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linux-next/drivers/rtc/rtc-pic32.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+
/*
* PIC32 RTC driver
*
* Joshua Henderson <joshua.henderson@microchip.com>
* Copyright (C) 2016 Microchip Technology Inc. All rights reserved.
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <asm/mach-pic32/pic32.h>
#define PIC32_RTCCON 0x00
#define PIC32_RTCCON_ON BIT(15)
#define PIC32_RTCCON_SIDL BIT(13)
#define PIC32_RTCCON_RTCCLKSEL (3 << 9)
#define PIC32_RTCCON_RTCCLKON BIT(6)
#define PIC32_RTCCON_RTCWREN BIT(3)
#define PIC32_RTCCON_RTCSYNC BIT(2)
#define PIC32_RTCCON_HALFSEC BIT(1)
#define PIC32_RTCCON_RTCOE BIT(0)
#define PIC32_RTCALRM 0x10
#define PIC32_RTCALRM_ALRMEN BIT(15)
#define PIC32_RTCALRM_CHIME BIT(14)
#define PIC32_RTCALRM_PIV BIT(13)
#define PIC32_RTCALRM_ALARMSYNC BIT(12)
#define PIC32_RTCALRM_AMASK 0x0F00
#define PIC32_RTCALRM_ARPT 0xFF
#define PIC32_RTCHOUR 0x23
#define PIC32_RTCMIN 0x22
#define PIC32_RTCSEC 0x21
#define PIC32_RTCYEAR 0x33
#define PIC32_RTCMON 0x32
#define PIC32_RTCDAY 0x31
#define PIC32_ALRMTIME 0x40
#define PIC32_ALRMDATE 0x50
#define PIC32_ALRMHOUR 0x43
#define PIC32_ALRMMIN 0x42
#define PIC32_ALRMSEC 0x41
#define PIC32_ALRMYEAR 0x53
#define PIC32_ALRMMON 0x52
#define PIC32_ALRMDAY 0x51
struct pic32_rtc_dev {
struct rtc_device *rtc;
void __iomem *reg_base;
struct clk *clk;
spinlock_t alarm_lock;
int alarm_irq;
bool alarm_clk_enabled;
};
static void pic32_rtc_alarm_clk_enable(struct pic32_rtc_dev *pdata,
bool enable)
{
unsigned long flags;
spin_lock_irqsave(&pdata->alarm_lock, flags);
if (enable) {
if (!pdata->alarm_clk_enabled) {
clk_enable(pdata->clk);
pdata->alarm_clk_enabled = true;
}
} else {
if (pdata->alarm_clk_enabled) {
clk_disable(pdata->clk);
pdata->alarm_clk_enabled = false;
}
}
spin_unlock_irqrestore(&pdata->alarm_lock, flags);
}
static irqreturn_t pic32_rtc_alarmirq(int irq, void *id)
{
struct pic32_rtc_dev *pdata = (struct pic32_rtc_dev *)id;
clk_enable(pdata->clk);
rtc_update_irq(pdata->rtc, 1, RTC_AF | RTC_IRQF);
clk_disable(pdata->clk);
pic32_rtc_alarm_clk_enable(pdata, false);
return IRQ_HANDLED;
}
static int pic32_rtc_setaie(struct device *dev, unsigned int enabled)
{
struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
void __iomem *base = pdata->reg_base;
clk_enable(pdata->clk);
writel(PIC32_RTCALRM_ALRMEN,
base + (enabled ? PIC32_SET(PIC32_RTCALRM) :
PIC32_CLR(PIC32_RTCALRM)));
clk_disable(pdata->clk);
pic32_rtc_alarm_clk_enable(pdata, enabled);
return 0;
}
static int pic32_rtc_setfreq(struct device *dev, int freq)
{
struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
void __iomem *base = pdata->reg_base;
clk_enable(pdata->clk);
writel(PIC32_RTCALRM_AMASK, base + PIC32_CLR(PIC32_RTCALRM));
writel(freq << 8, base + PIC32_SET(PIC32_RTCALRM));
writel(PIC32_RTCALRM_CHIME, base + PIC32_SET(PIC32_RTCALRM));
clk_disable(pdata->clk);
return 0;
}
static int pic32_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
{
struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
void __iomem *base = pdata->reg_base;
unsigned int tries = 0;
clk_enable(pdata->clk);
do {
rtc_tm->tm_hour = readb(base + PIC32_RTCHOUR);
rtc_tm->tm_min = readb(base + PIC32_RTCMIN);
rtc_tm->tm_mon = readb(base + PIC32_RTCMON);
rtc_tm->tm_mday = readb(base + PIC32_RTCDAY);
rtc_tm->tm_year = readb(base + PIC32_RTCYEAR);
rtc_tm->tm_sec = readb(base + PIC32_RTCSEC);
/*
* The only way to work out whether the system was mid-update
* when we read it is to check the second counter, and if it
* is zero, then we re-try the entire read.
