[PATCH 2/2] drivers: rtc: add xilinx zynqmp rtc driver

Suneel Garapati
2015-07-23T10:51:50Z

adds support for RTC controller found on
Xilinx Zynq Ultrascale+ MPSoC platform.

Signed-off-by: Suneel Garapati <suneel.garapati@xilinx.com>
---
drivers/rtc/Kconfig | 7 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-zynqmp.c | 278 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 286 insertions(+)
create mode 100644 drivers/rtc/rtc-zynqmp.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e132ccb..e44705b 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1116,6 +1116,13 @@ config RTC_DRV_OPAL
This driver can also be built as a module. If so, the module
will be called rtc-opal.

+config RTC_DRV_ZYNQMP
+ tristate "Xilinx Zynq Ultrascale+ MPSoC RTC"
+ depends on OF
+ help
+ If you say yes here you get support for the RTC controller found on
+ Xilinx Zynq Ultrascale+ MPSoC.
+
comment "on-CPU RTC drivers"

config RTC_DRV_DAVINCI
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 2797384..e491eb5 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -159,3 +159,4 @@ obj-$(CONFIG_RTC_DRV_WM831X) += rtc-wm831x.o
obj-$(CONFIG_RTC_DRV_WM8350) += rtc-wm8350.o
obj-$(CONFIG_RTC_DRV_X1205) += rtc-x1205.o
obj-$(CONFIG_RTC_DRV_XGENE) += rtc-xgene.o
+obj-$(CONFIG_RTC_DRV_ZYNQMP) += rtc-zynqmp.o
diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
new file mode 100644
index 0000000..59018b7
--- /dev/null
+++ b/drivers/rtc/rtc-zynqmp.c
@@ -0,0 +1,278 @@
+/*
+ * 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/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/delay.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_CALIB_DEF 0x198233
+#define RTC_CALIB_MASK 0x1FFFFF
+
+struct xlnx_rtc_dev {
+ struct rtc_device *rtc;
+ void __iomem *reg_base;
+ int alm_irq;
+ int sec_irq;
+};
+
+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;
+
+ rtc_tm_to_time(tm, &new_time);
+ writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
+
+ return 0;
+}
+
+static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
+
+ rtc_time_to_tm(readl(xrtcdev->reg_base + RTC_CUR_TM), tm);
+
+ return rtc_valid_tm(tm);
+}
+
+static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
+
+ rtc_time_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;
+
+ rtc_tm_to_time(&alrm->time, &alarm_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 calibval)
+{
+ /*
+ * Based on crystal freq of 33.330 KHz
+ * set the secounds counter and enable, set fractions counter
+ * to default value suggested as per design spec
+ * to correct RTC delay in frequency over period of time.
+ */
+ calibval &= RTC_CALIB_MASK;
+ writel(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 interrupt */
+ writel(status, xrtcdev->reg_base + RTC_INT_STS);
+
+ if (status & RTC_INT_SEC)
+ rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_UF);
+ if (status & RTC_INT_ALRM)
+ rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
+ if (status & RTC_INT_ALRM)
+ printk("alarm interrupt\n");
+ return IRQ_HANDLED;
+}
+
+static int xlnx_rtc_probe(struct platform_device *pdev)
+{
+ struct xlnx_rtc_dev *xrtcdev;
+ struct resource *res;
+ int ret;
+ unsigned int calibvalue;
+
+ xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL);
+ if (!xrtcdev)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, xrtcdev);
+
+ 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->alm_irq = platform_get_irq_byname(pdev, "alm");
+ if (xrtcdev->alm_irq < 0) {
+ dev_err(&pdev->dev, "no irq resource\n");
+ return xrtcdev->alm_irq;
+ }
+ ret = devm_request_irq(&pdev->dev, xrtcdev->alm_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",
+ &calibvalue);
+ if (ret)
+ calibvalue = RTC_CALIB_DEF;
+
+ xlnx_init_rtc(xrtcdev, calibvalue);
+
+ device_init_wakeup(&pdev->dev, 1);
+
+ xrtcdev->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
+ &xlnx_rtc_ops, THIS_MODULE);
+ if (IS_ERR(xrtcdev->rtc)) {
+ return PTR_ERR(xrtcdev->rtc);
+ }
+
+ return 0;
+}
+
+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 platform_device *pdev = to_platform_device(dev);
+ struct xlnx_rtc_dev *xrtcdev = platform_get_drvdata(pdev);
+
+ if (device_may_wakeup(&pdev->dev)) {
+ enable_irq_wake(xrtcdev->alm_irq);
+ } else {
+ xlnx_rtc_alarm_irq_enable(dev, 0);
+ }
+
+ return 0;
+}
+
+static int __maybe_unused xlnx_rtc_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct xlnx_rtc_dev *xrtcdev = platform_get_drvdata(pdev);
+
+ if (device_may_wakeup(&pdev->dev)) {
+ disable_irq_wake(xrtcdev->alm_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");
--
2.1.2