/* * pwm-fan.c - Hwmon driver for fans connected to PWM lines. * * Copyright (c) 2014 Samsung Electronics Co., Ltd. * * Author: Kamil Debski <k.debski@samsung.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/pwm.h> #include <linux/sysfs.h> #include <linux/thermal.h> #define MAX_PWM 255 struct pwm_fan_ctx { struct mutex lock; struct pwm_device *pwm; unsigned int pwm_value; unsigned int pwm_fan_state; unsigned int pwm_fan_max_state; unsigned int *pwm_fan_cooling_levels; struct thermal_cooling_device *cdev; }; static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) { unsigned long period; int ret = 0; struct pwm_state state = { }; mutex_lock(&ctx->lock); if (ctx->pwm_value == pwm) goto exit_set_pwm_err; pwm_init_state(ctx->pwm, &state); period = ctx->pwm->args.period; state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM); state.enabled = pwm ? true : false; ret = pwm_apply_state(ctx->pwm, &state); if (!ret) ctx->pwm_value = pwm; exit_set_pwm_err: mutex_unlock(&ctx->lock); return ret; } static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm) { int i; for (i = 0; i < ctx->pwm_fan_max_state; ++i) if (pwm < ctx->pwm_fan_cooling_levels[i + 1]) break; ctx->pwm_fan_state = i; } static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); unsigned long pwm; int ret; if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM) return -EINVAL; ret = __set_pwm(ctx, pwm); if (ret) return ret; pwm_fan_update_state(ctx, pwm); return count; } static ssize_t show_pwm(struct device *dev, struct device_attribute *attr, char *buf) { struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); return sprintf(buf, "%u\n", ctx->pwm_value); } static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0); static struct attribute *pwm_fan_attrs[] = { &sensor_dev_attr_pwm1.dev_attr.attr, NULL, }; ATTRIBUTE_GROUPS(pwm_fan); /* thermal cooling device callbacks */ static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) { struct pwm_fan_ctx *ctx = cdev->devdata; if (!ctx) return -EINVAL; *state = ctx->pwm_fan_max_state; return 0; } static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) { struct pwm_fan_ctx *ctx = cdev->devdata; if (!ctx) return -EINVAL; *state = ctx->pwm_fan_state; return 0; } static int pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) { struct pwm_fan_ctx *ctx = cdev->devdata; int ret; if (!ctx || (state > ctx->pwm_fan_max_state)) return -EINVAL; if (state == ctx->pwm_fan_state) return 0; ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]); if (ret) { dev_err(&cdev->device, "Cannot set pwm!\n"); return ret; } ctx->pwm_fan_state = state; return ret; } static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = { .get_max_state = pwm_fan_get_max_state, .get_cur_state = pwm_fan_get_cur_state, .set_cur_state = pwm_fan_set_cur_state, }; static int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx) { struct device_node *np = dev->of_node; int num, i, ret; if (!of_find_property(np, "cooling-levels", NULL)) return 0; ret = of_property_count_u32_elems(np, "cooling-levels"); if (ret <= 0) { dev_err(dev, "Wrong data!\n"); return ret ? : -EINVAL; } num = ret; ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32), GFP_KERNEL); if (!ctx->pwm_fan_cooling_levels) return -ENOMEM; ret = of_property_read_u32_array(np, "cooling-levels", ctx->pwm_fan_cooling_levels, num); if (ret) { dev_err(dev, "Property 'cooling-levels' cannot be read!\n"); return ret; } for (i = 0; i < num; i++) { if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) { dev_err(dev, "PWM fan state[%d]:%d > %d\n", i, ctx->pwm_fan_cooling_levels[i], MAX_PWM); return -EINVAL; } } ctx->pwm_fan_max_state = num - 1; return 0; } static int pwm_fan_probe(struct platform_device *pdev) { struct thermal_cooling_device *cdev; struct pwm_fan_ctx *ctx; struct device *hwmon; int ret; struct pwm_state state = { }; ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); if (!ctx) return -ENOMEM; mutex_init(&ctx->lock); ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL); if (IS_ERR(ctx->pwm)) { dev_err(&pdev->dev, "Could not get PWM\n"); return PTR_ERR(ctx->pwm); } platform_set_drvdata(pdev, ctx); ctx->pwm_value = MAX_PWM; /* Set duty cycle to maximum allowed and enable PWM output */ pwm_init_state(ctx->pwm, &state); state.duty_cycle = ctx->pwm->args.period - 1; state.enabled = true; ret = pwm_apply_state(ctx->pwm, &state); if (ret) { dev_err(&pdev->dev, "Failed to configure PWM\n"); return ret; } hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", ctx, pwm_fan_groups); if (IS_ERR(hwmon)) { dev_err(&pdev->dev, "Failed to register hwmon device\n"); ret = PTR_ERR(hwmon); goto err_pwm_disable; } ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx); if (ret) return ret; ctx->pwm_fan_state = ctx->pwm_fan_max_state; if (IS_ENABLED(CONFIG_THERMAL)) { cdev = thermal_of_cooling_device_register(pdev->dev.of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops); if (IS_ERR(cdev)) { dev_err(&pdev->dev, "Failed to register pwm-fan as cooling device"); ret = PTR_ERR(cdev); goto err_pwm_disable; } ctx->cdev = cdev; thermal_cdev_update(cdev); } return 0; err_pwm_disable: state.enabled = false; pwm_apply_state(ctx->pwm, &state); return ret; } static int pwm_fan_remove(struct platform_device *pdev) { struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); thermal_cooling_device_unregister(ctx->cdev); if (ctx->pwm_value) pwm_disable(ctx->pwm); return 0; } #ifdef CONFIG_PM_SLEEP static int pwm_fan_suspend(struct device *dev) { struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); if (ctx->pwm_value) pwm_disable(ctx->pwm); return 0; } static int pwm_fan_resume(struct device *dev) { struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); struct pwm_args pargs; unsigned long duty; int ret; if (ctx->pwm_value == 0) return 0; pwm_get_args(ctx->pwm, &pargs); duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM); ret = pwm_config(ctx->pwm, duty, pargs.period); if (ret) return ret; return pwm_enable(ctx->pwm); } #endif static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume); static const struct of_device_id of_pwm_fan_match[] = { { .compatible = "pwm-fan", }, {}, }; MODULE_DEVICE_TABLE(of, of_pwm_fan_match); static struct platform_driver pwm_fan_driver = { .probe = pwm_fan_probe, .remove = pwm_fan_remove, .driver = { .name = "pwm-fan", .pm = &pwm_fan_pm, .of_match_table = of_pwm_fan_match, }, }; module_platform_driver(pwm_fan_driver); MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>"); MODULE_ALIAS("platform:pwm-fan"); MODULE_DESCRIPTION("PWM FAN driver"); MODULE_LICENSE("GPL");