1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * LED driver for WM831x status LEDs
4  *
5  * Copyright(C) 2009 Wolfson Microelectronics PLC.
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/platform_device.h>
10 #include <linux/slab.h>
11 #include <linux/leds.h>
12 #include <linux/err.h>
13 #include <linux/mfd/wm831x/core.h>
14 #include <linux/mfd/wm831x/pdata.h>
15 #include <linux/mfd/wm831x/status.h>
16 #include <linux/module.h>
17 
18 
19 struct wm831x_status {
20 	struct led_classdev cdev;
21 	struct wm831x *wm831x;
22 	struct mutex mutex;
23 
24 	spinlock_t value_lock;
25 	int reg;     /* Control register */
26 	int reg_val; /* Control register value */
27 
28 	int blink;
29 	int blink_time;
30 	int blink_cyc;
31 	int src;
32 	enum led_brightness brightness;
33 };
34 
35 #define to_wm831x_status(led_cdev) \
36 	container_of(led_cdev, struct wm831x_status, cdev)
37 
38 static void wm831x_status_set(struct wm831x_status *led)
39 {
40 	unsigned long flags;
41 
42 	mutex_lock(&led->mutex);
43 
44 	led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
45 			  WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
46 
47 	spin_lock_irqsave(&led->value_lock, flags);
48 
49 	led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
50 	if (led->blink) {
51 		led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
52 		led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
53 		led->reg_val |= led->blink_cyc;
54 	} else {
55 		if (led->brightness != LED_OFF)
56 			led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
57 	}
58 
59 	spin_unlock_irqrestore(&led->value_lock, flags);
60 
61 	wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
62 
63 	mutex_unlock(&led->mutex);
64 }
65 
66 static int wm831x_status_brightness_set(struct led_classdev *led_cdev,
67 					 enum led_brightness value)
68 {
69 	struct wm831x_status *led = to_wm831x_status(led_cdev);
70 	unsigned long flags;
71 
72 	spin_lock_irqsave(&led->value_lock, flags);
73 	led->brightness = value;
74 	if (value == LED_OFF)
75 		led->blink = 0;
76 	spin_unlock_irqrestore(&led->value_lock, flags);
77 	wm831x_status_set(led);
78 
79 	return 0;
80 }
81 
82 static int wm831x_status_blink_set(struct led_classdev *led_cdev,
83 				   unsigned long *delay_on,
84 				   unsigned long *delay_off)
85 {
86 	struct wm831x_status *led = to_wm831x_status(led_cdev);
87 	unsigned long flags;
88 	int ret = 0;
89 
90 	/* Pick some defaults if we've not been given times */
91 	if (*delay_on == 0 && *delay_off == 0) {
92 		*delay_on = 250;
93 		*delay_off = 250;
94 	}
95 
96 	spin_lock_irqsave(&led->value_lock, flags);
97 
98 	/* We only have a limited selection of settings, see if we can
99 	 * support the configuration we're being given */
100 	switch (*delay_on) {
101 	case 1000:
102 		led->blink_time = 0;
103 		break;
104 	case 250:
105 		led->blink_time = 1;
106 		break;
107 	case 125:
108 		led->blink_time = 2;
109 		break;
110 	case 62:
111 	case 63:
112 		/* Actually 62.5ms */
113 		led->blink_time = 3;
114 		break;
115 	default:
116 		ret = -EINVAL;
117 		break;
118 	}
119 
120 	if (ret == 0) {
121 		switch (*delay_off / *delay_on) {
122 		case 1:
123 			led->blink_cyc = 0;
124 			break;
125 		case 3:
126 			led->blink_cyc = 1;
127 			break;
128 		case 4:
129 			led->blink_cyc = 2;
130 			break;
131 		case 8:
132 			led->blink_cyc = 3;
133 			break;
134 		default:
135 			ret = -EINVAL;
136 			break;
137 		}
138 	}
139 
140 	if (ret == 0)
141 		led->blink = 1;
142 	else
143 		led->blink = 0;
144 
145 	spin_unlock_irqrestore(&led->value_lock, flags);
146 	wm831x_status_set(led);
147 
148 	return ret;
149 }
150 
151 static const char * const led_src_texts[] = {
152 	"otp",
153 	"power",
154 	"charger",
155 	"soft",
156 };
157 
158 static ssize_t wm831x_status_src_show(struct device *dev,
159 				      struct device_attribute *attr, char *buf)
160 {
