467 lines
10 KiB
C
467 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* pwm-fan.c - Hwmon driver for fans connected to PWM lines.
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*
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* Copyright (c) 2014 Samsung Electronics Co., Ltd.
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*
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* Author: Kamil Debski <k.debski@samsung.com>
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*/
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/regulator/consumer.h>
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#include <linux/sysfs.h>
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#include <linux/thermal.h>
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#include <linux/timer.h>
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#define MAX_PWM 255
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struct pwm_fan_ctx {
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struct mutex lock;
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struct pwm_device *pwm;
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struct regulator *reg_en;
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int irq;
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atomic_t pulses;
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unsigned int rpm;
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u8 pulses_per_revolution;
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ktime_t sample_start;
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struct timer_list rpm_timer;
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unsigned int pwm_value;
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unsigned int pwm_fan_state;
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unsigned int pwm_fan_max_state;
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unsigned int *pwm_fan_cooling_levels;
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struct thermal_cooling_device *cdev;
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};
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/* This handler assumes self resetting edge triggered interrupt. */
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static irqreturn_t pulse_handler(int irq, void *dev_id)
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{
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struct pwm_fan_ctx *ctx = dev_id;
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atomic_inc(&ctx->pulses);
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return IRQ_HANDLED;
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}
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static void sample_timer(struct timer_list *t)
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{
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struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
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int pulses;
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u64 tmp;
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pulses = atomic_read(&ctx->pulses);
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atomic_sub(pulses, &ctx->pulses);
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tmp = (u64)pulses * ktime_ms_delta(ktime_get(), ctx->sample_start) * 60;
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do_div(tmp, ctx->pulses_per_revolution * 1000);
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ctx->rpm = tmp;
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ctx->sample_start = ktime_get();
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mod_timer(&ctx->rpm_timer, jiffies + HZ);
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}
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static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
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{
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unsigned long period;
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int ret = 0;
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struct pwm_state state = { };
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mutex_lock(&ctx->lock);
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if (ctx->pwm_value == pwm)
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goto exit_set_pwm_err;
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pwm_init_state(ctx->pwm, &state);
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period = ctx->pwm->args.period;
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state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
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state.enabled = pwm ? true : false;
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ret = pwm_apply_state(ctx->pwm, &state);
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if (!ret)
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ctx->pwm_value = pwm;
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exit_set_pwm_err:
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mutex_unlock(&ctx->lock);
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return ret;
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}
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static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
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{
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int i;
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for (i = 0; i < ctx->pwm_fan_max_state; ++i)
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if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
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break;
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ctx->pwm_fan_state = i;
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}
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static ssize_t pwm_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 pwm_fan_ctx *ctx = dev_get_drvdata(dev);
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unsigned long pwm;
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int ret;
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if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM)
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return -EINVAL;
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ret = __set_pwm(ctx, pwm);
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if (ret)
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return ret;
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pwm_fan_update_state(ctx, pwm);
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return count;
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}
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static ssize_t pwm_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", ctx->pwm_value);
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}
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static ssize_t rpm_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", ctx->rpm);
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}
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static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0);
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static SENSOR_DEVICE_ATTR_RO(fan1_input, rpm, 0);
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static struct attribute *pwm_fan_attrs[] = {
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&sensor_dev_attr_pwm1.dev_attr.attr,
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&sensor_dev_attr_fan1_input.dev_attr.attr,
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NULL,
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};
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static umode_t pwm_fan_attrs_visible(struct kobject *kobj, struct attribute *a,
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int n)
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{
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struct device *dev = container_of(kobj, struct device, kobj);
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struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
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/* Hide fan_input in case no interrupt is available */
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if (n == 1 && ctx->irq <= 0)
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return 0;
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return a->mode;
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}
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static const struct attribute_group pwm_fan_group = {
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.attrs = pwm_fan_attrs,
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.is_visible = pwm_fan_attrs_visible,
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};
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static const struct attribute_group *pwm_fan_groups[] = {
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&pwm_fan_group,
