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linux/drivers/rtc/rtc-pcf8563.c
Arnd Bergmann cd1420d3a9 rtc: pfc8563: fix uninitialized variable warning 
Gcc is unable to prove that alm_pending is always initialized
when it is used, so it prints a harmless warning:

drivers/rtc/rtc-pcf8563.c: In function 'pcf8563_probe':
drivers/rtc/rtc-pcf8563.c:449:5: warning: 'alm_pending' may be used uninitialized in this function [-Wmaybe-uninitialized]

This uses the same conditional expression that is used inside of
the pcf8563_get_alarm_mode() function, to help gcc figure it out
and shut up that warning, and make the ARM defconfigs build again
with no warnings.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: a45d528aab ("rtc: pcf8563: clear expired alarm at boot time")
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2015-06-25 01:13:46 +02:00

499 lines
13 KiB
C
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/*
* An I2C driver for the Philips PCF8563 RTC
* Copyright 2005-06 Tower Technologies
*
* Author: Alessandro Zummo <a.zummo@towertech.it>
* Maintainers: http://www.nslu2-linux.org/
*
* based on the other drivers in this same directory.
*
* http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
*
* 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/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/err.h>
#define DRV_VERSION "0.4.4"
#define PCF8563_REG_ST1 0x00 /* status */
#define PCF8563_REG_ST2 0x01
#define PCF8563_BIT_AIE (1 << 1)
#define PCF8563_BIT_AF (1 << 3)
#define PCF8563_BITS_ST2_N (7 << 5)
#define PCF8563_REG_SC 0x02 /* datetime */
#define PCF8563_REG_MN 0x03
#define PCF8563_REG_HR 0x04
#define PCF8563_REG_DM 0x05
#define PCF8563_REG_DW 0x06
#define PCF8563_REG_MO 0x07
#define PCF8563_REG_YR 0x08
#define PCF8563_REG_AMN 0x09 /* alarm */
#define PCF8563_REG_CLKO 0x0D /* clock out */
#define PCF8563_REG_TMRC 0x0E /* timer control */
#define PCF8563_TMRC_ENABLE BIT(7)
#define PCF8563_TMRC_4096 0
#define PCF8563_TMRC_64 1
#define PCF8563_TMRC_1 2
#define PCF8563_TMRC_1_60 3
#define PCF8563_TMRC_MASK 3
#define PCF8563_REG_TMR 0x0F /* timer */
#define PCF8563_SC_LV 0x80 /* low voltage */
#define PCF8563_MO_C 0x80 /* century */
static struct i2c_driver pcf8563_driver;
struct pcf8563 {
struct rtc_device *rtc;
/*
* The meaning of MO_C bit varies by the chip type.
* From PCF8563 datasheet: this bit is toggled when the years
* register overflows from 99 to 00
* 0 indicates the century is 20xx
* 1 indicates the century is 19xx
* From RTC8564 datasheet: this bit indicates change of
* century. When the year digit data overflows from 99 to 00,
* this bit is set. By presetting it to 0 while still in the
* 20th century, it will be set in year 2000, ...
* There seems no reliable way to know how the system use this
* bit. So let's do it heuristically, assuming we are live in
* 1970...2069.
