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Linux/drivers/leds/leds-wm831x-status.c

  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/init.h>
 14 #include <linux/platform_device.h>
 15 #include <linux/slab.h>
 16 #include <linux/leds.h>
 17 #include <linux/err.h>
 18 #include <linux/mfd/wm831x/core.h>
 19 #include <linux/mfd/wm831x/pdata.h>
 20 #include <linux/mfd/wm831x/status.h>
 21 #include <linux/module.h>
 22 
 23 
 24 struct wm831x_status {
 25         struct led_classdev cdev;
 26         struct wm831x *wm831x;
 27         struct work_struct work;
 28         struct mutex mutex;
 29 
 30         spinlock_t value_lock;
 31         int reg;     /* Control register */
 32         int reg_val; /* Control register value */
 33 
 34         int blink;
 35         int blink_time;
 36         int blink_cyc;
 37         int src;
 38         enum led_brightness brightness;
 39 };
 40 
 41 #define to_wm831x_status(led_cdev) \
 42         container_of(led_cdev, struct wm831x_status, cdev)
 43 
 44 static void wm831x_status_work(struct work_struct *work)
 45 {
 46         struct wm831x_status *led = container_of(work, struct wm831x_status,
 47                                                  work);
 48         unsigned long flags;
 49 
 50         mutex_lock(&led->mutex);
 51 
 52         led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
 53                           WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
 54 
 55         spin_lock_irqsave(&led->value_lock, flags);
 56 
 57         led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
 58         if (led->blink) {
 59                 led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
 60                 led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
 61                 led->reg_val |= led->blink_cyc;
 62         } else {
 63                 if (led->brightness != LED_OFF)
 64                         led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
 65         }
 66 
 67         spin_unlock_irqrestore(&led->value_lock, flags);
 68 
 69         wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
 70 
 71         mutex_unlock(&led->mutex);
 72 }
 73 
 74 static void wm831x_status_set(struct led_classdev *led_cdev,
 75                            enum led_brightness value)
 76 {
 77         struct wm831x_status *led = to_wm831x_status(led_cdev);
 78         unsigned long flags;
 79 
 80         spin_lock_irqsave(&led->value_lock, flags);
 81         led->brightness = value;
 82         if (value == LED_OFF)
 83                 led->blink = 0;
 84         schedule_work(&led->work);
 85         spin_unlock_irqrestore(&led->value_lock, flags);
 86 }
 87 
 88 static int wm831x_status_blink_set(struct led_classdev *led_cdev,
 89                                    unsigned long *delay_on,
 90                                    unsigned long *delay_off)
 91 {
 92         struct wm831x_status *led = to_wm831x_status(led_cdev);
 93         unsigned long flags;
 94         int ret = 0;
 95 
 96         /* Pick some defaults if we've not been given times */
 97         if (*delay_on == 0 && *delay_off == 0) {
 98                 *delay_on = 250;
 99                 *delay_off = 250;
100         }
101 
102         spin_lock_irqsave(&led->value_lock, flags);
103 
104         /* We only have a limited selection of settings, see if we can
105          * support the configuration we're being given */
106         switch (*delay_on) {
107         case 1000:
108                 led->blink_time = 0;
109                 break;
110         case 250:
111                 led->blink_time = 1;
112                 break;
113         case 125:
114                 led->blink_time = 2;
115                 break;
116         case 62:
117         case 63:
118                 /* Actually 62.5ms */
119                 led->blink_time = 3;
120                 break;
121         default:
122                 ret = -EINVAL;
123                 break;
124         }
125 
126         if (ret == 0) {
127                 switch (*delay_off / *delay_on) {
128                 case 1:
129                         led->blink_cyc = 0;
130                         break;
131                 case 3:
132                         led->blink_cyc = 1;
133                         break;
134                 case 4:
135                         led->blink_cyc = 2;
136                         break;
137                 case 8:
138                         led->blink_cyc = 3;
139                         break;
140                 default:
141                         ret = -EINVAL;
142                         break;
143                 }
144         }
145 
146         if (ret == 0)
147                 led->blink = 1;
148         else
149                 led->blink = 0;
150 
151         /* Always update; if we fail turn off blinking since we expect
152          * a software fallback. */
153         schedule_work(&led->work);
154 
155         spin_unlock_irqrestore(&led->value_lock, flags);
156 
157         return ret;
158 }
159 
160 static const char * const led_src_texts[] = {
161         "otp",
162         "power",
163         "charger",
164         "soft",
165 };
166 
167 static ssize_t wm831x_status_src_show(struct device *dev,
168                                       struct device_attribute *attr, char *buf)
169 {
170         struct led_classdev *led_cdev = dev_get_drvdata(dev);
171         struct wm831x_status *led = to_wm831x_status(led_cdev);
172         int i;
173         ssize_t ret = 0;
174 
175         mutex_lock(&led->mutex);
176 
