2021-10-18 15:22:19

by Alexandre Belloni

Subject: [PATCH v2 2/7] 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: Alexandre Belloni <[email protected]>
---
drivers/rtc/dev.c | 40 ++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/rtc.h | 18 ++++++++++++++++++
2 files changed, 58 insertions(+)

diff --git a/drivers/rtc/dev.c b/drivers/rtc/dev.c
index 5b8ebe86124a..143c097eff0f 100644
--- a/drivers/rtc/dev.c
+++ b/drivers/rtc/dev.c
@@ -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) {
diff --git a/include/uapi/linux/rtc.h b/include/uapi/linux/rtc.h
index f4037c541925..3241f9ecc639 100644
--- a/include/uapi/linux/rtc.h
+++ b/include/uapi/linux/rtc.h
@@ -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


--
2.31.1