drivers/leds/leds-wm831x-status.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * LED driver for WM831x status LEDs
0004  *
0005  * Copyright(C) 2009 Wolfson Microelectronics PLC.
0006  */
0007
0008 #include <linux/kernel.h>
0009 #include <linux/platform_device.h>
0010 #include <linux/slab.h>
0011 #include <linux/leds.h>
0012 #include <linux/err.h>
0013 #include <linux/mfd/wm831x/core.h>
0014 #include <linux/mfd/wm831x/pdata.h>
0015 #include <linux/mfd/wm831x/status.h>
0016 #include <linux/module.h>
0017
0018
0019 struct wm831x_status {
0020     struct led_classdev cdev;
0021     struct wm831x *wm831x;
0022     struct mutex mutex;
0023
0024     spinlock_t value_lock;
0025     int reg;     /* Control register */
0026     int reg_val; /* Control register value */
0027
0028     int blink;
0029     int blink_time;
0030     int blink_cyc;
0031     int src;
0032     enum led_brightness brightness;
0033 };
0034
0035 #define to_wm831x_status(led_cdev) \
0036     container_of(led_cdev, struct wm831x_status, cdev)
0037
0038 static void wm831x_status_set(struct wm831x_status *led)
0039 {
0040     unsigned long flags;
0041
0042     mutex_lock(&led->mutex);
0043
0044     led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
0045               WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
0046
0047     spin_lock_irqsave(&led->value_lock, flags);
0048
0049     led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
0050     if (led->blink) {
0051         led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
0052         led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
0053         led->reg_val |= led->blink_cyc;
0054     } else {
0055         if (led->brightness != LED_OFF)
0056             led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
0057     }
0058
0059     spin_unlock_irqrestore(&led->value_lock, flags);
0060
0061     wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
0062
0063     mutex_unlock(&led->mutex);
0064 }
0065
0066 static int wm831x_status_brightness_set(struct led_classdev *led_cdev,
0067                      enum led_brightness value)
0068 {
0069     struct wm831x_status *led = to_wm831x_status(led_cdev);
0070     unsigned long flags;
0071
0072     spin_lock_irqsave(&led->value_lock, flags);
0073     led->brightness = value;
0074     if (value == LED_OFF)
0075         led->blink = 0;
0076     spin_unlock_irqrestore(&led->value_lock, flags);
0077     wm831x_status_set(led);
0078
0079     return 0;
0080 }
0081
0082 static int wm831x_status_blink_set(struct led_classdev *led_cdev,
0083                    unsigned long *delay_on,
0084                    unsigned long *delay_off)
0085 {
0086     struct wm831x_status *led = to_wm831x_status(led_cdev);
0087     unsigned long flags;
0088     int ret = 0;
0089
0090     /* Pick some defaults if we've not been given times */
0091     if (*delay_on == 0 && *delay_off == 0) {
0092         *delay_on = 250;
0093         *delay_off = 250;
0094     }
0095
0096     spin_lock_irqsave(&led->value_lock, flags);
0097
0098     /* We only have a limited selection of settings, see if we can
0099      * support the configuration we're being given */
0100     switch (*delay_on) {
0101     case 1000:
0102         led->blink_time = 0;
0103         break;
0104     case 250:
0105         led->blink_time = 1;
0106         break;
0107     case 125:
0108         led->blink_time = 2;
0109         break;
0110     case 62:
0111     case 63:
0112         /* Actually 62.5ms */
0113         led->blink_time = 3;
0114         break;
0115     default:
0116         ret = -EINVAL;
0117         break;
0118     }
0119
0120     if (ret == 0) {
0121         switch (*delay_off / *delay_on) {
0122         case 1:
0123             led->blink_cyc = 0;
0124             break;
0125         case 3:
0126             led->blink_cyc = 1;
0127             break;
0128         case 4:
0129             led->blink_cyc = 2;
0130             break;
0131         case 8:
0132             led->blink_cyc = 3;
0133             break;
0134         default:
0135             ret = -EINVAL;
0136             break;
0137         }
0138     }
0139
0140     if (ret == 0)
0141         led->blink = 1;
0142     else
0143         led->blink = 0;
0144
0145     spin_unlock_irqrestore(&led->value_lock, flags);
0146     wm831x_status_set(led);
0147
0148     return ret;
0149 }
0150
0151 static const char * const led_src_texts[] = {
0152     "otp",
0153     "power",
0154     "charger",
0155     "soft",
0156 };
0157
0158 static ssize_t src_show(struct device *dev,
0159             struct device_attribute *attr, char *buf)
0160 {
