 reg;
  26         u32 mask;
  27 };
  28
  29 struct zx_vga_i2c {
  30         struct i2c_adapter adap;
  31         struct mutex lock;
  32 };
  33
  34 struct zx_vga {
  35         struct drm_connector connector;
  36         struct drm_encoder encoder;
  37         struct zx_vga_i2c *ddc;
  38         struct device *dev;
  39         void __iomem *mmio;
  40         struct clk *i2c_wclk;
  41         struct zx_vga_pwrctrl pwrctrl;
  42         struct completion complete;
  43         bool connected;
  44 };
  45
  46 #define to_zx_vga(x) container_of(x, struct zx_vga, x)
  47
  48 static void zx_vga_encoder_enable(struct drm_encoder *encoder)
  49 {
  50         struct zx_vga *vga = to_zx_vga(encoder);
  51         struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
  52
  53         /* Set bit to power up VGA DACs */
  54         regmap_update_bits(pwrctrl->regmap, pwrctrl->reg, pwrctrl->mask,
  55                            pwrctrl->mask);
  56
  57         vou_inf_enable(VOU_VGA, encoder->crtc);
  58 }
  59
  60 static void zx_vga_encoder_disable(struct drm_encoder *encoder)
  61 {
  62         struct zx_vga *vga = to_zx_vga(encoder);
  63         struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
  64
  65         vou_inf_disable(VOU_VGA, encoder->crtc);
  66
  67         /* Clear bit to power down VGA DACs */
  68         regmap_update_bits(pwrctrl->regmap, pwrctrl->reg, pwrctrl->mask, 0);
  69 }
  70
  71 static const struct drm_encoder_helper_funcs zx_vga_encoder_helper_funcs = {
  72         .enable = zx_vga_encoder_enable,
  73         .disable = zx_vga_encoder_disable,
  74 };
  75
  76 static const struct drm_encoder_funcs zx_vga_encoder_funcs = {
  77         .destroy = drm_encoder_cleanup,
  78 };
  79
  80 static int zx_vga_connector_get_modes(struct drm_connector *connector)
  81 {
  82         struct zx_vga *vga = to_zx_vga(connector);
  83         struct edid *edid;
  84         int ret;
  85
  86         /*
  87          * Clear both detection bits to switch I2C bus from device
  88          * detecting to EDID reading.
  89          */
  90         zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, 0);
  91
  92         edid = drm_get_edid(connector, &vga->ddc->adap);
  93         if (!edid) {
  94                 /*
  95                  * If EDID reading fails, we set the device state into
  96                  * disconnected.  Locking is not required here, since the
  97                  * VGA_AUTO_DETECT_SEL register write in irq handler cannot
  98                  * be triggered when both detection bits are cleared as above.
  99                  */
 100                 zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL,
 101                           VGA_DETECT_SEL_NO_DEVICE);
 102                 vga->connected = false;
 103                 return 0;
 104         }
 105
 106         /*
 107          * As edid reading succeeds, device must be connected, so we set
 108          * up detection bit for unplug interrupt here.
 109          */
 110         zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, VGA_DETECT_SEL_HAS_DEVICE);
 111
 112         drm_mode_connector_update_edid_property(connector, edid);
 113         ret = drm_add_edid_modes(connector, edid);
 114         kfree(edid);
 115
 116         return ret;
 117 }
 118
 119 static enum drm_mode_status
 120 zx_vga_connector_mode_valid(struct drm_connector *connector,
 121                             struct drm_display_mode *mode)
 122 {
 123         return MODE_OK;
 124 }
 125
 126 static struct drm_connector_helper_funcs zx_vga_connector_helper_funcs = {
 127         .get_modes = zx_vga_connector_get_modes,
 128         .mode_valid = zx_vga_connector_mode_valid,
 129 };
 130
 131 static enum drm_connector_status
 132 zx_vga_connector_detect(struct drm_connector *connector, bool force)
 133 {
 134         struct zx_vga *vga = to_zx_vga(connector);
 135
 136         return vga->connected ? connector_status_connected :
 137                                 connector_status_disconnected;
 138 }
 139
 140 static const struct drm_connector_funcs zx_vga_connector_funcs = {
 141         .fill_modes = drm_helper_probe_single_connector_modes,
 142         .detect = zx_vga_connector_detect,
 143         .destroy = drm_connector_cleanup,
 144         .reset = drm_atomic_helper_connector_reset,
 145         .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 146         .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 147 };
 148
 149 static int zx_vga_register(struct drm_device *drm, struct zx_vga *vga)
