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
23struct 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
43static 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
73static 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
87static 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
159static const char * const led_src_texts[] = {
160	"otp",
161	"power",
162	"charger",
163	"soft",
164};
165
166static 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
189static 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
220static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
221
222static struct attribute *wm831x_status_attrs[] = {
223	&dev_attr_src.attr,
224	NULL
225};
226ATTRIBUTE_GROUPS(wm831x_status);
227
228static 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
303static 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
312static struct platform_driver wm831x_status_driver = {
313	.driver = {
314		   .name = "wm831x-status",
315		   },
316	.probe = wm831x_status_probe,
317	.remove = wm831x_status_remove,
318};
319
320module_platform_driver(wm831x_status_driver);
321
322MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
323MODULE_DESCRIPTION("WM831x status LED driver");
324MODULE_LICENSE("GPL");
325MODULE_ALIAS("platform:wm831x-status");
326