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601 lines
14 KiB
601 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* gpio-fan.c - Hwmon driver for fans connected to GPIO lines. |
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* |
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* Copyright (C) 2010 LaCie |
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* |
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* Author: Simon Guinot <[email protected]> |
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*/ |
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|
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/slab.h> |
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#include <linux/interrupt.h> |
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#include <linux/irq.h> |
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#include <linux/platform_device.h> |
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#include <linux/err.h> |
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#include <linux/mutex.h> |
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#include <linux/hwmon.h> |
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#include <linux/gpio/consumer.h> |
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#include <linux/of.h> |
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#include <linux/of_platform.h> |
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#include <linux/thermal.h> |
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struct gpio_fan_speed { |
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int rpm; |
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int ctrl_val; |
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}; |
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struct gpio_fan_data { |
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struct device *dev; |
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struct device *hwmon_dev; |
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/* Cooling device if any */ |
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struct thermal_cooling_device *cdev; |
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struct mutex lock; /* lock GPIOs operations. */ |
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int num_gpios; |
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struct gpio_desc **gpios; |
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int num_speed; |
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struct gpio_fan_speed *speed; |
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int speed_index; |
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#ifdef CONFIG_PM_SLEEP |
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int resume_speed; |
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#endif |
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bool pwm_enable; |
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struct gpio_desc *alarm_gpio; |
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struct work_struct alarm_work; |
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}; |
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/* |
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* Alarm GPIO. |
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*/ |
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static void fan_alarm_notify(struct work_struct *ws) |
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{ |
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struct gpio_fan_data *fan_data = |
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container_of(ws, struct gpio_fan_data, alarm_work); |
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sysfs_notify(&fan_data->hwmon_dev->kobj, NULL, "fan1_alarm"); |
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kobject_uevent(&fan_data->hwmon_dev->kobj, KOBJ_CHANGE); |
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} |
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static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id) |
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{ |
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struct gpio_fan_data *fan_data = dev_id; |
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schedule_work(&fan_data->alarm_work); |
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return IRQ_NONE; |
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} |
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static ssize_t fan1_alarm_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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return sprintf(buf, "%d\n", |
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gpiod_get_value_cansleep(fan_data->alarm_gpio)); |
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} |
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static DEVICE_ATTR_RO(fan1_alarm); |
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static int fan_alarm_init(struct gpio_fan_data *fan_data) |
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{ |
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int alarm_irq; |
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struct device *dev = fan_data->dev; |
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/* |
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* If the alarm GPIO don't support interrupts, just leave |
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* without initializing the fail notification support. |
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*/ |
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alarm_irq = gpiod_to_irq(fan_data->alarm_gpio); |
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if (alarm_irq <= 0) |
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return 0; |
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INIT_WORK(&fan_data->alarm_work, fan_alarm_notify); |
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irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH); |
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return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler, |
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IRQF_SHARED, "GPIO fan alarm", fan_data); |
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} |
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/* |
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* Control GPIOs. |
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*/ |
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/* Must be called with fan_data->lock held, except during initialization. */ |
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static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val) |
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{ |
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int i; |
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for (i = 0; i < fan_data->num_gpios; i++) |
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gpiod_set_value_cansleep(fan_data->gpios[i], |
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(ctrl_val >> i) & 1); |
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} |
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static int __get_fan_ctrl(struct gpio_fan_data *fan_data) |
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{ |
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int i; |
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int ctrl_val = 0; |
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for (i = 0; i < fan_data->num_gpios; i++) { |
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int value; |
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value = gpiod_get_value_cansleep(fan_data->gpios[i]); |
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ctrl_val |= (value << i); |
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} |
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return ctrl_val; |
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} |
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/* Must be called with fan_data->lock held, except during initialization. */ |
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static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index) |
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{ |
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if (fan_data->speed_index == speed_index) |
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return; |
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__set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val); |
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fan_data->speed_index = speed_index; |
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} |
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static int get_fan_speed_index(struct gpio_fan_data *fan_data) |
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{ |
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int ctrl_val = __get_fan_ctrl(fan_data); |
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int i; |
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for (i = 0; i < fan_data->num_speed; i++) |
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if (fan_data->speed[i].ctrl_val == ctrl_val) |
