1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
4  */
5 
6 #include <linux/module.h>
7 #include <linux/interrupt.h>
8 #include <linux/delay.h>
9 #include <linux/platform_device.h>
10 #include <linux/gpio/consumer.h>
11 #include <media/cec-notifier.h>
12 #include <media/cec-pin.h>
13 
14 struct cec_gpio {
15 	struct cec_adapter	*adap;
16 	struct cec_notifier	*notifier;
17 	struct device		*dev;
18 
19 	struct gpio_desc	*cec_gpio;
20 	int			cec_irq;
21 	bool			cec_is_low;
22 
23 	struct gpio_desc	*hpd_gpio;
24 	int			hpd_irq;
25 	bool			hpd_is_high;
26 	ktime_t			hpd_ts;
27 
28 	struct gpio_desc	*v5_gpio;
29 	int			v5_irq;
30 	bool			v5_is_high;
31 	ktime_t			v5_ts;
32 };
33 
34 static int cec_gpio_read(struct cec_adapter *adap)
35 {
36 	struct cec_gpio *cec = cec_get_drvdata(adap);
37 
38 	if (cec->cec_is_low)
39 		return 0;
40 	return gpiod_get_value(cec->cec_gpio);
41 }
42 
43 static void cec_gpio_high(struct cec_adapter *adap)
44 {
45 	struct cec_gpio *cec = cec_get_drvdata(adap);
46 
47 	if (!cec->cec_is_low)
48 		return;
49 	cec->cec_is_low = false;
50 	gpiod_set_value(cec->cec_gpio, 1);
51 }
52 
53 static void cec_gpio_low(struct cec_adapter *adap)
54 {
55 	struct cec_gpio *cec = cec_get_drvdata(adap);
56 
57 	if (cec->cec_is_low)
58 		return;
59 	cec->cec_is_low = true;
60 	gpiod_set_value(cec->cec_gpio, 0);
61 }
62 
63 static irqreturn_t cec_hpd_gpio_irq_handler_thread(int irq, void *priv)
64 {
65 	struct cec_gpio *cec = priv;
66 
67 	cec_queue_pin_hpd_event(cec->adap, cec->hpd_is_high, cec->hpd_ts);
68 	return IRQ_HANDLED;
69 }
70 
71 static irqreturn_t cec_5v_gpio_irq_handler(int irq, void *priv)
72 {
73 	struct cec_gpio *cec = priv;
74 	int val = gpiod_get_value(cec->v5_gpio);
75 	bool is_high = val > 0;
76 
77 	if (val < 0 || is_high == cec->v5_is_high)
78 		return IRQ_HANDLED;
79 	cec->v5_ts = ktime_get();
80 	cec->v5_is_high = is_high;
81 	return IRQ_WAKE_THREAD;
82 }
83 
84 static irqreturn_t cec_5v_gpio_irq_handler_thread(int irq, void *priv)
85 {
86 	struct cec_gpio *cec = priv;
87 
88 	cec_queue_pin_5v_event(cec->adap, cec->v5_is_high, cec->v5_ts);
89 	return IRQ_HANDLED;
90 }
91 
92 static irqreturn_t cec_hpd_gpio_irq_handler(int irq, void *priv)
93 {
94 	struct cec_gpio *cec = priv;
95 	int val = gpiod_get_value(cec->hpd_gpio);
96 	bool is_high = val > 0;
97 
98 	if (val < 0 || is_high == cec->hpd_is_high)
99 		return IRQ_HANDLED;
100 	cec->hpd_ts = ktime_get();
101 	cec->hpd_is_high = is_high;
102 	return IRQ_WAKE_THREAD;
103 }
104 
105 static irqreturn_t cec_gpio_irq_handler(int irq, void *priv)
106 {
107 	struct cec_gpio *cec = priv;
108 	int val = gpiod_get_value(cec->cec_gpio);
109 
110 	if (val >= 0)
111 		cec_pin_changed(cec->adap, val > 0);
112 	return IRQ_HANDLED;
113 }
114 
115 static bool cec_gpio_enable_irq(struct cec_adapter *adap)
116 {
117 	struct cec_gpio *cec = cec_get_drvdata(adap);
118 
119 	enable_irq(cec->cec_irq);
120 	return true;
121 }
122 
123 static void cec_gpio_disable_irq(struct cec_adapter *adap)
124 {
125 	struct cec_gpio *cec = cec_get_drvdata(adap);
126 
127 	disable_irq(cec->cec_irq);
128 }
129 
130 static void cec_gpio_status(struct cec_adapter *adap, struct seq_file *file)
131 {
132 	struct cec_gpio *cec = cec_get_drvdata(adap);
133 
134 	seq_printf(file, "mode: %s\n", cec->cec_is_low ? "low-drive" : "read");
135 	seq_printf(file, "using irq: %d\n", cec->cec_irq);
136 	if (cec->hpd_gpio)
137 		seq_printf(file, "hpd: %s\n",
138 			   cec->hpd_is_high ? "high" : "low");
139 	if (cec->v5_gpio)
140 		seq_printf(file, "5V: %s\n",
141 			   cec->v5_is_high ? "high" : "low");
142 }
143 
144 static int cec_gpio_read_hpd(struct cec_adapter *adap)
145 {
146 	struct cec_gpio *cec = cec_get_drvdata(adap);
147 
148 	if (!cec->hpd_gpio)
149 		return -ENOTTY;
150 	return gpiod_get_value(cec->hpd_gpio);
151 }
152 
153 static int cec_gpio_read_5v(struct cec_adapter *adap)
154 {
155 	struct cec_gpio *cec = cec_get_drvdata(adap);
156 
157 	if (!cec->v5_gpio)
158 		return -ENOTTY;
159 	return gpiod_get_value(cec->v5_gpio);
160 }
161 
