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"); 322