1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2019 Crane Merchandising Systems. All rights reserved.
3// Copyright (C) 2019 Oleh Kravchenko <oleg@kaa.org.ua>
4
5#include <linux/delay.h>
6#include <linux/leds.h>
7#include <linux/mod_devicetable.h>
8#include <linux/module.h>
9#include <linux/property.h>
10#include <linux/spi/spi.h>
11
12/*
13 * EL15203000 SPI protocol description:
14 * +-----+---------+
15 * | LED | COMMAND |
16 * +-----+---------+
17 * |  1  |    1    |
18 * +-----+---------+
19 * (*) LEDs MCU board expects 20 msec delay per byte.
20 *
21 * LEDs:
22 * +----------+--------------+-------------------------------------------+
23 * |    ID    |     NAME     |         DESCRIPTION                       |
24 * +----------+--------------+-------------------------------------------+
25 * | 'P' 0x50 |     Pipe     | Consists from 5 LEDs, controlled by board |
26 * +----------+--------------+-------------------------------------------+
27 * | 'S' 0x53 | Screen frame | Light tube around the screen              |
28 * +----------+--------------+-------------------------------------------+
29 * | 'V' 0x56 | Vending area | Highlights a cup of coffee                |
30 * +----------+--------------+-------------------------------------------+
31 *
32 * COMMAND:
33 * +----------+-----------------+--------------+--------------+
34 * |  VALUES  |       PIPE      | SCREEN FRAME | VENDING AREA |
35 * +----------+-----------------+--------------+--------------+
36 * | '0' 0x30 |                      Off                      |
37 * +----------+-----------------------------------------------+
38 * | '1' 0x31 |                      On                       |
39 * +----------+-----------------+--------------+--------------+
40 * | '2' 0x32 |     Cascade     |   Breathing  |
41 * +----------+-----------------+--------------+
42 * | '3' 0x33 | Inverse cascade |
43 * +----------+-----------------+
44 * | '4' 0x34 |     Bounce      |
45 * +----------+-----------------+
46 * | '5' 0x35 | Inverse bounce  |
47 * +----------+-----------------+
48 */
49
50/* EL15203000 default settings */
51#define EL_FW_DELAY_USEC	20000ul
52#define EL_PATTERN_DELAY_MSEC	800u
53#define EL_PATTERN_LEN		10u
54#define EL_PATTERN_HALF_LEN	(EL_PATTERN_LEN / 2)
55
56enum el15203000_command {
57	/* for all LEDs */
58	EL_OFF			= '0',
59	EL_ON			= '1',
60
61	/* for Screen LED */
62	EL_SCREEN_BREATHING	= '2',
63
64	/* for Pipe LED */
65	EL_PIPE_CASCADE		= '2',
66	EL_PIPE_INV_CASCADE	= '3',
67	EL_PIPE_BOUNCE		= '4',
68	EL_PIPE_INV_BOUNCE	= '5',
69};
70
71struct el15203000_led {
72	struct led_classdev	ldev;
73	struct el15203000	*priv;
74	u32			reg;
75};
76
77struct el15203000 {
78	struct device		*dev;
79	struct mutex		lock;
80	struct spi_device	*spi;
81	unsigned long		delay;
82	size_t			count;
83	struct el15203000_led	leds[] __counted_by(count);
84};
85
86#define to_el15203000_led(d)	container_of(d, struct el15203000_led, ldev)
87
88static int el15203000_cmd(struct el15203000_led *led, u8 brightness)
89{
90	int		ret;
91	u8		cmd[2];
92	size_t		i;
93
94	mutex_lock(&led->priv->lock);
95
96	dev_dbg(led->priv->dev, "Set brightness of 0x%02x(%c) to 0x%02x(%c)",
97		led->reg, led->reg, brightness, brightness);
98
99	/* to avoid SPI mistiming with firmware we should wait some time */
