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
 21enum {
 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
 54struct 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
 67static void dw_hdmi_write(struct dw_hdmi_cec *cec, u8 val, int offset)
 68{
 69	cec->ops->write(cec->hdmi, val, offset);
 70}
 71
 72static u8 dw_hdmi_read(struct dw_hdmi_cec *cec, int offset)
 73{
 74	return cec->ops->read(cec->hdmi, offset);
 75}
 76
 77static 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
 92static 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
120static 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
169static 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
186static 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
216static 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
222static void dw_hdmi_cec_del(void *data)
223{
224	struct dw_hdmi_cec *cec = data;
225
226	cec_delete_adapter(cec->adap);
227}
228
229static 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(&pdev->dev, dw_hdmi_cec_del, cec);
269	if (ret) {
270		cec_delete_adapter(cec->adap);
271		return ret;
272	}
273
274	ret = devm_request_threaded_irq(&pdev->dev, cec->irq,
275					dw_hdmi_cec_hardirq,
276					dw_hdmi_cec_thread, IRQF_SHARED,
277					"dw-hdmi-cec", cec->adap);
278	if (ret < 0)
279		return ret;
280
281	cec->notify = cec_notifier_cec_adap_register(pdev->dev.parent,
282						     NULL, cec->adap);
283	if (!cec->notify)
284		return -ENOMEM;
285
286	ret = cec_register_adapter(cec->adap, pdev->dev.parent);
287	if (ret < 0) {
288		cec_notifier_cec_adap_unregister(cec->notify);
289		return ret;
290	}
291
292	/*
293	 * CEC documentation says we must not call cec_delete_adapter
294	 * after a successful call to cec_register_adapter().
295	 */
296	devm_remove_action(&pdev->dev, dw_hdmi_cec_del, cec);
297
298	return 0;
299}
300
301static int dw_hdmi_cec_remove(struct platform_device *pdev)
302{
303	struct dw_hdmi_cec *cec = platform_get_drvdata(pdev);
304
305	cec_notifier_cec_adap_unregister(cec->notify);
306	cec_unregister_adapter(cec->adap);
307
308	return 0;
309}
310
311static struct platform_driver dw_hdmi_cec_driver = {
312	.probe	= dw_hdmi_cec_probe,
313	.remove	= dw_hdmi_cec_remove,
314	.driver = {
315		.name = "dw-hdmi-cec",
316	},
317};
318module_platform_driver(dw_hdmi_cec_driver);
319
320MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
321MODULE_DESCRIPTION("Synopsys Designware HDMI CEC driver for i.MX");
322MODULE_LICENSE("GPL");
323MODULE_ALIAS(PLATFORM_MODULE_PREFIX "dw-hdmi-cec");