drivers/rtc/rtc-sirfsoc.c: add rtc drivers for CSR SiRFprimaII and SiRFatlasVI
On CSR SiRFprimaII/atlasVI, there is a programmable 16-bit divider
(RTC_DIV) that divides the input 32.768KHz clock to the frequency that
users need (E.g. 1 Hz). The divided real-time clock will be used to
drive a 32-bit counter (RTC_COUNTER) that provides users with the actual
time.
In each cycle of the divided real-time clock, there is a Hertz interrupt
generated to the RISC. Users can also configure an alarm (RTC_ALARM).
When RTC_COUNTER matches the alarm, there will be an alarm interrupt
generated to the RISC.
The system RTC can generate an alarm wake-up signal to notify the power
controller to wake up from power saving mode.
Signed-off-by: Xianglong Du <Xianglong.Du@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 8009e5d..9e3498b 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1242,6 +1242,13 @@
This driver can also be built as a module, if so, the module
will be called "rtc-snvs".
+config RTC_DRV_SIRFSOC
+ tristate "SiRFSOC RTC"
+ depends on ARCH_SIRF
+ help
+ Say "yes" here to support the real time clock on SiRF SOC chips.
+ This driver can also be built as a module called rtc-sirfsoc.
+
comment "HID Sensor RTC drivers"
config RTC_DRV_HID_SENSOR_TIME
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 994a2fa..d3b4488 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -129,3 +129,4 @@
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_SIRFSOC) += rtc-sirfsoc.o
diff --git a/drivers/rtc/rtc-sirfsoc.c b/drivers/rtc/rtc-sirfsoc.c
new file mode 100644
index 0000000..aa7ed4b
--- /dev/null
+++ b/drivers/rtc/rtc-sirfsoc.c
@@ -0,0 +1,475 @@
+/*
+ * SiRFSoC Real Time Clock interface for Linux
+ *
+ * Copyright (c) 2013 Cambridge Silicon Radio Limited, a CSR plc group company.
+ *
+ * Licensed under GPLv2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/rtc/sirfsoc_rtciobrg.h>
+
+
+#define RTC_CN 0x00
+#define RTC_ALARM0 0x04
+#define RTC_ALARM1 0x18
+#define RTC_STATUS 0x08
+#define RTC_SW_VALUE 0x40
+#define SIRFSOC_RTC_AL1E (1<<6)
+#define SIRFSOC_RTC_AL1 (1<<4)
+#define SIRFSOC_RTC_HZE (1<<3)
+#define SIRFSOC_RTC_AL0E (1<<2)
+#define SIRFSOC_RTC_HZ (1<<1)
+#define SIRFSOC_RTC_AL0 (1<<0)
+#define RTC_DIV 0x0c
+#define RTC_DEEP_CTRL 0x14
+#define RTC_CLOCK_SWITCH 0x1c
+#define SIRFSOC_RTC_CLK 0x03 /* others are reserved */
+
+/* Refer to RTC DIV switch */
+#define RTC_HZ 16
+
+/* This macro is also defined in arch/arm/plat-sirfsoc/cpu.c */
+#define RTC_SHIFT 4
+
+#define INTR_SYSRTC_CN 0x48
+
+struct sirfsoc_rtc_drv {
+ struct rtc_device *rtc;
+ u32 rtc_base;
+ u32 irq;
+ /* Overflow for every 8 years extra time */
+ u32 overflow_rtc;
+#ifdef CONFIG_PM
+ u32 saved_counter;
+ u32 saved_overflow_rtc;
+#endif
+};
+
+static int sirfsoc_rtc_read_alarm(struct device *dev,
+ struct rtc_wkalrm *alrm)
+{
+ unsigned long rtc_alarm, rtc_count;
+ struct sirfsoc_rtc_drv *rtcdrv;
+
+ rtcdrv = (struct sirfsoc_rtc_drv *)dev_get_drvdata(dev);
