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linux-next/drivers/rtc/rtc-stmp3xxx.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+
/*
* Freescale STMP37XX/STMP378X Real Time Clock driver
*
* Copyright (c) 2007 Sigmatel, Inc.
* Peter Hartley, <peter.hartley@sigmatel.com>
*
* Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
* Copyright 2011 Wolfram Sang, Pengutronix e.K.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/of_device.h>
#include <linux/of.h>
#include <linux/stmp_device.h>
#include <linux/stmp3xxx_rtc_wdt.h>
#define STMP3XXX_RTC_CTRL 0x0
#define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN 0x00000001
#define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN 0x00000002
#define STMP3XXX_RTC_CTRL_ALARM_IRQ 0x00000004
#define STMP3XXX_RTC_CTRL_WATCHDOGEN 0x00000010
#define STMP3XXX_RTC_STAT 0x10
#define STMP3XXX_RTC_STAT_STALE_SHIFT 16
#define STMP3XXX_RTC_STAT_RTC_PRESENT 0x80000000
#define STMP3XXX_RTC_STAT_XTAL32000_PRESENT 0x10000000
#define STMP3XXX_RTC_STAT_XTAL32768_PRESENT 0x08000000
#define STMP3XXX_RTC_SECONDS 0x30
#define STMP3XXX_RTC_ALARM 0x40
#define STMP3XXX_RTC_WATCHDOG 0x50
#define STMP3XXX_RTC_PERSISTENT0 0x60
#define STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE (1 << 0)
#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN (1 << 1)
#define STMP3XXX_RTC_PERSISTENT0_ALARM_EN (1 << 2)
#define STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP (1 << 4)
#define STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP (1 << 5)
#define STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ (1 << 6)
#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE (1 << 7)
#define STMP3XXX_RTC_PERSISTENT1 0x70
/* missing bitmask in headers */
#define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER 0x80000000
struct stmp3xxx_rtc_data {
struct rtc_device *rtc;
void __iomem *io;
int irq_alarm;
};
#if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG)
/**
* stmp3xxx_wdt_set_timeout - configure the watchdog inside the STMP3xxx RTC
* @dev: the parent device of the watchdog (= the RTC)
* @timeout: the desired value for the timeout register of the watchdog.
* 0 disables the watchdog
*
* The watchdog needs one register and two bits which are in the RTC domain.
* To handle the resource conflict, the RTC driver will create another
* platform_device for the watchdog driver as a child of the RTC device.
* The watchdog driver is passed the below accessor function via platform_data
* to configure the watchdog. Locking is not needed because accessing SET/CLR
* registers is atomic.
*/
static void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
if (timeout) {
writel(timeout, rtc_data->io + STMP3XXX_RTC_WATCHDOG);
writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET);
writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_SET);
} else {
writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_CLR);
}
}
static struct stmp3xxx_wdt_pdata wdt_pdata = {
.wdt_set_timeout = stmp3xxx_wdt_set_timeout,
};
static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
{
int rc = -1;
struct platform_device *wdt_pdev =
platform_device_alloc("stmp3xxx_rtc_wdt", rtc_pdev->id);
if (wdt_pdev) {
wdt_pdev->dev.parent = &rtc_pdev->dev;
wdt_pdev->dev.platform_data = &wdt_pdata;
rc = platform_device_add(wdt_pdev);
}
if (rc)
dev_err(&rtc_pdev->dev,
"failed to register stmp3xxx_rtc_wdt\n");
}
#else
static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
{
}
#endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */
static int stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
{
int timeout = 5000; /* 3ms according to i.MX28 Ref Manual */
/*
* The i.MX28 Applications Processor Reference Manual, Rev. 1, 2010
* states:
* | The order in which registers are updated is
* | Persistent 0, 1, 2, 3, 4, 5, Alarm, Seconds.
* | (This list is in bitfield order, from LSB to MSB, as they would
* | appear in the STALE_REGS and NEW_REGS bitfields of the HW_RTC_STAT
* | register. For example, the Seconds register corresponds to
* | STALE_REGS or NEW_REGS containing 0x80.)
