aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/leds/leds-cr0014114.c
blob: 0e4262462cb9d34ca1a6a767b1ad813cd537bcb2 (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
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Crane Merchandising Systems. All rights reserved.
// Copyright (C) 2018 Oleh Kravchenko <oleg@kaa.org.ua>

#include <linux/delay.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/spi/spi.h>
#include <linux/workqueue.h>
#include <uapi/linux/uleds.h>

/*
 *  CR0014114 SPI protocol descrtiption:
 *  +----+-----------------------------------+----+
 *  | CMD|             BRIGHTNESS            |CRC |
 *  +----+-----------------------------------+----+
 *  |    | LED0| LED1| LED2| LED3| LED4| LED5|    |
 *  |    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+    |
 *  |    |R|G|B|R|G|B|R|G|B|R|G|B|R|G|B|R|G|B|    |
 *  | 1  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1  |
 *  |    |1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|    |
 *  |    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+    |
 *  |    |               18                  |    |
 *  +----+-----------------------------------+----+
 *  |                    20                       |
 *  +---------------------------------------------+
 *
 *  PS: Boards can be connected to the chain:
 *      SPI -> board0 -> board1 -> board2 ..
 */

/* CR0014114 SPI commands */
#define CR_SET_BRIGHTNESS	0x80
#define CR_INIT_REENUMERATE	0x81
#define CR_NEXT_REENUMERATE	0x82

/* CR0014114 default settings */
#define CR_MAX_BRIGHTNESS	GENMASK(6, 0)
#define CR_FW_DELAY_MSEC	10
#define CR_RECOUNT_DELAY	(HZ * 3600)

struct cr0014114_led {
	char			name[LED_MAX_NAME_SIZE];
	struct cr0014114	*priv;
	struct led_classdev	ldev;
	u8			brightness;
};

struct cr0014114 {
	bool			do_recount;
	size_t			count;
	struct delayed_work	work;
	struct device		*dev;
	struct mutex		lock;
	struct spi_device	*spi;
	u8			*buf;
	unsigned long		delay;
	struct cr0014114_led	leds[];
};

static void cr0014114_calc_crc(u8 *buf, const size_t len)
{
	size_t	i;
	u8	crc;

	for (i = 1, crc = 1; i < len - 1; i++)
		crc += buf[i];
	crc |= BIT(7);

	/* special case when CRC matches the SPI commands */
	if (crc == CR_SET_BRIGHTNESS ||
	    crc == CR_INIT_REENUMERATE ||
	    crc == CR_NEXT_REENUMERATE)
		crc = 0xfe;

	buf[len - 1] = crc;
}

static int cr0014114_recount(struct cr0014114 *priv)
{
	int	ret;
	size_t	i;
	u8	cmd;

	dev_dbg(priv->dev, "LEDs recount is started\n");

	cmd = CR_INIT_REENUMERATE;
	ret = spi_write(priv->spi, &cmd, sizeof(cmd));
	if (ret)
		goto err;

	cmd = CR_NEXT_REENUMERATE;
	for (i = 0; i < priv->count; i++) {
		msleep(CR_FW_DELAY_MSEC);

		ret = spi_write(priv->spi, &cmd, sizeof(cmd));
		if (ret)
			goto err;
	}

err:
	dev_dbg(priv->dev, "LEDs recount is finished\n");

	if (ret)
		dev_err(priv->dev, "with error %d", ret);

	return ret;
}

static int cr0014114_sync(struct cr0014114 *priv)
{
	int		ret;
	size_t		i;
	unsigned long	udelay, now = jiffies;

	/* to avoid SPI mistiming with firmware we should wait some time */
	if (time_after(priv->delay, now)) {
		udelay = jiffies_to_usecs(priv->delay - now);
		usleep_range(udelay, udelay + 1);
	}

	if (unlikely(priv->do_recount)) {
		ret = cr0014114_recount(priv);
		if (ret)
			goto err;

		priv->do_recount = false;
		msleep(CR_FW_DELAY_MSEC);
	}

	priv->buf[0] = CR_SET_BRIGHTNESS;
	for (i = 0; i < priv->count; i++)
		priv->buf[i + 1] = priv->leds[i].brightness;
	cr0014114_calc_crc(priv->buf, priv->count + 2);
	ret = spi_write(priv->spi, priv->buf, priv->count + 2);

err:
	priv->delay = jiffies + msecs_to_jiffies(CR_FW_DELAY_MSEC);