+
+ local_irq_disable();
+
+ rtc_count = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
+
+ rtc_alarm = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_ALARM0);
+ memset(alrm, 0, sizeof(struct rtc_wkalrm));
+
+ /*
+ * assume alarm interval not beyond one round counter overflow_rtc:
+ * 0->0xffffffff
+ */
+ /* if alarm is in next overflow cycle */
+ if (rtc_count > rtc_alarm)
+ rtc_time_to_tm((rtcdrv->overflow_rtc + 1)
+ << (BITS_PER_LONG - RTC_SHIFT)
+ | rtc_alarm >> RTC_SHIFT, &(alrm->time));
+ else
+ rtc_time_to_tm(rtcdrv->overflow_rtc
+ << (BITS_PER_LONG - RTC_SHIFT)
+ | rtc_alarm >> RTC_SHIFT, &(alrm->time));
+ if (sirfsoc_rtc_iobrg_readl(
+ rtcdrv->rtc_base + RTC_STATUS) & SIRFSOC_RTC_AL0E)
+ alrm->enabled = 1;
+ local_irq_enable();
+
+ return 0;
+}
+
+static int sirfsoc_rtc_set_alarm(struct device *dev,
+ struct rtc_wkalrm *alrm)
+{
+ unsigned long rtc_status_reg, rtc_alarm;
+ struct sirfsoc_rtc_drv *rtcdrv;
+ rtcdrv = (struct sirfsoc_rtc_drv *)dev_get_drvdata(dev);
+
+ if (alrm->enabled) {
+ rtc_tm_to_time(&(alrm->time), &rtc_alarm);
+
+ local_irq_disable();
+
+ rtc_status_reg = sirfsoc_rtc_iobrg_readl(
+ rtcdrv->rtc_base + RTC_STATUS);
+ if (rtc_status_reg & SIRFSOC_RTC_AL0E) {
+ /*
+ * An ongoing alarm in progress - ingore it and not
+ * to return EBUSY
+ */
+ dev_info(dev, "An old alarm was set, will be replaced by a new one\n");
+ }
+
+ sirfsoc_rtc_iobrg_writel(
+ rtc_alarm << RTC_SHIFT, rtcdrv->rtc_base + RTC_ALARM0);
+ rtc_status_reg &= ~0x07; /* mask out the lower status bits */
+ /*
+ * This bit RTC_AL sets it as a wake-up source for Sleep Mode
+ * Writing 1 into this bit will clear it
+ */
+ rtc_status_reg |= SIRFSOC_RTC_AL0;
+ /* enable the RTC alarm interrupt */
+ rtc_status_reg |= SIRFSOC_RTC_AL0E;
+ sirfsoc_rtc_iobrg_writel(
+ rtc_status_reg, rtcdrv->rtc_base + RTC_STATUS);
+ local_irq_enable();
+ } else {
+ /*
+ * if this function was called with enabled=0
+ * then it could mean that the application is
+ * trying to cancel an ongoing alarm
+ */
+ local_irq_disable();
+
+ rtc_status_reg = sirfsoc_rtc_iobrg_readl(
+ rtcdrv->rtc_base + RTC_STATUS);
+ if (rtc_status_reg & SIRFSOC_RTC_AL0E) {
+ /* clear the RTC status register's alarm bit */
+ rtc_status_reg &= ~0x07;
+ /* write 1 into SIRFSOC_RTC_AL0 to force a clear */
+ rtc_status_reg |= (SIRFSOC_RTC_AL0);
+ /* Clear the Alarm enable bit */
+ rtc_status_reg &= ~(SIRFSOC_RTC_AL0E);
+
+ sirfsoc_rtc_iobrg_writel(rtc_status_reg,
+ rtcdrv->rtc_base + RTC_STATUS);
+ }
+
+ local_irq_enable();
+ }
+
+ return 0;
+}
+
+static int sirfsoc_rtc_read_time(struct device *dev,
+ struct rtc_time *tm)
+{
+ unsigned long tmp_rtc = 0;
+ struct sirfsoc_rtc_drv *rtcdrv;
+ rtcdrv = (struct sirfsoc_rtc_drv *)dev_get_drvdata(dev);
+ /*
+ * This patch is taken from WinCE - Need to validate this for
+ * correctness. To work around sirfsoc RTC counter double sync logic
+ * fail, read several times to make sure get stable value.
