1 /*
2 * LED driver for WM831x status LEDs
3 *
4 * Copyright(C) 2009 Wolfson Microelectronics PLC.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/platform_device.h>
14 #include <linux/slab.h>
15 #include <linux/leds.h>
16 #include <linux/err.h>
17 #include <linux/mfd/wm831x/core.h>
18 #include <linux/mfd/wm831x/pdata.h>
19 #include <linux/mfd/wm831x/status.h>
20 #include <linux/module.h>
21
22
23 struct wm831x_status {
24 struct led_classdev cdev;
25 struct wm831x *wm831x;
26 struct work_struct work;
27 struct mutex mutex;
28
29 spinlock_t value_lock;
30 int reg; /* Control register */
31 int reg_val; /* Control register value */
32
33 int blink;
34 int blink_time;
35 int blink_cyc;
36 int src;
37 enum led_brightness brightness;
38 };
39
40 #define to_wm831x_status(led_cdev) \
41 container_of(led_cdev, struct wm831x_status, cdev)
42
wm831x_status_work(struct work_struct * work)43 static void wm831x_status_work(struct work_struct *work)
44 {
45 struct wm831x_status *led = container_of(work, struct wm831x_status,
46 work);
47 unsigned long flags;
48
49 mutex_lock(&led->mutex);
50
51 led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
52 WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
53
54 spin_lock_irqsave(&led->value_lock, flags);
55
56 led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
57 if (led->blink) {
58 led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
59 led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
60 led->reg_val |= led->blink_cyc;
61 } else {
62 if (led->brightness != LED_OFF)
63 led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
64 }
65
66 spin_unlock_irqrestore(&led->value_lock, flags);
67
68 wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
69
70 mutex_unlock(&led->mutex);
71 }
72
wm831x_status_set(struct led_classdev * led_cdev,enum led_brightness value)73 static void wm831x_status_set(struct led_classdev *led_cdev,
74 enum led_brightness value)
75 {
76 struct wm831x_status *led = to_wm831x_status(led_cdev);
77 unsigned long flags;
78
79 spin_lock_irqsave(&led->value_lock, flags);
80 led->brightness = value;
81 if (value == LED_OFF)
82 led->blink = 0;
83 schedule_work(&led->work);
84 spin_unlock_irqrestore(&led->value_lock, flags);
85 }
86
wm831x_status_blink_set(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off)87 static int wm831x_status_blink_set(struct led_classdev *led_cdev,
88 unsigned long *delay_on,
89 unsigned long *delay_off)
90 {
91 struct wm831x_status *led = to_wm831x_status(led_cdev);
92 unsigned long flags;
93 int ret = 0;
94
95 /* Pick some defaults if we've not been given times */
96 if (*delay_on == 0 && *delay_off == 0) {
97 *delay_on = 250;
98 *delay_off = 250;
99 }
100
101 spin_lock_irqsave(&led->value_lock, flags);
102
103 /* We only have a limited selection of settings, see if we can
104 * support the configuration we're being given */
105 switch (*delay_on) {
106 case 1000:
107 led->blink_time = 0;
108 break;
109 case 250:
110 led->blink_time = 1;
111 break;
112 case 125:
113 led->blink_time = 2;
114 break;
115 case 62:
116 case 63:
117 /* Actually 62.5ms */
118 led->blink_time = 3;
119 break;
120 default:
121 ret = -EINVAL;
122 break;
123 }
124
125 if (ret == 0) {
126 switch (*delay_off / *delay_on) {
127 case 1:
128 led->blink_cyc = 0;
129 break;
130 case 3:
131 led->blink_cyc = 1;
132 break;
133 case 4:
134 led->blink_cyc = 2;
135 break;
136 case 8:
137 led->blink_cyc = 3;
138 break;
139 default:
140 ret = -EINVAL;
141 break;
142 }
143 }
144
145 if (ret == 0)
146 led->blink = 1;
147 else
148 led->blink = 0;
149
150 /* Always update; if we fail turn off blinking since we expect
151 * a software fallback. */
152 schedule_work(&led->work);
153
154 spin_unlock_irqrestore(&led->value_lock, flags);
155
156 return ret;
157 }
158
159 static const char * const led_src_texts[] = {
160 "otp",
161 "power",
162 "charger",
163 "soft",
164 };
165
wm831x_status_src_show(struct device * dev,struct device_attribute * attr,char * buf)166 static ssize_t wm831x_status_src_show(struct device *dev,
167 struct device_attribute *attr, char *buf)
168 {
169 struct led_classdev *led_cdev = dev_get_drvdata(dev);
170 struct wm831x_status *led = to_wm831x_status(led_cdev);
171 int i;
172 ssize_t ret = 0;
173
174 mutex_lock(&led->mutex);
175