0161     struct led_classdev *led_cdev = dev_get_drvdata(dev);
0162     struct wm831x_status *led = to_wm831x_status(led_cdev);
0163     int i;
0164     ssize_t ret = 0;
0165
0166     mutex_lock(&led->mutex);
0167
0168     for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
0169         if (i == led->src)
0170             ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
0171         else
0172             ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
0173
0174     mutex_unlock(&led->mutex);
0175
0176     ret += sprintf(&buf[ret], "\n");
0177
0178     return ret;
0179 }
0180
0181 static ssize_t src_store(struct device *dev,
0182              struct device_attribute *attr,
0183              const char *buf, size_t size)
0184 {
0185     struct led_classdev *led_cdev = dev_get_drvdata(dev);
0186     struct wm831x_status *led = to_wm831x_status(led_cdev);
0187     int i;
0188
0189     i = sysfs_match_string(led_src_texts, buf);
0190     if (i >= 0) {
0191         mutex_lock(&led->mutex);
0192         led->src = i;
0193         mutex_unlock(&led->mutex);
0194         wm831x_status_set(led);
0195     }
0196
0197     return size;
0198 }
0199
0200 static DEVICE_ATTR_RW(src);
0201
0202 static struct attribute *wm831x_status_attrs[] = {
0203     &dev_attr_src.attr,
0204     NULL
0205 };
0206 ATTRIBUTE_GROUPS(wm831x_status);
0207
0208 static int wm831x_status_probe(struct platform_device *pdev)
0209 {
0210     struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
0211     struct wm831x_pdata *chip_pdata;
0212     struct wm831x_status_pdata pdata;
0213     struct wm831x_status *drvdata;
0214     struct resource *res;
0215     int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
0216     int ret;
0217
0218     res = platform_get_resource(pdev, IORESOURCE_REG, 0);
0219     if (res == NULL) {
0220         dev_err(&pdev->dev, "No register resource\n");
0221         return -EINVAL;
0222     }
0223
0224     drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
0225                    GFP_KERNEL);
0226     if (!drvdata)
0227         return -ENOMEM;
0228
0229     drvdata->wm831x = wm831x;
0230     drvdata->reg = res->start;
0231
0232     if (dev_get_platdata(wm831x->dev))
0233         chip_pdata = dev_get_platdata(wm831x->dev);
0234     else
0235         chip_pdata = NULL;
0236
0237     memset(&pdata, 0, sizeof(pdata));
0238     if (chip_pdata && chip_pdata->status[id])
0239         memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
0240     else
0241         pdata.name = dev_name(&pdev->dev);
0242
0243     mutex_init(&drvdata->mutex);
0244     spin_lock_init(&drvdata->value_lock);
0245
0246     /* We cache the configuration register and read startup values
0247      * from it. */
0248     drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
0249
0250     if (drvdata->reg_val & WM831X_LED_MODE_MASK)
0251         drvdata->brightness = LED_FULL;
0252     else
0253         drvdata->brightness = LED_OFF;
0254
0255     /* Set a default source if configured, otherwise leave the
0256      * current hardware setting.
0257      */
0258     if (pdata.default_src == WM831X_STATUS_PRESERVE) {
0259         drvdata->src = drvdata->reg_val;
0260         drvdata->src &= WM831X_LED_SRC_MASK;
0261         drvdata->src >>= WM831X_LED_SRC_SHIFT;
0262     } else {
0263         drvdata->src = pdata.default_src - 1;
0264     }
0265
0266     drvdata->cdev.name = pdata.name;
0267     drvdata->cdev.default_trigger = pdata.default_trigger;
0268     drvdata->cdev.brightness_set_blocking = wm831x_status_brightness_set;
0269     drvdata->cdev.blink_set = wm831x_status_blink_set;
0270     drvdata->cdev.groups = wm831x_status_groups;
0271
0272     ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
0273     if (ret < 0) {
0274         dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
0275         return ret;
0276     }
0277
0278     platform_set_drvdata(pdev, drvdata);
0279
0280     return 0;
0281 }
0282
0283 static int wm831x_status_remove(struct platform_device *pdev)
0284 {
0285     struct wm831x_status *drvdata = platform_get_drvdata(pdev);
0286
0287     led_classdev_unregister(&drvdata->cdev);
0288
0289     return 0;
0290 }
0291
0292 static struct platform_driver wm831x_status_driver = {
0293     .driver = {
0294            .name = "wm831x-status",
0295            },
0296     .probe = wm831x_status_probe,
0297     .remove = wm831x_status_remove,
0298 };
0299
0300 module_platform_driver(wm831x_status_driver);
0301
0302 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
0303 MODULE_DESCRIPTION("WM831x status LED driver");
0304 MODULE_LICENSE("GPL");
0305 MODULE_ALIAS("platform:wm831x-status");