 150 {
 151         struct drm_encoder *encoder = &vga->encoder;
 152         struct drm_connector *connector = &vga->connector;
 153         struct device *dev = vga->dev;
 154         int ret;
 155
 156         encoder->possible_crtcs = VOU_CRTC_MASK;
 157
 158         ret = drm_encoder_init(drm, encoder, &zx_vga_encoder_funcs,
 159                                DRM_MODE_ENCODER_DAC, NULL);
 160         if (ret) {
 161                 DRM_DEV_ERROR(dev, "failed to init encoder: %d\n", ret);
 162                 return ret;
 163         };
 164
 165         drm_encoder_helper_add(encoder, &zx_vga_encoder_helper_funcs);
 166
 167         vga->connector.polled = DRM_CONNECTOR_POLL_HPD;
 168
 169         ret = drm_connector_init(drm, connector, &zx_vga_connector_funcs,
 170                                  DRM_MODE_CONNECTOR_VGA);
 171         if (ret) {
 172                 DRM_DEV_ERROR(dev, "failed to init connector: %d\n", ret);
 173                 goto clean_encoder;
 174         };
 175
 176         drm_connector_helper_add(connector, &zx_vga_connector_helper_funcs);
 177
 178         ret = drm_mode_connector_attach_encoder(connector, encoder);
 179         if (ret) {
 180                 DRM_DEV_ERROR(dev, "failed to attach encoder: %d\n", ret);
 181                 goto clean_connector;
 182         };
 183
 184         return 0;
 185
 186 clean_connector:
 187         drm_connector_cleanup(connector);
 188 clean_encoder:
 189         drm_encoder_cleanup(encoder);
 190         return ret;
 191 }
 192
 193 static int zx_vga_pwrctrl_init(struct zx_vga *vga)
 194 {
 195         struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
 196         struct device *dev = vga->dev;
 197         struct of_phandle_args out_args;
 198         struct regmap *regmap;
 199         int ret;
 200
 201         ret = of_parse_phandle_with_fixed_args(dev->of_node,
 202                                 "zte,vga-power-control", 2, 0, &out_args);
 203         if (ret)
 204                 return ret;
 205
 206         regmap = syscon_node_to_regmap(out_args.np);
 207         if (IS_ERR(regmap)) {
 208                 ret = PTR_ERR(regmap);
 209                 goto out;
 210         }
 211
 212         pwrctrl->regmap = regmap;
 213         pwrctrl->reg = out_args.args[0];
 214         pwrctrl->mask = out_args.args[1];
 215
 216 out:
 217         of_node_put(out_args.np);
 218         return ret;
 219 }
 220
 221 static int zx_vga_i2c_read(struct zx_vga *vga, struct i2c_msg *msg)
 222 {
 223         int len = msg->len;
 224         u8 *buf = msg->buf;
 225         u32 offset = 0;
 226         int i;
 227
 228         reinit_completion(&vga->complete);
 229
 230         /* Select combo write */
 231         zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_COMBO, VGA_CMD_COMBO);
 232         zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_RW, 0);
 233
 234         while (len > 0) {
 235                 u32 cnt;
 236
 237                 /* Clear RX FIFO */
 238                 zx_writel_mask(vga->mmio + VGA_RXF_CTRL, VGA_RX_FIFO_CLEAR,
 239                                VGA_RX_FIFO_CLEAR);
 240
 241                 /* Data offset to read from */
 242                 zx_writel(vga->mmio + VGA_SUB_ADDR, offset);
 243
 244                 /* Kick off the transfer */
 245                 zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_TRANS,
 246                                VGA_CMD_TRANS);
 247
 248                 if (!wait_for_completion_timeout(&vga->complete,
 249                                                  msecs_to_jiffies(1000))) {
 250                         DRM_DEV_ERROR(vga->dev, "transfer timeout\n");
 251                         return -ETIMEDOUT;
 252                 }
 253
 254                 cnt = zx_readl(vga->mmio + VGA_RXF_STATUS);
 255                 cnt = (cnt & VGA_RXF_COUNT_MASK) >> VGA_RXF_COUNT_SHIFT;
 256                 /* FIFO status may report more data than we need to read */
 257                 cnt = min_t(u32, len, cnt);
 258
 259                 for (i = 0; i < cnt; i++)
 260                         *buf++ = zx_readl(vga->mmio + VGA_DATA);
 261
 262                 len -= cnt;
 263                 offset += cnt;
 264         }
 265
 266         return 0;
 267 }
 268
 269 static int zx_vga_i2c_write(struct zx_vga *vga, struct i2c_msg *msg)
 270 {
 271         /*
 272          * The DDC I2C adapter is only for reading EDID data, so we assume
 273          * that the write to this adapter must be the EDID data offset.
