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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/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 
 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 
 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 
 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 
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 
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 
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 
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 

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