*/
int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
int voltage_low; /* incicates if a low_voltage was detected */
struct i2c_client *client;
};
static int pcf8563_read_block_data(struct i2c_client *client, unsigned char reg,
unsigned char length, unsigned char *buf)
{
struct i2c_msg msgs[] = {
{/* setup read ptr */
.addr = client->addr,
.len = 1,
.buf = &reg,
},
{
.addr = client->addr,
.flags = I2C_M_RD,
.len = length,
.buf = buf
},
};
if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
return 0;
}
static int pcf8563_write_block_data(struct i2c_client *client,
unsigned char reg, unsigned char length,
unsigned char *buf)
{
int i, err;
for (i = 0; i < length; i++) {
unsigned char data[2] = { reg + i, buf[i] };
err = i2c_master_send(client, data, sizeof(data));
if (err != sizeof(data)) {
dev_err(&client->dev,
"%s: err=%d addr=%02x, data=%02x\n",
__func__, err, data[0], data[1]);
return -EIO;
}
}
return 0;
}
static int pcf8563_set_alarm_mode(struct i2c_client *client, bool on)
{
unsigned char buf;
int err;
err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
if (err < 0)
return err;
if (on)
buf |= PCF8563_BIT_AIE;
else
buf &= ~PCF8563_BIT_AIE;
buf &= ~(PCF8563_BIT_AF | PCF8563_BITS_ST2_N);
err = pcf8563_write_block_data(client, PCF8563_REG_ST2, 1, &buf);
if (err < 0) {
dev_err(&client->dev, "%s: write error\n", __func__);
return -EIO;
}
return 0;
}
static int pcf8563_get_alarm_mode(struct i2c_client *client, unsigned char *en,
unsigned char *pen)
{
unsigned char buf;
int err;
err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
if (err)
return err;
if (en)
*en = !!(buf & PCF8563_BIT_AIE);
if (pen)
*pen = !!(buf & PCF8563_BIT_AF);
return 0;
}
static irqreturn_t pcf8563_irq(int irq, void *dev_id)
{
struct pcf8563 *pcf8563 = i2c_get_clientdata(dev_id);
int err;
char pending;
err = pcf8563_get_alarm_mode(pcf8563->client, NULL, &pending);
if (err)
return IRQ_NONE;
if (pending) {
rtc_update_irq(pcf8563->rtc, 1, RTC_IRQF | RTC_AF);
pcf8563_set_alarm_mode(pcf8563->client, 1);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
/*
* In the routines that deal directly with the pcf8563 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
*/
static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
unsigned char buf[9];
int err;
err = pcf8563_read_block_data(client, PCF8563_REG_ST1, 9, buf);
if (err)
return err;
if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
pcf8563->voltage_low = 1;
dev_err(&client->dev,
"low voltage detected, date/time is not reliable.\n");
return -EINVAL;
}
dev_dbg(&client->dev,
"%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
__func__,
buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6], buf[7],
buf[8]);
tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
if (tm->tm_year < 70)
tm->tm_year += 100; /* assume we are in 1970...2069 */
/* detect the polarity heuristically. see note above. */
pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
(tm->tm_year >= 100) : (tm->tm_year < 100);
dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
return 0;
}
static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
unsigned char buf[9];
dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
/* hours, minutes and seconds */
buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
/* month, 1 - 12 */
buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
/* year and century */
buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
buf[PCF8563_REG_MO] |= PCF8563_MO_C;
buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
return pcf8563_write_block_data(client, PCF8563_REG_SC,
9 - PCF8563_REG_SC, buf + PCF8563_REG_SC);
}
#ifdef CONFIG_RTC_INTF_DEV
static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
struct rtc_time tm;
switch (cmd) {
case RTC_VL_READ:
if (pcf8563->voltage_low)
dev_info(dev, "low voltage detected, date/time is not reliable.\n");
if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
sizeof(int)))
return -EFAULT;
return 0;
case RTC_VL_CLR:
/*
* Clear the VL bit in the seconds register in case
* the time has not been set already (which would
* have cleared it). This does not really matter
* because of the cached voltage_low value but do it
* anyway for consistency.
*/
if (pcf8563_get_datetime(to_i2c_client(dev), &tm))
pcf8563_set_datetime(to_i2c_client(dev), &tm);
/* Clear the cached value. */
pcf8563->voltage_low = 0;
return 0;
default:
return -ENOIOCTLCMD;
}
}
#else
#define pcf8563_rtc_ioctl NULL
#endif
static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return pcf8563_get_datetime(to_i2c_client(dev), tm);