+ */
+ do {
+ tmp_rtc = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
+ cpu_relax();
+ } while (tmp_rtc != sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN));
+
+ rtc_time_to_tm(rtcdrv->overflow_rtc << (BITS_PER_LONG - RTC_SHIFT) |
+ tmp_rtc >> RTC_SHIFT, tm);
+ return 0;
+}
+
+static int sirfsoc_rtc_set_time(struct device *dev,
+ struct rtc_time *tm)
+{
+ unsigned long rtc_time;
+ struct sirfsoc_rtc_drv *rtcdrv;
+ rtcdrv = (struct sirfsoc_rtc_drv *)dev_get_drvdata(dev);
+
+ rtc_tm_to_time(tm, &rtc_time);
+
+ rtcdrv->overflow_rtc = rtc_time >> (BITS_PER_LONG - RTC_SHIFT);
+
+ sirfsoc_rtc_iobrg_writel(rtcdrv->overflow_rtc,
+ rtcdrv->rtc_base + RTC_SW_VALUE);
+ sirfsoc_rtc_iobrg_writel(
+ rtc_time << RTC_SHIFT, rtcdrv->rtc_base + RTC_CN);
+
+ return 0;
+}
+
+static int sirfsoc_rtc_ioctl(struct device *dev, unsigned int cmd,
+ unsigned long arg)
+{
+ switch (cmd) {
+ case RTC_PIE_ON:
+ case RTC_PIE_OFF:
+ case RTC_UIE_ON:
+ case RTC_UIE_OFF:
+ case RTC_AIE_ON:
+ case RTC_AIE_OFF:
+ return 0;
+
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
+static const struct rtc_class_ops sirfsoc_rtc_ops = {
+ .read_time = sirfsoc_rtc_read_time,
+ .set_time = sirfsoc_rtc_set_time,
+ .read_alarm = sirfsoc_rtc_read_alarm,
+ .set_alarm = sirfsoc_rtc_set_alarm,
+ .ioctl = sirfsoc_rtc_ioctl
+};
+
+static irqreturn_t sirfsoc_rtc_irq_handler(int irq, void *pdata)
+{
+ struct sirfsoc_rtc_drv *rtcdrv = pdata;
+ unsigned long rtc_status_reg = 0x0;
+ unsigned long events = 0x0;
+
+ rtc_status_reg = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_STATUS);
+ /* this bit will be set ONLY if an alarm was active
+ * and it expired NOW
+ * So this is being used as an ASSERT
+ */
+ if (rtc_status_reg & SIRFSOC_RTC_AL0) {
+ /*
+ * clear the RTC status register's alarm bit
+ * mask out the lower status bits
+ */
+ rtc_status_reg &= ~0x07;
+ /* write 1 into SIRFSOC_RTC_AL0 to ACK the alarm interrupt */
+ rtc_status_reg |= (SIRFSOC_RTC_AL0);
+ /* Clear the Alarm enable bit */
+ rtc_status_reg &= ~(SIRFSOC_RTC_AL0E);
+ }
+ sirfsoc_rtc_iobrg_writel(rtc_status_reg, rtcdrv->rtc_base + RTC_STATUS);
+ /* this should wake up any apps polling/waiting on the read
+ * after setting the alarm
+ */
+ events |= RTC_IRQF | RTC_AF;
+ rtc_update_irq(rtcdrv->rtc, 1, events);
+
+ return IRQ_HANDLED;
+}
+
+static const struct of_device_id sirfsoc_rtc_of_match[] = {
+ { .compatible = "sirf,prima2-sysrtc"},
+ {},
+};
+MODULE_DEVICE_TABLE(of, sirfsoc_rtc_of_match);
+
+static int sirfsoc_rtc_probe(struct platform_device *pdev)
+{
+ int err;
+ unsigned long rtc_div;
+ struct sirfsoc_rtc_drv *rtcdrv;
+ struct device_node *np = pdev->dev.of_node;
+
+ rtcdrv = devm_kzalloc(&pdev->dev,
