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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /drivers/rtc/rtc-au1xxx.c | |
parent | Initial commit. (diff) | |
download | linux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip |
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/rtc/rtc-au1xxx.c')
-rw-r--r-- | drivers/rtc/rtc-au1xxx.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-au1xxx.c b/drivers/rtc/rtc-au1xxx.c new file mode 100644 index 000000000..7c5530c71 --- /dev/null +++ b/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 0; +} + +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 const 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"); |