162 static void cec_gpio_free(struct cec_adapter *adap)
163 {
164 	cec_gpio_disable_irq(adap);
165 }
166 
167 static const struct cec_pin_ops cec_gpio_pin_ops = {
168 	.read = cec_gpio_read,
169 	.low = cec_gpio_low,
170 	.high = cec_gpio_high,
171 	.enable_irq = cec_gpio_enable_irq,
172 	.disable_irq = cec_gpio_disable_irq,
173 	.status = cec_gpio_status,
174 	.free = cec_gpio_free,
175 	.read_hpd = cec_gpio_read_hpd,
176 	.read_5v = cec_gpio_read_5v,
177 };
178 
179 static int cec_gpio_probe(struct platform_device *pdev)
180 {
181 	struct device *dev = &pdev->dev;
182 	struct device *hdmi_dev;
183 	struct cec_gpio *cec;
184 	u32 caps = CEC_CAP_DEFAULTS | CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN;
185 	int ret;
186 
187 	hdmi_dev = cec_notifier_parse_hdmi_phandle(dev);
188 	if (PTR_ERR(hdmi_dev) == -EPROBE_DEFER)
189 		return PTR_ERR(hdmi_dev);
190 	if (IS_ERR(hdmi_dev))
191 		caps |= CEC_CAP_PHYS_ADDR;
192 
193 	cec = devm_kzalloc(dev, sizeof(*cec), GFP_KERNEL);
194 	if (!cec)
195 		return -ENOMEM;
196 
197 	cec->dev = dev;
198 
199 	cec->cec_gpio = devm_gpiod_get(dev, "cec", GPIOD_OUT_HIGH_OPEN_DRAIN);
200 	if (IS_ERR(cec->cec_gpio))
201 		return PTR_ERR(cec->cec_gpio);
202 	cec->cec_irq = gpiod_to_irq(cec->cec_gpio);
203 
204 	cec->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN);
205 	if (IS_ERR(cec->hpd_gpio))
206 		return PTR_ERR(cec->hpd_gpio);
207 
208 	cec->v5_gpio = devm_gpiod_get_optional(dev, "v5", GPIOD_IN);
209 	if (IS_ERR(cec->v5_gpio))
210 		return PTR_ERR(cec->v5_gpio);
211 
212 	cec->adap = cec_pin_allocate_adapter(&cec_gpio_pin_ops,
213 					     cec, pdev->name, caps);
214 	if (IS_ERR(cec->adap))
215 		return PTR_ERR(cec->adap);
216 
217 	ret = devm_request_irq(dev, cec->cec_irq, cec_gpio_irq_handler,
218 			       IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
219 			       cec->adap->name, cec);
220 	if (ret)
221 		goto del_adap;
222 
223 	cec_gpio_disable_irq(cec->adap);
224 
225 	if (cec->hpd_gpio) {
226 		cec->hpd_irq = gpiod_to_irq(cec->hpd_gpio);
227 		ret = devm_request_threaded_irq(dev, cec->hpd_irq,
228 			cec_hpd_gpio_irq_handler,
229 			cec_hpd_gpio_irq_handler_thread,
230 			IRQF_ONESHOT |
231 			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
232 			"hpd-gpio", cec);
233 		if (ret)
234 			goto del_adap;
235 	}
236 
237 	if (cec->v5_gpio) {
238 		cec->v5_irq = gpiod_to_irq(cec->v5_gpio);
239 		ret = devm_request_threaded_irq(dev, cec->v5_irq,
240 			cec_5v_gpio_irq_handler,
241 			cec_5v_gpio_irq_handler_thread,
242 			IRQF_ONESHOT |
243 			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
244 			"v5-gpio", cec);
245 		if (ret)
246 			goto del_adap;
247 	}
248 
249 	if (!IS_ERR(hdmi_dev)) {
250 		cec->notifier = cec_notifier_cec_adap_register(hdmi_dev, NULL,
251 							       cec->adap);
252 		if (!cec->notifier) {
253 			ret = -ENOMEM;
254 			goto del_adap;
255 		}
256 	}
257 
258 	ret = cec_register_adapter(cec->adap, &pdev->dev);
259 	if (ret)
260 		goto unreg_notifier;
261 
262 	platform_set_drvdata(pdev, cec);
263 	return 0;
264 
265 unreg_notifier:
266 	cec_notifier_cec_adap_unregister(cec->notifier, cec->adap);
267 del_adap:
268 	cec_delete_adapter(cec->adap);
269 	return ret;
270 }
271 
272 static int cec_gpio_remove(struct platform_device *pdev)
273 {
274 	struct cec_gpio *cec = platform_get_drvdata(pdev);
275 
276 	cec_notifier_cec_adap_unregister(cec->notifier, cec->adap);
277 	cec_unregister_adapter(cec->adap);
278 	return 0;
279 }
280 
281 static const struct of_device_id cec_gpio_match[] = {
282 	{
283 		.compatible	= "cec-gpio",
284 	},
285 	{},
286 };
287 MODULE_DEVICE_TABLE(of, cec_gpio_match);
288 
289 static struct platform_driver cec_gpio_pdrv = {
290 	.probe	= cec_gpio_probe,
291 	.remove = cec_gpio_remove,
292 	.driver = {
293 		.name		= "cec-gpio",
294 		.of_match_table	= cec_gpio_match,
295 	},
296 };
297 
298 module_platform_driver(cec_gpio_pdrv);
299 
300 MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
301 MODULE_LICENSE("GPL v2");
302 MODULE_DESCRIPTION("CEC GPIO driver");
303