drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Designware HDMI CEC driver
   4  *
   5  * Copyright (C) 2015-2017 Russell King.
   6  */
   7 #include <linux/interrupt.h>
   8 #include <linux/io.h>
   9 #include <linux/module.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/sched.h>
  12 #include <linux/slab.h>
  13
  14 #include <drm/drm_edid.h>
  15
  16 #include <media/cec.h>
  17 #include <media/cec-notifier.h>
  18
  19 #include "dw-hdmi-cec.h"
  20
  21 enum {
  22         HDMI_IH_CEC_STAT0       = 0x0106,
  23         HDMI_IH_MUTE_CEC_STAT0  = 0x0186,
  24
  25         HDMI_CEC_CTRL           = 0x7d00,
  26         CEC_CTRL_START          = BIT(0),
  27         CEC_CTRL_FRAME_TYP      = 3 << 1,
  28         CEC_CTRL_RETRY          = 0 << 1,
  29         CEC_CTRL_NORMAL         = 1 << 1,
  30         CEC_CTRL_IMMED          = 2 << 1,
  31
  32         HDMI_CEC_STAT           = 0x7d01,
  33         CEC_STAT_DONE           = BIT(0),
  34         CEC_STAT_EOM            = BIT(1),
  35         CEC_STAT_NACK           = BIT(2),
  36         CEC_STAT_ARBLOST        = BIT(3),
  37         CEC_STAT_ERROR_INIT     = BIT(4),
  38         CEC_STAT_ERROR_FOLL     = BIT(5),
  39         CEC_STAT_WAKEUP         = BIT(6),
  40
  41         HDMI_CEC_MASK           = 0x7d02,
  42         HDMI_CEC_POLARITY       = 0x7d03,
  43         HDMI_CEC_INT            = 0x7d04,
  44         HDMI_CEC_ADDR_L         = 0x7d05,
  45         HDMI_CEC_ADDR_H         = 0x7d06,
  46         HDMI_CEC_TX_CNT         = 0x7d07,
  47         HDMI_CEC_RX_CNT         = 0x7d08,
  48         HDMI_CEC_TX_DATA0       = 0x7d10,
  49         HDMI_CEC_RX_DATA0       = 0x7d20,
  50         HDMI_CEC_LOCK           = 0x7d30,
  51         HDMI_CEC_WKUPCTRL       = 0x7d31,
  52 };
  53
  54 struct dw_hdmi_cec {
  55         struct dw_hdmi *hdmi;
  56         const struct dw_hdmi_cec_ops *ops;
  57         u32 addresses;
  58         struct cec_adapter *adap;
  59         struct cec_msg rx_msg;
  60         unsigned int tx_status;
  61         bool tx_done;
  62         bool rx_done;
  63         struct cec_notifier *notify;
  64         int irq;
  65 };
  66
  67 static void dw_hdmi_write(struct dw_hdmi_cec *cec, u8 val, int offset)
  68 {
  69         cec->ops->write(cec->hdmi, val, offset);
  70 }
  71
  72 static u8 dw_hdmi_read(struct dw_hdmi_cec *cec, int offset)
  73 {
  74         return cec->ops->read(cec->hdmi, offset);
  75 }
  76
  77 static int dw_hdmi_cec_log_addr(struct cec_adapter *adap, u8 logical_addr)
  78 {
  79         struct dw_hdmi_cec *cec = cec_get_drvdata(adap);
  80
  81         if (logical_addr == CEC_LOG_ADDR_INVALID)
  82                 cec->addresses = 0;
  83         else
  84                 cec->addresses |= BIT(logical_addr) | BIT(15);
  85
  86         dw_hdmi_write(cec, cec->addresses & 255, HDMI_CEC_ADDR_L);
  87         dw_hdmi_write(cec, cec->addresses >> 8, HDMI_CEC_ADDR_H);
  88
  89         return 0;
  90 }
  91
  92 static int dw_hdmi_cec_transmit(struct cec_adapter *adap, u8 attempts,
  93                                 u32 signal_free_time, struct cec_msg *msg)
  94 {
  95         struct dw_hdmi_cec *cec = cec_get_drvdata(adap);
  96         unsigned int i, ctrl;
  97
  98         switch (signal_free_time) {
  99         case CEC_SIGNAL_FREE_TIME_RETRY:
 100                 ctrl = CEC_CTRL_RETRY;
 101                 break;
 102         case CEC_SIGNAL_FREE_TIME_NEW_INITIATOR:
 103         default:
 104                 ctrl = CEC_CTRL_NORMAL;
 105                 break;
 106         case CEC_SIGNAL_FREE_TIME_NEXT_XFER:
 107                 ctrl = CEC_CTRL_IMMED;
 108                 break;
 109         }
 110
 111         for (i = 0; i < msg->len; i++)
 112                 dw_hdmi_write(cec, msg->msg[i], HDMI_CEC_TX_DATA0 + i);
 113
 114         dw_hdmi_write(cec, msg->len, HDMI_CEC_TX_CNT);
 115         dw_hdmi_write(cec, ctrl | CEC_CTRL_START, HDMI_CEC_CTRL);
 116
 117         return 0;
 118 }
 119
 120 static irqreturn_t dw_hdmi_cec_hardirq(int irq, void *data)
 121 {
 122         struct cec_adapter *adap = data;
 123         struct dw_hdmi_cec *cec = cec_get_drvdata(adap);
 124         unsigned int stat = dw_hdmi_read(cec, HDMI_IH_CEC_STAT0);