}
static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return pcf8563_set_datetime(to_i2c_client(dev), tm);
}
static int pcf8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
{
struct i2c_client *client = to_i2c_client(dev);
unsigned char buf[4];
int err;
err = pcf8563_read_block_data(client, PCF8563_REG_AMN, 4, buf);
if (err)
return err;
dev_dbg(&client->dev,
"%s: raw data is min=%02x, hr=%02x, mday=%02x, wday=%02x\n",
__func__, buf[0], buf[1], buf[2], buf[3]);
tm->time.tm_min = bcd2bin(buf[0] & 0x7F);
tm->time.tm_hour = bcd2bin(buf[1] & 0x3F);
tm->time.tm_mday = bcd2bin(buf[2] & 0x3F);
tm->time.tm_wday = bcd2bin(buf[3] & 0x7);
tm->time.tm_mon = -1;
tm->time.tm_year = -1;
tm->time.tm_yday = -1;
tm->time.tm_isdst = -1;
err = pcf8563_get_alarm_mode(client, &tm->enabled, &tm->pending);
if (err < 0)
return err;
dev_dbg(&client->dev, "%s: tm is mins=%d, hours=%d, mday=%d, wday=%d,"
" enabled=%d, pending=%d\n", __func__, tm->time.tm_min,
tm->time.tm_hour, tm->time.tm_mday, tm->time.tm_wday,
tm->enabled, tm->pending);
return 0;
}
static int pcf8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
{
struct i2c_client *client = to_i2c_client(dev);
unsigned char buf[4];
int err;
/* The alarm has no seconds, round up to nearest minute */
if (tm->time.tm_sec) {
time64_t alarm_time = rtc_tm_to_time64(&tm->time);
alarm_time += 60 - tm->time.tm_sec;
rtc_time64_to_tm(alarm_time, &tm->time);
}
dev_dbg(dev, "%s, min=%d hour=%d wday=%d mday=%d "
"enabled=%d pending=%d\n", __func__,
tm->time.tm_min, tm->time.tm_hour, tm->time.tm_wday,
tm->time.tm_mday, tm->enabled, tm->pending);
buf[0] = bin2bcd(tm->time.tm_min);
buf[1] = bin2bcd(tm->time.tm_hour);
buf[2] = bin2bcd(tm->time.tm_mday);
buf[3] = tm->time.tm_wday & 0x07;
err = pcf8563_write_block_data(client, PCF8563_REG_AMN, 4, buf);
if (err)
return err;
return pcf8563_set_alarm_mode(client, 1);
}
static int pcf8563_irq_enable(struct device *dev, unsigned int enabled)
{
dev_dbg(dev, "%s: en=%d\n", __func__, enabled);
return pcf8563_set_alarm_mode(to_i2c_client(dev), !!enabled);
}
static const struct rtc_class_ops pcf8563_rtc_ops = {
.ioctl = pcf8563_rtc_ioctl,
.read_time = pcf8563_rtc_read_time,
.set_time = pcf8563_rtc_set_time,
.read_alarm = pcf8563_rtc_read_alarm,
.set_alarm = pcf8563_rtc_set_alarm,
.alarm_irq_enable = pcf8563_irq_enable,
};
static int pcf8563_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pcf8563 *pcf8563;
int err;
unsigned char buf;
unsigned char alm_pending;
dev_dbg(&client->dev, "%s\n", __func__);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
pcf8563 = devm_kzalloc(&client->dev, sizeof(struct pcf8563),
GFP_KERNEL);
if (!pcf8563)
return -ENOMEM;
dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
i2c_set_clientdata(client, pcf8563);
pcf8563->client = client;
device_set_wakeup_capable(&client->dev, 1);
/* Set timer to lowest frequency to save power (ref Haoyu datasheet) */
buf = PCF8563_TMRC_1_60;
err = pcf8563_write_block_data(client, PCF8563_REG_TMRC, 1, &buf);
if (err < 0) {
dev_err(&client->dev, "%s: write error\n", __func__);
return err;
}
err = pcf8563_get_alarm_mode(client, NULL, &alm_pending);
if (err) {
dev_err(&client->dev, "%s: read error\n", __func__);
return err;
}
if (alm_pending)
pcf8563_set_alarm_mode(client, 0);
pcf8563->rtc = devm_rtc_device_register(&client->dev,
pcf8563_driver.driver.name,
&pcf8563_rtc_ops, THIS_MODULE);
if (IS_ERR(pcf8563->rtc))
return PTR_ERR(pcf8563->rtc);
if (client->irq > 0) {
err = devm_request_threaded_irq(&client->dev, client->irq,
NULL, pcf8563_irq,
IRQF_SHARED|IRQF_ONESHOT|IRQF_TRIGGER_FALLING,
pcf8563->rtc->name, client);
if (err) {
dev_err(&client->dev, "unable to request IRQ %d\n",
client->irq);
return err;
}
}
/* the pcf8563 alarm only supports a minute accuracy */
pcf8563->rtc->uie_unsupported = 1;
return 0;
}
static const struct i2c_device_id pcf8563_id[] = {
{ "pcf8563", 0 },
{ "rtc8564", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf8563_id);
#ifdef CONFIG_OF
static const struct of_device_id pcf8563_of_match[] = {
{ .compatible = "nxp,pcf8563" },
{}
};
MODULE_DEVICE_TABLE(of, pcf8563_of_match);
#endif
static struct i2c_driver pcf8563_driver = {
.driver = {
.name = "rtc-pcf8563",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(pcf8563_of_match),
},
.probe = pcf8563_probe,
.id_table = pcf8563_id,
};
module_i2c_driver(pcf8563_driver);
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
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