Commit 6a8af1b6 authored by Alexandre Belloni's avatar Alexandre Belloni
Browse files

rtc: add parameter ioctl 



Add an ioctl allowing to get and set extra parameters for an RTC. For now,
only handle getting available features.

Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211018151933.76865-3-alexandre.belloni@bootlin.com
parent 917425f7

drivers/rtc/dev.c

+40 −0
Original line number Diff line number Diff line
@@ -208,6 +208,7 @@ static long rtc_dev_ioctl(struct file *file, 
	const struct rtc_class_ops *ops = rtc->ops;

	struct rtc_time tm;

	struct rtc_wkalrm alarm;

	struct rtc_param param;

	void __user *uarg = (void __user *)arg;



	err = mutex_lock_interruptible(&rtc->ops_lock);
@@ -221,6 +222,7 @@ static long rtc_dev_ioctl(struct file *file, 
	switch (cmd) {

	case RTC_EPOCH_SET:

	case RTC_SET_TIME:

	case RTC_PARAM_SET:

		if (!capable(CAP_SYS_TIME))

			err = -EACCES;

		break;
@@ -382,6 +384,44 @@ static long rtc_dev_ioctl(struct file *file, 
			err = -EFAULT;

		return err;



	case RTC_PARAM_GET:

		if (copy_from_user(&param, uarg, sizeof(param))) {

			mutex_unlock(&rtc->ops_lock);

			return -EFAULT;

		}



		switch(param.param) {

			long offset;

		case RTC_PARAM_FEATURES:

			if (param.index != 0)

				err = -EINVAL;

			param.uvalue = rtc->features[0];

			break;



		default:

			err = -EINVAL;

		}



		if (!err)

			if (copy_to_user(uarg, &param, sizeof(param)))

				err = -EFAULT;



		break;



	case RTC_PARAM_SET:

		if (copy_from_user(&param, uarg, sizeof(param))) {

			mutex_unlock(&rtc->ops_lock);

			return -EFAULT;

		}



		switch(param.param) {

		case RTC_PARAM_FEATURES:

		default:

			err = -EINVAL;

		}



		break;



	default:

		/* Finally try the driver's ioctl interface */

		if (ops->ioctl) {

include/uapi/linux/rtc.h

+18 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 


#include <linux/const.h>

#include <linux/ioctl.h>

#include <linux/types.h>



/*

 * The struct used to pass data via the following ioctl. Similar to the
@@ -66,6 +67,17 @@ struct rtc_pll_info { 
	long pll_clock;     /* base PLL frequency */

};



struct rtc_param {

	__u64 param;

	union {

		__u64 uvalue;

		__s64 svalue;

		__u64 ptr;

	};

	__u32 index;

	__u32 __pad;

};



/*

 * ioctl calls that are permitted to the /dev/rtc interface, if

 * any of the RTC drivers are enabled.
@@ -95,6 +107,9 @@ struct rtc_pll_info { 
#define RTC_PLL_GET	_IOR('p', 0x11, struct rtc_pll_info)  /* Get PLL correction */

#define RTC_PLL_SET	_IOW('p', 0x12, struct rtc_pll_info)  /* Set PLL correction */



#define RTC_PARAM_GET	_IOW('p', 0x13, struct rtc_param)  /* Get parameter */

#define RTC_PARAM_SET	_IOW('p', 0x14, struct rtc_param)  /* Set parameter */



#define RTC_VL_DATA_INVALID	_BITUL(0) /* Voltage too low, RTC data is invalid */

#define RTC_VL_BACKUP_LOW	_BITUL(1) /* Backup voltage is low */

#define RTC_VL_BACKUP_EMPTY	_BITUL(2) /* Backup empty or not present */
@@ -118,6 +133,9 @@ struct rtc_pll_info { 
#define RTC_FEATURE_UPDATE_INTERRUPT	4

#define RTC_FEATURE_CNT			5



/* parameter list */

#define RTC_PARAM_FEATURES		0



#define RTC_MAX_FREQ	8192