summaryrefslogtreecommitdiff
path: root/drivers/gnss/sirf.c
blob: 226f6e6fe01bcbf63aca6005a25a4e6578b65115 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
// SPDX-License-Identifier: GPL-2.0
/*
 * SiRFstar GNSS receiver driver
 *
 * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
 */

#include <linux/errno.h>
#include <linux/gnss.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/sched.h>
#include <linux/serdev.h>
#include <linux/slab.h>
#include <linux/wait.h>

#define SIRF_BOOT_DELAY			500
#define SIRF_ON_OFF_PULSE_TIME		100
#define SIRF_ACTIVATE_TIMEOUT		200
#define SIRF_HIBERNATE_TIMEOUT		200

struct sirf_data {
	struct gnss_device *gdev;
	struct serdev_device *serdev;
	speed_t	speed;
	struct regulator *vcc;
	struct gpio_desc *on_off;
	struct gpio_desc *wakeup;
	int irq;
	bool active;
	wait_queue_head_t power_wait;
};

static int sirf_open(struct gnss_device *gdev)
{
	struct sirf_data *data = gnss_get_drvdata(gdev);
	struct serdev_device *serdev = data->serdev;
	int ret;

	ret = serdev_device_open(serdev);
	if (ret)
		return ret;

	serdev_device_set_baudrate(serdev, data->speed);
	serdev_device_set_flow_control(serdev, false);

	ret = pm_runtime_get_sync(&serdev->dev);
	if (ret < 0) {
		dev_err(&gdev->dev, "failed to runtime resume: %d\n", ret);
		pm_runtime_put_noidle(&serdev->dev);
		goto err_close;
	}

	return 0;

err_close:
	serdev_device_close(serdev);

	return ret;
}

static void sirf_close(struct gnss_device *gdev)
{
	struct sirf_data *data = gnss_get_drvdata(gdev);
	struct serdev_device *serdev = data->serdev;

	serdev_device_close(serdev);

	pm_runtime_put(&serdev->dev);
}

static int sirf_write_raw(struct gnss_device *gdev, const unsigned char *buf,
				size_t count)
{
	struct sirf_data *data = gnss_get_drvdata(gdev);
	struct serdev_device *serdev = data->serdev;
	int ret;

	/* write is only buffered synchronously */
	ret = serdev_device_write(serdev, buf, count, MAX_SCHEDULE_TIMEOUT);
	if (ret < 0 || ret < count)
		return ret;

	/* FIXME: determine if interrupted? */
	serdev_device_wait_until_sent(serdev, 0);

	return count;
}

static const struct gnss_operations sirf_gnss_ops = {
	.open		= sirf_open,
	.close		= sirf_close,
	.write_raw	= sirf_write_raw,
};

static int sirf_receive_buf(struct serdev_device *serdev,
				const unsigned char *buf, size_t count)
{
	struct sirf_data *data = serdev_device_get_drvdata(serdev);
	struct gnss_device *gdev = data->gdev;

	return gnss_insert_raw(gdev, buf, count);
}

static const struct serdev_device_ops sirf_serdev_ops = {
	.receive_buf	= sirf_receive_buf,
	.write_wakeup	= serdev_device_write_wakeup,
};

static irqreturn_t sirf_wakeup_handler(int irq, void *dev_id)
{
	struct sirf_data *data = dev_id;
	struct device *dev = &data->serdev->dev;
	int ret;

	ret = gpiod_get_value_cansleep(data->wakeup);
	dev_dbg(dev, "%s - wakeup = %d\n", __func__, ret);
	if (ret < 0)
		goto out;

	data->active = !!ret;
	wake_up_interruptible(&data->power_wait);
out:
	return IRQ_HANDLED;
}

static int sirf_wait_for_power_state(struct sirf_data *data, bool active,
					unsigned long timeout)
{
	int ret;

	ret = wait_event_interruptible_timeout(data->power_wait,
			data->active == active, msecs_to_jiffies(timeout));
	if (ret < 0)
		return ret;

	if (ret == 0) {
		dev_warn(&data->serdev->dev, "timeout waiting for active state = %d\n",
				active);
		return -ETIMEDOUT;
	}

	return 0;
}

static void sirf_pulse_on_off(struct sirf_data *data)
{
	gpiod_set_value_cansleep(data->on_off, 1);
	msleep(SIRF_ON_OFF_PULSE_TIME);
	gpiod_set_value_cansleep(data->on_off, 0);
}

static int sirf_set_active(struct sirf_data *data, bool active)
{
	unsigned long timeout;
	int retries = 3;
	int ret;

	if (active)
		timeout = SIRF_ACTIVATE_TIMEOUT;
	else
		timeout = SIRF_HIBERNATE_TIMEOUT;

	do {
		sirf_pulse_on_off(data);
		ret = sirf_wait_for_power_state(data, active, timeout);
		if (ret < 0) {
			if (ret == -ETIMEDOUT)
				continue;

			return ret;
		}

		break;
	} while (retries--);

	if (retries < 0)
		return -ETIMEDOUT;

	return 0;
}

static int sirf_runtime_suspend(struct device *dev)
{
	struct sirf_data *data = dev_get_drvdata(dev);

	if (!data->on_off)
		return regulator_disable(data->vcc);

	return sirf_set_active(data, false);
}

static int sirf_runtime_resume(struct device *dev)
{
	struct sirf_data *data = dev_get_drvdata(dev);

	if (!data->on_off)
		return regulator_enable(data->vcc);

