1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Copyright (C) 2008 Nokia Corporation
4 *
5 *  Based on lirc_serial.c
6 */
7#include <linux/clk.h>
8#include <linux/module.h>
9#include <linux/platform_device.h>
10#include <linux/wait.h>
11#include <linux/pwm.h>
12#include <linux/of.h>
13#include <linux/hrtimer.h>
14
15#include <media/rc-core.h>
16
17#define WBUF_LEN 256
18
19struct ir_rx51 {
20	struct rc_dev *rcdev;
21	struct pwm_device *pwm;
22	struct hrtimer timer;
23	struct device	     *dev;
24	wait_queue_head_t     wqueue;
25
26	unsigned int	freq;		/* carrier frequency */
27	unsigned int	duty_cycle;	/* carrier duty cycle */
28	int		wbuf[WBUF_LEN];
29	int		wbuf_index;
30	unsigned long	device_is_open;
31};
32
33static inline void ir_rx51_on(struct ir_rx51 *ir_rx51)
34{
35	pwm_enable(ir_rx51->pwm);
36}
37
38static inline void ir_rx51_off(struct ir_rx51 *ir_rx51)
39{
40	pwm_disable(ir_rx51->pwm);
41}
42
43static int init_timing_params(struct ir_rx51 *ir_rx51)
44{
45	struct pwm_device *pwm = ir_rx51->pwm;
46	int duty, period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, ir_rx51->freq);
47
48	duty = DIV_ROUND_CLOSEST(ir_rx51->duty_cycle * period, 100);
49
50	pwm_config(pwm, duty, period);
51
52	return 0;
53}
54
55static enum hrtimer_restart ir_rx51_timer_cb(struct hrtimer *timer)
56{
57	struct ir_rx51 *ir_rx51 = container_of(timer, struct ir_rx51, timer);
58	ktime_t now;
59
60	if (ir_rx51->wbuf_index < 0) {
61		dev_err_ratelimited(ir_rx51->dev,
62				    "BUG wbuf_index has value of %i\n",
63				    ir_rx51->wbuf_index);
64		goto end;
65	}
66
67	/*
68	 * If we happen to hit an odd latency spike, loop through the
69	 * pulses until we catch up.
70	 */
71	do {
72		u64 ns;
73
74		if (ir_rx51->wbuf_index >= WBUF_LEN)
75			goto end;
76		if (ir_rx51->wbuf[ir_rx51->wbuf_index] == -1)
77			goto end;
78
79		if (ir_rx51->wbuf_index % 2)
80			ir_rx51_off(ir_rx51);
81		else
82			ir_rx51_on(ir_rx51);
83
84		ns = US_TO_NS(ir_rx51->wbuf[ir_rx51->wbuf_index]);
85		hrtimer_add_expires_ns(timer, ns);
86
87		ir_rx51->wbuf_index++;
88
89		now = timer->base->get_time();
90
91	} while (hrtimer_get_expires_tv64(timer) < now);
92
93	return HRTIMER_RESTART;
94end:
95	/* Stop TX here */
96	ir_rx51_off(ir_rx51);
97	ir_rx51->wbuf_index = -1;
98
99	wake_up_interruptible(&ir_rx51->wqueue);
100
101	return HRTIMER_NORESTART;
102}
103
104static int ir_rx51_tx(struct rc_dev *dev, unsigned int *buffer,
105		      unsigned int count)
106{
107	struct ir_rx51 *ir_rx51 = dev->priv;
108
109	if (count > WBUF_LEN)
110		return -EINVAL;
111
112	memcpy(ir_rx51->wbuf, buffer, count * sizeof(unsigned int));
113
114	/* Wait any pending transfers to finish */
115	wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);
116
117	init_timing_params(ir_rx51);
118	if (count < WBUF_LEN)
119		ir_rx51->wbuf[count] = -1; /* Insert termination mark */
120
121	/*
122	 * REVISIT: Adjust latency requirements so the device doesn't go in too
123	 * deep sleep states with pm_qos_add_request().