+ sizeof(struct sirfsoc_rtc_drv), GFP_KERNEL);
+ if (rtcdrv == NULL) {
+ dev_err(&pdev->dev,
+ "%s: can't alloc mem for drv struct\n",
+ pdev->name);
+ return -ENOMEM;
+ }
+
+ err = of_property_read_u32(np, "reg", &rtcdrv->rtc_base);
+ if (err) {
+ dev_err(&pdev->dev, "unable to find base address of rtc node in dtb\n");
+ goto error;
+ }
+
+ platform_set_drvdata(pdev, rtcdrv);
+
+ /* Register rtc alarm as a wakeup source */
+ device_init_wakeup(&pdev->dev, 1);
+
+ /*
+ * Set SYS_RTC counter in RTC_HZ HZ Units
+ * We are using 32K RTC crystal (32768 / RTC_HZ / 2) -1
+ * If 16HZ, therefore RTC_DIV = 1023;
+ */
+ rtc_div = ((32768 / RTC_HZ) / 2) - 1;
+ sirfsoc_rtc_iobrg_writel(rtc_div, rtcdrv->rtc_base + RTC_DIV);
+
+ rtcdrv->rtc = rtc_device_register(pdev->name, &(pdev->dev),
+ &sirfsoc_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtcdrv->rtc)) {
+ err = PTR_ERR(rtcdrv->rtc);
+ dev_err(&pdev->dev, "can't register RTC device\n");
+ return err;
+ }
+
+ /* 0x3 -> RTC_CLK */
+ sirfsoc_rtc_iobrg_writel(SIRFSOC_RTC_CLK,
+ rtcdrv->rtc_base + RTC_CLOCK_SWITCH);
+
+ /* reset SYS RTC ALARM0 */
+ sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM0);
+
+ /* reset SYS RTC ALARM1 */
+ sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM1);
+
+ /* Restore RTC Overflow From Register After Command Reboot */
+ rtcdrv->overflow_rtc =
+ sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_SW_VALUE);
+
+ rtcdrv->irq = platform_get_irq(pdev, 0);
+ err = devm_request_irq(
+ &pdev->dev,
+ rtcdrv->irq,
+ sirfsoc_rtc_irq_handler,
+ IRQF_SHARED,
+ pdev->name,
+ rtcdrv);
+ if (err) {
+ dev_err(&pdev->dev, "Unable to register for the SiRF SOC RTC IRQ\n");
+ goto error;
+ }
+
+ return 0;
+
+error:
+ if (rtcdrv->rtc)
+ rtc_device_unregister(rtcdrv->rtc);
+
+ return err;
+}
+
+static int sirfsoc_rtc_remove(struct platform_device *pdev)
+{
+ struct sirfsoc_rtc_drv *rtcdrv = platform_get_drvdata(pdev);
+
+ device_init_wakeup(&pdev->dev, 0);
+ rtc_device_unregister(rtcdrv->rtc);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+
+static int sirfsoc_rtc_suspend(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct sirfsoc_rtc_drv *rtcdrv = platform_get_drvdata(pdev);
+ rtcdrv->overflow_rtc =
+ sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_SW_VALUE);
+
+ rtcdrv->saved_counter =
+ sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
+ rtcdrv->saved_overflow_rtc = rtcdrv->overflow_rtc;
+ if (device_may_wakeup(&pdev->dev))
+ enable_irq_wake(rtcdrv->irq);
+
+ return 0;
+}
+
+static int sirfsoc_rtc_freeze(struct device *dev)
+{
+ sirfsoc_rtc_suspend(dev);
+
+ return 0;
+}
+
+static int sirfsoc_rtc_thaw(struct device *dev)
+{
+ u32 tmp;
