1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* drivers/media/platform/s5p-cec/s5p_cec.c
3  *
4  * Samsung S5P CEC driver
5  *
6  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
7  *
8  * This driver is based on the "cec interface driver for exynos soc" by
9  * SangPil Moon.
10  */
11 
12 #include <linux/clk.h>
13 #include <linux/interrupt.h>
14 #include <linux/kernel.h>
15 #include <linux/mfd/syscon.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/of_platform.h>
19 #include <linux/platform_device.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/timer.h>
22 #include <linux/workqueue.h>
23 #include <media/cec.h>
24 #include <media/cec-notifier.h>
25 
26 #include "exynos_hdmi_cec.h"
27 #include "regs-cec.h"
28 #include "s5p_cec.h"
29 
30 #define CEC_NAME	"s5p-cec"
31 
32 static int debug;
33 module_param(debug, int, 0644);
34 MODULE_PARM_DESC(debug, "debug level (0-2)");
35 
36 static int s5p_cec_adap_enable(struct cec_adapter *adap, bool enable)
37 {
38 	int ret;
39 	struct s5p_cec_dev *cec = cec_get_drvdata(adap);
40 
41 	if (enable) {
42 		ret = pm_runtime_resume_and_get(cec->dev);
43 		if (ret < 0)
44 			return ret;
45 
46 		s5p_cec_reset(cec);
47 
48 		s5p_cec_set_divider(cec);
49 		s5p_cec_threshold(cec);
50 
51 		s5p_cec_unmask_tx_interrupts(cec);
52 		s5p_cec_unmask_rx_interrupts(cec);
53 		s5p_cec_enable_rx(cec);
54 	} else {
55 		s5p_cec_mask_tx_interrupts(cec);
56 		s5p_cec_mask_rx_interrupts(cec);
57 		pm_runtime_put(cec->dev);
58 	}
59 
60 	return 0;
61 }
62 
63 static int s5p_cec_adap_log_addr(struct cec_adapter *adap, u8 addr)
64 {
65 	struct s5p_cec_dev *cec = cec_get_drvdata(adap);
66 
67 	s5p_cec_set_addr(cec, addr);
68 	return 0;
69 }
70 
71 static int s5p_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
72 				 u32 signal_free_time, struct cec_msg *msg)
73 {
74 	struct s5p_cec_dev *cec = cec_get_drvdata(adap);
75 
76 	/*
77 	 * Unclear if 0 retries are allowed by the hardware, so have 1 as
78 	 * the minimum.
79 	 */
80 	s5p_cec_copy_packet(cec, msg->msg, msg->len, max(1, attempts - 1));
81 	return 0;
82 }
83 
84 static irqreturn_t s5p_cec_irq_handler(int irq, void *priv)
85 {
86 	struct s5p_cec_dev *cec = priv;
87 	u32 status = 0;
88 
89 	status = s5p_cec_get_status(cec);
90 
91 	dev_dbg(cec->dev, "irq received\n");
92 
93 	if (status & CEC_STATUS_TX_DONE) {
94 		if (status & CEC_STATUS_TX_NACK) {
95 			dev_dbg(cec->dev, "CEC_STATUS_TX_NACK set\n");
96 			cec->tx = STATE_NACK;
97 		} else if (status & CEC_STATUS_TX_ERROR) {
98 			dev_dbg(cec->dev, "CEC_STATUS_TX_ERROR set\n");
99 			cec->tx = STATE_ERROR;
100 		} else {
101 			dev_dbg(cec->dev, "CEC_STATUS_TX_DONE\n");
102 			cec->tx = STATE_DONE;
103 		}
104 		s5p_clr_pending_tx(cec);
105 	}
106 
107 	if (status & CEC_STATUS_RX_DONE) {