*/
do {
if (!(readl(rtc_data->io + STMP3XXX_RTC_STAT) &
(0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT)))
return 0;
udelay(1);
} while (--timeout > 0);
return (readl(rtc_data->io + STMP3XXX_RTC_STAT) &
(0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT)) ? -ETIME : 0;
}
/* Time read/write */
static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
{
int ret;
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
ret = stmp3xxx_wait_time(rtc_data);
if (ret)
return ret;
rtc_time64_to_tm(readl(rtc_data->io + STMP3XXX_RTC_SECONDS), rtc_tm);
return 0;
}
static int stmp3xxx_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
writel(rtc_tm_to_time64(rtc_tm), rtc_data->io + STMP3XXX_RTC_SECONDS);
return stmp3xxx_wait_time(rtc_data);
}
/* interrupt(s) handler */
static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev_id);
u32 status = readl(rtc_data->io + STMP3XXX_RTC_CTRL);
if (status & STMP3XXX_RTC_CTRL_ALARM_IRQ) {
writel(STMP3XXX_RTC_CTRL_ALARM_IRQ,
rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
rtc_update_irq(rtc_data->rtc, 1, RTC_AF | RTC_IRQF);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
if (enabled) {
writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0 +
STMP_OFFSET_REG_SET);
writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET);
} else {
writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0 +
STMP_OFFSET_REG_CLR);
writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
}
return 0;
}
static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
rtc_time64_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time);
return 0;
}
static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
writel(rtc_tm_to_time64(&alm->time), rtc_data->io + STMP3XXX_RTC_ALARM);
stmp3xxx_alarm_irq_enable(dev, alm->enabled);
return 0;
}
static const struct rtc_class_ops stmp3xxx_rtc_ops = {
.alarm_irq_enable =
stmp3xxx_alarm_irq_enable,
.read_time = stmp3xxx_rtc_gettime,
.set_time = stmp3xxx_rtc_settime,
.read_alarm = stmp3xxx_rtc_read_alarm,
.set_alarm = stmp3xxx_rtc_set_alarm,
};
static int stmp3xxx_rtc_remove(struct platform_device *pdev)
{
struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev);
if (!rtc_data)
return 0;
writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
return 0;
}
static int stmp3xxx_rtc_probe(struct platform_device *pdev)
{
struct stmp3xxx_rtc_data *rtc_data;
struct resource *r;
u32 rtc_stat;
u32 pers0_set, pers0_clr;
u32 crystalfreq = 0;
int err;
rtc_data = devm_kzalloc(&pdev->dev, sizeof(*rtc_data), GFP_KERNEL);
if (!rtc_data)
return -ENOMEM;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!r) {
dev_err(&pdev->dev, "failed to get resource\n");
return -ENXIO;
}
rtc_data->io = devm_ioremap(&pdev->dev, r->start, resource_size(r));
if (!rtc_data->io) {
dev_err(&pdev->dev, "ioremap failed\n");
return -EIO;
}
rtc_data->irq_alarm = platform_get_irq(pdev, 0);
rtc_stat = readl(rtc_data->io + STMP3XXX_RTC_STAT);
if (!(rtc_stat & STMP3XXX_RTC_STAT_RTC_PRESENT)) {
dev_err(&pdev->dev, "no device onboard\n");
return -ENODEV;
}
platform_set_drvdata(pdev, rtc_data);
/*
* Resetting the rtc stops the watchdog timer that is potentially
* running. So (assuming it is running on purpose) don't reset if the
* watchdog is enabled.
*/
if (readl(rtc_data->io + STMP3XXX_RTC_CTRL) &
STMP3XXX_RTC_CTRL_WATCHDOGEN) {
dev_info(&pdev->dev,
"Watchdog is running, skip resetting rtc\n");
} else {
err = stmp_reset_block(rtc_data->io);
if (err) {
dev_err(&pdev->dev, "stmp_reset_block failed: %d\n",
err);
return err;
}
}
/*
* Obviously the rtc needs a clock input to be able to run.
* This clock can be provided by an external 32k crystal. If that one is
* missing XTAL must not be disabled in suspend which consumes a
* lot of power. Normally the presence and exact frequency (supported
* are 32000 Hz and 32768 Hz) is detectable from fuses, but as reality
* proves these fuses are not blown correctly on all machines, so the
* frequency can be overridden in the device tree.
*/
if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32000_PRESENT)
crystalfreq = 32000;
else if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32768_PRESENT)
crystalfreq = 32768;
of_property_read_u32(pdev->dev.of_node, "stmp,crystal-freq",
&crystalfreq);
switch (crystalfreq) {
case 32000:
/* keep 32kHz crystal running in low-power mode */
pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ |
STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE;
pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP;
break;
case 32768:
/* keep 32.768kHz crystal running in low-power mode */
pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE;
pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP |
STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ;
break;
default:
dev_warn(&pdev->dev,
"invalid crystal-freq specified in device-tree. Assuming no crystal\n");
fallthrough;
case 0:
/* keep XTAL on in low-power mode */
pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP;
pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE;
}
writel(pers0_set, rtc_data->io + STMP3XXX_RTC_PERSISTENT0 +
STMP_OFFSET_REG_SET);
writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE | pers0_clr,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + STMP_OFFSET_REG_CLR);
writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN |
STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
rtc_data->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc_data->rtc))
return PTR_ERR(rtc_data->rtc);
err = devm_request_irq(&pdev->dev, rtc_data->irq_alarm,
stmp3xxx_rtc_interrupt, 0, "RTC alarm", &pdev->dev);
if (err) {
dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
rtc_data->irq_alarm);
return err;
}
rtc_data->rtc->ops = &stmp3xxx_rtc_ops;
rtc_data->rtc->range_max = U32_MAX;
err = devm_rtc_register_device(rtc_data->rtc);
if (err)
return err;
stmp3xxx_wdt_register(pdev);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int stmp3xxx_rtc_suspend(struct device *dev)
{
return 0;
}
static int stmp3xxx_rtc_resume(struct device *dev)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
stmp_reset_block(rtc_data->io);
writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + STMP_OFFSET_REG_CLR);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(stmp3xxx_rtc_pm_ops, stmp3xxx_rtc_suspend,
stmp3xxx_rtc_resume);
static const struct of_device_id rtc_dt_ids[] = {
{ .compatible = "fsl,stmp3xxx-rtc", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rtc_dt_ids);
static struct platform_driver stmp3xxx_rtcdrv = {
.probe = stmp3xxx_rtc_probe,
.remove = stmp3xxx_rtc_remove,
.driver = {
.name = "stmp3xxx-rtc",
.pm = &stmp3xxx_rtc_pm_ops,
.of_match_table = rtc_dt_ids,
},
};
module_platform_driver(stmp3xxx_rtcdrv);
MODULE_DESCRIPTION("STMP3xxx RTC Driver");
MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and "
"Wolfram Sang <kernel@pengutronix.de>");
MODULE_LICENSE("GPL");
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