+ struct sirfsoc_rtc_drv *rtcdrv;
+ rtcdrv = (struct sirfsoc_rtc_drv *)dev_get_drvdata(dev);
+
+ /*
+ * if resume from snapshot and the rtc power is losed,
+ * restroe the rtc settings
+ */
+ if (SIRFSOC_RTC_CLK != sirfsoc_rtc_iobrg_readl(
+ rtcdrv->rtc_base + RTC_CLOCK_SWITCH)) {
+ u32 rtc_div;
+ /* 0x3 -> RTC_CLK */
+ sirfsoc_rtc_iobrg_writel(SIRFSOC_RTC_CLK,
+ rtcdrv->rtc_base + RTC_CLOCK_SWITCH);
+ /*
+ * Set SYS_RTC counter in RTC_HZ HZ Units
+ * We are using 32K RTC crystal (32768 / RTC_HZ / 2) -1
+ * If 16HZ, therefore RTC_DIV = 1023;
+ */
+ rtc_div = ((32768 / RTC_HZ) / 2) - 1;
+
+ sirfsoc_rtc_iobrg_writel(rtc_div, rtcdrv->rtc_base + RTC_DIV);
+
+ /* reset SYS RTC ALARM0 */
+ sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM0);
+
+ /* reset SYS RTC ALARM1 */
+ sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM1);
+ }
+ rtcdrv->overflow_rtc = rtcdrv->saved_overflow_rtc;
+
+ /*
+ * if current counter is small than previous,
+ * it means overflow in sleep
+ */
+ tmp = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
+ if (tmp <= rtcdrv->saved_counter)
+ rtcdrv->overflow_rtc++;
+ /*
+ *PWRC Value Be Changed When Suspend, Restore Overflow
+ * In Memory To Register
+ */
+ sirfsoc_rtc_iobrg_writel(rtcdrv->overflow_rtc,
+ rtcdrv->rtc_base + RTC_SW_VALUE);
+
+ return 0;
+}
+
+static int sirfsoc_rtc_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct sirfsoc_rtc_drv *rtcdrv = platform_get_drvdata(pdev);
+ sirfsoc_rtc_thaw(dev);
+ if (device_may_wakeup(&pdev->dev))
+ disable_irq_wake(rtcdrv->irq);
+
+ return 0;
+}
+
+static int sirfsoc_rtc_restore(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct sirfsoc_rtc_drv *rtcdrv = platform_get_drvdata(pdev);
+
+ if (device_may_wakeup(&pdev->dev))
+ disable_irq_wake(rtcdrv->irq);
+ return 0;
+}
+
+#else
+#define sirfsoc_rtc_suspend NULL
+#define sirfsoc_rtc_resume NULL
+#define sirfsoc_rtc_freeze NULL
+#define sirfsoc_rtc_thaw NULL
+#define sirfsoc_rtc_restore NULL
+#endif
+
+static const struct dev_pm_ops sirfsoc_rtc_pm_ops = {
+ .suspend = sirfsoc_rtc_suspend,
+ .resume = sirfsoc_rtc_resume,
+ .freeze = sirfsoc_rtc_freeze,
+ .thaw = sirfsoc_rtc_thaw,
+ .restore = sirfsoc_rtc_restore,
+};
+
+static struct platform_driver sirfsoc_rtc_driver = {
+ .driver = {
+ .name = "sirfsoc-rtc",
+ .owner = THIS_MODULE,
+#ifdef CONFIG_PM
+ .pm = &sirfsoc_rtc_pm_ops,
+#endif
+ .of_match_table = of_match_ptr(sirfsoc_rtc_of_match),
+ },
+ .probe = sirfsoc_rtc_probe,
+ .remove = sirfsoc_rtc_remove,
+};
+module_platform_driver(sirfsoc_rtc_driver);
+
+MODULE_DESCRIPTION("SiRF SoC rtc driver");
+MODULE_AUTHOR("Xianglong Du <Xianglong.Du@csr.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:sirfsoc-rtc");