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NULL,
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};
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/* thermal cooling device callbacks */
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static int pwm_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 pwm_fan_ctx *ctx = cdev->devdata;
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if (!ctx)
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return -EINVAL;
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*state = ctx->pwm_fan_max_state;
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return 0;
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}
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static int pwm_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 pwm_fan_ctx *ctx = cdev->devdata;
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if (!ctx)
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return -EINVAL;
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*state = ctx->pwm_fan_state;
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return 0;
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}
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static int
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pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
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{
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struct pwm_fan_ctx *ctx = cdev->devdata;
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int ret;
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if (!ctx || (state > ctx->pwm_fan_max_state))
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return -EINVAL;
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if (state == ctx->pwm_fan_state)
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return 0;
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ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
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if (ret) {
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dev_err(&cdev->device, "Cannot set pwm!\n");
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return ret;
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}
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ctx->pwm_fan_state = state;
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return ret;
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}
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static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
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.get_max_state = pwm_fan_get_max_state,
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.get_cur_state = pwm_fan_get_cur_state,
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.set_cur_state = pwm_fan_set_cur_state,
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};
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static int pwm_fan_of_get_cooling_data(struct device *dev,
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struct pwm_fan_ctx *ctx)
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{
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struct device_node *np = dev->of_node;
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int num, i, ret;
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if (!of_find_property(np, "cooling-levels", NULL))
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return 0;
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ret = of_property_count_u32_elems(np, "cooling-levels");
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if (ret <= 0) {
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dev_err(dev, "Wrong data!\n");
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return ret ? : -EINVAL;
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}
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num = ret;
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ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
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GFP_KERNEL);
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if (!ctx->pwm_fan_cooling_levels)
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return -ENOMEM;
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ret = of_property_read_u32_array(np, "cooling-levels",
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ctx->pwm_fan_cooling_levels, num);
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if (ret) {
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dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
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return ret;
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}
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for (i = 0; i < num; i++) {
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if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
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dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
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ctx->pwm_fan_cooling_levels[i], MAX_PWM);
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return -EINVAL;
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}
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}
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ctx->pwm_fan_max_state = num - 1;
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return 0;
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}
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static void pwm_fan_regulator_disable(void *data)
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{
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regulator_disable(data);
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}
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static void pwm_fan_pwm_disable(void *__ctx)
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{
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struct pwm_fan_ctx *ctx = __ctx;
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pwm_disable(ctx->pwm);
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del_timer_sync(&ctx->rpm_timer);
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}
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static int pwm_fan_probe(struct platform_device *pdev)
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{
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struct thermal_cooling_device *cdev;
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struct device *dev = &pdev->dev;
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struct pwm_fan_ctx *ctx;
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struct device *hwmon;
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int ret;
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struct pwm_state state = { };
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u32 ppr = 2;
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ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
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if (!ctx)
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return -ENOMEM;
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mutex_init(&ctx->lock);
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ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
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if (IS_ERR(ctx->pwm)) {
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ret = PTR_ERR(ctx->pwm);
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if (ret != -EPROBE_DEFER)
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dev_err(dev, "Could not get PWM: %d\n", ret);
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return ret;
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}
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platform_set_drvdata(pdev, ctx);
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ctx->irq = platform_get_irq(pdev, 0);
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if (ctx->irq == -EPROBE_DEFER)
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return ctx->irq;
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ctx->reg_en = devm_regulator_get_optional(dev, "fan");
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if (IS_ERR(ctx->reg_en)) {
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if (PTR_ERR(ctx->reg_en) != -ENODEV)
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return PTR_ERR(ctx->reg_en);
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ctx->reg_en = NULL;
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} else {
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ret = regulator_enable(ctx->reg_en);
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if (ret) {
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dev_err(dev, "Failed to enable fan supply: %d\n", ret);
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return ret;
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}
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devm_add_action_or_reset(dev, pwm_fan_regulator_disable,