*/
tries += 1;
} while (rtc_tm->tm_sec == 0 && tries < 2);
rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon) - 1;
rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
rtc_tm->tm_year += 100;
dev_dbg(dev, "read time %ptR\n", rtc_tm);
clk_disable(pdata->clk);
return 0;
}
static int pic32_rtc_settime(struct device *dev, struct rtc_time *tm)
{
struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
void __iomem *base = pdata->reg_base;
dev_dbg(dev, "set time %ptR\n", tm);
clk_enable(pdata->clk);
writeb(bin2bcd(tm->tm_sec), base + PIC32_RTCSEC);
writeb(bin2bcd(tm->tm_min), base + PIC32_RTCMIN);
writeb(bin2bcd(tm->tm_hour), base + PIC32_RTCHOUR);
writeb(bin2bcd(tm->tm_mday), base + PIC32_RTCDAY);
writeb(bin2bcd(tm->tm_mon + 1), base + PIC32_RTCMON);
writeb(bin2bcd(tm->tm_year - 100), base + PIC32_RTCYEAR);
clk_disable(pdata->clk);
return 0;
}
static int pic32_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
struct rtc_time *alm_tm = &alrm->time;
void __iomem *base = pdata->reg_base;
unsigned int alm_en;
clk_enable(pdata->clk);
alm_tm->tm_sec = readb(base + PIC32_ALRMSEC);
alm_tm->tm_min = readb(base + PIC32_ALRMMIN);
alm_tm->tm_hour = readb(base + PIC32_ALRMHOUR);
alm_tm->tm_mon = readb(base + PIC32_ALRMMON);
alm_tm->tm_mday = readb(base + PIC32_ALRMDAY);
alm_tm->tm_year = readb(base + PIC32_ALRMYEAR);
alm_en = readb(base + PIC32_RTCALRM);
alrm->enabled = (alm_en & PIC32_RTCALRM_ALRMEN) ? 1 : 0;
dev_dbg(dev, "getalarm: %d, %ptR\n", alm_en, alm_tm);
alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);
alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon) - 1;
alm_tm->tm_year = bcd2bin(alm_tm->tm_year);
clk_disable(pdata->clk);
return 0;
}
static int pic32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
struct rtc_time *tm = &alrm->time;
void __iomem *base = pdata->reg_base;
clk_enable(pdata->clk);
dev_dbg(dev, "setalarm: %d, %ptR\n", alrm->enabled, tm);
writel(0x00, base + PIC32_ALRMTIME);
writel(0x00, base + PIC32_ALRMDATE);
pic32_rtc_setaie(dev, alrm->enabled);
clk_disable(pdata->clk);
return 0;
}
static int pic32_rtc_proc(struct device *dev, struct seq_file *seq)
{
struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
void __iomem *base = pdata->reg_base;
unsigned int repeat;
clk_enable(pdata->clk);
repeat = readw(base + PIC32_RTCALRM);
repeat &= PIC32_RTCALRM_ARPT;
seq_printf(seq, "periodic_IRQ\t: %s\n", repeat ? "yes" : "no");
clk_disable(pdata->clk);
return 0;
}
static const struct rtc_class_ops pic32_rtcops = {
.read_time = pic32_rtc_gettime,
.set_time = pic32_rtc_settime,
.read_alarm = pic32_rtc_getalarm,
.set_alarm = pic32_rtc_setalarm,
.proc = pic32_rtc_proc,
.alarm_irq_enable = pic32_rtc_setaie,
};
