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 *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_IO, 0);
234 	if (res == NULL) {
235 		dev_err(&pdev->dev, "No I/O 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 	dev_set_drvdata(&pdev->dev, drvdata);
245 
246 	drvdata->wm831x = wm831x;
247 	drvdata->reg = res->start;
248 
249 	if (wm831x->dev->platform_data)
250 		chip_pdata = wm831x->dev->platform_data;
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