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return i; |
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dev_warn(fan_data->dev, |
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"missing speed array entry for GPIO value 0x%x\n", ctrl_val); |
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return -ENODEV; |
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} |
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static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm) |
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{ |
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struct gpio_fan_speed *speed = fan_data->speed; |
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int i; |
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for (i = 0; i < fan_data->num_speed; i++) |
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if (speed[i].rpm >= rpm) |
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return i; |
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return fan_data->num_speed - 1; |
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} |
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static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1); |
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return sprintf(buf, "%d\n", pwm); |
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} |
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static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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unsigned long pwm; |
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int speed_index; |
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int ret = count; |
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if (kstrtoul(buf, 10, &pwm) || pwm > 255) |
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return -EINVAL; |
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mutex_lock(&fan_data->lock); |
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if (!fan_data->pwm_enable) { |
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ret = -EPERM; |
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goto exit_unlock; |
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} |
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speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255); |
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set_fan_speed(fan_data, speed_index); |
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exit_unlock: |
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mutex_unlock(&fan_data->lock); |
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return ret; |
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} |
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static ssize_t pwm1_enable_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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return sprintf(buf, "%d\n", fan_data->pwm_enable); |
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} |
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static ssize_t pwm1_enable_store(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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unsigned long val; |
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if (kstrtoul(buf, 10, &val) || val > 1) |
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return -EINVAL; |
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if (fan_data->pwm_enable == val) |
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return count; |
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mutex_lock(&fan_data->lock); |
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fan_data->pwm_enable = val; |
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/* Disable manual control mode: set fan at full speed. */ |
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if (val == 0) |
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set_fan_speed(fan_data, fan_data->num_speed - 1); |
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mutex_unlock(&fan_data->lock); |
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return count; |
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} |
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static ssize_t pwm1_mode_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sprintf(buf, "0\n"); |
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} |
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static ssize_t fan1_min_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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return sprintf(buf, "%d\n", fan_data->speed[0].rpm); |
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} |
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static ssize_t fan1_max_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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return sprintf(buf, "%d\n", |
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fan_data->speed[fan_data->num_speed - 1].rpm); |
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} |
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static ssize_t fan1_input_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm); |
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} |
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static ssize_t set_rpm(struct device *dev, struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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unsigned long rpm; |
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int ret = count; |
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if (kstrtoul(buf, 10, &rpm)) |
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return -EINVAL; |
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mutex_lock(&fan_data->lock); |
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if (!fan_data->pwm_enable) { |
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ret = -EPERM; |
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goto exit_unlock; |
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} |
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set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm)); |
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exit_unlock: |
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mutex_unlock(&fan_data->lock); |
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return ret; |
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} |
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static DEVICE_ATTR_RW(pwm1); |
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static DEVICE_ATTR_RW(pwm1_enable); |
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static DEVICE_ATTR_RO(pwm1_mode); |
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static DEVICE_ATTR_RO(fan1_min); |
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static DEVICE_ATTR_RO(fan1_max); |
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static DEVICE_ATTR_RO(fan1_input); |
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static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm); |
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static umode_t gpio_fan_is_visible(struct kobject *kobj, |
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struct attribute *attr, int index) |
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{ |
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struct device *dev = kobj_to_dev(kobj); |
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struct gpio_fan_data *data = dev_get_drvdata(dev); |
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if (index == 0 && !data->alarm_gpio) |
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return 0; |
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if (index > 0 && !data->gpios) |
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return 0; |
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return attr->mode; |
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} |
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static struct attribute *gpio_fan_attributes[] = { |
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&dev_attr_fan1_alarm.attr, /* 0 */ |
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&dev_attr_pwm1.attr, /* 1 */ |
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&dev_attr_pwm1_enable.attr, |
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&dev_attr_pwm1_mode.attr, |
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&dev_attr_fan1_input.attr, |
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&dev_attr_fan1_target.attr, |
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&dev_attr_fan1_min.attr, |
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&dev_attr_fan1_max.attr, |
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NULL |
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}; |
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static const struct attribute_group gpio_fan_group = { |
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.attrs = gpio_fan_attributes, |
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.is_visible = gpio_fan_is_visible, |
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}; |
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static const struct attribute_group *gpio_fan_groups[] = { |