100	if (time_after(led->priv->delay, jiffies)) {
101		dev_dbg(led->priv->dev, "Wait %luus to sync",
102			EL_FW_DELAY_USEC);
103
104		usleep_range(EL_FW_DELAY_USEC,
105			     EL_FW_DELAY_USEC + 1);
106	}
107
108	cmd[0] = led->reg;
109	cmd[1] = brightness;
110
111	for (i = 0; i < ARRAY_SIZE(cmd); i++) {
112		if (i)
113			usleep_range(EL_FW_DELAY_USEC,
114				     EL_FW_DELAY_USEC + 1);
115
116		ret = spi_write(led->priv->spi, &cmd[i], sizeof(cmd[i]));
117		if (ret) {
118			dev_err(led->priv->dev,
119				"spi_write() error %d", ret);
120			break;
121		}
122	}
123
124	led->priv->delay = jiffies + usecs_to_jiffies(EL_FW_DELAY_USEC);
125
126	mutex_unlock(&led->priv->lock);
127
128	return ret;
129}
130
131static int el15203000_set_blocking(struct led_classdev *ldev,
132				   enum led_brightness brightness)
133{
134	struct el15203000_led *led = to_el15203000_led(ldev);
135
136	return el15203000_cmd(led, brightness == LED_OFF ? EL_OFF : EL_ON);
137}
138
139static int el15203000_pattern_set_S(struct led_classdev *ldev,
140				    struct led_pattern *pattern,
141				    u32 len, int repeat)
142{
143	struct el15203000_led *led = to_el15203000_led(ldev);
144
145	if (repeat > 0 || len != 2 ||
146	    pattern[0].delta_t != 4000 || pattern[0].brightness != 0 ||
147	    pattern[1].delta_t != 4000 || pattern[1].brightness != 1)
148		return -EINVAL;
149
150	dev_dbg(led->priv->dev, "Breathing mode for 0x%02x(%c)",
151		led->reg, led->reg);
152
153	return el15203000_cmd(led, EL_SCREEN_BREATHING);
154}
155
156static bool is_cascade(const struct led_pattern *pattern, u32 len,
157		       bool inv, bool right)
158{
159	int val, t;
160	u32 i;
161
162	if (len != EL_PATTERN_HALF_LEN)
163		return false;
164
165	val = right ? BIT(4) : BIT(0);
166
167	for (i = 0; i < len; i++) {
168		t = inv ? ~val & GENMASK(4, 0) : val;
169
170		if (pattern[i].delta_t != EL_PATTERN_DELAY_MSEC ||
171		    pattern[i].brightness != t)
172			return false;
173
174		val = right ? val >> 1 : val << 1;
175	}
176
177	return true;
178}
179
180static bool is_bounce(const struct led_pattern *pattern, u32 len, bool inv)
181{
182	if (len != EL_PATTERN_LEN)
183		return false;
184
185	return is_cascade(pattern, EL_PATTERN_HALF_LEN, inv, false) &&
186	       is_cascade(pattern + EL_PATTERN_HALF_LEN,
187			  EL_PATTERN_HALF_LEN, inv, true);
188}
189
190static int el15203000_pattern_set_P(struct led_classdev *ldev,
191				    struct led_pattern *pattern,
192				    u32 len, int repeat)
193{
194	struct el15203000_led	*led = to_el15203000_led(ldev);
195	u8			cmd;
196
197	if (repeat > 0)
198		return -EINVAL;
199
200	if (is_cascade(pattern, len, false, false)) {
201		dev_dbg(led->priv->dev, "Cascade mode for 0x%02x(%c)",
202			led->reg, led->reg);
203
204		cmd = EL_PIPE_CASCADE;
205	} else if (is_cascade(pattern, len, true, false)) {
206		dev_dbg(led->priv->dev, "Inverse cascade mode for 0x%02x(%c)",
207			led->reg, led->reg);
208
209		cmd = EL_PIPE_INV_CASCADE;
210	} else if (is_bounce(pattern, len, false)) {
211		dev_dbg(led->priv->dev, "Bounce mode for 0x%02x(%c)",
212			led->reg, led->reg);
213
214		cmd = EL_PIPE_BOUNCE;
215	} else if (is_bounce(pattern, len, true)) {
216		dev_dbg(led->priv->dev, "Inverse bounce mode for 0x%02x(%c)",