	return ret;
}

static void cr0014114_recount_work(struct work_struct *work)
{
	int			ret;
	struct cr0014114	*priv = container_of(work,
						     struct cr0014114,
						     work.work);

	mutex_lock(&priv->lock);
	priv->do_recount = true;
	ret = cr0014114_sync(priv);
	mutex_unlock(&priv->lock);

	if (ret)
		dev_warn(priv->dev, "sync of LEDs failed %d\n", ret);

	schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);
}

static int cr0014114_set_sync(struct led_classdev *ldev,
			      enum led_brightness brightness)
{
	int			ret;
	struct cr0014114_led    *led = container_of(ldev,
						    struct cr0014114_led,
						    ldev);

	dev_dbg(led->priv->dev, "Set brightness of %s to %d\n",
		led->name, brightness);

	mutex_lock(&led->priv->lock);
	led->brightness = (u8)brightness;
	ret = cr0014114_sync(led->priv);
	mutex_unlock(&led->priv->lock);

	return ret;
}

static int cr0014114_probe_dt(struct cr0014114 *priv)
{
	size_t			i = 0;
	struct cr0014114_led	*led;
	struct fwnode_handle	*child;
	struct device_node	*np;
	int			ret;
	const char		*str;

	device_for_each_child_node(priv->dev, child) {
		np = to_of_node(child);
		led = &priv->leds[i];

		ret = fwnode_property_read_string(child, "label", &str);
		if (ret)
			snprintf(led->name, sizeof(led->name),
				 "cr0014114::");
		else
			snprintf(led->name, sizeof(led->name),
				 "cr0014114:%s", str);

		fwnode_property_read_string(child, "linux,default-trigger",
					    &led->ldev.default_trigger);

		led->priv			  = priv;
		led->ldev.name			  = led->name;
		led->ldev.max_brightness	  = CR_MAX_BRIGHTNESS;
		led->ldev.brightness_set_blocking = cr0014114_set_sync;

		ret = devm_of_led_classdev_register(priv->dev, np,
						    &led->ldev);
		if (ret) {
			dev_err(priv->dev,
				"failed to register LED device %s, err %d",
				led->name, ret);
			fwnode_handle_put(child);
			return ret;
		}

		led->ldev.dev->of_node = np;

		i++;
	}

	return 0;
}

static int cr0014114_probe(struct spi_device *spi)
{
	struct cr0014114	*priv;
	size_t			count;
	int			ret;

	count = device_get_child_node_count(&spi->dev);
	if (!count) {
		dev_err(&spi->dev, "LEDs are not defined in device tree!");
		return -ENODEV;
	}

	priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
			    GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->buf = devm_kzalloc(&spi->dev, count + 2, GFP_KERNEL);
	if (!priv->buf)
		return -ENOMEM;

	mutex_init(&priv->lock);
	INIT_DELAYED_WORK(&priv->work, cr0014114_recount_work);
	priv->count	= count;
	priv->dev	= &spi->dev;
	priv->spi	= spi;
	priv->delay	= jiffies -
			  msecs_to_jiffies(CR_FW_DELAY_MSEC);

	priv->do_recount = true;
	ret = cr0014114_sync(priv);
	if (ret) {
		dev_err(priv->dev, "first recount failed %d\n", ret);
		return ret;
	}

	priv->do_recount = true;
	ret = cr0014114_sync(priv);
	if (ret) {
		dev_err(priv->dev, "second recount failed %d\n", ret);
		return ret;
	}

	ret = cr0014114_probe_dt(priv);
	if (ret)
		return ret;

	/* setup recount work to workaround buggy firmware */
	schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);

	spi_set_drvdata(spi, priv);

	return 0;
}

static int cr0014114_remove(struct spi_device *spi)
{
	struct cr0014114 *priv = spi_get_drvdata(spi);

	cancel_delayed_work_sync(&priv->work);
	mutex_destroy(&priv->lock);

	return 0;
}

static const struct of_device_id cr0014114_dt_ids[] = {
	{ .compatible = "crane,cr0014114", },
	{},
};

MODULE_DEVICE_TABLE(of, cr0014114_dt_ids);

static struct spi_driver cr0014114_driver = {
	.probe		= cr0014114_probe,
	.remove		= cr0014114_remove,
	.driver = {
		.name		= KBUILD_MODNAME,
		.of_match_table	= cr0014114_dt_ids,
	},
};

module_spi_driver(cr0014114_driver);

MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
MODULE_DESCRIPTION("cr0014114 LED driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("spi:cr0014114");

Privacy Policy