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linux/drivers/rtc/rtc-rv3029c2.c
Gregory Hermant 67ab2440b4 drivers/rtc/rtc-rv3029c2.c: fix potential race condition 
RTC drivers must not return an error after device registration.

Signed-off-by: Gregory Hermant <gregory.hermant@calao-systems.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:24 -07:00

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/*
* Micro Crystal RV-3029C2 rtc class driver
*
* Author: Gregory Hermant <gregory.hermant@calao-systems.com>
*
* based on previously existing rtc class drivers
*
* 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.
*
* NOTE: Currently this driver only supports the bare minimum for read
* and write the RTC and alarms. The extra features provided by this chip
* (trickle charger, eeprom, T° compensation) are unavailable.
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
/* Register map */
/* control section */
#define RV3029C2_ONOFF_CTRL 0x00
#define RV3029C2_IRQ_CTRL 0x01
#define RV3029C2_IRQ_CTRL_AIE (1 << 0)
#define RV3029C2_IRQ_FLAGS 0x02
#define RV3029C2_IRQ_FLAGS_AF (1 << 0)
#define RV3029C2_STATUS 0x03
#define RV3029C2_STATUS_VLOW1 (1 << 2)
#define RV3029C2_STATUS_VLOW2 (1 << 3)
#define RV3029C2_STATUS_SR (1 << 4)
#define RV3029C2_STATUS_PON (1 << 5)
#define RV3029C2_STATUS_EEBUSY (1 << 7)
#define RV3029C2_RST_CTRL 0x04
#define RV3029C2_CONTROL_SECTION_LEN 0x05
/* watch section */
#define RV3029C2_W_SEC 0x08
#define RV3029C2_W_MINUTES 0x09
#define RV3029C2_W_HOURS 0x0A
#define RV3029C2_REG_HR_12_24 (1<<6) /* 24h/12h mode */
#define RV3029C2_REG_HR_PM (1<<5) /* PM/AM bit in 12h mode */
#define RV3029C2_W_DATE 0x0B
#define RV3029C2_W_DAYS 0x0C
#define RV3029C2_W_MONTHS 0x0D
#define RV3029C2_W_YEARS 0x0E
#define RV3029C2_WATCH_SECTION_LEN 0x07
/* alarm section */
#define RV3029C2_A_SC 0x10
#define RV3029C2_A_MN 0x11
#define RV3029C2_A_HR 0x12
#define RV3029C2_A_DT 0x13
#define RV3029C2_A_DW 0x14
#define RV3029C2_A_MO 0x15
#define RV3029C2_A_YR 0x16
#define RV3029C2_ALARM_SECTION_LEN 0x07
/* timer section */
#define RV3029C2_TIMER_LOW 0x18
#define RV3029C2_TIMER_HIGH 0x19
/* temperature section */
#define RV3029C2_TEMP_PAGE 0x20
/* eeprom data section */
#define RV3029C2_E2P_EEDATA1 0x28
#define RV3029C2_E2P_EEDATA2 0x29
/* eeprom control section */
#define RV3029C2_CONTROL_E2P_EECTRL 0x30
#define RV3029C2_TRICKLE_1K (1<<0) /* 1K resistance */
#define RV3029C2_TRICKLE_5K (1<<1) /* 5K resistance */
#define RV3029C2_TRICKLE_20K (1<<2) /* 20K resistance */
#define RV3029C2_TRICKLE_80K (1<<3) /* 80K resistance */
#define RV3029C2_CONTROL_E2P_XTALOFFSET 0x31
#define RV3029C2_CONTROL_E2P_QCOEF 0x32
#define RV3029C2_CONTROL_E2P_TURNOVER 0x33
/* user ram section */
#define RV3029C2_USR1_RAM_PAGE 0x38
#define RV3029C2_USR1_SECTION_LEN 0x04
#define RV3029C2_USR2_RAM_PAGE 0x3C
#define RV3029C2_USR2_SECTION_LEN 0x04
static int
rv3029c2_i2c_read_regs(struct i2c_client *client, u8 reg, u8 *buf,
unsigned len)
{
int ret;
if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
(reg + len > RV3029C2_USR1_RAM_PAGE + 8))
return -EINVAL;
ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
if (ret < 0)
return ret;
if (ret < len)
return -EIO;
return 0;
}
static int
rv3029c2_i2c_write_regs(struct i2c_client *client, u8 reg, u8 const buf[],
unsigned len)
{
if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
(reg + len > RV3029C2_USR1_RAM_PAGE + 8))
return -EINVAL;
