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