1 /* 2 * Designware HDMI CEC driver 3 * 4 * Copyright (C) 2015-2017 Russell King. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 #include <linux/interrupt.h> 11 #include <linux/io.h> 12 #include <linux/module.h> 13 #include <linux/platform_device.h> 14 #include <linux/sched.h> 15 #include <linux/slab.h> 16 17 #include <drm/drm_edid.h> 18 19 #include <media/cec.h> 20 #include <media/cec-notifier.h> 21 22 #include "dw-hdmi-cec.h" 23 24 enum { 25 HDMI_IH_CEC_STAT0 = 0x0106, 26 HDMI_IH_MUTE_CEC_STAT0 = 0x0186, 27 28 HDMI_CEC_CTRL = 0x7d00, 29 CEC_CTRL_START = BIT(0), 30 CEC_CTRL_FRAME_TYP = 3 << 1, 31 CEC_CTRL_RETRY = 0 << 1, 32 CEC_CTRL_NORMAL = 1 << 1, 33 CEC_CTRL_IMMED = 2 << 1, 34 35 HDMI_CEC_STAT = 0x7d01, 36 CEC_STAT_DONE = BIT(0), 37 CEC_STAT_EOM = BIT(1), 38 CEC_STAT_NACK = BIT(2), 39 CEC_STAT_ARBLOST = BIT(3), 40 CEC_STAT_ERROR_INIT = BIT(4), 41 CEC_STAT_ERROR_FOLL = BIT(5), 42 CEC_STAT_WAKEUP = BIT(6), 43 44 HDMI_CEC_MASK = 0x7d02, 45 HDMI_CEC_POLARITY = 0x7d03, 46 HDMI_CEC_INT = 0x7d04, 47 HDMI_CEC_ADDR_L = 0x7d05, 48 HDMI_CEC_ADDR_H = 0x7d06, 49 HDMI_CEC_TX_CNT = 0x7d07, 50 HDMI_CEC_RX_CNT = 0x7d08, 51 HDMI_CEC_TX_DATA0 = 0x7d10, 52 HDMI_CEC_RX_DATA0 = 0x7d20, 53 HDMI_CEC_LOCK = 0x7d30, 54 HDMI_CEC_WKUPCTRL = 0x7d31, 55 }; 56 57 struct dw_hdmi_cec { 58 struct dw_hdmi *hdmi; 59 const struct dw_hdmi_cec_ops *ops; 60 u32 addresses; 61 struct cec_adapter *adap; 62 struct cec_msg rx_msg; 63 unsigned int tx_status; 64 bool tx_done; 65 bool rx_done; 66 struct cec_notifier *notify; 67 int irq; 68 }; 69 70 static void dw_hdmi_write(struct dw_hdmi_cec *cec, u8 val, int offset) 71 { 72 cec->ops->write(cec->hdmi, val, offset); 73 } 74 75 static u8 dw_hdmi_read(struct dw_hdmi_cec *cec, int offset) 76 { 77 return cec->ops->read(cec->hdmi, offset); 78 } 79 80 static int dw_hdmi_cec_log_addr(struct cec_adapter *adap, u8 logical_addr) 81 { 82 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 83 84 if (logical_addr == CEC_LOG_ADDR_INVALID) 85 cec->addresses = 0; 86 else 87 cec->addresses |= BIT(logical_addr) | BIT(15); 88 89 dw_hdmi_write(cec, cec->addresses & 255, HDMI_CEC_ADDR_L); 90 dw_hdmi_write(cec, cec->addresses >> 8, HDMI_CEC_ADDR_H); 91 92 return 0; 93 } 94 95 static int dw_hdmi_cec_transmit(struct cec_adapter *adap, u8 attempts, 96 u32 signal_free_time, struct cec_msg *msg) 97 { 98 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 99 unsigned int i, ctrl; 100 101 switch (signal_free_time) { 102 case CEC_SIGNAL_FREE_TIME_RETRY: 103 ctrl = CEC_CTRL_RETRY; 104 break; 105 case CEC_SIGNAL_FREE_TIME_NEW_INITIATOR: 106 default: 107 ctrl = CEC_CTRL_NORMAL; 108 break; 109 case CEC_SIGNAL_FREE_TIME_NEXT_XFER: 110 ctrl = CEC_CTRL_IMMED; 111 break; 112 } 113 114 for (i = 0; i < msg->len; i++) 115 