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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>
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32
33#define CR_SET_BRIGHTNESS 0x80
34#define CR_INIT_REENUMERATE 0x81
35#define CR_NEXT_REENUMERATE 0x82
36
37
38#define CR_MAX_BRIGHTNESS GENMASK(6, 0)
39#define CR_FW_DELAY_MSEC 10
40#define CR_RECOUNT_DELAY (HZ * 3600)
41
42#define CR_DEV_NAME "cr0014114"
43
44struct cr0014114_led {
45 struct cr0014114 *priv;
46 struct led_classdev ldev;
47 u8 brightness;
48};
49
50struct 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
62static 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
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
80static 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
102err:
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
111static int cr0014114_sync(struct cr0014114 *priv)
112{
113 int ret;
114 size_t i;
115 unsigned long udelay, now = jiffies;
116
117
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
138err:
139 priv->delay = jiffies + msecs_to_jiffies(CR_FW_DELAY_MSEC);
140
141 return ret;
142}
143
144static 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
162static 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 to %d\n", brightness);
171
172 mutex_lock(&led->priv->lock);
173 led->brightness = (u8)brightness;
174 ret = cr0014114_sync(led->priv);
175 mutex_unlock(&led->priv->lock);
176
177 return ret;
178}
179
180static int cr0014114_probe_dt(struct cr0014114 *priv)
181{
182 size_t i = 0;
183 struct cr0014114_led *led;
184 struct fwnode_handle *child;
185 struct led_init_data init_data = {};
186 int ret;
187
188 device_for_each_child_node(priv->dev, child) {
189 led = &priv->leds[i];
190
191 fwnode_property_read_string(child, "linux,default-trigger",
192 &led->ldev.default_trigger);
193
194 led->priv = priv;
195 led->ldev.max_brightness = CR_MAX_BRIGHTNESS;
196 led->ldev.brightness_set_blocking = cr0014114_set_sync;
197
198 init_data.fwnode = child;
199 init_data.devicename = CR_DEV_NAME;
200 init_data.default_label = ":";
201
202 ret = devm_led_classdev_register_ext(priv->dev, &led->ldev,
203 &init_data);
204 if (ret) {
205 dev_err(priv->dev,
206 "failed to register LED device, err %d", ret);
207 fwnode_handle_put(child);
208 return ret;
209 }
210
211 i++;
212 }
213
214 return 0;
215}
216
217static int cr0014114_probe(struct spi_device *spi)
218{
219 struct cr0014114 *priv;
220 size_t count;
221 int ret;
222
223 count = device_get_child_node_count(&spi->dev);
224 if (!count) {
225 dev_err(&spi->dev, "LEDs are not defined in device tree!");
226 return -ENODEV;
227 }
228
229 priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
230 GFP_KERNEL);
231 if (!priv)
232 return -ENOMEM;
233
234 priv->buf = devm_kzalloc(&spi->dev, count + 2, GFP_KERNEL);
235 if (!priv->buf)
236 return -ENOMEM;
237
238 mutex_init(&priv->lock);
239 INIT_DELAYED_WORK(&priv->work, cr0014114_recount_work);
240 priv->count = count;
241 priv->dev = &spi->dev;
242 priv->spi = spi;
243 priv->delay = jiffies -
244 msecs_to_jiffies(CR_FW_DELAY_MSEC);
245
246 priv->do_recount = true;
247 ret = cr0014114_sync(priv);
248 if (ret) {
249 dev_err(priv->dev, "first recount failed %d\n", ret);
250 return ret;
251 }
252
253 priv->do_recount = true;
254 ret = cr0014114_sync(priv);
255 if (ret) {
256 dev_err(priv->dev, "second recount failed %d\n", ret);
257 return ret;
258 }
259
260 ret = cr0014114_probe_dt(priv);
261 if (ret)
262 return ret;
263
264
265 schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);
266
267 spi_set_drvdata(spi, priv);
268
269 return 0;
270}
271
272static int cr0014114_remove(struct spi_device *spi)
273{
274 struct cr0014114 *priv = spi_get_drvdata(spi);
275
276 cancel_delayed_work_sync(&priv->work);
277 mutex_destroy(&priv->lock);
278
279 return 0;
280}
281
282static const struct of_device_id cr0014114_dt_ids[] = {
283 { .compatible = "crane,cr0014114", },
284 {},
285};
286
287MODULE_DEVICE_TABLE(of, cr0014114_dt_ids);
288
289static struct spi_driver cr0014114_driver = {
290 .probe = cr0014114_probe,
291 .remove = cr0014114_remove,
292 .driver = {
293 .name = KBUILD_MODNAME,
294 .of_match_table = cr0014114_dt_ids,
295 },
296};
297
298module_spi_driver(cr0014114_driver);
299
300MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
301MODULE_DESCRIPTION("cr0014114 LED driver");
302MODULE_LICENSE("GPL v2");
303MODULE_ALIAS("spi:cr0014114");
304
