Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / rtc / rtc-au1xxx.c

diff --git a/kernel/drivers/rtc/rtc-au1xxx.c b/kernel/drivers/rtc/rtc-au1xxx.c
new file mode 100644 (file)
index 0000000..84d6e02
--- /dev/null
+++ b/kernel/drivers/rtc/rtc-au1xxx.c
@@ -0,0 +1,128 @@
+/*
+ * Au1xxx counter0 (aka Time-Of-Year counter) RTC interface driver.
+ *
+ * Copyright (C) 2008 Manuel Lauss <mano@roarinelk.homelinux.net>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+/* All current Au1xxx SoCs have 2 counters fed by an external 32.768 kHz
+ * crystal. Counter 0, which keeps counting during sleep/powerdown, is
+ * used to count seconds since the beginning of the unix epoch.
+ *
+ * The counters must be configured and enabled by bootloader/board code;
+ * no checks as to whether they really get a proper 32.768kHz clock are
+ * made as this would take far too long.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <asm/mach-au1x00/au1000.h>
+
+/* 32kHz clock enabled and detected */
+#define CNTR_OK (SYS_CNTRL_E0 | SYS_CNTRL_32S)
+
+static int au1xtoy_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+       unsigned long t;
+
+       t = alchemy_rdsys(AU1000_SYS_TOYREAD);
+
+       rtc_time_to_tm(t, tm);
+
+       return rtc_valid_tm(tm);
+}
+
+static int au1xtoy_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+       unsigned long t;
+
+       rtc_tm_to_time(tm, &t);
+
+       alchemy_wrsys(t, AU1000_SYS_TOYWRITE);
+
+       /* wait for the pending register write to succeed.  This can
+        * take up to 6 seconds...
+        */
+       while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
+               msleep(1);
+
+       return 0;
+}
+
+static struct rtc_class_ops au1xtoy_rtc_ops = {
+       .read_time      = au1xtoy_rtc_read_time,
+       .set_time       = au1xtoy_rtc_set_time,
+};
+
+static int au1xtoy_rtc_probe(struct platform_device *pdev)
+{
+       struct rtc_device *rtcdev;
+       unsigned long t;
+       int ret;
+
+       t = alchemy_rdsys(AU1000_SYS_CNTRCTRL);
+       if (!(t & CNTR_OK)) {
+               dev_err(&pdev->dev, "counters not working; aborting.\n");
+               ret = -ENODEV;
+               goto out_err;
+       }
+
+       ret = -ETIMEDOUT;
+
+       /* set counter0 tickrate to 1Hz if necessary */
+       if (alchemy_rdsys(AU1000_SYS_TOYTRIM) != 32767) {
+               /* wait until hardware gives access to TRIM register */
+               t = 0x00100000;
+               while ((alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_T0S) && --t)
+                       msleep(1);
+
+               if (!t) {
+                       /* timed out waiting for register access; assume
+                        * counters are unusable.
+                        */
+                       dev_err(&pdev->dev, "timeout waiting for access\n");
+                       goto out_err;
+               }
+
+               /* set 1Hz TOY tick rate */
+               alchemy_wrsys(32767, AU1000_SYS_TOYTRIM);
+       }
+
+       /* wait until the hardware allows writes to the counter reg */
+       while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
+               msleep(1);
+
+       rtcdev = devm_rtc_device_register(&pdev->dev, "rtc-au1xxx",
+                                    &au1xtoy_rtc_ops, THIS_MODULE);
+       if (IS_ERR(rtcdev)) {
+               ret = PTR_ERR(rtcdev);
+               goto out_err;
+       }
+
+       platform_set_drvdata(pdev, rtcdev);
+
+       return 0;
+
+out_err:
+       return ret;
+}
+
+static struct platform_driver au1xrtc_driver = {
+       .driver         = {
+               .name   = "rtc-au1xxx",
+       },
+};
+
+module_platform_driver_probe(au1xrtc_driver, au1xtoy_rtc_probe);
+
+MODULE_DESCRIPTION("Au1xxx TOY-counter-based RTC driver");
+MODULE_AUTHOR("Manuel Lauss <manuel.lauss@gmail.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-au1xxx");