Root/drivers/leds/leds-wm831x-status.c

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
24struct 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
44static 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
74static 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
88static 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
160static const char * const led_src_texts[] = {
161    "otp",
162    "power",
163    "charger",
164    "soft",
165};
166
167static 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
190static 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
221static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
222
223static 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
302err_led:
303    led_classdev_unregister(&drvdata->cdev);
304err:
305    return ret;
306}
307
308static 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
318static 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
327module_platform_driver(wm831x_status_driver);
328
329MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
330MODULE_DESCRIPTION("WM831x status LED driver");
331MODULE_LICENSE("GPL");
332MODULE_ALIAS("platform:wm831x-status");
333

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