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linux/drivers/rtc/rtc-vr41xx.c
Bartosz Golaszewski fdcfd85433 rtc: rework rtc_register_device() resource management 
rtc_register_device() is a managed interface but it doesn't use devres
by itself - instead it marks an rtc_device as "registered" and the devres
callback for devm_rtc_allocate_device() takes care of resource release.

This doesn't correspond with the design behind devres where managed
structures should not be aware of being managed. The correct solution
here is to register a separate devres callback for unregistering the
device.

While at it: rename rtc_register_device() to devm_rtc_register_device()
and add it to the list of managed interfaces in devres.rst. This way we
can avoid any potential confusion of driver developers who may expect
there to exist a corresponding unregister function.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201109163409.24301-8-brgl@bgdev.pl
2020-11-19 12:50:12 +01:00

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// 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 = devm_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);
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