1 /* 2 * pwm-fan.c - Hwmon driver for fans connected to PWM lines. 3 * 4 * Copyright (c) 2014 Samsung Electronics Co., Ltd. 5 * 6 * Author: Kamil Debski <k.debski@samsung.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 */ 18 19 #include <linux/hwmon.h> 20 #include <linux/hwmon-sysfs.h> 21 #include <linux/module.h> 22 #include <linux/mutex.h> 23 #include <linux/of.h> 24 #include <linux/platform_device.h> 25 #include <linux/pwm.h> 26 #include <linux/regulator/consumer.h> 27 #include <linux/sysfs.h> 28 #include <linux/thermal.h> 29 30 #define MAX_PWM 255 31 32 struct pwm_fan_ctx { 33 struct mutex lock; 34 struct pwm_device *pwm; 35 struct regulator *reg_en; 36 unsigned int pwm_value; 37 unsigned int pwm_fan_state; 38 unsigned int pwm_fan_max_state; 39 unsigned int *pwm_fan_cooling_levels; 40 struct thermal_cooling_device *cdev; 41 }; 42 43 static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) 44 { 45 unsigned long period; 46 int ret = 0; 47 struct pwm_state state = { }; 48 49 mutex_lock(&ctx->lock); 50 if (ctx->pwm_value == pwm) 51 goto exit_set_pwm_err; 52 53 pwm_init_state(ctx->pwm, &state); 54 period = ctx->pwm->args.period; 55 state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM); 56 state.enabled = pwm ? true : false; 57 58 ret = pwm_apply_state(ctx->pwm, &state); 59 if (!ret) 60 ctx->pwm_value = pwm; 61 exit_set_pwm_err: 62 mutex_unlock(&ctx->lock); 63 return ret; 64 } 65 66 static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm) 67 { 68 int i; 69 70 for (i = 0; i < ctx->pwm_fan_max_state; ++i) 71 if (pwm < ctx->pwm_fan_cooling_levels[i + 1]) 72 break; 73 74 ctx->pwm_fan_state = i; 75 } 76 77 static ssize_t pwm_store(struct device *dev, struct device_attribute *attr, 78 const char *buf, size_t count) 79 { 80 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); 81 unsigned long pwm; 82 int ret; 83 84 if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM) 85 return -EINVAL; 86 87 ret = __set_pwm(ctx, pwm); 88 if (ret) 89 return ret; 90 91 pwm_fan_update_state(ctx, pwm); 92 return count; 93 } 94 95 static ssize_t pwm_show(struct device *dev, struct device_attribute *attr, 96 char *buf) 97 { 98 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); 99 100 return sprintf(buf, "%u\n", ctx->pwm_value); 101 } 102 103 104 static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0); 105 106 static struct attribute *pwm_fan_attrs[] = { 107 &sensor_dev_attr_pwm1.dev_attr.attr, 108 NULL, 109 }; 110 111 ATTRIBUTE_GROUPS(pwm_fan); 112 113 /* thermal cooling device callbacks */ 114 static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, 115 unsigned long *state) 116 { 117 struct pwm_fan_ctx *ctx = cdev->devdata; 118 119 if (!ctx) 120 return -EINVAL; 121 122 *state = ctx->pwm_fan_max_state; 123 124 return 0; 125 } 126 127 static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev, 128 unsigned long *state) 129 { 130 struct pwm_fan_ctx *ctx = cdev->devdata; 131 132 if (!ctx) 133 return -EINVAL; 134 135 *state = ctx->pwm_fan_state; 136 137 return 0; 138 } 139 140 static int 141 pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) 142 { 143 struct pwm_fan_ctx *ctx = cdev->devdata; 144 int ret; 145 146 if (!ctx || (state > ctx->pwm_fan_max_state)) 147 return -EINVAL; 148 149 if (state == ctx->pwm_fan_state) 150 return 0; 151 152 ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]); 153 if (ret) { 154 dev_err(&cdev->device, "Cannot set pwm!\n"); 155 return ret; 156 } 157 158 ctx->pwm_fan_state = state; 159 160 return ret; 161 } 162 163 static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = { 164 .get_max_state = pwm_fan_get_max_state, 165 .get_cur_state = pwm_fan_get_cur_state, 166 .set_cur_state = pwm_fan_set_cur_state, 167 }; 168 169 static int pwm_fan_of_get_cooling_data(struct device *dev, 170 struct pwm_fan_ctx *ctx) 171 { 172 struct device_node *np = dev->of_node; 173 int num, i, ret; 174 175 if (!of_find_property(np, "cooling-levels", NULL)) 176 return 0; 177 178 ret = of_property_count_u32_elems(np, "cooling-levels"); 179 if (ret <= 0) { 180 dev_err(dev, "Wrong data!\n"); 181 return ret ? : -EINVAL; 182 } 183 184 num = ret; 185 ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32), 186 GFP_KERNEL); 187 if (!ctx->pwm_fan_cooling_levels) 188 return -ENOMEM; 189 190 ret = of_property_read_u32_array(np, "cooling-levels", 191 ctx->pwm_fan_cooling_levels, num); 192 if (ret) { 193 dev_err(dev, "Property 'cooling-levels' cannot be read!