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linux/drivers/rtc/rtc-m48t59.c
Vladimir Zapolskiy 99be3e371b rtc: m48t59: clean up m48t59_nvram_read()/m48t59_nvram_write() 
The change removes redundant sysfs binary file boundary checks, since
this task is already done on caller side in fs/sysfs/file.c

Spinlock acquisition/release is moved out of the loop body to get
atomic states of NVRAM reading and writing operations.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2015-09-05 13:19:10 +02:00

519 lines
14 KiB
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/*
* ST M48T59 RTC driver
*
* Copyright (c) 2007 Wind River Systems, Inc.
*
* Author: Mark Zhan <rongkai.zhan@windriver.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/rtc/m48t59.h>
#include <linux/bcd.h>
#include <linux/slab.h>
#ifndef NO_IRQ
#define NO_IRQ (-1)
#endif
#define M48T59_READ(reg) (pdata->read_byte(dev, pdata->offset + reg))
#define M48T59_WRITE(val, reg) \
(pdata->write_byte(dev, pdata->offset + reg, val))
#define M48T59_SET_BITS(mask, reg) \
M48T59_WRITE((M48T59_READ(reg) | (mask)), (reg))
#define M48T59_CLEAR_BITS(mask, reg) \
M48T59_WRITE((M48T59_READ(reg) & ~(mask)), (reg))
struct m48t59_private {
void __iomem *ioaddr;
int irq;
struct rtc_device *rtc;
spinlock_t lock; /* serialize the NVRAM and RTC access */
};
/*
* This is the generic access method when the chip is memory-mapped
*/
static void
m48t59_mem_writeb(struct device *dev, u32 ofs, u8 val)
{
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
writeb(val, m48t59->ioaddr+ofs);
}
static u8
m48t59_mem_readb(struct device *dev, u32 ofs)
{
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
return readb(m48t59->ioaddr+ofs);
}
/*
* NOTE: M48T59 only uses BCD mode
*/
static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
unsigned long flags;
u8 val;
spin_lock_irqsave(&m48t59->lock, flags);
/* Issue the READ command */
M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
/* tm_mon is 0-11 */
tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
tm->tm_mday = bcd2bin(M48T59_READ(M48T59_MDAY));
val = M48T59_READ(M48T59_WDAY);
if ((pdata->type == M48T59RTC_TYPE_M48T59) &&
(val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) {
dev_dbg(dev, "Century bit is enabled\n");
tm->tm_year += 100; /* one century */
}
#ifdef CONFIG_SPARC
/* Sun SPARC machines count years since 1968 */
tm->tm_year += 68;
#endif
tm->tm_wday = bcd2bin(val & 0x07);
tm->tm_hour = bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
tm->tm_min = bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F);
tm->tm_sec = bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F);
/* Clear the READ bit */
M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
spin_unlock_irqrestore(&m48t59->lock, flags);
dev_dbg(dev, "RTC read time %04d-%02d-%02d %02d/%02d/%02d\n",
tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
return rtc_valid_tm(tm);
}
static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
unsigned long flags;
u8 val = 0;
int year = tm->tm_year;
#ifdef CONFIG_SPARC
/* Sun SPARC machines count years since 1968 */
year -= 68;
#endif
dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
year + 1900, tm->tm_mon, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
if (year < 0)
return -EINVAL;
spin_lock_irqsave(&m48t59->lock, flags);
/* Issue the WRITE command */
M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC);
M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN);
M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR);
M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY);
/* tm_mon is 0-11 */
M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH);
M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR);
if (pdata->type == M48T59RTC_TYPE_M48T59 && (year / 100))
val = (M48T59_WDAY_CEB | M48T59_WDAY_CB);
val |= (bin2bcd(tm->tm_wday) & 0x07);
M48T59_WRITE(val, M48T59_WDAY);
/* Clear the WRITE bit */
M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
spin_unlock_irqrestore(&m48t59->lock, flags);
return 0;
}
/*
* Read alarm time and date in RTC
*/
static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
struct rtc_time *tm = &alrm->time;
unsigned long flags;
u8 val;
/* If no irq, we don't support ALARM */
if (m48t59->irq == NO_IRQ)
return -EIO;
spin_lock_irqsave(&m48t59->lock, flags);
/* Issue the READ command */
M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
#ifdef CONFIG_SPARC
/* Sun SPARC machines count years since 1968 */
tm->tm_year += 68;
#endif
/* tm_mon is 0-11 */
tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
val = M48T59_READ(M48T59_WDAY);
if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB))
tm->tm_year += 100; /* one century */
tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE));
tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR));
tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN));
tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC));
/* Clear the READ bit */
M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
spin_unlock_irqrestore(&m48t59->lock, flags);
dev_dbg(dev, "RTC read alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
return rtc_valid_tm(tm);
}
/*
* Set alarm time and date in RTC
*/
static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
struct rtc_time *tm = &alrm->time;
u8 mday, hour, min, sec;
unsigned long flags;
int year = tm->tm_year;
#ifdef CONFIG_SPARC
/* Sun SPARC machines count years since 1968 */
year -= 68;
#endif
/* If no irq, we don't support ALARM */
if (m48t59->irq == NO_IRQ)
return -EIO;
if (year < 0)
return -EINVAL;
/*
* 0xff means "always match"
*/
mday = tm->tm_mday;
mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
if (mday == 0xff)
mday = M48T59_READ(M48T59_MDAY);
hour = tm->tm_hour;
hour = (hour < 24) ? bin2bcd(hour) : 0x00;
min = tm->tm_min;
min = (min < 60) ? bin2bcd(min) : 0x00;
sec = tm->tm_sec;
sec = (sec < 60) ? bin2bcd(sec) : 0x00;
spin_lock_irqsave(&m48t59->lock, flags);
/* Issue the WRITE command */
M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
M48T59_WRITE(mday, M48T59_ALARM_DATE);
M48T59_WRITE(hour, M48T59_ALARM_HOUR);
M48T59_WRITE(min, M48T59_ALARM_MIN);
M48T59_WRITE(sec, M48T59_ALARM_SEC);
/* Clear the WRITE bit */
M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
spin_unlock_irqrestore(&m48t59->lock, flags);
dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
year + 1900, tm->tm_mon, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
return 0;
}
/*
* Handle commands from user-space
*/
static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
unsigned long flags;
spin_lock_irqsave(&m48t59->lock, flags);
if (enabled)
M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR);
else
M48T59_WRITE(0x00, M48T59_INTR);
spin_unlock_irqrestore(&m48t59->lock, flags);
return 0;
}
static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq)
{
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
unsigned long flags;
u8 val;
spin_lock_irqsave(&m48t59->lock, flags);
val = M48T59_READ(M48T59_FLAGS);
spin_unlock_irqrestore(&m48t59->lock, flags);
seq_printf(seq, "battery\t\t: %s\n",
(val & M48T59_FLAGS_BF) ? "low" : "normal");
return 0;
}
/*
* IRQ handler for the RTC
*/
static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id)
{
struct device *dev = (struct device *)dev_id;
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
u8 event;
spin_lock(&m48t59->lock);
event = M48T59_READ(M48T59_FLAGS);
spin_unlock(&m48t59->lock);
if (event & M48T59_FLAGS_AF) {
rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF));
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static const struct rtc_class_ops m48t59_rtc_ops = {
.read_time = m48t59_rtc_read_time,
.set_time = m48t59_rtc_set_time,
.read_alarm = m48t59_rtc_readalarm,
.set_alarm = m48t59_rtc_setalarm,
.proc = m48t59_rtc_proc,
.alarm_irq_enable = m48t59_rtc_alarm_irq_enable,
};
static const struct rtc_class_ops m48t02_rtc_ops = {
.read_time = m48t59_rtc_read_time,
.set_time = m48t59_rtc_set_time,
};
static ssize_t m48t59_nvram_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t size)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
ssize_t cnt = 0;
unsigned long flags;
spin_lock_irqsave(&m48t59->lock, flags);
for (; cnt < size; cnt++)
*buf++ = M48T59_READ(cnt);
spin_unlock_irqrestore(&m48t59->lock, flags);
return cnt;
}
static ssize_t m48t59_nvram_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t size)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct platform_device *pdev = to_platform_device(dev);
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
ssize_t cnt = 0;
unsigned long flags;
spin_lock_irqsave(&m48t59->lock, flags);
for (; cnt < size; cnt++)
M48T59_WRITE(*buf++, cnt);
spin_unlock_irqrestore(&m48t59->lock, flags);
return cnt;
}
static struct bin_attribute m48t59_nvram_attr = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUSR,
},
.read = m48t59_nvram_read,
.write = m48t59_nvram_write,
};
static int m48t59_rtc_probe(struct platform_device *pdev)
{
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = NULL;
struct resource *res;
int ret = -ENOMEM;
char *name;
const struct rtc_class_ops *ops;
/* This chip could be memory-mapped or I/O-mapped */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
if (!res)
return -EINVAL;
}
if (res->flags & IORESOURCE_IO) {
/* If we are I/O-mapped, the platform should provide
* the operations accessing chip registers.
