drivers/rtc: add APM X-Gene SoC RTC driver
authorLoc Ho <lho@apm.com>
Fri, 6 Jun 2014 21:35:42 +0000 (14:35 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 6 Jun 2014 23:08:06 +0000 (16:08 -0700)
Add support for the APM X-Gene SoC RTC driver.

Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com>
Signed-off-by: Loc Ho <lho@apm.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-xgene.c [new file with mode: 0644]

index 2e565f8..ac4fa56 100644 (file)
@@ -1327,6 +1327,15 @@ config RTC_DRV_MOXART
           This driver can also be built as a module. If so, the module
           will be called rtc-moxart
 
+config RTC_DRV_XGENE
+       tristate "APM X-Gene RTC"
+       help
+         If you say yes here you get support for the APM X-Gene SoC real time
+         clock.
+
+         This driver can also be built as a module, if so, the module
+         will be called "rtc-xgene".
+
 comment "HID Sensor RTC drivers"
 
 config RTC_DRV_HID_SENSOR_TIME
index 40a0991..4545b4a 100644 (file)
@@ -135,5 +135,6 @@ obj-$(CONFIG_RTC_DRV_VT8500)        += rtc-vt8500.o
 obj-$(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_SIRFSOC)  += rtc-sirfsoc.o
 obj-$(CONFIG_RTC_DRV_MOXART)   += rtc-moxart.o
diff --git a/drivers/rtc/rtc-xgene.c b/drivers/rtc/rtc-xgene.c
new file mode 100644 (file)
index 0000000..14129cc
--- /dev/null
@@ -0,0 +1,278 @@
+/*
+ * 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");