 125         irqreturn_t ret = IRQ_HANDLED;
 126
 127         if (stat == 0)
 128                 return IRQ_NONE;
 129
 130         dw_hdmi_write(cec, stat, HDMI_IH_CEC_STAT0);
 131
 132         if (stat & CEC_STAT_ERROR_INIT) {
 133                 cec->tx_status = CEC_TX_STATUS_ERROR;
 134                 cec->tx_done = true;
 135                 ret = IRQ_WAKE_THREAD;
 136         } else if (stat & CEC_STAT_DONE) {
 137                 cec->tx_status = CEC_TX_STATUS_OK;
 138                 cec->tx_done = true;
 139                 ret = IRQ_WAKE_THREAD;
 140         } else if (stat & CEC_STAT_NACK) {
 141                 cec->tx_status = CEC_TX_STATUS_NACK;
 142                 cec->tx_done = true;
 143                 ret = IRQ_WAKE_THREAD;
 144         }
 145
 146         if (stat & CEC_STAT_EOM) {
 147                 unsigned int len, i;
 148
 149                 len = dw_hdmi_read(cec, HDMI_CEC_RX_CNT);
 150                 if (len > sizeof(cec->rx_msg.msg))
 151                         len = sizeof(cec->rx_msg.msg);
 152
 153                 for (i = 0; i < len; i++)
 154                         cec->rx_msg.msg[i] =
 155                                 dw_hdmi_read(cec, HDMI_CEC_RX_DATA0 + i);
 156
 157                 dw_hdmi_write(cec, 0, HDMI_CEC_LOCK);
 158
 159                 cec->rx_msg.len = len;
 160                 smp_wmb();
 161                 cec->rx_done = true;
 162
 163                 ret = IRQ_WAKE_THREAD;
 164         }
 165
 166         return ret;
 167 }
 168
 169 static irqreturn_t dw_hdmi_cec_thread(int irq, void *data)
 170 {
 171         struct cec_adapter *adap = data;
 172         struct dw_hdmi_cec *cec = cec_get_drvdata(adap);
 173
 174         if (cec->tx_done) {
 175                 cec->tx_done = false;
 176                 cec_transmit_attempt_done(adap, cec->tx_status);
 177         }
 178         if (cec->rx_done) {
 179                 cec->rx_done = false;
 180                 smp_rmb();
 181                 cec_received_msg(adap, &cec->rx_msg);
 182         }
 183         return IRQ_HANDLED;
 184 }
 185
 186 static int dw_hdmi_cec_enable(struct cec_adapter *adap, bool enable)
 187 {
 188         struct dw_hdmi_cec *cec = cec_get_drvdata(adap);
 189
 190         if (!enable) {
 191                 dw_hdmi_write(cec, ~0, HDMI_CEC_MASK);
 192                 dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0);
 193                 dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY);
 194
 195                 cec->ops->disable(cec->hdmi);
 196         } else {
 197                 unsigned int irqs;
 198
 199                 dw_hdmi_write(cec, 0, HDMI_CEC_CTRL);
 200                 dw_hdmi_write(cec, ~0, HDMI_IH_CEC_STAT0);
 201                 dw_hdmi_write(cec, 0, HDMI_CEC_LOCK);
 202
 203                 dw_hdmi_cec_log_addr(cec->adap, CEC_LOG_ADDR_INVALID);
 204
 205                 cec->ops->enable(cec->hdmi);
 206
 207                 irqs = CEC_STAT_ERROR_INIT | CEC_STAT_NACK | CEC_STAT_EOM |
 208                        CEC_STAT_DONE;
 209                 dw_hdmi_write(cec, irqs, HDMI_CEC_POLARITY);
 210                 dw_hdmi_write(cec, ~irqs, HDMI_CEC_MASK);
 211                 dw_hdmi_write(cec, ~irqs, HDMI_IH_MUTE_CEC_STAT0);
 212         }
 213         return 0;
 214 }
 215
 216 static const struct cec_adap_ops dw_hdmi_cec_ops = {
 217         .adap_enable = dw_hdmi_cec_enable,
 218         .adap_log_addr = dw_hdmi_cec_log_addr,
 219         .adap_transmit = dw_hdmi_cec_transmit,
 220 };
 221
 222 static void dw_hdmi_cec_del(void *data)
 223 {
 224         struct dw_hdmi_cec *cec = data;
 225
 226         cec_delete_adapter(cec->adap);
 227 }
 228
 229 static int dw_hdmi_cec_probe(struct platform_device *pdev)
 230 {
 231         struct dw_hdmi_cec_data *data = dev_get_platdata(&pdev->dev);
 232         struct dw_hdmi_cec *cec;
 233         int ret;
 234
 235         if (!data)
 236                 return -ENXIO;
 237
 238         /*
 239          * Our device is just a convenience - we want to link to the real
 240          * hardware device here, so that userspace can see the association
 241          * between the HDMI hardware and its associated CEC chardev.
