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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 mutex mutex;
 27 
 28         spinlock_t value_lock;
 29         int reg;     /* Control register */
 30         int reg_val; /* Control register value */
 31 
 32         int blink;
 33         int blink_time;
 34         int blink_cyc;
 35         int src;
 36         enum led_brightness brightness;
 37 };
 38 
 39 #define to_wm831x_status(led_cdev) \
 40         container_of(led_cdev, struct wm831x_status, cdev)
 41 
 42 static void wm831x_status_set(struct wm831x_status *led)
 43 {
 44         unsigned long flags;
 45 
 46         mutex_lock(&led->mutex);
 47 
 48         led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
 49                           WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
 50 
 51         spin_lock_irqsave(&led->value_lock, flags);
 52 
 53         led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
 54         if (led->blink) {
 55                 led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
 56                 led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
 57                 led->reg_val |= led->blink_cyc;
 58         } else {
 59                 if (led->brightness != LED_OFF)
 60                         led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
 61         }
 62 
 63         spin_unlock_irqrestore(&led->value_lock, flags);
 64 
 65         wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
 66 
 67         mutex_unlock(&led->mutex);
 68 }
 69 
 70 static int wm831x_status_brightness_set(struct led_classdev *led_cdev,
 71                                          enum led_brightness value)
 72 {
 73         struct wm831x_status *led = to_wm831x_status(led_cdev);
 74         unsigned long flags;
 75 
 76         spin_lock_irqsave(&led->value_lock, flags);
 77         led->brightness = value;
 78         if (value == LED_OFF)
 79                 led->blink = 0;
 80         spin_unlock_irqrestore(&led->value_lock, flags);
 81         wm831x_status_set(led);
 82 
 83         return 0;
 84 }
 85 
 86 static int wm831x_status_blink_set(struct led_classdev *led_cdev,
 87                                    unsigned long *delay_on,
 88                                    unsigned long *delay_off)
 89 {
 90         struct wm831x_status *led = to_wm831x_status(led_cdev);
 91         unsigned long flags;
 92         int ret = 0;
 93 
 94         /* Pick some defaults if we've not been given times */
 95         if (*delay_on == 0 && *delay_off == 0) {
 96                 *delay_on = 250;
 97                 *delay_off = 250;
 98         }
 99 
100         spin_lock_irqsave(&led->value_lock, flags);
101 
102         /* We only have a limited selection of settings, see if we can
103          * support the configuration we're being given */
104         switch (*delay_on) {
105         case 1000:
106                 led->blink_time = 0;
107                 break;
108         case 250:
109                 led->blink_time = 1;
110                 break;
111         case 125:
112                 led->blink_time = 2;
113                 break;
114         case 62:
115         case 63:
116                 /* Actually 62.5ms */
117                 led->blink_time = 3;
118                 break;
119         default:
120                 ret = -EINVAL;
121                 break;
122         }
123 
124         if (ret == 0) {
125                 switch (*delay_off / *delay_on) {
126                 case 1:
127                         led->blink_cyc = 0;
128                         break;
129                 case 3:
130                         led->blink_cyc = 1;
131                         break;
132                 case 4:
133                         led->blink_cyc = 2;
134                         break;
135                 case 8:
136                         led->blink_cyc = 3;
137                         break;
138                 default:
139                         ret = -EINVAL;
140                         break;
141                 }
142         }
143 
144         if (ret == 0)
145                 led->blink = 1;
146         else
147                 led->blink = 0;
148 
149         spin_unlock_irqrestore(&led->value_lock, flags);
150         wm831x_status_set(led);
151 
152         return ret;
153 }
154 
155 static const char * const led_src_texts[] = {
156         "otp",
157         "power",
158         "charger",
159         "soft",
160 };
161 
162 static ssize_t wm831x_status_src_show(struct device *dev,
163                                       struct device_attribute *attr, char *buf)
164 {
165         struct led_classdev *led_cdev = dev_get_drvdata(dev);
166         struct wm831x_status *led = to_wm831x_status(led_cdev);
167         int i;
168         ssize_t ret = 0;
169 
170         mutex_lock(&led->mutex);
171 
172         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
