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linux/drivers/rtc/rtc-tx4939.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
/*
* TX4939 internal RTC driver
* Based on RBTX49xx patch from CELF patch archive.
*
* (C) Copyright TOSHIBA CORPORATION 2005-2007
*/
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/gfp.h>
#define TX4939_RTCCTL_ALME 0x00000080
#define TX4939_RTCCTL_ALMD 0x00000040
#define TX4939_RTCCTL_BUSY 0x00000020
#define TX4939_RTCCTL_COMMAND 0x00000007
#define TX4939_RTCCTL_COMMAND_NOP 0x00000000
#define TX4939_RTCCTL_COMMAND_GETTIME 0x00000001
#define TX4939_RTCCTL_COMMAND_SETTIME 0x00000002
#define TX4939_RTCCTL_COMMAND_GETALARM 0x00000003
#define TX4939_RTCCTL_COMMAND_SETALARM 0x00000004
#define TX4939_RTCTBC_PM 0x00000080
#define TX4939_RTCTBC_COMP 0x0000007f
#define TX4939_RTC_REG_RAMSIZE 0x00000100
#define TX4939_RTC_REG_RWBSIZE 0x00000006
struct tx4939_rtc_reg {
__u32 ctl;
__u32 adr;
__u32 dat;
__u32 tbc;
};
struct tx4939rtc_plat_data {
struct rtc_device *rtc;
struct tx4939_rtc_reg __iomem *rtcreg;
spinlock_t lock;
};
static int tx4939_rtc_cmd(struct tx4939_rtc_reg __iomem *rtcreg, int cmd)
{
int i = 0;
__raw_writel(cmd, &rtcreg->ctl);
/* This might take 30us (next 32.768KHz clock) */
while (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_BUSY) {
/* timeout on approx. 100us (@ GBUS200MHz) */
if (i++ > 200 * 100)
return -EBUSY;
cpu_relax();
}
return 0;
}
static int tx4939_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
unsigned long secs = rtc_tm_to_time64(tm);
int i, ret;
unsigned char buf[6];
buf[0] = 0;
buf[1] = 0;
buf[2] = secs;
buf[3] = secs >> 8;
buf[4] = secs >> 16;
buf[5] = secs >> 24;
spin_lock_irq(&pdata->lock);
__raw_writel(0, &rtcreg->adr);
for (i = 0; i < 6; i++)
__raw_writel(buf[i], &rtcreg->dat);
ret = tx4939_rtc_cmd(rtcreg,
TX4939_RTCCTL_COMMAND_SETTIME |
(__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
spin_unlock_irq(&pdata->lock);
return ret;
}
static int tx4939_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
int i, ret;
unsigned long sec;
unsigned char buf[6];
spin_lock_irq(&pdata->lock);
ret = tx4939_rtc_cmd(rtcreg,
TX4939_RTCCTL_COMMAND_GETTIME |
(__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
if (ret) {
spin_unlock_irq(&pdata->lock);
return ret;
}
__raw_writel(2, &rtcreg->adr);
for (i = 2; i < 6; i++)
buf[i] = __raw_readl(&rtcreg->dat);
spin_unlock_irq(&pdata->lock);
sec = ((unsigned long)buf[5] << 24) | (buf[4] << 16) |
(buf[3] << 8) | buf[2];
rtc_time64_to_tm(sec, tm);
return 0;
}
static int tx4939_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
int i, ret;
unsigned long sec;
unsigned char buf[6];
sec = rtc_tm_to_time64(&alrm->time);
buf[0] = 0;
buf[1] = 0;
buf[2] = sec;
buf[3] = sec >> 8;
buf[4] = sec >> 16;
buf[5] = sec >> 24;
spin_lock_irq(&pdata->lock);
__raw_writel(0, &rtcreg->adr);
for (i = 0; i < 6; i++)
__raw_writel(buf[i], &rtcreg->dat);
ret = tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_SETALARM |
(alrm->enabled ? TX4939_RTCCTL_ALME : 0));
spin_unlock_irq(&pdata->lock);
return ret;
}
static int tx4939_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
int i, ret;
unsigned long sec;
unsigned char buf[6];
u32 ctl;
spin_lock_irq(&pdata->lock);
ret = tx4939_rtc_cmd(rtcreg,
TX4939_RTCCTL_COMMAND_GETALARM |
(__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
if (ret) {
spin_unlock_irq(&pdata->lock);
return ret;
}
__raw_writel(2, &rtcreg->adr);
for (i = 2; i < 6; i++)
buf[i] = __raw_readl(&rtcreg->dat);
ctl = __raw_readl(&rtcreg->ctl);
alrm->enabled = (ctl & TX4939_RTCCTL_ALME) ? 1 : 0;