217			led->reg, led->reg);
218
219		cmd = EL_PIPE_INV_BOUNCE;
220	} else {
221		dev_err(led->priv->dev, "Invalid hw_pattern for 0x%02x(%c)!",
222			led->reg, led->reg);
223
224		return -EINVAL;
225	}
226
227	return el15203000_cmd(led, cmd);
228}
229
230static int el15203000_pattern_clear(struct led_classdev *ldev)
231{
232	struct el15203000_led *led = to_el15203000_led(ldev);
233
234	return el15203000_cmd(led, EL_OFF);
235}
236
237static int el15203000_probe_dt(struct el15203000 *priv)
238{
239	struct el15203000_led	*led = priv->leds;
240	struct fwnode_handle	*child;
241	int			ret;
242
243	device_for_each_child_node(priv->dev, child) {
244		struct led_init_data init_data = {};
245
246		ret = fwnode_property_read_u32(child, "reg", &led->reg);
247		if (ret) {
248			dev_err(priv->dev, "LED without ID number");
249			goto err_child_out;
250		}
251
252		if (led->reg > U8_MAX) {
253			dev_err(priv->dev, "LED value %d is invalid", led->reg);
254			ret = -EINVAL;
255			goto err_child_out;
256		}
257
258		led->priv			  = priv;
259		led->ldev.max_brightness	  = LED_ON;
260		led->ldev.brightness_set_blocking = el15203000_set_blocking;
261
262		if (led->reg == 'S') {
263			led->ldev.pattern_set	= el15203000_pattern_set_S;
264			led->ldev.pattern_clear	= el15203000_pattern_clear;
265		} else if (led->reg == 'P') {
266			led->ldev.pattern_set	= el15203000_pattern_set_P;
267			led->ldev.pattern_clear	= el15203000_pattern_clear;
268		}
269
270		init_data.fwnode = child;
271		ret = devm_led_classdev_register_ext(priv->dev, &led->ldev,
272						     &init_data);
273		if (ret) {
274			dev_err(priv->dev,
275				"failed to register LED device %s, err %d",
276				led->ldev.name, ret);
277			goto err_child_out;
278		}
279
280		led++;
281	}
282
283	return 0;
284
285err_child_out:
286	fwnode_handle_put(child);
287	return ret;
288}
289
290static int el15203000_probe(struct spi_device *spi)
291{
292	struct el15203000	*priv;
293	size_t			count;
294
295	count = device_get_child_node_count(&spi->dev);
296	if (!count) {
297		dev_err(&spi->dev, "LEDs are not defined in device tree!");
298		return -ENODEV;
299	}
300
301	priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
302			    GFP_KERNEL);
303	if (!priv)
304		return -ENOMEM;
305
306	mutex_init(&priv->lock);
307	priv->count	= count;
308	priv->dev	= &spi->dev;
309	priv->spi	= spi;
310	priv->delay	= jiffies -
311			  usecs_to_jiffies(EL_FW_DELAY_USEC);
312
313	spi_set_drvdata(spi, priv);
314
315	return el15203000_probe_dt(priv);
316}
317
318static void el15203000_remove(struct spi_device *spi)
319{
320	struct el15203000 *priv = spi_get_drvdata(spi);
321
322	mutex_destroy(&priv->lock);
323}
324
325static const struct of_device_id el15203000_dt_ids[] = {
326	{ .compatible = "crane,el15203000", },
327	{},
328};
329
330MODULE_DEVICE_TABLE(of, el15203000_dt_ids);
331
332static struct spi_driver el15203000_driver = {
333	.probe		= el15203000_probe,
334	.remove		= el15203000_remove,
335	.driver = {
336		.name		= KBUILD_MODNAME,
337		.of_match_table	= el15203000_dt_ids,
338	},
339};
340
341module_spi_driver(el15203000_driver);
342
343MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
344MODULE_DESCRIPTION("el15203000 LED driver");
345MODULE_LICENSE("GPL v2");
346MODULE_ALIAS("spi:el15203000");
347