/*
* Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver
*
* Copyright (C) 2015 Xilinx, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
/* RTC Registers */
#define RTC_SET_TM_WR 0x00
#define RTC_SET_TM_RD 0x04
#define RTC_CALIB_WR 0x08
#define RTC_CALIB_RD 0x0C
#define RTC_CUR_TM 0x10
#define RTC_CUR_TICK 0x14
#define RTC_ALRM 0x18
#define RTC_INT_STS 0x20
#define RTC_INT_MASK 0x24
#define RTC_INT_EN 0x28
#define RTC_INT_DIS 0x2C
#define RTC_CTRL 0x40
#define RTC_FR_EN BIT(20)
#define RTC_FR_DATSHIFT 16
#define RTC_TICK_MASK 0xFFFF
#define RTC_INT_SEC BIT(0)
#define RTC_INT_ALRM BIT(1)
#define RTC_OSC_EN BIT(24)
#define RTC_BATT_EN BIT(31)
#define RTC_CALIB_DEF 0x198233
#define RTC_CALIB_MASK 0x1FFFFF
struct xlnx_rtc_dev {
struct rtc_device *rtc;
void __iomem *reg_base;
int alarm_irq;
int sec_irq;
int calibval;
};
static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long new_time;
/*
* The value written will be updated after 1 sec into the
* seconds read register, so we need to program time +1 sec
* to get the correct time on read.
*/
new_time = rtc_tm_to_time64(tm) + 1;
/*
* Writing into calibration register will clear the Tick Counter and
* force the next second to be signaled exactly in 1 second period
*/
xrtcdev->calibval &= RTC_CALIB_MASK;
writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
/*
* Clear the rtc interrupt status register after setting the
* time. During a read_time function, the code should read the
* RTC_INT_STATUS register and if bit 0 is still 0, it means
* that one second has not elapsed yet since RTC was set and
* the current time should be read from SET_TIME_READ register;
* otherwise, CURRENT_TIME register is read to report the time
*/
writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS);
return 0;
}
static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
u32 status;
unsigned long read_time;
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
status = readl(xrtcdev->reg_base + RTC_INT_STS);
if (status & RTC_INT_SEC) {
/*
* RTC has updated the CURRENT_TIME with the time written into
* SET_TIME_WRITE register.
*/
rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_CUR_TM), tm);
} else {
/*
* Time written in SET_TIME_WRITE has not yet updated into
* the seconds read register, so read the time from the
* SET_TIME_WRITE instead of CURRENT_TIME register.
* Since we add +1 sec while writing, we need to -1 sec while
* reading.
*/
read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1;
rtc_time64_to_tm(read_time, tm);
}
return 0;
}
static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time);
alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM;
return 0;
}
static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
if (enabled)
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN);
else
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
return 0;
}
static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long alarm_time;
alarm_time = rtc_tm_to_time64(&alrm->time);
writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM));
xlnx_rtc_alarm_irq_enable(dev, alrm->enabled);
return 0;
}
static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev)
{
u32 rtc_ctrl;
/* Enable RTC switch to battery when VCC_PSAUX is not available */
rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL);
rtc_ctrl |= RTC_BATT_EN;
writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL);
/*
* Based on crystal freq of 33.330 KHz
* set the seconds counter and enable, set fractions counter
* to default value suggested as per design spec
* to correct RTC delay in frequency over period of time.
*/
xrtcdev->calibval &= RTC_CALIB_MASK;
writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
}
static const struct rtc_class_ops xlnx_rtc_ops = {
.set_time = xlnx_rtc_set_time,
.read_time = xlnx_rtc_read_time,
.read_alarm = xlnx_rtc_read_alarm,
.set_alarm = xlnx_rtc_set_alarm,
.alarm_irq_enable = xlnx_rtc_alarm_irq_enable,
};
static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
{
struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id;
unsigned int status;
status = readl(xrtcdev->reg_base + RTC_INT_STS);
/* Check if interrupt asserted */
if (!(status & (RTC_INT_SEC | RTC_INT_ALRM)))
return IRQ_NONE;
/* Clear RTC_INT_ALRM interrupt only */
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS);
if (status & RTC_INT_ALRM)
rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static int xlnx_rtc_probe(struct platform_device *pdev)
{
struct xlnx_rtc_dev *xrtcdev;
struct resource *res;
int ret;
xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL);
if (!xrtcdev)
return -ENOMEM;
platform_set_drvdata(pdev, xrtcdev);
xrtcdev->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(xrtcdev->rtc))
return PTR_ERR(xrtcdev->rtc);
xrtcdev->rtc->ops = &xlnx_rtc_ops;
xrtcdev->rtc->range_max = U32_MAX;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
xrtcdev->reg_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(xrtcdev->reg_base))
return PTR_ERR(xrtcdev->reg_base);
xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm");
if (xrtcdev->alarm_irq < 0) {
dev_err(&pdev->dev, "no irq resource\n");
return xrtcdev->alarm_irq;
}
ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq,
xlnx_rtc_interrupt, 0,
dev_name(&pdev->dev), xrtcdev);
if (ret) {
dev_err(&pdev->dev, "request irq failed\n");
return ret;
}
xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec");
if (xrtcdev->sec_irq < 0) {
dev_err(&pdev->dev, "no irq resource\n");
return xrtcdev->sec_irq;
}
ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq,
xlnx_rtc_interrupt, 0,
dev_name(&pdev->dev), xrtcdev);
if (ret) {
dev_err(&pdev->dev, "request irq failed\n");
return ret;
}
ret = of_property_read_u32(pdev->dev.of_node, "calibration",
&xrtcdev->calibval);
if (ret)
xrtcdev->calibval = RTC_CALIB_DEF;
xlnx_init_rtc(xrtcdev);
device_init_wakeup(&pdev->dev, 1);
return rtc_register_device(xrtcdev->rtc);
}
static int xlnx_rtc_remove(struct platform_device *pdev)
{
xlnx_rtc_alarm_irq_enable(&pdev->dev, 0);
device_init_wakeup(&pdev->dev, 0);
return 0;
}
static int __maybe_unused xlnx_rtc_suspend(struct device *dev)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(xrtcdev->alarm_irq);
else
xlnx_rtc_alarm_irq_enable(dev, 0);
return 0;
}
static int __maybe_unused xlnx_rtc_resume(struct device *dev)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(xrtcdev->alarm_irq);
else
xlnx_rtc_alarm_irq_enable(dev, 1);
return 0;
}
static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume);
static const struct of_device_id xlnx_rtc_of_match[] = {
{.compatible = "xlnx,zynqmp-rtc" },
{ }
};
MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match);
static struct platform_driver xlnx_rtc_driver = {
.probe = xlnx_rtc_probe,
.remove = xlnx_rtc_remove,
.driver = {
.name = KBUILD_MODNAME,
.pm = &xlnx_rtc_pm_ops,
.of_match_table = xlnx_rtc_of_match,
},
};
module_platform_driver(xlnx_rtc_driver);
MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver");
MODULE_AUTHOR("Xilinx Inc.");
MODULE_LICENSE("GPL v2");
