diff options
Diffstat (limited to 'drivers/rtc/rtc-vr41xx.c')
| -rw-r--r-- | drivers/rtc/rtc-vr41xx.c | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-vr41xx.c b/drivers/rtc/rtc-vr41xx.c new file mode 100644 index 000000000..c3671043a --- /dev/null +++ b/drivers/rtc/rtc-vr41xx.c @@ -0,0 +1,363 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Driver for NEC VR4100 series Real Time Clock unit. + * + * Copyright (C) 2003-2008 Yoichi Yuasa <yuasa@linux-mips.org> + */ +#include <linux/compat.h> +#include <linux/err.h> +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/spinlock.h> +#include <linux/types.h> +#include <linux/uaccess.h> +#include <linux/log2.h> + +#include <asm/div64.h> + +MODULE_AUTHOR("Yoichi Yuasa <yuasa@linux-mips.org>"); +MODULE_DESCRIPTION("NEC VR4100 series RTC driver"); +MODULE_LICENSE("GPL v2"); + +/* RTC 1 registers */ +#define ETIMELREG 0x00 +#define ETIMEMREG 0x02 +#define ETIMEHREG 0x04 +/* RFU */ +#define ECMPLREG 0x08 +#define ECMPMREG 0x0a +#define ECMPHREG 0x0c +/* RFU */ +#define RTCL1LREG 0x10 +#define RTCL1HREG 0x12 +#define RTCL1CNTLREG 0x14 +#define RTCL1CNTHREG 0x16 +#define RTCL2LREG 0x18 +#define RTCL2HREG 0x1a +#define RTCL2CNTLREG 0x1c +#define RTCL2CNTHREG 0x1e + +/* RTC 2 registers */ +#define TCLKLREG 0x00 +#define TCLKHREG 0x02 +#define TCLKCNTLREG 0x04 +#define TCLKCNTHREG 0x06 +/* RFU */ +#define RTCINTREG 0x1e + #define TCLOCK_INT 0x08 + #define RTCLONG2_INT 0x04 + #define RTCLONG1_INT 0x02 + #define ELAPSEDTIME_INT 0x01 + +#define RTC_FREQUENCY 32768 +#define MAX_PERIODIC_RATE 6553 + +static void __iomem *rtc1_base; +static void __iomem *rtc2_base; + +#define rtc1_read(offset) readw(rtc1_base + (offset)) +#define rtc1_write(offset, value) writew((value), rtc1_base + (offset)) + +#define rtc2_read(offset) readw(rtc2_base + (offset)) +#define rtc2_write(offset, value) writew((value), rtc2_base + (offset)) + +/* 32-bit compat for ioctls that nobody else uses */ +#define RTC_EPOCH_READ32 _IOR('p', 0x0d, __u32) + +static unsigned long epoch = 1970; /* Jan 1 1970 00:00:00 */ + +static DEFINE_SPINLOCK(rtc_lock); +static char rtc_name[] = "RTC"; +static unsigned long periodic_count; +static unsigned int alarm_enabled; +static int aie_irq; +static int pie_irq; + +static inline time64_t read_elapsed_second(void) +{ + + unsigned long first_low, first_mid, first_high; + + unsigned long second_low, second_mid, second_high; + + do { + first_low = rtc1_read(ETIMELREG); + first_mid = rtc1_read(ETIMEMREG); + first_high = rtc1_read(ETIMEHREG); + second_low = rtc1_read(ETIMELREG); + second_mid = rtc1_read(ETIMEMREG); + second_high = rtc1_read(ETIMEHREG); + } while (first_low != second_low || first_mid != second_mid || + first_high != second_high); + + return ((u64)first_high << 17) | (first_mid << 1) | (first_low >> 15); +} + +static inline void write_elapsed_second(time64_t sec) +{ + spin_lock_irq(&rtc_lock); + + rtc1_write(ETIMELREG, (uint16_t)(sec << 15)); + rtc1_write(ETIMEMREG, (uint16_t)(sec >> 1)); + rtc1_write(ETIMEHREG, (uint16_t)(sec >> 17)); + + spin_unlock_irq(&rtc_lock); +} + +static int vr41xx_rtc_read_time(struct device *dev, struct rtc_time *time) +{ + time64_t epoch_sec, elapsed_sec; + + epoch_sec = mktime64(epoch, 1, 1, 0, 0, 0); + elapsed_sec = read_elapsed_second(); + + rtc_time64_to_tm(epoch_sec + elapsed_sec, time); + + return 0; +} + +static int vr41xx_rtc_set_time(struct device *dev, struct rtc_time *time) +{ + time64_t epoch_sec, current_sec; + + epoch_sec = mktime64(epoch, 1, 1, 0, 0, 0); + current_sec = rtc_tm_to_time64(time); + + write_elapsed_second(current_sec - epoch_sec); + + return 0; +} + +static int vr41xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) +{ + unsigned long low, mid, high; + struct rtc_time *time = &wkalrm->time; + + spin_lock_irq(&rtc_lock); + + low = rtc1_read(ECMPLREG); + mid = rtc1_read(ECMPMREG); + high = rtc1_read(ECMPHREG); + wkalrm->enabled = alarm_enabled; + + spin_unlock_irq(&rtc_lock); + + rtc_time64_to_tm((high << 17) | (mid << 1) | (low >> 15), time); + + return 0; +} + +static int vr41xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) +{ + time64_t alarm_sec; + + alarm_sec = rtc_tm_to_time64(&wkalrm->time); + + spin_lock_irq(&rtc_lock); + + if (alarm_enabled) + disable_irq(aie_irq); + + rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15)); + rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1)); + rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17)); + + if (wkalrm->enabled) + enable_irq(aie_irq); + + alarm_enabled = wkalrm->enabled; + + spin_unlock_irq(&rtc_lock); + + return 0; +} + +static int vr41xx_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) +{ + switch (cmd) { + case RTC_EPOCH_READ: + return put_user(epoch, (unsigned long __user *)arg); +#ifdef CONFIG_64BIT + case RTC_EPOCH_READ32: + return put_user(epoch, (unsigned int __user *)arg); +#endif + case RTC_EPOCH_SET: + /* Doesn't support before 1900 */ + if (arg < 1900) + return -EINVAL; + epoch = arg; + break; + default: + return -ENOIOCTLCMD; + } + + return 0; +} + +static int vr41xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + spin_lock_irq(&rtc_lock); + if (enabled) { + if (!alarm_enabled) { + enable_irq(aie_irq); + alarm_enabled = 1; + } + } else { + if (alarm_enabled) { + disable_irq(aie_irq); + alarm_enabled = 0; + } + } + spin_unlock_irq(&rtc_lock); + return 0; +} + +static irqreturn_t elapsedtime_interrupt(int irq, void *dev_id) +{ + struct platform_device *pdev = (struct platform_device *)dev_id; + struct rtc_device *rtc = platform_get_drvdata(pdev); + + rtc2_write(RTCINTREG, ELAPSEDTIME_INT); + + rtc_update_irq(rtc, 1, RTC_AF); + + return IRQ_HANDLED; +} + +static irqreturn_t rtclong1_interrupt(int irq, void *dev_id) +{ + struct platform_device *pdev = (struct platform_device *)dev_id; + struct rtc_device *rtc = platform_get_drvdata(pdev); + unsigned long count = periodic_count; + + rtc2_write(RTCINTREG, RTCLONG1_INT); + + rtc1_write(RTCL1LREG, count); + rtc1_write(RTCL1HREG, count >> 16); + + rtc_update_irq(rtc, 1, RTC_PF); + + return IRQ_HANDLED; +} + +static const struct rtc_class_ops vr41xx_rtc_ops = { + .ioctl = vr41xx_rtc_ioctl, + .read_time = vr41xx_rtc_read_time, + .set_time = vr41xx_rtc_set_time, + .read_alarm = vr41xx_rtc_read_alarm, + .set_alarm = vr41xx_rtc_set_alarm, + .alarm_irq_enable = vr41xx_rtc_alarm_irq_enable, +}; + +static int rtc_probe(struct platform_device *pdev) +{ + struct resource *res; + struct rtc_device *rtc; + int retval; + + if (pdev->num_resources != 4) + return -EBUSY; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -EBUSY; + + rtc1_base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); + if (!rtc1_base) + return -EBUSY; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 1); + if (!res) { + retval = -EBUSY; + goto err_rtc1_iounmap; + } + + rtc2_base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); + if (!rtc2_base) { + retval = -EBUSY; + goto err_rtc1_iounmap; + } + + rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc)) { + retval = PTR_ERR(rtc); + goto err_iounmap_all; + } + + rtc->ops = &vr41xx_rtc_ops; + + /* 48-bit counter at 32.768 kHz */ + rtc->range_max = (1ULL << 33) - 1; + rtc->max_user_freq = MAX_PERIODIC_RATE; + + spin_lock_irq(&rtc_lock); + + rtc1_write(ECMPLREG, 0); + rtc1_write(ECMPMREG, 0); + rtc1_write(ECMPHREG, 0); + rtc1_write(RTCL1LREG, 0); + rtc1_write(RTCL1HREG, 0); + + spin_unlock_irq(&rtc_lock); + + aie_irq = platform_get_irq(pdev, 0); + if (aie_irq <= 0) { + retval = -EBUSY; + goto err_iounmap_all; + } + + retval = devm_request_irq(&pdev->dev, aie_irq, elapsedtime_interrupt, 0, + "elapsed_time", pdev); + if (retval < 0) + goto err_iounmap_all; + + pie_irq = platform_get_irq(pdev, 1); + if (pie_irq <= 0) { + retval = -EBUSY; + goto err_iounmap_all; + } + + retval = devm_request_irq(&pdev->dev, pie_irq, rtclong1_interrupt, 0, + "rtclong1", pdev); + if (retval < 0) + goto err_iounmap_all; + + platform_set_drvdata(pdev, rtc); + + disable_irq(aie_irq); + disable_irq(pie_irq); + + dev_info(&pdev->dev, "Real Time Clock of NEC VR4100 series\n"); + + retval = rtc_register_device(rtc); + if (retval) + goto err_iounmap_all; + + return 0; + +err_iounmap_all: + rtc2_base = NULL; + +err_rtc1_iounmap: + rtc1_base = NULL; + + return retval; +} + +/* work with hotplug and coldplug */ +MODULE_ALIAS("platform:RTC"); + +static struct platform_driver rtc_platform_driver = { + .probe = rtc_probe, + .driver = { + .name = rtc_name, + }, +}; + +module_platform_driver(rtc_platform_driver); |