173                 if (i == led->src)
174                         ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
175                 else
176                         ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
177 
178         mutex_unlock(&led->mutex);
179 
180         ret += sprintf(&buf[ret], "\n");
181 
182         return ret;
183 }
184 
185 static ssize_t wm831x_status_src_store(struct device *dev,
186                                        struct device_attribute *attr,
187                                        const char *buf, size_t size)
188 {
189         struct led_classdev *led_cdev = dev_get_drvdata(dev);
190         struct wm831x_status *led = to_wm831x_status(led_cdev);
191         char name[20];
192         int i;
193         size_t len;
194 
195         name[sizeof(name) - 1] = '\0';
196         strncpy(name, buf, sizeof(name) - 1);
197         len = strlen(name);
198 
199         if (len && name[len - 1] == '\n')
200                 name[len - 1] = '\0';
201 
202         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
203                 if (!strcmp(name, led_src_texts[i])) {
204                         mutex_lock(&led->mutex);
205                         led->src = i;
206                         mutex_unlock(&led->mutex);
207                         wm831x_status_set(led);
208                 }
209         }
210 
211         return size;
212 }
213 
214 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
215 
216 static struct attribute *wm831x_status_attrs[] = {
217         &dev_attr_src.attr,
218         NULL
219 };
220 ATTRIBUTE_GROUPS(wm831x_status);
221 
222 static int wm831x_status_probe(struct platform_device *pdev)
223 {
224         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
225         struct wm831x_pdata *chip_pdata;
226         struct wm831x_status_pdata pdata;
227         struct wm831x_status *drvdata;
228         struct resource *res;
229         int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
230         int ret;
231 
232         res = platform_get_resource(pdev, IORESOURCE_REG, 0);
233         if (res == NULL) {
234                 dev_err(&pdev->dev, "No register resource\n");
235                 return -EINVAL;
236         }
237 
238         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
239                                GFP_KERNEL);
240         if (!drvdata)
241                 return -ENOMEM;
242 
243         drvdata->wm831x = wm831x;
244         drvdata->reg = res->start;
245 
246         if (dev_get_platdata(wm831x->dev))
247                 chip_pdata = dev_get_platdata(wm831x->dev);
248         else
249                 chip_pdata = NULL;
250 
251         memset(&pdata, 0, sizeof(pdata));
252         if (chip_pdata && chip_pdata->status[id])
253                 memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
254         else
255                 pdata.name = dev_name(&pdev->dev);
256 
257         mutex_init(&drvdata->mutex);
258         spin_lock_init(&drvdata->value_lock);
259 
260         /* We cache the configuration register and read startup values
261          * from it. */
262         drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
263 
264         if (drvdata->reg_val & WM831X_LED_MODE_MASK)
265                 drvdata->brightness = LED_FULL;
266         else
267                 drvdata->brightness = LED_OFF;
268 
269         /* Set a default source if configured, otherwise leave the
270          * current hardware setting.
271          */
272         if (pdata.default_src == WM831X_STATUS_PRESERVE) {
273                 drvdata->src = drvdata->reg_val;
274                 drvdata->src &= WM831X_LED_SRC_MASK;
275                 drvdata->src >>= WM831X_LED_SRC_SHIFT;
276         } else {
277                 drvdata->src = pdata.default_src - 1;
278         }
279 
280         drvdata->cdev.name = pdata.name;
281         drvdata->cdev.default_trigger = pdata.default_trigger;
282         drvdata->cdev.brightness_set_blocking = wm831x_status_brightness_set;
283         drvdata->cdev.blink_set = wm831x_status_blink_set;
284         drvdata->cdev.groups = wm831x_status_groups;
285 
286         ret = devm_led_classdev_register(wm831x->dev, &drvdata->cdev);
287         if (ret < 0) {
288                 dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
289                 return ret;
290         }
291 
292         return 0;
293 }
294 
295 static struct platform_driver wm831x_status_driver = {
296         .driver = {
297                    .name = "wm831x-status",
298                    },
299         .probe = wm831x_status_probe,
300 };
301 
302 module_platform_driver(wm831x_status_driver);
303 
304 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
305 MODULE_DESCRIPTION("WM831x status LED driver");
306 MODULE_LICENSE("GPL");
307 MODULE_ALIAS("platform:wm831x-status");
308 

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