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leds: Use struct_size() in allocation
[linux-2.6/btrfs-unstable.git] / drivers / leds / leds-cr0014114.c
blob0e4262462cb9d34ca1a6a767b1ad813cd537bcb2
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2018 Crane Merchandising Systems. All rights reserved.
3 // Copyright (C) 2018 Oleh Kravchenko <oleg@kaa.org.ua>
4
5 #include <linux/delay.h>
6 #include <linux/leds.h>
7 #include <linux/module.h>
8 #include <linux/of_device.h>
9 #include <linux/spi/spi.h>
10 #include <linux/workqueue.h>
11 #include <uapi/linux/uleds.h>
12
13 /*
14 * CR0014114 SPI protocol descrtiption:
15 * +----+-----------------------------------+----+
16 * | CMD| BRIGHTNESS |CRC |
17 * +----+-----------------------------------+----+
18 * | | LED0| LED1| LED2| LED3| LED4| LED5| |
19 * | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
20 * | |R|G|B|R|G|B|R|G|B|R|G|B|R|G|B|R|G|B| |
21 * | 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1 |
22 * | |1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1| |
23 * | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
24 * | | 18 | |
25 * +----+-----------------------------------+----+
26 * | 20 |
27 * +---------------------------------------------+
28 *
29 * PS: Boards can be connected to the chain:
30 * SPI -> board0 -> board1 -> board2 ..
31 */
32
33 /* CR0014114 SPI commands */
34 #define CR_SET_BRIGHTNESS 0x80
35 #define CR_INIT_REENUMERATE 0x81
36 #define CR_NEXT_REENUMERATE 0x82
37
38 /* CR0014114 default settings */
39 #define CR_MAX_BRIGHTNESS GENMASK(6, 0)
40 #define CR_FW_DELAY_MSEC 10
41 #define CR_RECOUNT_DELAY (HZ * 3600)
42
43 struct cr0014114_led {
44 char name[LED_MAX_NAME_SIZE];
45 struct cr0014114 *priv;
46 struct led_classdev ldev;
47 u8 brightness;
48 };
49
50 struct cr0014114 {
51 bool do_recount;
52 size_t count;
53 struct delayed_work work;
54 struct device *dev;
55 struct mutex lock;
56 struct spi_device *spi;
57 u8 *buf;
58 unsigned long delay;
59 struct cr0014114_led leds[];
60 };
61
62 static void cr0014114_calc_crc(u8 *buf, const size_t len)
63 {
64 size_t i;
65 u8 crc;
66
67 for (i = 1, crc = 1; i < len - 1; i++)
68 crc += buf[i];
69 crc |= BIT(7);
70
71 /* special case when CRC matches the SPI commands */
72 if (crc == CR_SET_BRIGHTNESS ||
73 crc == CR_INIT_REENUMERATE ||
74 crc == CR_NEXT_REENUMERATE)
75 crc = 0xfe;
76
77 buf[len - 1] = crc;
78 }
79
80 static int cr0014114_recount(struct cr0014114 *priv)
81 {
82 int ret;
83 size_t i;
84 u8 cmd;
85
86 dev_dbg(priv->dev, "LEDs recount is started\n");
87
88 cmd = CR_INIT_REENUMERATE;
89 ret = spi_write(priv->spi, &cmd, sizeof(cmd));
90 if (ret)
91 goto err;
92
93 cmd = CR_NEXT_REENUMERATE;
94 for (i = 0; i < priv->count; i++) {
95 msleep(CR_FW_DELAY_MSEC);
96
97 ret = spi_write(priv->spi, &cmd, sizeof(cmd));
98 if (ret)
99 goto err;
100 }
101
102 err:
103 dev_dbg(priv->dev, "LEDs recount is finished\n");
104
105 if (ret)
106 dev_err(priv->dev, "with error %d", ret);
107
108 return ret;
109 }
110
111 static int cr0014114_sync(struct cr0014114 *priv)
112 {
113 int ret;
114 size_t i;
115 unsigned long udelay, now = jiffies;
116
117 /* to avoid SPI mistiming with firmware we should wait some time */
118 if (time_after(priv->delay, now)) {
119 udelay = jiffies_to_usecs(priv->delay - now);
120 usleep_range(udelay, udelay + 1);
121 }
122
123 if (unlikely(priv->do_recount)) {
124 ret = cr0014114_recount(priv);
125 if (ret)
126 goto err;
127
128 priv->do_recount = false;
129 msleep(CR_FW_DELAY_MSEC);
130 }
131
132 priv->buf[0] = CR_SET_BRIGHTNESS;
133 for (i = 0; i < priv->count; i++)
134 priv->buf[i + 1] = priv->leds[i].brightness;
135 cr0014114_calc_crc(priv->buf, priv->count + 2);
136 ret = spi_write(priv->spi, priv->buf, priv->count + 2);
137
138 err:
139 priv->delay = jiffies + msecs_to_jiffies(CR_FW_DELAY_MSEC);
140
141 return ret;
142 }
143
144 static void cr0014114_recount_work(struct work_struct *work)
145 {
146 int ret;
147 struct cr0014114 *priv = container_of(work,
148 struct cr0014114,
149 work.work);
150