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ctx->reg_en);
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}
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ctx->pwm_value = MAX_PWM;
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/* Set duty cycle to maximum allowed and enable PWM output */
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pwm_init_state(ctx->pwm, &state);
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state.duty_cycle = ctx->pwm->args.period - 1;
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state.enabled = true;
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ret = pwm_apply_state(ctx->pwm, &state);
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if (ret) {
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dev_err(dev, "Failed to configure PWM: %d\n", ret);
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return ret;
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}
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timer_setup(&ctx->rpm_timer, sample_timer, 0);
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devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx);
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of_property_read_u32(dev->of_node, "pulses-per-revolution", &ppr);
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ctx->pulses_per_revolution = ppr;
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if (!ctx->pulses_per_revolution) {
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dev_err(dev, "pulses-per-revolution can't be zero.\n");
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return -EINVAL;
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}
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if (ctx->irq > 0) {
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ret = devm_request_irq(dev, ctx->irq, pulse_handler, 0,
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pdev->name, ctx);
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if (ret) {
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dev_err(dev, "Failed to request interrupt: %d\n", ret);
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return ret;
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}
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ctx->sample_start = ktime_get();
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mod_timer(&ctx->rpm_timer, jiffies + HZ);
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}
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hwmon = devm_hwmon_device_register_with_groups(dev, "pwmfan",
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ctx, pwm_fan_groups);
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if (IS_ERR(hwmon)) {
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dev_err(dev, "Failed to register hwmon device\n");
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return PTR_ERR(hwmon);
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}
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ret = pwm_fan_of_get_cooling_data(dev, ctx);
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if (ret)
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return ret;
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ctx->pwm_fan_state = ctx->pwm_fan_max_state;
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if (IS_ENABLED(CONFIG_THERMAL)) {
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cdev = devm_thermal_of_cooling_device_register(dev,
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dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops);
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if (IS_ERR(cdev)) {
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ret = PTR_ERR(cdev);
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dev_err(dev,
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"Failed to register pwm-fan as cooling device: %d\n",
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ret);
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return ret;
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}
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ctx->cdev = cdev;
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thermal_cdev_update(cdev);
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}
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int pwm_fan_suspend(struct device *dev)
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{
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struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
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struct pwm_args args;
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int ret;
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pwm_get_args(ctx->pwm, &args);
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if (ctx->pwm_value) {
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ret = pwm_config(ctx->pwm, 0, args.period);
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if (ret < 0)
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return ret;
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pwm_disable(ctx->pwm);
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}
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if (ctx->reg_en) {
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ret = regulator_disable(ctx->reg_en);
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if (ret) {
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dev_err(dev, "Failed to disable fan supply: %d\n", ret);
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return ret;
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}
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}
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return 0;
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}
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static int pwm_fan_resume(struct device *dev)
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{
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struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
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struct pwm_args pargs;
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unsigned long duty;
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int ret;
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if (ctx->reg_en) {
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ret = regulator_enable(ctx->reg_en);
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if (ret) {
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dev_err(dev, "Failed to enable fan supply: %d\n", ret);
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return ret;
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}
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}
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if (ctx->pwm_value == 0)
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return 0;
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pwm_get_args(ctx->pwm, &pargs);
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duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
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ret = pwm_config(ctx->pwm, duty, pargs.period);
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if (ret)
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return ret;
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return pwm_enable(ctx->pwm);
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}
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#endif
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static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
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static const struct of_device_id of_pwm_fan_match[] = {
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{ .compatible = "pwm-fan", },
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{},
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};
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MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
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static struct platform_driver pwm_fan_driver = {
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.probe = pwm_fan_probe,
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.driver = {
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.name = "pwm-fan",
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.pm = &pwm_fan_pm,
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.of_match_table = of_pwm_fan_match,
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},
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};
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module_platform_driver(pwm_fan_driver);
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MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
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MODULE_ALIAS("platform:pwm-fan");
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MODULE_DESCRIPTION("PWM FAN driver");
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MODULE_LICENSE("GPL");
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