alrm->pending = (ctl & TX4939_RTCCTL_ALMD) ? 1 : 0;
spin_unlock_irq(&pdata->lock);
sec = ((unsigned long)buf[5] << 24) | (buf[4] << 16) |
(buf[3] << 8) | buf[2];
rtc_time64_to_tm(sec, &alrm->time);
return rtc_valid_tm(&alrm->time);
}
static int tx4939_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
spin_lock_irq(&pdata->lock);
tx4939_rtc_cmd(pdata->rtcreg,
TX4939_RTCCTL_COMMAND_NOP |
(enabled ? TX4939_RTCCTL_ALME : 0));
spin_unlock_irq(&pdata->lock);
return 0;
}
static irqreturn_t tx4939_rtc_interrupt(int irq, void *dev_id)
{
struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev_id);
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
unsigned long events = RTC_IRQF;
spin_lock(&pdata->lock);
if (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALMD) {
events |= RTC_AF;
tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_NOP);
}
spin_unlock(&pdata->lock);
rtc_update_irq(pdata->rtc, 1, events);
return IRQ_HANDLED;
}
static const struct rtc_class_ops tx4939_rtc_ops = {
.read_time = tx4939_rtc_read_time,
.read_alarm = tx4939_rtc_read_alarm,
.set_alarm = tx4939_rtc_set_alarm,
.set_time = tx4939_rtc_set_time,
.alarm_irq_enable = tx4939_rtc_alarm_irq_enable,
};
static int tx4939_nvram_read(void *priv, unsigned int pos, void *val,
size_t bytes)
{
struct tx4939rtc_plat_data *pdata = priv;
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
u8 *buf = val;
spin_lock_irq(&pdata->lock);
for (; bytes; bytes--) {
__raw_writel(pos++, &rtcreg->adr);
*buf++ = __raw_readl(&rtcreg->dat);
}
spin_unlock_irq(&pdata->lock);
return 0;
}
static int tx4939_nvram_write(void *priv, unsigned int pos, void *val,
size_t bytes)
{
struct tx4939rtc_plat_data *pdata = priv;
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
u8 *buf = val;
spin_lock_irq(&pdata->lock);
for (; bytes; bytes--) {
__raw_writel(pos++, &rtcreg->adr);
__raw_writel(*buf++, &rtcreg->dat);
}
spin_unlock_irq(&pdata->lock);
return 0;
}
static int __init tx4939_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
struct tx4939rtc_plat_data *pdata;
int irq, ret;
struct nvmem_config nvmem_cfg = {
.name = "tx4939_nvram",
.size = TX4939_RTC_REG_RAMSIZE,
.reg_read = tx4939_nvram_read,
.reg_write = tx4939_nvram_write,
};
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return -ENODEV;
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
platform_set_drvdata(pdev, pdata);
pdata->rtcreg = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(pdata->rtcreg))
return PTR_ERR(pdata->rtcreg);
spin_lock_init(&pdata->lock);
tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
if (devm_request_irq(&pdev->dev, irq, tx4939_rtc_interrupt,
0, pdev->name, &pdev->dev) < 0)
return -EBUSY;
rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
rtc->ops = &tx4939_rtc_ops;
rtc->range_max = U32_MAX;
pdata->rtc = rtc;
nvmem_cfg.priv = pdata;
ret = devm_rtc_nvmem_register(rtc, &nvmem_cfg);
if (ret)
return ret;
return devm_rtc_register_device(rtc);
}
static int __exit tx4939_rtc_remove(struct platform_device *pdev)
{
struct tx4939rtc_plat_data *pdata = platform_get_drvdata(pdev);
spin_lock_irq(&pdata->lock);
tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
spin_unlock_irq(&pdata->lock);
return 0;
}
static struct platform_driver tx4939_rtc_driver = {
.remove = __exit_p(tx4939_rtc_remove),
.driver = {
.name = "tx4939rtc",
},
};
module_platform_driver_probe(tx4939_rtc_driver, tx4939_rtc_probe);
MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
MODULE_DESCRIPTION("TX4939 internal RTC driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:tx4939rtc");
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