dw_hdmi_write(cec, msg->msg[i], HDMI_CEC_TX_DATA0 + i); 116 117 dw_hdmi_write(cec, msg->len, HDMI_CEC_TX_CNT); 118 dw_hdmi_write(cec, ctrl | CEC_CTRL_START, HDMI_CEC_CTRL); 119 120 return 0; 121 } 122 123 static irqreturn_t dw_hdmi_cec_hardirq(int irq, void *data) 124 { 125 struct cec_adapter *adap = data; 126 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 127 unsigned int stat = dw_hdmi_read(cec, HDMI_IH_CEC_STAT0); 128 irqreturn_t ret = IRQ_HANDLED; 129 130 if (stat == 0) 131 return IRQ_NONE; 132 133 dw_hdmi_write(cec, stat, HDMI_IH_CEC_STAT0); 134 135 if (stat & CEC_STAT_ERROR_INIT) { 136 cec->tx_status = CEC_TX_STATUS_ERROR; 137 cec->tx_done = true; 138 ret = IRQ_WAKE_THREAD; 139 } else if (stat & CEC_STAT_DONE) { 140 cec->tx_status = CEC_TX_STATUS_OK; 141 cec->tx_done = true; 142 ret = IRQ_WAKE_THREAD; 143 } else if (stat & CEC_STAT_NACK) { 144 cec->tx_status = CEC_TX_STATUS_NACK; 145 cec->tx_done = true; 146 ret = IRQ_WAKE_THREAD; 147 } 148 149 if (stat & CEC_STAT_EOM) { 150 unsigned int len, i; 151 152 len = dw_hdmi_read(cec, HDMI_CEC_RX_CNT); 153 if (len > sizeof(cec->rx_msg.msg)) 154 len = sizeof(cec->rx_msg.msg); 155 156 for (i = 0; i < len; i++) 157 cec->rx_msg.msg[i] = 158 dw_hdmi_read(cec, HDMI_CEC_RX_DATA0 + i); 159 160 dw_hdmi_write(cec, 0, HDMI_CEC_LOCK); 161 162 cec->rx_msg.len = len; 163 smp_wmb(); 164 cec->rx_done = true; 165 166 ret = IRQ_WAKE_THREAD; 167 } 168 169 return ret; 170 } 171 172 static irqreturn_t dw_hdmi_cec_thread(int irq, void *data) 173 { 174 struct cec_adapter *adap = data; 175 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 176 177 if (cec->tx_done) { 178 cec->tx_done = false; 179 cec_transmit_attempt_done(adap, cec->tx_status); 180 } 181 if (cec->rx_done) { 182 cec->rx_done = false; 183 smp_rmb(); 184 cec_received_msg(adap, &cec->rx_msg); 185 } 186 return IRQ_HANDLED; 187 } 188 189 static int dw_hdmi_cec_enable(struct cec_adapter *adap, bool enable) 190 { 191 struct dw_hdmi_cec *cec = cec_get_drvdata(adap); 192 193 if (!enable) { 194 dw_hdmi_write(cec, ~0, HDMI_CEC_MASK); 195 dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0); 196 dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY); 197 198 cec->ops->disable(cec->hdmi); 199 } else { 200 unsigned int irqs; 201 202 dw_hdmi_write(cec, 0, HDMI_CEC_CTRL); 203 dw_hdmi_write(cec, ~0, HDMI_IH_CEC_STAT0); 204 dw_hdmi_write(cec, 0, HDMI_CEC_LOCK); 205 206 dw_hdmi_cec_log_addr(cec->adap, CEC_LOG_ADDR_INVALID); 207 208 cec->ops->enable(cec->hdmi); 209 210 irqs = CEC_STAT_ERROR_INIT | CEC_STAT_NACK | CEC_STAT_EOM | 211 CEC_STAT_DONE; 212 dw_hdmi_write(cec, irqs, HDMI_CEC_POLARITY); 213 dw_hdmi_write(cec, ~irqs, HDMI_CEC_MASK); 214 dw_hdmi_write(cec, ~irqs, HDMI_IH_MUTE_CEC_STAT0); 215 } 216 return 0; 217 } 218 219 static const struct cec_adap_ops