--- /dev/null
+/*
+ * APM X-Gene SoC Real Time Clock Driver
+ *
+ * Copyright (c) 2014, Applied Micro Circuits Corporation
+ * Author: Rameshwar Prasad Sahu <rsahu@apm.com>
+ * Loc Ho <lho@apm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that 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/slab.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/rtc.h>
+
+/* RTC CSR Registers */
+#define RTC_CCVR 0x00
+#define RTC_CMR 0x04
+#define RTC_CLR 0x08
+#define RTC_CCR 0x0C
+#define RTC_CCR_IE BIT(0)
+#define RTC_CCR_MASK BIT(1)
+#define RTC_CCR_EN BIT(2)
+#define RTC_CCR_WEN BIT(3)
+#define RTC_STAT 0x10
+#define RTC_STAT_BIT BIT(0)
+#define RTC_RSTAT 0x14
+#define RTC_EOI 0x18
+#define RTC_VER 0x1C
+
+struct xgene_rtc_dev {
+ struct rtc_device *rtc;
+ struct device *dev;
+ unsigned long alarm_time;
+ void __iomem *csr_base;
+ struct clk *clk;
+ unsigned int irq_wake;
+};
+
+static int xgene_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
+
+ rtc_time_to_tm(readl(pdata->csr_base + RTC_CCVR), tm);
+ return rtc_valid_tm(tm);
+}
+
+static int xgene_rtc_set_mmss(struct device *dev, unsigned long secs)
+{
+ struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
+
+ /*
+ * NOTE: After the following write, the RTC_CCVR is only reflected
+ * after the update cycle of 1 seconds.
+ */
+ writel((u32) secs, pdata->csr_base + RTC_CLR);
+ readl(pdata->csr_base + RTC_CLR); /* Force a barrier */
+
+ return 0;
+}
+
+static int xgene_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
+
+ rtc_time_to_tm(pdata->alarm_time, &alrm->time);
+ alrm->enabled = readl(pdata->csr_base + RTC_CCR) & RTC_CCR_IE;
+
+ return 0;
+}
+
+static int xgene_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
+{
+ struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
+ u32 ccr;
+
+ ccr = readl(pdata->csr_base + RTC_CCR);
+ if (enabled) {
+ ccr &= ~RTC_CCR_MASK;
+ ccr |= RTC_CCR_IE;
+ } else {
+ ccr &= ~RTC_CCR_IE;
+ ccr |= RTC_CCR_MASK;
+ }
+ writel(ccr, pdata->csr_base + RTC_CCR);
+
+ return 0;
+}
+
+static int xgene_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
+ unsigned long rtc_time;
+ unsigned long alarm_time;
+
+ rtc_time = readl(pdata->csr_base + RTC_CCVR);
+ rtc_tm_to_time(&alrm->time, &alarm_time);
+
+ pdata->alarm_time = alarm_time;
+ writel((u32) pdata->alarm_time, pdata->csr_base + RTC_CMR);
+
+ xgene_rtc_alarm_irq_enable(dev, alrm->enabled);
+
+ return 0;
+}
+
+static const struct rtc_class_ops xgene_rtc_ops = {
+ .read_time = xgene_rtc_read_time,
+ .set_mmss = xgene_rtc_set_mmss,
+ .read_alarm = xgene_rtc_read_alarm,
+ .set_alarm = xgene_rtc_set_alarm,
+ .alarm_irq_enable = xgene_rtc_alarm_irq_enable,
+};
+
+static irqreturn_t xgene_rtc_interrupt(int irq, void *id)
+{
+ struct xgene_rtc_dev *pdata = (struct xgene_rtc_dev *) id;
+
+ /* Check if interrupt asserted */
+ if (!(readl(pdata->csr_base + RTC_STAT) & RTC_STAT_BIT))
+ return IRQ_NONE;
+
+ /* Clear interrupt */
+ readl(pdata->csr_base + RTC_EOI);
+
+ rtc_update_irq(pdata->rtc, 1, RTC_IRQF | RTC_AF);
+
+ return IRQ_HANDLED;
+}
+
+static int xgene_rtc_probe(struct platform_device *pdev)
+{
+ struct xgene_rtc_dev *pdata;
+ struct resource *res;
+ int ret;
+ int irq;
+
+ pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return -ENOMEM;
+ platform_set_drvdata(pdev, pdata);
+ pdata->dev = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ pdata->csr_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(pdata->csr_base))
+ return PTR_ERR(pdata->csr_base);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "No IRQ resource\n");
+ return irq;
+ }
+ ret = devm_request_irq(&pdev->dev, irq, xgene_rtc_interrupt, 0,
+ dev_name(&pdev->dev), pdata);
+ if (ret) {
+ dev_err(&pdev->dev, "Could not request IRQ\n");
+ return ret;
+ }
+
+ pdata->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(pdata->clk)) {
+ dev_err(&pdev->dev, "Couldn't get the clock for RTC\n");
+ return -ENODEV;
+ }
+ clk_prepare_enable(pdata->clk);
+
+ /* Turn on the clock and the crystal */
+ writel(RTC_CCR_EN, pdata->csr_base + RTC_CCR);
+
+ device_init_wakeup(&pdev->dev, 1);
+
+ pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
+ &xgene_rtc_ops, THIS_MODULE);
+ if (IS_ERR(pdata->rtc)) {
+ clk_disable_unprepare(pdata->clk);
+ return PTR_ERR(pdata->rtc);
+ }
+
+ /* HW does not support update faster than 1 seconds */
+ pdata->rtc->uie_unsupported = 1;
+
+ return 0;
+}
+
+static int xgene_rtc_remove(struct platform_device *pdev)
+{
+ struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
+
+ xgene_rtc_alarm_irq_enable(&pdev->dev, 0);
+ device_init_wakeup(&pdev->dev, 0);
+ clk_disable_unprepare(pdata->clk);
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int xgene_rtc_suspend(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
+ int irq;
+
+ irq = platform_get_irq(pdev, 0);
+ if (device_may_wakeup(&pdev->dev)) {
+ if (!enable_irq_wake(irq))
+ pdata->irq_wake = 1;
+ } else {
+ xgene_rtc_alarm_irq_enable(dev, 0);
+ clk_disable(pdata->clk);
+ }
+
+ return 0;
+}
+
+static int xgene_rtc_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
+ int irq;
+
+ irq = platform_get_irq(pdev, 0);
+ if (device_may_wakeup(&pdev->dev)) {
+ if (pdata->irq_wake) {
+ disable_irq_wake(irq);
+ pdata->irq_wake = 0;
+ }
+ } else {
+ clk_enable(pdata->clk);
+ xgene_rtc_alarm_irq_enable(dev, 1);
+ }
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(xgene_rtc_pm_ops, xgene_rtc_suspend, xgene_rtc_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id xgene_rtc_of_match[] = {
+ {.compatible = "apm,xgene-rtc" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, xgene_rtc_of_match);
+#endif
+
+static struct platform_driver xgene_rtc_driver = {
+ .probe = xgene_rtc_probe,
+ .remove = xgene_rtc_remove,
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "xgene-rtc",
+ .pm = &xgene_rtc_pm_ops,
+ .of_match_table = of_match_ptr(xgene_rtc_of_match),
+ },
+};
+
+module_platform_driver(xgene_rtc_driver);
+
+MODULE_DESCRIPTION("APM X-Gene SoC RTC driver");
+MODULE_AUTHOR("Rameshwar Sahu <rsahu@apm.com>");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-rpi3.git / commitdiff