那你能帮我写一个linux的pwm驱动吗

当然可以，以下是一个简单的Linux PWM驱动程序的示例代码：

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>

static struct pwm_device *pwm_dev;

static int pwm_probe(struct platform_device *pdev)
{
struct pwm_args args;
int ret;

args.period = 1000000; // 1ms
args.duty_cycle = 500000; // 50%
args.polarity = PWM_POLARITY_NORMAL;

pwm_dev = pwm_request(pdev->dev.parent, "pwm_test");
if (IS_ERR(pwm_dev)) {
ret = PTR_ERR(pwm_dev);
printk(KERN_ERR "Failed to request PWM: %d\n", ret);
return ret;
}

ret = pwm_apply_args(pwm_dev, &args);
if (ret < 0) {
printk(KERN_ERR "Failed to apply PWM args: %d\n", ret);
pwm_free(pwm_dev);
return ret;
}

ret = pwm_enable(pwm_dev);
if (ret < 0) {
printk(KERN_ERR "Failed to enable PWM: %d\n", ret);
pwm_free(pwm_dev);
return ret;
}

return 0;
}

static int pwm_remove(struct platform_device *pdev)
{
pwm_disable(pwm_dev);
pwm_free(pwm_dev);
return 0;
}

static struct platform_driver pwm_driver = {
.probe = pwm_probe,
.remove = pwm_remove,
.driver = {
.name = "pwm_test",
.owner = THIS_MODULE,
},
};

static int __init pwm_init(void)
{
return platform_driver_register(&pwm_driver);
}

static void __exit pwm_exit(void)
{
platform_driver_unregister(&pwm_driver);
}

module_init(pwm_init);
module_exit(pwm_exit);
MODULE_LICENSE("GPL");