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 
56 enum 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 
71 struct el15203000_led {
72 	struct led_classdev	ldev;
73 	struct el15203000	*priv;
74 	u32			reg;
75 };
76 
77 struct 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[];
84 };
85 
86 #define to_el15203000_led(d)	container_of(d, struct el15203000_led, ldev)
87 
88 static 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 
131 static 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 
139 static 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 
156 static 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 
180 static 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 
190 static 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 
230 static 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 
237 static 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 
285 err_child_out:
286 	fwnode_handle_put(child);
287 	return ret;
288 }
289 
290 static 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 
318 static int el15203000_remove(struct spi_device *spi)
319 {
320 	struct el15203000 *priv = spi_get_drvdata(spi);
321 
322 	mutex_destroy(&priv->lock);
323 
324 	return 0;
325 }
326 
327 static const struct of_device_id el15203000_dt_ids[] = {
328 	{ .compatible = "crane,el15203000", },
329 	{},
330 };
331 
332 MODULE_DEVICE_TABLE(of, el15203000_dt_ids);
333 
334 static struct spi_driver el15203000_driver = {
335 	.probe		= el15203000_probe,
336 	.remove		= el15203000_remove,
337 	.driver = {
338 		.name		= KBUILD_MODNAME,
339 		.of_match_table	= el15203000_dt_ids,
340 	},
341 };
342 
343 module_spi_driver(el15203000_driver);
344 
345 MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
346 MODULE_DESCRIPTION("el15203000 LED driver");
347 MODULE_LICENSE("GPL v2");
348 MODULE_ALIAS("spi:el15203000");
349