*/
if (!pdata || !pdata->write_byte || !pdata->read_byte)
return -EINVAL;
} else if (res->flags & IORESOURCE_MEM) {
/* we are memory-mapped */
if (!pdata) {
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata),
GFP_KERNEL);
if (!pdata)
return -ENOMEM;
/* Ensure we only kmalloc platform data once */
pdev->dev.platform_data = pdata;
}
if (!pdata->type)
pdata->type = M48T59RTC_TYPE_M48T59;
/* Try to use the generic memory read/write ops */
if (!pdata->write_byte)
pdata->write_byte = m48t59_mem_writeb;
if (!pdata->read_byte)
pdata->read_byte = m48t59_mem_readb;
}
m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL);
if (!m48t59)
return -ENOMEM;
m48t59->ioaddr = pdata->ioaddr;
if (!m48t59->ioaddr) {
/* ioaddr not mapped externally */
m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
if (!m48t59->ioaddr)
return ret;
}
/* Try to get irq number. We also can work in
* the mode without IRQ.
*/
m48t59->irq = platform_get_irq(pdev, 0);
if (m48t59->irq <= 0)
m48t59->irq = NO_IRQ;
if (m48t59->irq != NO_IRQ) {
ret = devm_request_irq(&pdev->dev, m48t59->irq,
m48t59_rtc_interrupt, IRQF_SHARED,
"rtc-m48t59", &pdev->dev);
if (ret)
return ret;
}
switch (pdata->type) {
case M48T59RTC_TYPE_M48T59:
name = "m48t59";
ops = &m48t59_rtc_ops;
pdata->offset = 0x1ff0;
break;
case M48T59RTC_TYPE_M48T02:
name = "m48t02";
ops = &m48t02_rtc_ops;
pdata->offset = 0x7f0;
break;
case M48T59RTC_TYPE_M48T08:
name = "m48t08";
ops = &m48t02_rtc_ops;
pdata->offset = 0x1ff0;
break;
default:
dev_err(&pdev->dev, "Unknown RTC type\n");
return -ENODEV;
}
spin_lock_init(&m48t59->lock);
platform_set_drvdata(pdev, m48t59);
m48t59->rtc = devm_rtc_device_register(&pdev->dev, name, ops,
THIS_MODULE);
if (IS_ERR(m48t59->rtc))
return PTR_ERR(m48t59->rtc);
m48t59_nvram_attr.size = pdata->offset;
ret = sysfs_create_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
if (ret)
return ret;
return 0;
}
static int m48t59_rtc_remove(struct platform_device *pdev)
{
sysfs_remove_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
return 0;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:rtc-m48t59");
static struct platform_driver m48t59_rtc_driver = {
.driver = {
.name = "rtc-m48t59",
},
.probe = m48t59_rtc_probe,
.remove = m48t59_rtc_remove,
};
module_platform_driver(m48t59_rtc_driver);
MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>");
MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver");
MODULE_LICENSE("GPL");
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