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 u8 regs_polarity; 67 u8 regs_mask; 68 u8 regs_mute_stat0; 69 }; 70 71 static void dw_hdmi_write(struct dw_hdmi_cec *cec, u8 val, int offset) 72 { 73 cec->ops->write(cec->hdmi, val, offset); 74 } 75 76 static u8 dw_hdmi_read(struct dw_hdmi_cec *cec, int offset) 77 { 78 return cec->ops->read(cec->hdmi, offset); 79 } 80 81 static int dw_hdmi_cec_log_addr(struct cec_adapter *adap, u8 logical_addr) 82 { 83 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 84 85 if (logical_addr == CEC_LOG_ADDR_INVALID) 86 cec->addresses = 0; 87 else 88 cec->addresses |= BIT(logical_addr) | BIT(15); 89 90 dw_hdmi_write(cec, cec->addresses & 255, HDMI_CEC_ADDR_L); 91 dw_hdmi_write(cec, cec->addresses >> 8, HDMI_CEC_ADDR_H); 92 93 return 0; 94 } 95 96 static int dw_hdmi_cec_transmit(struct cec_adapter *adap, u8 attempts, 97 u32 signal_free_time, struct cec_msg *msg) 98 { 99 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 100 unsigned int i, ctrl; 101 102 switch (signal_free_time) { 103 case CEC_SIGNAL_FREE_TIME_RETRY: 104 ctrl = CEC_CTRL_RETRY; 105 break; 106 case CEC_SIGNAL_FREE_TIME_NEW_INITIATOR: 107 default: 108 ctrl = CEC_CTRL_NORMAL; 109 break; 110 case CEC_SIGNAL_FREE_TIME_NEXT_XFER: 111 ctrl = CEC_CTRL_IMMED; 112 break; 113 } 114 115 for (i = 0; i < msg->len; i++) 116 dw_hdmi_write(cec, msg->msg[i], HDMI_CEC_TX_DATA0 + i); 117 118 dw_hdmi_write(cec, msg->len, HDMI_CEC_TX_CNT); 119 dw_hdmi_write(cec, ctrl | CEC_CTRL_START, HDMI_CEC_CTRL); 120 121 return 0; 122 } 123 124 static irqreturn_t dw_hdmi_cec_hardirq(int irq, void *data) 125 { 126 struct cec_adapter *adap = data; 127 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 128 unsigned int stat = dw_hdmi_read(cec, HDMI_IH_CEC_STAT0); 129 irqreturn_t ret = IRQ_HANDLED; 130 131 if (stat == 0) 132 return IRQ_NONE; 133 134 dw_hdmi_write(cec, stat, HDMI_IH_CEC_STAT0); 135 136 if (stat & CEC_STAT_ERROR_INIT) { 137 cec->tx_status = CEC_TX_STATUS_ERROR; 138 cec->tx_done = true; 139 ret = IRQ_WAKE_THREAD; 140 } else if (stat & CEC_STAT_DONE) { 141 cec->tx_status = CEC_TX_STATUS_OK; 142 cec->tx_done = true; 143 ret = IRQ_WAKE_THREAD; 144 } else if (stat & CEC_STAT_NACK) { 145 cec->tx_status = CEC_TX_STATUS_NACK; 146 cec->tx_done = true; 147 ret = IRQ_WAKE_THREAD; 148 } 149 150 if (stat & CEC_STAT_EOM) { 151 unsigned int len, i; 152 153 len = dw_hdmi_read(cec, HDMI_CEC_RX_CNT); 154 if (len > sizeof(cec->rx_msg.msg)) 155 len = sizeof(cec->rx_msg.msg); 156 157 for (i = 0; i < len; i++) 158 cec->rx_msg.msg[i] = 159 dw_hdmi_read(cec, HDMI_CEC_RX_DATA0 + i); 160 161 dw_hdmi_write(cec, 0, HDMI_CEC_LOCK); 162 163 cec->rx_msg.len = len; 164 smp_wmb(); 165 cec->rx_done = true; 166 167 ret = IRQ_WAKE_THREAD; 168 } 169 170 return ret; 171 } 172 173 static irqreturn_t dw_hdmi_cec_thread(int irq, void *data) 174 { 175 struct cec_adapter *adap = data; 176 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 177 178 if (cec->tx_done) { 179 cec->tx_done = false; 180 cec_transmit_attempt_done(adap, cec->tx_status); 181 } 182 if (cec->rx_done) { 183 cec->rx_done = false; 184 smp_rmb(); 185 cec_received_msg(adap, &cec->rx_msg); 186 } 187 return IRQ_HANDLED; 188 } 189 190 static int dw_hdmi_cec_enable(struct cec_adapter *adap, bool enable) 191 { 192 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 193 194 if (!enable) { 195 dw_hdmi_write(cec, ~0, HDMI_CEC_MASK); 196 dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0); 197 dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY); 198 199 cec->ops->disable(cec->hdmi); 200 } else { 201 unsigned int irqs; 202 203 dw_hdmi_write(cec, 0, HDMI_CEC_CTRL); 204 dw_hdmi_write(cec, ~0, HDMI_IH_CEC_STAT0); 205 dw_hdmi_write(cec, 0, HDMI_CEC_LOCK); 206 207 dw_hdmi_cec_log_addr(cec->adap, CEC_LOG_ADDR_INVALID); 208 209 cec->ops->enable(cec->hdmi); 210 211 irqs = CEC_STAT_ERROR_INIT | CEC_STAT_NACK | CEC_STAT_EOM | 212 CEC_STAT_DONE; 213 dw_hdmi_write(cec, irqs, HDMI_CEC_POLARITY); 214 dw_hdmi_write(cec, ~irqs, HDMI_CEC_MASK); 215 dw_hdmi_write(cec, ~irqs, HDMI_IH_MUTE_CEC_STAT0); 216 } 217 return 0; 218 } 219 220 static