xref: /linux/drivers/leds/leds-wm831x-status.c (revision 04eeb606a8383b306f4bc6991da8231b5f3924b0)
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