	return sirf_set_active(data, true);
}

static int __maybe_unused sirf_suspend(struct device *dev)
{
	struct sirf_data *data = dev_get_drvdata(dev);
	int ret = 0;

	if (!pm_runtime_suspended(dev))
		ret = sirf_runtime_suspend(dev);

	if (data->wakeup)
		disable_irq(data->irq);

	return ret;
}

static int __maybe_unused sirf_resume(struct device *dev)
{
	struct sirf_data *data = dev_get_drvdata(dev);
	int ret = 0;

	if (data->wakeup)
		enable_irq(data->irq);

	if (!pm_runtime_suspended(dev))
		ret = sirf_runtime_resume(dev);

	return ret;
}

static const struct dev_pm_ops sirf_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(sirf_suspend, sirf_resume)
	SET_RUNTIME_PM_OPS(sirf_runtime_suspend, sirf_runtime_resume, NULL)
};

static int sirf_parse_dt(struct serdev_device *serdev)
{
	struct sirf_data *data = serdev_device_get_drvdata(serdev);
	struct device_node *node = serdev->dev.of_node;
	u32 speed = 9600;

	of_property_read_u32(node, "current-speed", &speed);

	data->speed = speed;

	return 0;
}

static int sirf_probe(struct serdev_device *serdev)
{
	struct device *dev = &serdev->dev;
	struct gnss_device *gdev;
	struct sirf_data *data;
	int ret;

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	gdev = gnss_allocate_device(dev);
	if (!gdev)
		return -ENOMEM;

	gdev->type = GNSS_TYPE_SIRF;
	gdev->ops = &sirf_gnss_ops;
	gnss_set_drvdata(gdev, data);

	data->serdev = serdev;
	data->gdev = gdev;

	init_waitqueue_head(&data->power_wait);

	serdev_device_set_drvdata(serdev, data);
	serdev_device_set_client_ops(serdev, &sirf_serdev_ops);

	ret = sirf_parse_dt(serdev);
	if (ret)
		goto err_put_device;

	data->vcc = devm_regulator_get(dev, "vcc");
	if (IS_ERR(data->vcc)) {
		ret = PTR_ERR(data->vcc);
		goto err_put_device;
	}

	data->on_off = devm_gpiod_get_optional(dev, "sirf,onoff",
			GPIOD_OUT_LOW);
	if (IS_ERR(data->on_off))
		goto err_put_device;

	if (data->on_off) {
		data->wakeup = devm_gpiod_get_optional(dev, "sirf,wakeup",
				GPIOD_IN);
		if (IS_ERR(data->wakeup))
			goto err_put_device;

		/*
		 * Configurations where WAKEUP has been left not connected,
		 * are currently not supported.
		 */
		if (!data->wakeup) {
			dev_err(dev, "no wakeup gpio specified\n");
			ret = -ENODEV;
			goto err_put_device;
		}
	}

	if (data->wakeup) {
		ret = gpiod_to_irq(data->wakeup);
		if (ret < 0)
			goto err_put_device;

		data->irq = ret;

		ret = devm_request_threaded_irq(dev, data->irq, NULL,
				sirf_wakeup_handler,
				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
				"wakeup", data);
		if (ret)
			goto err_put_device;
	}

	if (data->on_off) {
		ret = regulator_enable(data->vcc);
		if (ret)
			goto err_put_device;

		/* Wait for chip to boot into hibernate mode */
		msleep(SIRF_BOOT_DELAY);
	}

	if (IS_ENABLED(CONFIG_PM)) {
		pm_runtime_set_suspended(dev);	/* clear runtime_error flag */
		pm_runtime_enable(dev);
	} else {
		ret = sirf_runtime_resume(dev);
		if (ret < 0)
			goto err_disable_vcc;
	}

	ret = gnss_register_device(gdev);
	if (ret)
		goto err_disable_rpm;

	return 0;

err_disable_rpm:
	if (IS_ENABLED(CONFIG_PM))
		pm_runtime_disable(dev);
	else
		sirf_runtime_suspend(dev);
err_disable_vcc:
	if (data->on_off)
		regulator_disable(data->vcc);
err_put_device:
	gnss_put_device(data->gdev);

	return ret;
}

static void sirf_remove(struct serdev_device *serdev)
{
	struct sirf_data *data = serdev_device_get_drvdata(serdev);

	gnss_deregister_device(data->gdev);

	if (IS_ENABLED(CONFIG_PM))
		pm_runtime_disable(&serdev->dev);
	else
		sirf_runtime_suspend(&serdev->dev);

	if (data->on_off)
		regulator_disable(data->vcc);

	gnss_put_device(data->gdev);
};

#ifdef CONFIG_OF
static const struct of_device_id sirf_of_match[] = {
	{ .compatible = "fastrax,uc430" },
	{ .compatible = "linx,r4" },
	{ .compatible = "wi2wi,w2sg0008i" },
	{ .compatible = "wi2wi,w2sg0084i" },
	{},
};
MODULE_DEVICE_TABLE(of, sirf_of_match);
#endif

static struct serdev_device_driver sirf_driver = {
	.driver	= {
		.name		= "gnss-sirf",
		.of_match_table	= of_match_ptr(sirf_of_match),
		.pm		= &sirf_pm_ops,
	},
	.probe	= sirf_probe,
	.remove	= sirf_remove,
};
module_serdev_device_driver(sirf_driver);

MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
MODULE_DESCRIPTION("SiRFstar GNSS receiver driver");
MODULE_LICENSE("GPL v2");