151 mutex_lock(&priv->lock);
152 priv->do_recount = true;
153 ret = cr0014114_sync(priv);
154 mutex_unlock(&priv->lock);
155
156 if (ret)
157 dev_warn(priv->dev, "sync of LEDs failed %d\n", ret);
158
159 schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);
160 }
161
162 static int cr0014114_set_sync(struct led_classdev *ldev,
163 enum led_brightness brightness)
164 {
165 int ret;
166 struct cr0014114_led *led = container_of(ldev,
167 struct cr0014114_led,
168 ldev);
169
170 dev_dbg(led->priv->dev, "Set brightness of %s to %d\n",
171 led->name, brightness);
172
173 mutex_lock(&led->priv->lock);
174 led->brightness = (u8)brightness;
175 ret = cr0014114_sync(led->priv);
176 mutex_unlock(&led->priv->lock);
177
178 return ret;
179 }
180
181 static int cr0014114_probe_dt(struct cr0014114 *priv)
182 {
183 size_t i = 0;
184 struct cr0014114_led *led;
185 struct fwnode_handle *child;
186 struct device_node *np;
187 int ret;
188 const char *str;
189
190 device_for_each_child_node(priv->dev, child) {
191 np = to_of_node(child);
192 led = &priv->leds[i];
193
194 ret = fwnode_property_read_string(child, "label", &str);
195 if (ret)
196 snprintf(led->name, sizeof(led->name),
197 "cr0014114::");
198 else
199 snprintf(led->name, sizeof(led->name),
200 "cr0014114:%s", str);
201
202 fwnode_property_read_string(child, "linux,default-trigger",
203 &led->ldev.default_trigger);
204
205 led->priv = priv;
206 led->ldev.name = led->name;
207 led->ldev.max_brightness = CR_MAX_BRIGHTNESS;
208 led->ldev.brightness_set_blocking = cr0014114_set_sync;
209
210 ret = devm_of_led_classdev_register(priv->dev, np,
211 &led->ldev);
212 if (ret) {
213 dev_err(priv->dev,
214 "failed to register LED device %s, err %d",
215 led->name, ret);
216 fwnode_handle_put(child);
217 return ret;
218 }
219
220 led->ldev.dev->of_node = np;
221
222 i++;
223 }
224
225 return 0;
226 }
227
228 static int cr0014114_probe(struct spi_device *spi)
229 {
230 struct cr0014114 *priv;
231 size_t count;
232 int ret;
233
234 count = device_get_child_node_count(&spi->dev);
235 if (!count) {
236 dev_err(&spi->dev, "LEDs are not defined in device tree!");
237 return -ENODEV;
238 }
239
240 priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
241 GFP_KERNEL);
242 if (!priv)
243 return -ENOMEM;
244
245 priv->buf = devm_kzalloc(&spi->dev, count + 2, GFP_KERNEL);
246 if (!priv->buf)
247 return -ENOMEM;
248
249 mutex_init(&priv->lock);
250 INIT_DELAYED_WORK(&priv->work, cr0014114_recount_work);
251 priv->count = count;
252 priv->dev = &spi->dev;
253 priv->spi = spi;
254 priv->delay = jiffies -
255 msecs_to_jiffies(CR_FW_DELAY_MSEC);
256
257 priv->do_recount = true;
258 ret = cr0014114_sync(priv);
259 if (ret) {
260 dev_err(priv->dev, "first recount failed %d\n", ret);
261 return ret;
262 }
263
264 priv->do_recount = true;
265 ret = cr0014114_sync(priv);
266 if (ret) {
267 dev_err(priv->dev, "second recount failed %d\n", ret);
268 return ret;
269 }
270
271 ret = cr0014114_probe_dt(priv);
272 if (ret)
273 return ret;
274
275 /* setup recount work to workaround buggy firmware */
276 schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);
277
278 spi_set_drvdata(spi, priv);
279
280 return 0;
281 }
282
283 static int cr0014114_remove(struct spi_device *spi)
284 {
285 struct cr0014114 *priv = spi_get_drvdata(spi);
286
287 cancel_delayed_work_sync(&priv->work);
288 mutex_destroy(&priv->lock);
289
290 return 0;
291 }
292
293 static const struct of_device_id cr0014114_dt_ids[] = {
294 { .compatible = "crane,cr0014114", },
295 {},
296 };
297
298 MODULE_DEVICE_TABLE(of, cr0014114_dt_ids);
299
300 static struct spi_driver cr0014114_driver = {
301 .probe = cr0014114_probe,
302 .remove = cr0014114_remove,
303 .driver = {
304 .name = KBUILD_MODNAME,
305 .of_match_table = cr0014114_dt_ids,
306 },
307 };
308
309 module_spi_driver(cr0014114_driver);
310
311 MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
312 MODULE_DESCRIPTION("cr0014114 LED driver");
313 MODULE_LICENSE("GPL v2");
314 MODULE_ALIAS("spi:cr0014114");
(deprecated) Btrfs devel tree