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 24 struct 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 44 static 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 74 static 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 88 static 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 } 159 160 static const char *led_src_texts[] = { 161 "otp", 162 "power", 163 "charger", 164 "soft", 165 }; 166 167 static 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 } 189 190 static 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 } 220 221 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store); 222 223 static 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 = kzalloc(sizeof(struct wm831x_status), GFP_KERNEL); 241 if (!drvdata) 242 return -ENOMEM; 243 dev_set_drvdata(&pdev->dev, drvdata); 244 245 drvdata->wm831x = wm831x; 246 drvdata->reg = res->start; 247 248 if (wm831x->dev->platform_data) 249 chip_pdata = wm831x->dev->platform_data; 250 else 251 chip_pdata = NULL; 252 253 memset(&pdata, 0, sizeof(pdata)); 254 if (chip_pdata && chip_pdata->status[id]) 255 memcpy(&pdata, chip_pdata->status[id], sizeof(pdata)); 256 else 257 pdata.name = dev_name(&pdev->dev); 258 259 mutex_init(&drvdata->mutex); 260 INIT_WORK(&drvdata->work, wm831x_status_work); 261 spin_lock_init(&drvdata->value_lock); 262 263 /* We cache the configuration register and read startup values 264 * from it. */ 265 drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg); 266 267 if (drvdata->reg_val & WM831X_LED_MODE_MASK) 268 drvdata->brightness = LED_FULL; 269 else 270 drvdata->brightness = LED_OFF; 271 272 /* Set a default source if configured, otherwise leave the 273 * current hardware setting. 274 */ 275 if (pdata.default_src == WM831X_STATUS_PRESERVE) { 276 drvdata->src = drvdata->reg_val; 277 drvdata->src &= WM831X_LED_SRC_MASK; 278 drvdata->src >>= WM831X_LED_SRC_SHIFT; 279 } else { 280 drvdata->src = pdata.default_src - 1; 281 } 282 283 drvdata->cdev.name = pdata.name; 284 drvdata->cdev.default_trigger = pdata.default_trigger; 285 drvdata->cdev.brightness_set = wm831x_status_set; 286 drvdata->cdev.blink_set = wm831x_status_blink_set; 287 288 ret = led_classdev_register(wm831x->dev, &drvdata->cdev); 289 if (ret < 0) { 290 dev_err(&pdev->dev, "Failed to register LED: %d\n", ret); 291 goto err_led; 292 } 293 294 ret = device_create_file(drvdata->cdev.dev, &dev_attr_src); 295 if (ret != 0) 296 dev_err(&pdev->dev, 297 "No source control for LED: %d\n", ret); 298 299 return 0; 300 301 err_led: 302 led_classdev_unregister(&drvdata->cdev); 303 kfree(drvdata); 304 err: 305 return ret; 306 } 307 308 static 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 kfree(drvdata); 315 316 return 0; 317 } 318 319 static struct platform_driver wm831x_status_driver = { 320 .driver = { 321 .name = "wm831x-status", 322 .owner = THIS_MODULE, 323 }, 324 .probe = wm831x_status_probe, 325 .remove = wm831x_status_remove, 326 }; 327 328 static int __devinit wm831x_status_init(void) 329 { 330 return platform_driver_register(&wm831x_status_driver); 331 } 332 module_init(wm831x_status_init); 333 334 static void wm831x_status_exit(void) 335 { 336 platform_driver_unregister(&wm831x_status_driver); 337 } 338 module_exit(wm831x_status_exit); 339 340 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); 341 MODULE_DESCRIPTION("WM831x status LED driver"); 342 MODULE_LICENSE("GPL"); 343 MODULE_ALIAS("platform:wm831x-status"); 344