dw_hdmi_cec_ops = { 220 .adap_enable = dw_hdmi_cec_enable, 221 .adap_log_addr = dw_hdmi_cec_log_addr, 222 .adap_transmit = dw_hdmi_cec_transmit, 223 }; 224 225 static void dw_hdmi_cec_del(void *data) 226 { 227 struct dw_hdmi_cec *cec = data; 228 229 cec_delete_adapter(cec->adap); 230 } 231 232 static int dw_hdmi_cec_probe(struct platform_device *pdev) 233 { 234 struct dw_hdmi_cec_data *data = dev_get_platdata(&pdev->dev); 235 struct dw_hdmi_cec *cec; 236 int ret; 237 238 if (!data) 239 return -ENXIO; 240 241 /* 242 * Our device is just a convenience - we want to link to the real 243 * hardware device here, so that userspace can see the association 244 * between the HDMI hardware and its associated CEC chardev. 245 */ 246 cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL); 247 if (!cec) 248 return -ENOMEM; 249 250 cec->irq = data->irq; 251 cec->ops = data->ops; 252 cec->hdmi = data->hdmi; 253 254 platform_set_drvdata(pdev, cec); 255 256 dw_hdmi_write(cec, 0, HDMI_CEC_TX_CNT); 257 dw_hdmi_write(cec, ~0, HDMI_CEC_MASK); 258 dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0); 259 dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY); 260 261 cec->adap = cec_allocate_adapter(&dw_hdmi_cec_ops, cec, "dw_hdmi", 262 CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT | 263 CEC_CAP_RC | CEC_CAP_PASSTHROUGH, 264 CEC_MAX_LOG_ADDRS); 265 if (IS_ERR(cec->adap)) 266 return PTR_ERR(cec->adap); 267 268 /* override the module pointer */ 269 cec->adap->owner = THIS_MODULE; 270 271 ret = devm_add_action(&pdev->dev, dw_hdmi_cec_del, cec); 272 if (ret) { 273 cec_delete_adapter(cec->adap); 274 return ret; 275 } 276 277 ret = devm_request_threaded_irq(&pdev->dev, cec->irq, 278 dw_hdmi_cec_hardirq, 279 dw_hdmi_cec_thread, IRQF_SHARED, 280 "dw-hdmi-cec", cec->adap); 281 if (ret < 0) 282 return ret; 283 284 cec->notify = cec_notifier_get(pdev->dev.parent); 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_put(cec->notify); 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 cec_register_cec_notifier(cec->adap, cec->notify); 301 302 return 0; 303 } 304 305 static int dw_hdmi_cec_remove(struct platform_device *pdev) 306 { 307 struct dw_hdmi_cec *cec = platform_get_drvdata(pdev); 308 309 cec_unregister_adapter(cec->adap); 310 cec_notifier_put(cec->notify); 311 312 return 0; 313 } 314 315 static struct platform_driver dw_hdmi_cec_driver = { 316 .probe = dw_hdmi_cec_probe, 317 .remove = dw_hdmi_cec_remove, 318 .driver = { 319 .name = "dw-hdmi-cec", 320 }, 321 }; 322 module_platform_driver(dw_hdmi_cec_driver); 323 324 MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>"); 325 MODULE_DESCRIPTION("Synopsys Designware HDMI CEC driver for i.MX"); 326 MODULE_LICENSE("GPL"); 327 MODULE_ALIAS(PLATFORM_MODULE_PREFIX "dw-hdmi-cec"); 328