177         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
178                 if (i == led->src)
179                         ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
180                 else
181                         ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
182 
183         mutex_unlock(&led->mutex);
184 
185         ret += sprintf(&buf[ret], "\n");
186 
187         return ret;
188 }
189 
190 static ssize_t wm831x_status_src_store(struct device *dev,
191                                        struct device_attribute *attr,
192                                        const char *buf, size_t size)
193 {
194         struct led_classdev *led_cdev = dev_get_drvdata(dev);
195         struct wm831x_status *led = to_wm831x_status(led_cdev);
196         char name[20];
197         int i;
198         size_t len;
199 
200         name[sizeof(name) - 1] = '\0';
201         strncpy(name, buf, sizeof(name) - 1);
202         len = strlen(name);
203 
204         if (len && name[len - 1] == '\n')
205                 name[len - 1] = '\0';
206 
207         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
208                 if (!strcmp(name, led_src_texts[i])) {
209                         mutex_lock(&led->mutex);
210 
211                         led->src = i;
212                         schedule_work(&led->work);
213 
214                         mutex_unlock(&led->mutex);
215                 }
216         }
217 
218         return size;
219 }
220 
221 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
222 
223 static int wm831x_status_probe(struct platform_device *pdev)
224 {
225         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
226         struct wm831x_pdata *chip_pdata;
227         struct wm831x_status_pdata pdata;
228         struct wm831x_status *drvdata;
229         struct resource *res;
230         int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
231         int ret;
232 
233         res = platform_get_resource(pdev, IORESOURCE_REG, 0);
234         if (res == NULL) {
235                 dev_err(&pdev->dev, "No register resource\n");
236                 ret = -EINVAL;
237                 goto err;
238         }
239 
240         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
241                                GFP_KERNEL);
242         if (!drvdata)
243                 return -ENOMEM;
244         platform_set_drvdata(pdev, drvdata);
245 
246         drvdata->wm831x = wm831x;
247         drvdata->reg = res->start;
248 
249         if (dev_get_platdata(wm831x->dev))
250                 chip_pdata = dev_get_platdata(wm831x->dev);
251         else
252                 chip_pdata = NULL;
253 
254         memset(&pdata, 0, sizeof(pdata));
255         if (chip_pdata && chip_pdata->status[id])
256                 memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
257         else
258                 pdata.name = dev_name(&pdev->dev);
259 
260         mutex_init(&drvdata->mutex);
261         INIT_WORK(&drvdata->work, wm831x_status_work);
262         spin_lock_init(&drvdata->value_lock);
263 
264         /* We cache the configuration register and read startup values
265          * from it. */
266         drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
267 
268         if (drvdata->reg_val & WM831X_LED_MODE_MASK)
269                 drvdata->brightness = LED_FULL;
270         else
271                 drvdata->brightness = LED_OFF;
272 
273         /* Set a default source if configured, otherwise leave the
274          * current hardware setting.
275          */
276         if (pdata.default_src == WM831X_STATUS_PRESERVE) {
277                 drvdata->src = drvdata->reg_val;
278                 drvdata->src &= WM831X_LED_SRC_MASK;
279                 drvdata->src >>= WM831X_LED_SRC_SHIFT;
280         } else {
281                 drvdata->src = pdata.default_src - 1;
282         }
283 
284         drvdata->cdev.name = pdata.name;
285         drvdata->cdev.default_trigger = pdata.default_trigger;
286         drvdata->cdev.brightness_set = wm831x_status_set;
287         drvdata->cdev.blink_set = wm831x_status_blink_set;
288 
289         ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
290         if (ret < 0) {
291                 dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
292                 goto err_led;
293         }
294 
295         ret = device_create_file(drvdata->cdev.dev, &dev_attr_src);
296         if (ret != 0)
297                 dev_err(&pdev->dev,
298                         "No source control for LED: %d\n", ret);
299 
300         return 0;
301 
302 err_led:
303         led_classdev_unregister(&drvdata->cdev);
304 err:
305         return ret;
306 }
307 
308 static int wm831x_status_remove(struct platform_device *pdev)
309 {
310         struct wm831x_status *drvdata = platform_get_drvdata(pdev);
311 
312         device_remove_file(drvdata->cdev.dev, &dev_attr_src);
313         led_classdev_unregister(&drvdata->cdev);
314 
315         return 0;
316 }
317 
318 static struct platform_driver wm831x_status_driver = {
319         .driver = {
320                    .name = "wm831x-status",
321                    .owner = THIS_MODULE,
322                    },
323         .probe = wm831x_status_probe,
324         .remove = wm831x_status_remove,
325 };
326 
327 module_platform_driver(wm831x_status_driver);
328 
329 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
330 MODULE_DESCRIPTION("WM831x status LED driver");
331 MODULE_LICENSE("GPL");
332 MODULE_ALIAS("platform:wm831x-status");
333 

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