static void pic32_rtc_enable(struct pic32_rtc_dev *pdata, int en)
{
void __iomem *base = pdata->reg_base;
if (!base)
return;
clk_enable(pdata->clk);
if (!en) {
writel(PIC32_RTCCON_ON, base + PIC32_CLR(PIC32_RTCCON));
} else {
pic32_syskey_unlock();
writel(PIC32_RTCCON_RTCWREN, base + PIC32_SET(PIC32_RTCCON));
writel(3 << 9, base + PIC32_CLR(PIC32_RTCCON));
if (!(readl(base + PIC32_RTCCON) & PIC32_RTCCON_ON))
writel(PIC32_RTCCON_ON, base + PIC32_SET(PIC32_RTCCON));
}
clk_disable(pdata->clk);
}
static int pic32_rtc_remove(struct platform_device *pdev)
{
struct pic32_rtc_dev *pdata = platform_get_drvdata(pdev);
pic32_rtc_setaie(&pdev->dev, 0);
clk_unprepare(pdata->clk);
pdata->clk = NULL;
return 0;
}
static int pic32_rtc_probe(struct platform_device *pdev)
{
struct pic32_rtc_dev *pdata;
int ret;
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
platform_set_drvdata(pdev, pdata);
pdata->alarm_irq = platform_get_irq(pdev, 0);
if (pdata->alarm_irq < 0)
return pdata->alarm_irq;
pdata->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(pdata->reg_base))
return PTR_ERR(pdata->reg_base);
pdata->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(pdata->clk)) {
dev_err(&pdev->dev, "failed to find rtc clock source\n");
ret = PTR_ERR(pdata->clk);
pdata->clk = NULL;
return ret;
}
spin_lock_init(&pdata->alarm_lock);
clk_prepare_enable(pdata->clk);
pic32_rtc_enable(pdata, 1);
device_init_wakeup(&pdev->dev, 1);
pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(pdata->rtc))
return PTR_ERR(pdata->rtc);
pdata->rtc->ops = &pic32_rtcops;
pdata->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
pdata->rtc->range_max = RTC_TIMESTAMP_END_2099;
ret = devm_rtc_register_device(pdata->rtc);
if (ret)
goto err_nortc;
pdata->rtc->max_user_freq = 128;
pic32_rtc_setfreq(&pdev->dev, 1);
ret = devm_request_irq(&pdev->dev, pdata->alarm_irq,
pic32_rtc_alarmirq, 0,
dev_name(&pdev->dev), pdata);
if (ret) {
dev_err(&pdev->dev,
"IRQ %d error %d\n", pdata->alarm_irq, ret);
goto err_nortc;
}
clk_disable(pdata->clk);
return 0;
err_nortc:
pic32_rtc_enable(pdata, 0);
clk_disable_unprepare(pdata->clk);
return ret;
}
static const struct of_device_id pic32_rtc_dt_ids[] = {
{ .compatible = "microchip,pic32mzda-rtc" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pic32_rtc_dt_ids);
static struct platform_driver pic32_rtc_driver = {
.probe = pic32_rtc_probe,
.remove = pic32_rtc_remove,
.driver = {
.name = "pic32-rtc",
.of_match_table = of_match_ptr(pic32_rtc_dt_ids),
},
};
module_platform_driver(pic32_rtc_driver);
MODULE_DESCRIPTION("Microchip PIC32 RTC Driver");
MODULE_AUTHOR("Joshua Henderson <joshua.henderson@microchip.com>");
MODULE_LICENSE("GPL");
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