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&gpio_fan_group, |
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NULL |
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}; |
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static int fan_ctrl_init(struct gpio_fan_data *fan_data) |
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{ |
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int num_gpios = fan_data->num_gpios; |
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struct gpio_desc **gpios = fan_data->gpios; |
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int i, err; |
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for (i = 0; i < num_gpios; i++) { |
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/* |
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* The GPIO descriptors were retrieved with GPIOD_ASIS so here |
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* we set the GPIO into output mode, carefully preserving the |
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* current value by setting it to whatever it is already set |
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* (no surprise changes in default fan speed). |
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*/ |
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err = gpiod_direction_output(gpios[i], |
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gpiod_get_value_cansleep(gpios[i])); |
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if (err) |
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return err; |
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} |
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fan_data->pwm_enable = true; /* Enable manual fan speed control. */ |
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fan_data->speed_index = get_fan_speed_index(fan_data); |
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if (fan_data->speed_index < 0) |
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return fan_data->speed_index; |
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return 0; |
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} |
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static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev, |
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unsigned long *state) |
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{ |
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struct gpio_fan_data *fan_data = cdev->devdata; |
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if (!fan_data) |
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return -EINVAL; |
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*state = fan_data->num_speed - 1; |
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return 0; |
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} |
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static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev, |
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unsigned long *state) |
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{ |
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struct gpio_fan_data *fan_data = cdev->devdata; |
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if (!fan_data) |
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return -EINVAL; |
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*state = fan_data->speed_index; |
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return 0; |
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} |
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static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev, |
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unsigned long state) |
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{ |
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struct gpio_fan_data *fan_data = cdev->devdata; |
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if (!fan_data) |
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return -EINVAL; |
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set_fan_speed(fan_data, state); |
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return 0; |
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} |
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static const struct thermal_cooling_device_ops gpio_fan_cool_ops = { |
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.get_max_state = gpio_fan_get_max_state, |
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.get_cur_state = gpio_fan_get_cur_state, |
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.set_cur_state = gpio_fan_set_cur_state, |
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}; |
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/* |
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* Translate OpenFirmware node properties into platform_data |
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*/ |
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static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data) |
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{ |
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struct gpio_fan_speed *speed; |
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struct device *dev = fan_data->dev; |
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struct device_node *np = dev->of_node; |
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struct gpio_desc **gpios; |
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unsigned i; |
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u32 u; |
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struct property *prop; |
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const __be32 *p; |
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/* Alarm GPIO if one exists */ |
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fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN); |
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if (IS_ERR(fan_data->alarm_gpio)) |
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return PTR_ERR(fan_data->alarm_gpio); |
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/* Fill GPIO pin array */ |
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fan_data->num_gpios = gpiod_count(dev, NULL); |
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if (fan_data->num_gpios <= 0) { |
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if (fan_data->alarm_gpio) |
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return 0; |
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dev_err(dev, "DT properties empty / missing"); |
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return -ENODEV; |
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} |
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gpios = devm_kcalloc(dev, |
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fan_data->num_gpios, sizeof(struct gpio_desc *), |
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GFP_KERNEL); |
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if (!gpios) |
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return -ENOMEM; |
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for (i = 0; i < fan_data->num_gpios; i++) { |
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gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS); |
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if (IS_ERR(gpios[i])) |
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return PTR_ERR(gpios[i]); |
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} |
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fan_data->gpios = gpios; |
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/* Get number of RPM/ctrl_val pairs in speed map */ |
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prop = of_find_property(np, "gpio-fan,speed-map", &i); |
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if (!prop) { |
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dev_err(dev, "gpio-fan,speed-map DT property missing"); |
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return -ENODEV; |
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} |
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i = i / sizeof(u32); |
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if (i == 0 || i & 1) { |
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dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries"); |
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return -ENODEV; |
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} |
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fan_data->num_speed = i / 2; |
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/* |
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* Populate speed map |
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* Speed map is in the form <RPM ctrl_val RPM ctrl_val ...> |
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* this needs splitting into pairs to create gpio_fan_speed structs |
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*/ |
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speed = devm_kcalloc(dev, |
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fan_data->num_speed, sizeof(struct gpio_fan_speed), |
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GFP_KERNEL); |