108 		if (status & CEC_STATUS_RX_ERROR) {
109 			dev_dbg(cec->dev, "CEC_STATUS_RX_ERROR set\n");
110 			s5p_cec_rx_reset(cec);
111 			s5p_cec_enable_rx(cec);
112 		} else {
113 			dev_dbg(cec->dev, "CEC_STATUS_RX_DONE set\n");
114 			if (cec->rx != STATE_IDLE)
115 				dev_dbg(cec->dev, "Buffer overrun (worker did not process previous message)\n");
116 			cec->rx = STATE_BUSY;
117 			cec->msg.len = status >> 24;
118 			cec->msg.rx_status = CEC_RX_STATUS_OK;
119 			s5p_cec_get_rx_buf(cec, cec->msg.len,
120 					cec->msg.msg);
121 			cec->rx = STATE_DONE;
122 			s5p_cec_enable_rx(cec);
123 		}
124 		/* Clear interrupt pending bit */
125 		s5p_clr_pending_rx(cec);
126 	}
127 	return IRQ_WAKE_THREAD;
128 }
129 
130 static irqreturn_t s5p_cec_irq_handler_thread(int irq, void *priv)
131 {
132 	struct s5p_cec_dev *cec = priv;
133 
134 	dev_dbg(cec->dev, "irq processing thread\n");
135 	switch (cec->tx) {
136 	case STATE_DONE:
137 		cec_transmit_done(cec->adap, CEC_TX_STATUS_OK, 0, 0, 0, 0);
138 		cec->tx = STATE_IDLE;
139 		break;
140 	case STATE_NACK:
141 		cec_transmit_done(cec->adap,
142 			CEC_TX_STATUS_MAX_RETRIES | CEC_TX_STATUS_NACK,
143 			0, 1, 0, 0);
144 		cec->tx = STATE_IDLE;
145 		break;
146 	case STATE_ERROR:
147 		cec_transmit_done(cec->adap,
148 			CEC_TX_STATUS_MAX_RETRIES | CEC_TX_STATUS_ERROR,
149 			0, 0, 0, 1);
150 		cec->tx = STATE_IDLE;
151 		break;
152 	case STATE_BUSY:
153 		dev_err(cec->dev, "state set to busy, this should not occur here\n");
154 		break;
155 	default:
156 		break;
157 	}
158 
159 	switch (cec->rx) {
160 	case STATE_DONE:
161 		cec_received_msg(cec->adap, &cec->msg);
162 		cec->rx = STATE_IDLE;
163 		break;
164 	default:
165 		break;
166 	}
167 
168 	return IRQ_HANDLED;
169 }
170 
171 static const struct cec_adap_ops s5p_cec_adap_ops = {
172 	.adap_enable = s5p_cec_adap_enable,
173 	.adap_log_addr = s5p_cec_adap_log_addr,
174 	.adap_transmit = s5p_cec_adap_transmit,
175 };
176 
177 static int s5p_cec_probe(struct platform_device *pdev)
178 {
179 	struct device *dev = &pdev->dev;
180 	struct device *hdmi_dev;
181 	struct resource *res;
182 	struct s5p_cec_dev *cec;
183 	bool needs_hpd = of_property_read_bool(pdev->dev.of_node, "needs-hpd");
184 	int ret;
185 
186 	hdmi_dev = cec_notifier_parse_hdmi_phandle(dev);
187 
188 	if (IS_ERR(hdmi_dev))
189 		return PTR_ERR(hdmi_dev);
190 
191 	cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL);
192 	if (!cec)
193 		return -ENOMEM;
194 
195 	cec->dev = dev;
196 
197 	cec->irq = platform_get_irq(pdev, 0);
198 	if (cec->irq < 0)
199 		return cec->irq;
200 
201 	ret = devm_request_threaded_irq(dev, cec->irq, s5p_cec_irq_handler,
202 		s5p_cec_irq_handler_thread, 0, pdev->name, cec);
203 	if (ret)
204 		return ret;
205 
206 	cec->clk = devm_clk_get(dev, "hdmicec");
207 	if (IS_ERR(cec->clk))
