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
wm831x_status_set(struct wm831x_status * led)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
wm831x_status_brightness_set(struct led_classdev * led_cdev,enum led_brightness value)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
wm831x_status_blink_set(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off)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
src_show(struct device * dev,struct device_attribute * attr,char * buf)158 static ssize_t 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
src_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)181 static ssize_t 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_RW(src);
201
202 static struct attribute *wm831x_status_attrs[] = {
203 &dev_attr_src.attr,
204 NULL
205 };
206 ATTRIBUTE_GROUPS(wm831x_status);
207
wm831x_status_probe(struct platform_device * pdev)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 = 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 platform_set_drvdata(pdev, drvdata);
279
280 return 0;
281 }
282
wm831x_status_remove(struct platform_device * pdev)283 static int wm831x_status_remove(struct platform_device *pdev)
284 {
285 struct wm831x_status *drvdata = platform_get_drvdata(pdev);
286
287 led_classdev_unregister(&drvdata->cdev);
288
289 return 0;
290 }
291
292 static struct platform_driver wm831x_status_driver = {
293 .driver = {
294 .name = "wm831x-status",
295 },
296 .probe = wm831x_status_probe,
297 .remove = wm831x_status_remove,
298 };
299
300 module_platform_driver(wm831x_status_driver);
301
302 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
303 MODULE_DESCRIPTION("WM831x status LED driver");
304 MODULE_LICENSE("GPL");
305 MODULE_ALIAS("platform:wm831x-status");
306