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if (!speed) |
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return -ENOMEM; |
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p = NULL; |
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for (i = 0; i < fan_data->num_speed; i++) { |
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p = of_prop_next_u32(prop, p, &u); |
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if (!p) |
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return -ENODEV; |
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speed[i].rpm = u; |
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p = of_prop_next_u32(prop, p, &u); |
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if (!p) |
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return -ENODEV; |
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speed[i].ctrl_val = u; |
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} |
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fan_data->speed = speed; |
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return 0; |
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} |
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static const struct of_device_id of_gpio_fan_match[] = { |
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{ .compatible = "gpio-fan", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, of_gpio_fan_match); |
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static void gpio_fan_stop(void *data) |
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{ |
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set_fan_speed(data, 0); |
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} |
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static int gpio_fan_probe(struct platform_device *pdev) |
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{ |
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int err; |
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struct gpio_fan_data *fan_data; |
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struct device *dev = &pdev->dev; |
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struct device_node *np = dev->of_node; |
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fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data), |
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GFP_KERNEL); |
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if (!fan_data) |
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return -ENOMEM; |
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fan_data->dev = dev; |
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err = gpio_fan_get_of_data(fan_data); |
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if (err) |
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return err; |
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platform_set_drvdata(pdev, fan_data); |
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mutex_init(&fan_data->lock); |
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|
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/* Configure control GPIOs if available. */ |
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if (fan_data->gpios && fan_data->num_gpios > 0) { |
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if (!fan_data->speed || fan_data->num_speed <= 1) |
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return -EINVAL; |
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err = fan_ctrl_init(fan_data); |
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if (err) |
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return err; |
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err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data); |
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if (err) |
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return err; |
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} |
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|
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/* Make this driver part of hwmon class. */ |
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fan_data->hwmon_dev = |
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devm_hwmon_device_register_with_groups(dev, |
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"gpio_fan", fan_data, |
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gpio_fan_groups); |
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if (IS_ERR(fan_data->hwmon_dev)) |
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return PTR_ERR(fan_data->hwmon_dev); |
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|
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/* Configure alarm GPIO if available. */ |
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if (fan_data->alarm_gpio) { |
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err = fan_alarm_init(fan_data); |
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if (err) |
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return err; |
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} |
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|
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/* Optional cooling device register for Device tree platforms */ |
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fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np, |
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"gpio-fan", fan_data, &gpio_fan_cool_ops); |
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dev_info(dev, "GPIO fan initialized\n"); |
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return 0; |
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} |
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static void gpio_fan_shutdown(struct platform_device *pdev) |
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{ |
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struct gpio_fan_data *fan_data = platform_get_drvdata(pdev); |
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if (fan_data->gpios) |
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set_fan_speed(fan_data, 0); |
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} |
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|
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#ifdef CONFIG_PM_SLEEP |
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static int gpio_fan_suspend(struct device *dev) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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|
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if (fan_data->gpios) { |
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fan_data->resume_speed = fan_data->speed_index; |
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set_fan_speed(fan_data, 0); |
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} |
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return 0; |
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} |
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|
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static int gpio_fan_resume(struct device *dev) |
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{ |
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struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
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|
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if (fan_data->gpios) |
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set_fan_speed(fan_data, fan_data->resume_speed); |
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|
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return 0; |
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} |
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|
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static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume); |
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#define GPIO_FAN_PM (&gpio_fan_pm) |
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#else |
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#define GPIO_FAN_PM NULL |
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#endif |
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static struct platform_driver gpio_fan_driver = { |
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.probe = gpio_fan_probe, |
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.shutdown = gpio_fan_shutdown, |
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.driver = { |
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.name = "gpio-fan", |
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.pm = GPIO_FAN_PM, |
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.of_match_table = of_match_ptr(of_gpio_fan_match), |
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}, |
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}; |
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module_platform_driver(gpio_fan_driver); |
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MODULE_AUTHOR("Simon Guinot <[email protected]>"); |
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MODULE_DESCRIPTION("GPIO FAN driver"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("platform:gpio-fan");
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