176 for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
177 if (i == led->src)
178 ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
179 else
180 ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
181
182 mutex_unlock(&led->mutex);
183
184 ret += sprintf(&buf[ret], "\n");
185
186 return ret;
187 }
188
wm831x_status_src_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)189 static ssize_t wm831x_status_src_store(struct device *dev,
190 struct device_attribute *attr,
191 const char *buf, size_t size)
192 {
193 struct led_classdev *led_cdev = dev_get_drvdata(dev);
194 struct wm831x_status *led = to_wm831x_status(led_cdev);
195 char name[20];
196 int i;
197 size_t len;
198
199 name[sizeof(name) - 1] = '\0';
200 strncpy(name, buf, sizeof(name) - 1);
201 len = strlen(name);
202
203 if (len && name[len - 1] == '\n')
204 name[len - 1] = '\0';
205
206 for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
207 if (!strcmp(name, led_src_texts[i])) {
208 mutex_lock(&led->mutex);
209
210 led->src = i;
211 schedule_work(&led->work);
212
213 mutex_unlock(&led->mutex);
214 }
215 }
216
217 return size;
218 }
219
220 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
221
222 static struct attribute *wm831x_status_attrs[] = {
223 &dev_attr_src.attr,
224 NULL
225 };
226 ATTRIBUTE_GROUPS(wm831x_status);
227
wm831x_status_probe(struct platform_device * pdev)228 static int wm831x_status_probe(struct platform_device *pdev)
229 {
230 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
231 struct wm831x_pdata *chip_pdata;
232 struct wm831x_status_pdata pdata;
233 struct wm831x_status *drvdata;
234 struct resource *res;
235 int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
236 int ret;
237
238 res = platform_get_resource(pdev, IORESOURCE_REG, 0);
239 if (res == NULL) {
240 dev_err(&pdev->dev, "No register resource\n");
241 return -EINVAL;
242 }
243
244 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
245 GFP_KERNEL);
246 if (!drvdata)
247 return -ENOMEM;
248 platform_set_drvdata(pdev, drvdata);
249
250 drvdata->wm831x = wm831x;
251 drvdata->reg = res->start;
252
253 if (dev_get_platdata(wm831x->dev))
254 chip_pdata = dev_get_platdata(wm831x->dev);
255 else
256 chip_pdata = NULL;
257
258 memset(&pdata, 0, sizeof(pdata));
259 if (chip_pdata && chip_pdata->status[id])
260 memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
261 else
262 pdata.name = dev_name(&pdev->dev);
263
264 mutex_init(&drvdata->mutex);
265 INIT_WORK(&drvdata->work, wm831x_status_work);
266 spin_lock_init(&drvdata->value_lock);
267
268 /* We cache the configuration register and read startup values
269 * from it. */
270 drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
271
272 if (drvdata->reg_val & WM831X_LED_MODE_MASK)
273 drvdata->brightness = LED_FULL;
274 else
275 drvdata->brightness = LED_OFF;
276
277 /* Set a default source if configured, otherwise leave the
278 * current hardware setting.
279 */
280 if (pdata.default_src == WM831X_STATUS_PRESERVE) {
281 drvdata->src = drvdata->reg_val;
282 drvdata->src &= WM831X_LED_SRC_MASK;
283 drvdata->src >>= WM831X_LED_SRC_SHIFT;
284 } else {
285 drvdata->src = pdata.default_src - 1;
286 }
287
288 drvdata->cdev.name = pdata.name;
289 drvdata->cdev.default_trigger = pdata.default_trigger;
290 drvdata->cdev.brightness_set = wm831x_status_set;
291 drvdata->cdev.blink_set = wm831x_status_blink_set;
292 drvdata->cdev.groups = wm831x_status_groups;
293
294 ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
295 if (ret < 0) {
296 dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
297 return ret;
298 }
299
300 return 0;
301 }
302
wm831x_status_remove(struct platform_device * pdev)303 static int wm831x_status_remove(struct platform_device *pdev)
304 {
305 struct wm831x_status *drvdata = platform_get_drvdata(pdev);
306
307 led_classdev_unregister(&drvdata->cdev);
308
309 return 0;
310 }
311
312 static struct platform_driver wm831x_status_driver = {
313 .driver = {
314 .name = "wm831x-status",
315 .owner = THIS_MODULE,
316 },
317 .probe = wm831x_status_probe,
318 .remove = wm831x_status_remove,
319 };
320
321 module_platform_driver(wm831x_status_driver);
322
323 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
324 MODULE_DESCRIPTION("WM831x status LED driver");
325 MODULE_LICENSE("GPL");
326 MODULE_ALIAS("platform:wm831x-status");
327