 274          */
 275         if ((msg->len != 1) || ((msg->addr != DDC_ADDR)))
 276                 return -EINVAL;
 277
 278         /* Hardware will take care of the slave address shifting */
 279         zx_writel(vga->mmio + VGA_DEVICE_ADDR, msg->addr);
 280
 281         return 0;
 282 }
 283
 284 static int zx_vga_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 285                            int num)
 286 {
 287         struct zx_vga *vga = i2c_get_adapdata(adap);
 288         struct zx_vga_i2c *ddc = vga->ddc;
 289         int ret = 0;
 290         int i;
 291
 292         mutex_lock(&ddc->lock);
 293
 294         for (i = 0; i < num; i++) {
 295                 if (msgs[i].flags & I2C_M_RD)
 296                         ret = zx_vga_i2c_read(vga, &msgs[i]);
 297                 else
 298                         ret = zx_vga_i2c_write(vga, &msgs[i]);
 299
 300                 if (ret < 0)
 301                         break;
 302         }
 303
 304         if (!ret)
 305                 ret = num;
 306
 307         mutex_unlock(&ddc->lock);
 308
 309         return ret;
 310 }
 311
 312 static u32 zx_vga_i2c_func(struct i2c_adapter *adapter)
 313 {
 314         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 315 }
 316
 317 static const struct i2c_algorithm zx_vga_algorithm = {
 318         .master_xfer    = zx_vga_i2c_xfer,
 319         .functionality  = zx_vga_i2c_func,
 320 };
 321
 322 static int zx_vga_ddc_register(struct zx_vga *vga)
 323 {
 324         struct device *dev = vga->dev;
 325         struct i2c_adapter *adap;
 326         struct zx_vga_i2c *ddc;
 327         int ret;
 328
 329         ddc = devm_kzalloc(dev, sizeof(*ddc), GFP_KERNEL);
 330         if (!ddc)
 331                 return -ENOMEM;
 332
 333         vga->ddc = ddc;
 334         mutex_init(&ddc->lock);
 335
 336         adap = &ddc->adap;
 337         adap->owner = THIS_MODULE;
 338         adap->class = I2C_CLASS_DDC;
 339         adap->dev.parent = dev;
 340         adap->algo = &zx_vga_algorithm;
 341         snprintf(adap->name, sizeof(adap->name), "zx vga i2c");
 342
 343         ret = i2c_add_adapter(adap);
 344         if (ret) {
 345                 DRM_DEV_ERROR(dev, "failed to add I2C adapter: %d\n", ret);
 346                 return ret;
 347         }
 348
 349         i2c_set_adapdata(adap, vga);
 350
 351         return 0;
 352 }
 353
 354 static irqreturn_t zx_vga_irq_thread(int irq, void *dev_id)
 355 {
 356         struct zx_vga *vga = dev_id;
 357
 358         drm_helper_hpd_irq_event(vga->connector.dev);
 359
 360         return IRQ_HANDLED;
 361 }
 362
 363 static irqreturn_t zx_vga_irq_handler(int irq, void *dev_id)
 364 {
 365         struct zx_vga *vga = dev_id;
 366         u32 status;
 367
 368         status = zx_readl(vga->mmio + VGA_I2C_STATUS);
 369
 370         /* Clear interrupt status */
 371         zx_writel_mask(vga->mmio + VGA_I2C_STATUS, VGA_CLEAR_IRQ,
 372                        VGA_CLEAR_IRQ);
 373
 374         if (status & VGA_DEVICE_CONNECTED) {
 375                 /*
 376                  * Since VGA_DETECT_SEL bits need to be reset for switching DDC
 377                  * bus from device detection to EDID read, rather than setting
 378                  * up HAS_DEVICE bit here, we need to do that in .get_modes
 379                  * hook for unplug detecting after EDID read succeeds.
 380                  */
 381                 vga->connected = true;
 382                 return IRQ_WAKE_THREAD;
 383         }
 384
 385         if (status & VGA_DEVICE_DISCONNECTED) {
 386                 zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL,
 387                           VGA_DETECT_SEL_NO_DEVICE);
 388                 vga->connected = false;
 389                 return IRQ_WAKE_THREAD;
 390         }
 391
 392         if (status & VGA_TRANS_DONE) {
 393                 complete(&vga->complete);
 394                 return IRQ_HANDLED;
 395         }
 396
 397         return IRQ_NONE;
 398 }
 399
 400 static void zx_vga_hw_init(struct zx_vga *vga)
 401 {
 402         unsigned long ref = clk_get_rate(vga->i2c_wclk);
 403         int div;
 404
 405         /*
 406          * Set up I2C fast speed divider per formula below to get 400kHz.