\n"); 194 return ret; 195 } 196 197 for (i = 0; i < num; i++) { 198 if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) { 199 dev_err(dev, "PWM fan state[%d]:%d > %d\n", i, 200 ctx->pwm_fan_cooling_levels[i], MAX_PWM); 201 return -EINVAL; 202 } 203 } 204 205 ctx->pwm_fan_max_state = num - 1; 206 207 return 0; 208 } 209 210 static int pwm_fan_probe(struct platform_device *pdev) 211 { 212 struct thermal_cooling_device *cdev; 213 struct pwm_fan_ctx *ctx; 214 struct device *hwmon; 215 int ret; 216 struct pwm_state state = { }; 217 218 ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); 219 if (!ctx) 220 return -ENOMEM; 221 222 mutex_init(&ctx->lock); 223 224 ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL); 225 if (IS_ERR(ctx->pwm)) { 226 ret = PTR_ERR(ctx->pwm); 227 228 if (ret != -EPROBE_DEFER) 229 dev_err(&pdev->dev, "Could not get PWM: %d\n", ret); 230 231 return ret; 232 } 233 234 platform_set_drvdata(pdev, ctx); 235 236 ctx->reg_en = devm_regulator_get_optional(&pdev->dev, "fan"); 237 if (IS_ERR(ctx->reg_en)) { 238 if (PTR_ERR(ctx->reg_en) != -ENODEV) 239 return PTR_ERR(ctx->reg_en); 240 241 ctx->reg_en = NULL; 242 } else { 243 ret = regulator_enable(ctx->reg_en); 244 if (ret) { 245 dev_err(&pdev->dev, 246 "Failed to enable fan supply: %d\n", ret); 247 return ret; 248 } 249 } 250 251 ctx->pwm_value = MAX_PWM; 252 253 /* Set duty cycle to maximum allowed and enable PWM output */ 254 pwm_init_state(ctx->pwm, &state); 255 state.duty_cycle = ctx->pwm->args.period - 1; 256 state.enabled = true; 257 258 ret = pwm_apply_state(ctx->pwm, &state); 259 if (ret) { 260 dev_err(&pdev->dev, "Failed to configure PWM\n"); 261 goto err_reg_disable; 262 } 263 264 hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", 265 ctx, pwm_fan_groups); 266 if (IS_ERR(hwmon)) { 267 dev_err(&pdev->dev, "Failed to register hwmon device\n"); 268 ret = PTR_ERR(hwmon); 269 goto err_pwm_disable; 270 } 271 272 ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx); 273 if (ret) 274 return ret; 275 276 ctx->pwm_fan_state = ctx->pwm_fan_max_state; 277 if (IS_ENABLED(CONFIG_THERMAL)) { 278 cdev = thermal_of_cooling_device_register(pdev->dev.of_node, 279 "pwm-fan", ctx, 280 &pwm_fan_cooling_ops); 281 if (IS_ERR(cdev)) { 282 dev_err(&pdev->dev, 283 "Failed to register pwm-fan as cooling device"); 284 ret = PTR_ERR(cdev); 285 goto err_pwm_disable; 286 } 287 ctx->cdev = cdev; 288 thermal_cdev_update(cdev); 289 } 290 291 return 0; 292 293 err_pwm_disable: 294 state.enabled = false; 295 pwm_apply_state(ctx->pwm, &state); 296 297 err_reg_disable: 298 if (ctx->reg_en) 299 regulator_disable(ctx->reg_en); 300 301 return ret; 302 } 303 304 static int pwm_fan_remove(struct platform_device *pdev) 305 { 306 struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); 307 308 thermal_cooling_device_unregister(ctx->cdev); 309 if (ctx->pwm_value) 310 pwm_disable(ctx->pwm); 311 312 if (ctx->reg_en) 313 regulator_disable(ctx->reg_en); 314 315 return 0; 316 } 317 318 #ifdef CONFIG_PM_SLEEP 319 static int pwm_fan_suspend(struct device *dev) 320 { 321 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); 322 struct pwm_args args; 323 int ret; 324 325 pwm_get_args(ctx->pwm, &args); 326 327 if (ctx->pwm_value) { 328 ret = pwm_config(ctx->pwm, 0, args.period); 329 if (ret < 0) 330 return ret; 331 332 pwm_disable(ctx->pwm); 333 } 334 335 if (ctx->reg_en) { 336 ret = regulator_disable(ctx->reg_en); 337 if (ret) { 338 dev_err(dev, "Failed to disable fan supply: %d\n", ret); 339 return ret; 340 } 341 } 342 343 return 0; 344 } 345 346 static int pwm_fan_resume(struct device *dev) 347 { 348 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); 349 struct pwm_args pargs; 350 unsigned long duty; 351 int ret; 352 353 if (ctx->reg_en) { 354 ret = regulator_enable(ctx->reg_en); 355 if (ret) { 356 dev_err(dev, "Failed to enable fan supply: %d\n", ret); 357 return ret; 358 } 359 } 360 361 if (ctx->pwm_value == 0) 362 return 0; 363 364 pwm_get_args(ctx->pwm, &pargs); 365 duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM); 366 ret = pwm_config(ctx->pwm, duty, pargs.period); 367 if (ret) 368 return ret; 369 return pwm_enable(ctx->pwm); 370 } 371 #endif 372 373 static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume); 374 375 static const struct of_device_id of_pwm_fan_match[] = { 376 { .compatible = "pwm-fan", }, 377 {}, 378 }; 379 MODULE_DEVICE_TABLE(of, of_pwm_fan_match); 380 381 static struct platform_driver pwm_fan_driver = { 382 .probe = pwm_fan_probe, 383 .remove = pwm_fan_remove, 384 .driver = { 385 .name = "pwm-fan", 386 .pm = &pwm_fan_pm, 387 .of_match_table = of_pwm_fan_match, 388 }, 389 }; 390 391 module_platform_driver(pwm_fan_driver); 392 393 MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>"); 394 MODULE_ALIAS("platform:pwm-fan"); 395 MODULE_DESCRIPTION("PWM FAN driver"); 396 MODULE_LICENSE("GPL"); 397