const struct cec_adap_ops dw_hdmi_cec_ops = { 221 .adap_enable = dw_hdmi_cec_enable, 222 .adap_log_addr = dw_hdmi_cec_log_addr, 223 .adap_transmit = dw_hdmi_cec_transmit, 224 }; 225 226 static void dw_hdmi_cec_del(void *data) 227 { 228 struct dw_hdmi_cec *cec = data; 229 230 cec_delete_adapter(cec->adap); 231 } 232 233 static int dw_hdmi_cec_probe(struct platform_device *pdev) 234 { 235 struct dw_hdmi_cec_data *data = dev_get_platdata(&pdev->dev); 236 struct dw_hdmi_cec *cec; 237 int ret; 238 239 if (!data) 240 return -ENXIO; 241 242 /* 243 * Our device is just a convenience - we want to link to the real 244 * hardware device here, so that userspace can see the association 245 * between the HDMI hardware and its associated CEC chardev. 246 */ 247 cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL); 248 if (!cec) 249 return -ENOMEM; 250 251 cec->irq = data->irq; 252 cec->ops = data->ops; 253 cec->hdmi = data->hdmi; 254 255 platform_set_drvdata(pdev, cec); 256 257 dw_hdmi_write(cec, 0, HDMI_CEC_TX_CNT); 258 dw_hdmi_write(cec, ~0, HDMI_CEC_MASK); 259 dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0); 260 dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY); 261 262 cec->adap = cec_allocate_adapter(&dw_hdmi_cec_ops, cec, "dw_hdmi", 263 CEC_CAP_DEFAULTS | 264 CEC_CAP_CONNECTOR_INFO, 265 CEC_MAX_LOG_ADDRS); 266 if (IS_ERR(cec->adap)) 267 return PTR_ERR(cec->adap); 268 269 /* override the module pointer */ 270 cec->adap->owner = THIS_MODULE; 271 272 ret = devm_add_action_or_reset(&pdev->dev, dw_hdmi_cec_del, cec); 273 if (ret) 274 return ret; 275 276 ret = devm_request_threaded_irq(&pdev->dev, cec->irq, 277 dw_hdmi_cec_hardirq, 278 dw_hdmi_cec_thread, IRQF_SHARED, 279 "dw-hdmi-cec", cec->adap); 280 if (ret < 0) 281 return ret; 282 283 cec->notify = cec_notifier_cec_adap_register(pdev->dev.parent, 284 NULL, cec->adap); 285 if (!cec->notify) 286 return -ENOMEM; 287 288 ret = cec_register_adapter(cec->adap, pdev->dev.parent); 289 if (ret < 0) { 290 cec_notifier_cec_adap_unregister(cec->notify, cec->adap); 291 return ret; 292 } 293 294 /* 295 * CEC documentation says we must not call cec_delete_adapter 296 * after a successful call to cec_register_adapter(). 297 */ 298 devm_remove_action(&pdev->dev, dw_hdmi_cec_del, cec); 299 300 return 0; 301 } 302 303 static void dw_hdmi_cec_remove(struct platform_device *pdev) 304 { 305 struct dw_hdmi_cec *cec = platform_get_drvdata(pdev); 306 307 cec_notifier_cec_adap_unregister(cec->notify, cec->adap); 308 cec_unregister_adapter(cec->adap); 309 } 310 311 static int __maybe_unused dw_hdmi_cec_resume(struct device *dev) 312 { 313 struct dw_hdmi_cec *cec = dev_get_drvdata(dev); 314 315 /* Restore logical address */ 316 dw_hdmi_write(cec, cec->addresses & 255, HDMI_CEC_ADDR_L); 317 dw_hdmi_write(cec, cec->addresses >> 8, HDMI_CEC_ADDR_H); 318 319 /* Restore interrupt status/mask registers */ 320 dw_hdmi_write(cec, cec->regs_polarity, HDMI_CEC_POLARITY); 321 dw_hdmi_write(cec, cec->regs_mask, HDMI_CEC_MASK); 322 dw_hdmi_write(cec, cec->regs_mute_stat0, HDMI_IH_MUTE_CEC_STAT0); 323 324 return 0; 325 } 326 327 static int __maybe_unused dw_hdmi_cec_suspend(struct device *dev) 328 { 329 struct dw_hdmi_cec *cec = dev_get_drvdata(dev); 330 331 /* store interrupt status/mask registers */ 332 cec->regs_polarity = dw_hdmi_read(cec, HDMI_CEC_POLARITY); 333 cec->regs_mask = dw_hdmi_read(cec, HDMI_CEC_MASK); 334 cec->regs_mute_stat0 = dw_hdmi_read(cec, HDMI_IH_MUTE_CEC_STAT0); 335 336 return 0; 337 } 338 339 static const struct dev_pm_ops dw_hdmi_cec_pm = { 340 SET_SYSTEM_SLEEP_PM_OPS(dw_hdmi_cec_suspend, dw_hdmi_cec_resume) 341 }; 342 343 static struct platform_driver dw_hdmi_cec_driver = { 344 .probe = dw_hdmi_cec_probe, 345 .remove_new = dw_hdmi_cec_remove, 346 .driver = { 347 .name = "dw-hdmi-cec", 348 .pm = &dw_hdmi_cec_pm, 349 }, 350 }; 351 module_platform_driver(dw_hdmi_cec_driver); 352 353 MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>"); 354 MODULE_DESCRIPTION("Synopsys Designware HDMI CEC driver for i.MX"); 355 MODULE_LICENSE("GPL"); 356 MODULE_ALIAS(PLATFORM_MODULE_PREFIX "dw-hdmi-cec"); 357