208 		return PTR_ERR(cec->clk);
209 
210 	cec->pmu = syscon_regmap_lookup_by_phandle(dev->of_node,
211 						 "samsung,syscon-phandle");
212 	if (IS_ERR(cec->pmu))
213 		return -EPROBE_DEFER;
214 
215 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
216 	cec->reg = devm_ioremap_resource(dev, res);
217 	if (IS_ERR(cec->reg))
218 		return PTR_ERR(cec->reg);
219 
220 	cec->adap = cec_allocate_adapter(&s5p_cec_adap_ops, cec, CEC_NAME,
221 		CEC_CAP_DEFAULTS | (needs_hpd ? CEC_CAP_NEEDS_HPD : 0) |
222 		CEC_CAP_CONNECTOR_INFO, 1);
223 	ret = PTR_ERR_OR_ZERO(cec->adap);
224 	if (ret)
225 		return ret;
226 
227 	cec->notifier = cec_notifier_cec_adap_register(hdmi_dev, NULL,
228 						       cec->adap);
229 	if (!cec->notifier) {
230 		ret = -ENOMEM;
231 		goto err_delete_adapter;
232 	}
233 
234 	ret = cec_register_adapter(cec->adap, &pdev->dev);
235 	if (ret)
236 		goto err_notifier;
237 
238 	platform_set_drvdata(pdev, cec);
239 	pm_runtime_enable(dev);
240 
241 	dev_dbg(dev, "successfully probed\n");
242 	return 0;
243 
244 err_notifier:
245 	cec_notifier_cec_adap_unregister(cec->notifier, cec->adap);
246 
247 err_delete_adapter:
248 	cec_delete_adapter(cec->adap);
249 	return ret;
250 }
251 
252 static int s5p_cec_remove(struct platform_device *pdev)
253 {
254 	struct s5p_cec_dev *cec = platform_get_drvdata(pdev);
255 
256 	cec_notifier_cec_adap_unregister(cec->notifier, cec->adap);
257 	cec_unregister_adapter(cec->adap);
258 	pm_runtime_disable(&pdev->dev);
259 	return 0;
260 }
261 
262 static int __maybe_unused s5p_cec_runtime_suspend(struct device *dev)
263 {
264 	struct s5p_cec_dev *cec = dev_get_drvdata(dev);
265 
266 	clk_disable_unprepare(cec->clk);
267 	return 0;
268 }
269 
270 static int __maybe_unused s5p_cec_runtime_resume(struct device *dev)
271 {
272 	struct s5p_cec_dev *cec = dev_get_drvdata(dev);
273 	int ret;
274 
275 	ret = clk_prepare_enable(cec->clk);
276 	if (ret < 0)
277 		return ret;
278 	return 0;
279 }
280 
281 static const struct dev_pm_ops s5p_cec_pm_ops = {
282 	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
283 				pm_runtime_force_resume)
284 	SET_RUNTIME_PM_OPS(s5p_cec_runtime_suspend, s5p_cec_runtime_resume,
285 			   NULL)
286 };
287 
288 static const struct of_device_id s5p_cec_match[] = {
289 	{
290 		.compatible	= "samsung,s5p-cec",
291 	},
292 	{},
293 };
294 MODULE_DEVICE_TABLE(of, s5p_cec_match);
295 
296 static struct platform_driver s5p_cec_pdrv = {
297 	.probe	= s5p_cec_probe,
298 	.remove	= s5p_cec_remove,
299 	.driver	= {
300 		.name		= CEC_NAME,
301 		.of_match_table	= s5p_cec_match,
302 		.pm		= &s5p_cec_pm_ops,
303 	},
304 };
305 
306 module_platform_driver(s5p_cec_pdrv);
307 
308 MODULE_AUTHOR("Kamil Debski <kamil@wypas.org>");
309 MODULE_LICENSE("GPL");
310 MODULE_DESCRIPTION("Samsung S5P CEC driver");
311