 242          */
 243         cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL);
 244         if (!cec)
 245                 return -ENOMEM;
 246
 247         cec->irq = data->irq;
 248         cec->ops = data->ops;
 249         cec->hdmi = data->hdmi;
 250
 251         platform_set_drvdata(pdev, cec);
 252
 253         dw_hdmi_write(cec, 0, HDMI_CEC_TX_CNT);
 254         dw_hdmi_write(cec, ~0, HDMI_CEC_MASK);
 255         dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0);
 256         dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY);
 257
 258         cec->adap = cec_allocate_adapter(&dw_hdmi_cec_ops, cec, "dw_hdmi",
 259                                          CEC_CAP_DEFAULTS |
 260                                          CEC_CAP_CONNECTOR_INFO,
 261                                          CEC_MAX_LOG_ADDRS);
 262         if (IS_ERR(cec->adap))
 263                 return PTR_ERR(cec->adap);
 264
 265         /* override the module pointer */
 266         cec->adap->owner = THIS_MODULE;
 267
 268         ret = devm_add_action_or_reset(&pdev->dev, dw_hdmi_cec_del, cec);
 269         if (ret)
 270                 return ret;
 271
 272         ret = devm_request_threaded_irq(&pdev->dev, cec->irq,
 273                                         dw_hdmi_cec_hardirq,
 274                                         dw_hdmi_cec_thread, IRQF_SHARED,
 275                                         "dw-hdmi-cec", cec->adap);
 276         if (ret < 0)
 277                 return ret;
 278
 279         cec->notify = cec_notifier_cec_adap_register(pdev->dev.parent,
 280                                                      NULL, cec->adap);
 281         if (!cec->notify)
 282                 return -ENOMEM;
 283
 284         ret = cec_register_adapter(cec->adap, pdev->dev.parent);
 285         if (ret < 0) {
 286                 cec_notifier_cec_adap_unregister(cec->notify, cec->adap);
 287                 return ret;
 288         }
 289
 290         /*
 291          * CEC documentation says we must not call cec_delete_adapter
 292          * after a successful call to cec_register_adapter().
 293          */
 294         devm_remove_action(&pdev->dev, dw_hdmi_cec_del, cec);
 295
 296         return 0;
 297 }
 298
 299 static int dw_hdmi_cec_remove(struct platform_device *pdev)
 300 {
 301         struct dw_hdmi_cec *cec = platform_get_drvdata(pdev);
 302
 303         cec_notifier_cec_adap_unregister(cec->notify, cec->adap);
 304         cec_unregister_adapter(cec->adap);
 305
 306         return 0;
 307 }
 308
 309 static struct platform_driver dw_hdmi_cec_driver = {
 310         .probe  = dw_hdmi_cec_probe,
 311         .remove = dw_hdmi_cec_remove,
 312         .driver = {
 313                 .name = "dw-hdmi-cec",
 314         },
 315 };
 316 module_platform_driver(dw_hdmi_cec_driver);
 317
 318 MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
 319 MODULE_DESCRIPTION("Synopsys Designware HDMI CEC driver for i.MX");
 320 MODULE_LICENSE("GPL");
 321 MODULE_ALIAS(PLATFORM_MODULE_PREFIX "dw-hdmi-cec");