 407          *   scl = ref / ((div + 1) * 4)
 408          */
 409         div = DIV_ROUND_UP(ref / 1000, 400 * 4) - 1;
 410         zx_writel(vga->mmio + VGA_CLK_DIV_FS, div);
 411
 412         /* Set up device detection */
 413         zx_writel(vga->mmio + VGA_AUTO_DETECT_PARA, 0x80);
 414         zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, VGA_DETECT_SEL_NO_DEVICE);
 415
 416         /*
 417          * We need to poke monitor via DDC bus to get connection irq
 418          * start working.
 419          */
 420         zx_writel(vga->mmio + VGA_DEVICE_ADDR, DDC_ADDR);
 421         zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_TRANS, VGA_CMD_TRANS);
 422 }
 423
 424 static int zx_vga_bind(struct device *dev, struct device *master, void *data)
 425 {
 426         struct platform_device *pdev = to_platform_device(dev);
 427         struct drm_device *drm = data;
 428         struct resource *res;
 429         struct zx_vga *vga;
 430         int irq;
 431         int ret;
 432
 433         vga = devm_kzalloc(dev, sizeof(*vga), GFP_KERNEL);
 434         if (!vga)
 435                 return -ENOMEM;
 436
 437         vga->dev = dev;
 438         dev_set_drvdata(dev, vga);
 439
 440         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 441         vga->mmio = devm_ioremap_resource(dev, res);
 442         if (IS_ERR(vga->mmio))
 443                 return PTR_ERR(vga->mmio);
 444
 445         irq = platform_get_irq(pdev, 0);
 446         if (irq < 0)
 447                 return irq;
 448
 449         vga->i2c_wclk = devm_clk_get(dev, "i2c_wclk");
 450         if (IS_ERR(vga->i2c_wclk)) {
 451                 ret = PTR_ERR(vga->i2c_wclk);
 452                 DRM_DEV_ERROR(dev, "failed to get i2c_wclk: %d\n", ret);
 453                 return ret;
 454         }
 455
 456         ret = zx_vga_pwrctrl_init(vga);
 457         if (ret) {
 458                 DRM_DEV_ERROR(dev, "failed to init power control: %d\n", ret);
 459                 return ret;
 460         }
 461
 462         ret = zx_vga_ddc_register(vga);
 463         if (ret) {
 464                 DRM_DEV_ERROR(dev, "failed to register ddc: %d\n", ret);
 465                 return ret;
 466         }
 467
 468         ret = zx_vga_register(drm, vga);
 469         if (ret) {
 470                 DRM_DEV_ERROR(dev, "failed to register vga: %d\n", ret);
 471                 return ret;
 472         }
 473
 474         init_completion(&vga->complete);
 475
 476         ret = devm_request_threaded_irq(dev, irq, zx_vga_irq_handler,
 477                                         zx_vga_irq_thread, IRQF_SHARED,
 478                                         dev_name(dev), vga);
 479         if (ret) {
 480                 DRM_DEV_ERROR(dev, "failed to request threaded irq: %d\n", ret);
 481                 return ret;
 482         }
 483
 484         ret = clk_prepare_enable(vga->i2c_wclk);
 485         if (ret)
 486                 return ret;
 487
 488         zx_vga_hw_init(vga);
 489
 490         return 0;
 491 }
 492
 493 static void zx_vga_unbind(struct device *dev, struct device *master,
 494                           void *data)
 495 {
 496         struct zx_vga *vga = dev_get_drvdata(dev);
 497
 498         clk_disable_unprepare(vga->i2c_wclk);
 499 }
 500
 501 static const struct component_ops zx_vga_component_ops = {
 502         .bind = zx_vga_bind,
 503         .unbind = zx_vga_unbind,
 504 };
 505
 506 static int zx_vga_probe(struct platform_device *pdev)
 507 {
 508         return component_add(&pdev->dev, &zx_vga_component_ops);
 509 }
 510
 511 static int zx_vga_remove(struct platform_device *pdev)
 512 {
 513         component_del(&pdev->dev, &zx_vga_component_ops);
 514         return 0;
 515 }
 516
 517 static const struct of_device_id zx_vga_of_match[] = {
 518         { .compatible = "zte,zx296718-vga", },
 519         { /* end */ },
 520 };
 521 MODULE_DEVICE_TABLE(of, zx_vga_of_match);
 522
 523 struct platform_driver zx_vga_driver = {
 524         .probe = zx_vga_probe,
 525         .remove = zx_vga_remove,
 526         .driver = {
 527                 .name = "zx-vga",
 528                 .of_match_table = zx_vga_of_match,
 529         },
 530 };