161 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
162 	struct wm831x_status *led = to_wm831x_status(led_cdev);
163 	int i;
164 	ssize_t ret = 0;
165 
166 	mutex_lock(&led->mutex);
167 
168 	for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
169 		if (i == led->src)
170 			ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
171 		else
172 			ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
173 
174 	mutex_unlock(&led->mutex);
175 
176 	ret += sprintf(&buf[ret], "\n");
177 
178 	return ret;
179 }
180 
181 static ssize_t wm831x_status_src_store(struct device *dev,
182 				       struct device_attribute *attr,
183 				       const char *buf, size_t size)
184 {
185 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
186 	struct wm831x_status *led = to_wm831x_status(led_cdev);
187 	int i;
188 
189 	i = sysfs_match_string(led_src_texts, buf);
190 	if (i >= 0) {
191 		mutex_lock(&led->mutex);
192 		led->src = i;
193 		mutex_unlock(&led->mutex);
194 		wm831x_status_set(led);
195 	}
196 
197 	return size;
198 }
199 
200 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
201 
202 static struct attribute *wm831x_status_attrs[] = {
203 	&dev_attr_src.attr,
204 	NULL
205 };
206 ATTRIBUTE_GROUPS(wm831x_status);
207 
208 static int wm831x_status_probe(struct platform_device *pdev)
209 {
210 	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
211 	struct wm831x_pdata *chip_pdata;
212 	struct wm831x_status_pdata pdata;
213 	struct wm831x_status *drvdata;
214 	struct resource *res;
215 	int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
216 	int ret;
217 
218 	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
219 	if (res == NULL) {
220 		dev_err(&pdev->dev, "No register resource\n");
221 		return -EINVAL;
222 	}
223 
224 	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
225 			       GFP_KERNEL);
226 	if (!drvdata)
227 		return -ENOMEM;
228 
229 	drvdata->wm831x = wm831x;
230 	drvdata->reg = res->start;
231 
232 	if (dev_get_platdata(wm831x->dev))
233 		chip_pdata = dev_get_platdata(wm831x->dev);
234 	else
235 		chip_pdata = NULL;
236 
237 	memset(&pdata, 0, sizeof(pdata));
238 	if (chip_pdata && chip_pdata->status[id])
239 		memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
240 	else
241 		pdata.name = dev_name(&pdev->dev);
242 
243 	mutex_init(&drvdata->mutex);
244 	spin_lock_init(&drvdata->value_lock);
245 
246 	/* We cache the configuration register and read startup values
247 	 * from it. */
248 	drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
249 
250 	if (drvdata->reg_val & WM831X_LED_MODE_MASK)
251 		drvdata->brightness = LED_FULL;
252 	else
253 		drvdata->brightness = LED_OFF;
254 
255 	/* Set a default source if configured, otherwise leave the
256 	 * current hardware setting.
257 	 */
258 	if (pdata.default_src == WM831X_STATUS_PRESERVE) {
259 		drvdata->src = drvdata->reg_val;
260 		drvdata->src &= WM831X_LED_SRC_MASK;
261 		drvdata->src >>= WM831X_LED_SRC_SHIFT;
262 	} else {
263 		drvdata->src = pdata.default_src - 1;
264 	}
265 
266 	drvdata->cdev.name = pdata.name;
267 	drvdata->cdev.default_trigger = pdata.default_trigger;
268 	drvdata->cdev.brightness_set_blocking = wm831x_status_brightness_set;
269 	drvdata->cdev.blink_set = wm831x_status_blink_set;
270 	drvdata->cdev.groups = wm831x_status_groups;
271 
272 	ret = devm_led_classdev_register(wm831x->dev, &drvdata->cdev);
273 	if (ret < 0) {
274 		dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
275 		return ret;
276 	}
277 
278 	return 0;
279 }
280 
281 static struct platform_driver wm831x_status_driver = {
282 	.driver = {
283 		   .name = "wm831x-status",
284 		   },
285 	.probe = wm831x_status_probe,
286 };
287 
288 module_platform_driver(wm831x_status_driver);
289 
290 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
291 MODULE_DESCRIPTION("WM831x status LED driver");
292 MODULE_LICENSE("GPL");
293 MODULE_ALIAS("platform:wm831x-status");
294