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/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 
21 
22 struct wm831x_status {
23 	struct led_classdev cdev;
24 	struct wm831x *wm831x;
25 	struct work_struct work;
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_work(struct work_struct *work)
43 {
44 	struct wm831x_status *led = container_of(work, struct wm831x_status,
45 						 work);
46 	unsigned long flags;
47 
48 	mutex_lock(&led->mutex);
49 
50 	led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
51 			  WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
52 
53 	spin_lock_irqsave(&led->value_lock, flags);
54 
55 	led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
56 	if (led->blink) {
57 		led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
58 		led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
59 		led->reg_val |= led->blink_cyc;
60 	} else {
61 		if (led->brightness != LED_OFF)
62 			led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
63 	}
64 
65 	spin_unlock_irqrestore(&led->value_lock, flags);
66 
67 	wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
68 
69 	mutex_unlock(&led->mutex);
70 }
71 
72 static void wm831x_status_set(struct led_classdev *led_cdev,
73 			   enum led_brightness value)
74 {
75 	struct wm831x_status *led = to_wm831x_status(led_cdev);
76 	unsigned long flags;
77 
78 	spin_lock_irqsave(&led->value_lock, flags);
79 	led->brightness = value;
80 	if (value == LED_OFF)
81 		led->blink = 0;
82 	schedule_work(&led->work);
83 	spin_unlock_irqrestore(&led->value_lock, flags);
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 	/* Always update; if we fail turn off blinking since we expect
150 	 * a software fallback. */
151 	schedule_work(&led->work);
152 
153 	spin_unlock_irqrestore(&led->value_lock, flags);
154 
155 	return ret;
156 }
157 
158 static const char *led_src_texts[] = {
159 	"otp",
160 	"power",
161 	"charger",
162 	"soft",
163 };
164 
165 static ssize_t wm831x_status_src_show(struct device *dev,
166 				      struct device_attribute *attr, char *buf)
167 {
168 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
169 	struct wm831x_status *led = to_wm831x_status(led_cdev);
170 	int i;
171 	ssize_t ret = 0;
172 
173 	mutex_lock(&led->mutex);
174 
175 	for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
176 		if (i == led->src)
177 			ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
178 		else
179 			ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
180 
181 	mutex_unlock(&led->mutex);
182 
183 	ret += sprintf(&buf[ret], "\n");
184 
185 	return ret;
186 }
187 
188 static ssize_t wm831x_status_src_store(struct device *dev,
189 				       struct device_attribute *attr,
190 				       const char *buf, size_t size)
191 {
192 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
193 	struct wm831x_status *led = to_wm831x_status(led_cdev);
194 	char name[20];
195 	int i;
196 	size_t len;
197 
198 	name[sizeof(name) - 1] = '\0';
199 	strncpy(name, buf, sizeof(name) - 1);
200 	len = strlen(name);
201 
202 	if (len && name[len - 1] == '\n')
203 		name[len - 1] = '\0';
204 
205 	for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
206 		if (!strcmp(name, led_src_texts[i])) {
207 			mutex_lock(&led->mutex);
208 
209 			led->src = i;
210 			schedule_work(&led->work);
211 
212 			mutex_unlock(&led->mutex);
213 		}
214 	}
215 
216 	return size;
217 }
218 
219 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
220 
221 static int wm831x_status_probe(struct platform_device *pdev)
222 {
223 	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
224 	struct wm831x_pdata *chip_pdata;
225 	struct wm831x_status_pdata pdata;
226 	struct wm831x_status *drvdata;
227 	struct resource *res;
228 	int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
229 	int ret;
230 
231 	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
232 	if (res == NULL) {
233 		dev_err(&pdev->dev, "No I/O resource\n");
234 		ret = -EINVAL;
235 		goto err;
236 	}
237 
238 	drvdata = kzalloc(sizeof(struct wm831x_status), GFP_KERNEL);
239 	if (!drvdata)
240 		return -ENOMEM;
241 	dev_set_drvdata(&pdev->dev, drvdata);
242 
243 	drvdata->wm831x = wm831x;
244 	drvdata->reg = res->start;
245 
246 	if (wm831x->dev->platform_data)
247 		chip_pdata = wm831x->dev->platform_data;
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 	INIT_WORK(&drvdata->work, wm831x_status_work);
259 	spin_lock_init(&drvdata->value_lock);
260 
261 	/* We cache the configuration register and read startup values
262 	 * from it. */
263 	drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
264 
265 	if (drvdata->reg_val & WM831X_LED_MODE_MASK)
266 		drvdata->brightness = LED_FULL;
267 	else
268 		drvdata->brightness = LED_OFF;
269 
270 	/* Set a default source if configured, otherwise leave the
271 	 * current hardware setting.
272 	 */
273 	if (pdata.default_src == WM831X_STATUS_PRESERVE) {
274 		drvdata->src = drvdata->reg_val;
275 		drvdata->src &= WM831X_LED_SRC_MASK;
276 		drvdata->src >>= WM831X_LED_SRC_SHIFT;
277 	} else {
278 		drvdata->src = pdata.default_src - 1;
279 	}
280 
281 	drvdata->cdev.name = pdata.name;
282 	drvdata->cdev.default_trigger = pdata.default_trigger;
283 	drvdata->cdev.brightness_set = wm831x_status_set;
284 	drvdata->cdev.blink_set = wm831x_status_blink_set;
285 
286 	ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
287 	if (ret < 0) {
288 		dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
289 		goto err_led;
290 	}
291 
292 	ret = device_create_file(drvdata->cdev.dev, &dev_attr_src);
293 	if (ret != 0)
294 		dev_err(&pdev->dev,
295 			"No source control for LED: %d\n", ret);
296 
297 	return 0;
298 
299 err_led:
300 	led_classdev_unregister(&drvdata->cdev);
301 	kfree(drvdata);
302 err:
303 	return ret;
304 }
305 
306 static int wm831x_status_remove(struct platform_device *pdev)
307 {
308 	struct wm831x_status *drvdata = platform_get_drvdata(pdev);
309 
310 	device_remove_file(drvdata->cdev.dev, &dev_attr_src);
311 	led_classdev_unregister(&drvdata->cdev);
312 	kfree(drvdata);
313 
314 	return 0;
315 }
316 
317 static struct platform_driver wm831x_status_driver = {
318 	.driver = {
319 		   .name = "wm831x-status",
320 		   .owner = THIS_MODULE,
321 		   },
322 	.probe = wm831x_status_probe,
323 	.remove = wm831x_status_remove,
324 };
325 
326 static int __devinit wm831x_status_init(void)
327 {
328 	return platform_driver_register(&wm831x_status_driver);
329 }
330 module_init(wm831x_status_init);
331 
332 static void wm831x_status_exit(void)
333 {
334 	platform_driver_unregister(&wm831x_status_driver);
335 }
336 module_exit(wm831x_status_exit);
337 
338 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
339 MODULE_DESCRIPTION("WM831x status LED driver");
340 MODULE_LICENSE("GPL");
341 MODULE_ALIAS("platform:wm831x-status");
342