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
dw_hdmi_write(struct dw_hdmi_cec * cec,u8 val,int offset)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
dw_hdmi_read(struct dw_hdmi_cec * cec,int offset)76 static u8 dw_hdmi_read(struct dw_hdmi_cec *cec, int offset)
77 {
78 return cec->ops->read(cec->hdmi, offset);
79 }
80
dw_hdmi_cec_log_addr(struct cec_adapter * adap,u8 logical_addr)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
dw_hdmi_cec_transmit(struct cec_adapter * adap,u8 attempts,u32 signal_free_time,struct cec_msg * msg)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
dw_hdmi_cec_hardirq(int irq,void * data)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
dw_hdmi_cec_thread(int irq,void * data)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
dw_hdmi_cec_enable(struct cec_adapter * adap,bool enable)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
dw_hdmi_cec_del(void * data)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
dw_hdmi_cec_probe(struct platform_device * pdev)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
dw_hdmi_cec_remove(struct platform_device * pdev)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
dw_hdmi_cec_resume(struct device * dev)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
dw_hdmi_cec_suspend(struct device * dev)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