124	 */
125
126	ir_rx51_on(ir_rx51);
127	ir_rx51->wbuf_index = 1;
128	hrtimer_start(&ir_rx51->timer,
129		      ns_to_ktime(US_TO_NS(ir_rx51->wbuf[0])),
130		      HRTIMER_MODE_REL);
131	/*
132	 * Don't return back to the userspace until the transfer has
133	 * finished
134	 */
135	wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);
136
137	/* REVISIT: Remove pm_qos constraint, we can sleep again */
138
139	return count;
140}
141
142static int ir_rx51_open(struct rc_dev *dev)
143{
144	struct ir_rx51 *ir_rx51 = dev->priv;
145
146	if (test_and_set_bit(1, &ir_rx51->device_is_open))
147		return -EBUSY;
148
149	ir_rx51->pwm = pwm_get(ir_rx51->dev, NULL);
150	if (IS_ERR(ir_rx51->pwm)) {
151		int res = PTR_ERR(ir_rx51->pwm);
152
153		dev_err(ir_rx51->dev, "pwm_get failed: %d\n", res);
154		return res;
155	}
156
157	return 0;
158}
159
160static void ir_rx51_release(struct rc_dev *dev)
161{
162	struct ir_rx51 *ir_rx51 = dev->priv;
163
164	hrtimer_cancel(&ir_rx51->timer);
165	ir_rx51_off(ir_rx51);
166	pwm_put(ir_rx51->pwm);
167
168	clear_bit(1, &ir_rx51->device_is_open);
169}
170
171static struct ir_rx51 ir_rx51 = {
172	.duty_cycle	= 50,
173	.wbuf_index	= -1,
174};
175
176static int ir_rx51_set_duty_cycle(struct rc_dev *dev, u32 duty)
177{
178	struct ir_rx51 *ir_rx51 = dev->priv;
179
180	ir_rx51->duty_cycle = duty;
181
182	return 0;
183}
184
185static int ir_rx51_set_tx_carrier(struct rc_dev *dev, u32 carrier)
186{
187	struct ir_rx51 *ir_rx51 = dev->priv;
188
189	if (carrier > 500000 || carrier < 20000)
190		return -EINVAL;
191
192	ir_rx51->freq = carrier;
193
194	return 0;
195}
196
197#ifdef CONFIG_PM
198
199static int ir_rx51_suspend(struct platform_device *dev, pm_message_t state)
200{
201	/*
202	 * In case the device is still open, do not suspend. Normally
203	 * this should not be a problem as lircd only keeps the device
204	 * open only for short periods of time. We also don't want to
205	 * get involved with race conditions that might happen if we
206	 * were in a middle of a transmit. Thus, we defer any suspend
207	 * actions until transmit has completed.
208	 */
209	if (test_and_set_bit(1, &ir_rx51.device_is_open))
210		return -EAGAIN;
211
212	clear_bit(1, &ir_rx51.device_is_open);
213
214	return 0;
215}
216
217static int ir_rx51_resume(struct platform_device *dev)
218{
219	return 0;
220}
221
222#else
223
224#define ir_rx51_suspend	NULL
225#define ir_rx51_resume	NULL
226
227#endif /* CONFIG_PM */
228
229static int ir_rx51_probe(struct platform_device *dev)
230{
231	struct pwm_device *pwm;
232	struct rc_dev *rcdev;
233
234	pwm = pwm_get(&dev->dev, NULL);
235	if (IS_ERR(pwm)) {
236		int err = PTR_ERR(pwm);
237
238		if (err != -EPROBE_DEFER)
239			dev_err(&dev->dev, "pwm_get failed: %d\n", err);
240		return err;
241	}
242
243	/* Use default, in case userspace does not set the carrier */
244	ir_rx51.freq = DIV_ROUND_CLOSEST_ULL(pwm_get_period(pwm), NSEC_PER_SEC);
245	pwm_put(pwm);
246
247	hrtimer_init(&ir_rx51.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
248	ir_rx51.timer.function = ir_rx51_timer_cb;
249
250	ir_rx51.dev = &dev->dev;
251
252	rcdev = devm_rc_allocate_device(&dev->dev, RC_DRIVER_IR_RAW_TX);
253	if (!rcdev)
254		return -ENOMEM;
255
256	rcdev->priv = &ir_rx51;
257	rcdev->open = ir_rx51_open;
258	rcdev->close = ir_rx51_release;
259	rcdev->tx_ir = ir_rx51_tx;
260	rcdev->s_tx_duty_cycle = ir_rx51_set_duty_cycle;
261	rcdev->s_tx_carrier = ir_rx51_set_tx_carrier;
262	rcdev->driver_name = KBUILD_MODNAME;
263
264	ir_rx51.rcdev = rcdev;
265
266	return devm_rc_register_device(&dev->dev, ir_rx51.rcdev);
267}
268
269static int ir_rx51_remove(struct platform_device *dev)
270{
271	return 0;
272}
273
274static const struct of_device_id ir_rx51_match[] = {
275	{
276		.compatible = "nokia,n900-ir",
277	},
278	{},
279};
280MODULE_DEVICE_TABLE(of, ir_rx51_match);
281
282static struct platform_driver ir_rx51_platform_driver = {
283	.probe		= ir_rx51_probe,
284	.remove		= ir_rx51_remove,
285	.suspend	= ir_rx51_suspend,
286	.resume		= ir_rx51_resume,
287	.driver		= {
288		.name	= KBUILD_MODNAME,
289		.of_match_table = of_match_ptr(ir_rx51_match),
290	},
291};
292module_platform_driver(ir_rx51_platform_driver);
293
294MODULE_DESCRIPTION("IR TX driver for Nokia RX51");
295MODULE_AUTHOR("Nokia Corporation");
296MODULE_LICENSE("GPL");
297