return i2c_smbus_write_i2c_block_data(client, reg, len, buf);
}
static int
rv3029c2_i2c_get_sr(struct i2c_client *client, u8 *buf)
{
int ret = rv3029c2_i2c_read_regs(client, RV3029C2_STATUS, buf, 1);
if (ret < 0)
return -EIO;
dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
return 0;
}
static int
rv3029c2_i2c_set_sr(struct i2c_client *client, u8 val)
{
u8 buf[1];
int sr;
buf[0] = val;
sr = rv3029c2_i2c_write_regs(client, RV3029C2_STATUS, buf, 1);
dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
if (sr < 0)
return -EIO;
return 0;
}
static int
rv3029c2_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
{
u8 buf[1];
int ret;
u8 regs[RV3029C2_WATCH_SECTION_LEN] = { 0, };
ret = rv3029c2_i2c_get_sr(client, buf);
if (ret < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return -EIO;
}
ret = rv3029c2_i2c_read_regs(client, RV3029C2_W_SEC , regs,
RV3029C2_WATCH_SECTION_LEN);
if (ret < 0) {
dev_err(&client->dev, "%s: reading RTC section failed\n",
__func__);
return ret;
}
tm->tm_sec = bcd2bin(regs[RV3029C2_W_SEC-RV3029C2_W_SEC]);
tm->tm_min = bcd2bin(regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC]);
/* HR field has a more complex interpretation */
{
const u8 _hr = regs[RV3029C2_W_HOURS-RV3029C2_W_SEC];
if (_hr & RV3029C2_REG_HR_12_24) {
/* 12h format */
tm->tm_hour = bcd2bin(_hr & 0x1f);
if (_hr & RV3029C2_REG_HR_PM) /* PM flag set */
tm->tm_hour += 12;
} else /* 24h format */
tm->tm_hour = bcd2bin(_hr & 0x3f);
}
tm->tm_mday = bcd2bin(regs[RV3029C2_W_DATE-RV3029C2_W_SEC]);
tm->tm_mon = bcd2bin(regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC]) - 1;
tm->tm_year = bcd2bin(regs[RV3029C2_W_YEARS-RV3029C2_W_SEC]) + 100;
tm->tm_wday = bcd2bin(regs[RV3029C2_W_DAYS-RV3029C2_W_SEC]) - 1;
return 0;
}
static int rv3029c2_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return rv3029c2_i2c_read_time(to_i2c_client(dev), tm);
}
static int
rv3029c2_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
{
struct rtc_time *const tm = &alarm->time;
int ret;
u8 regs[8];
ret = rv3029c2_i2c_get_sr(client, regs);
if (ret < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return -EIO;
}
ret = rv3029c2_i2c_read_regs(client, RV3029C2_A_SC, regs,
RV3029C2_ALARM_SECTION_LEN);
if (ret < 0) {
dev_err(&client->dev, "%s: reading alarm section failed\n",
__func__);
return ret;
}
tm->tm_sec = bcd2bin(regs[RV3029C2_A_SC-RV3029C2_A_SC] & 0x7f);
tm->tm_min = bcd2bin(regs[RV3029C2_A_MN-RV3029C2_A_SC] & 0x7f);
tm->tm_hour = bcd2bin(regs[RV3029C2_A_HR-RV3029C2_A_SC] & 0x3f);
tm->tm_mday = bcd2bin(regs[RV3029C2_A_DT-RV3029C2_A_SC] & 0x3f);
tm->tm_mon = bcd2bin(regs[RV3029C2_A_MO-RV3029C2_A_SC] & 0x1f) - 1;
tm->tm_year = bcd2bin(regs[RV3029C2_A_YR-RV3029C2_A_SC] & 0x7f) + 100;
tm->tm_wday = bcd2bin(regs[RV3029C2_A_DW-RV3029C2_A_SC] & 0x07) - 1;
return 0;
}
static int
rv3029c2_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
return rv3029c2_i2c_read_alarm(to_i2c_client(dev), alarm);
}
static int rv3029c2_rtc_i2c_alarm_set_irq(struct i2c_client *client,
int enable)
{
int ret;
u8 buf[1];
/* enable AIE irq */
ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
if (ret < 0) {
dev_err(&client->dev, "can't read INT reg\n");
return ret;
}
if (enable)
buf[0] |= RV3029C2_IRQ_CTRL_AIE;
else
buf[0] &= ~RV3029C2_IRQ_CTRL_AIE;
ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
if (ret < 0) {
dev_err(&client->dev, "can't set INT reg\n");
return ret;
}
return 0;
}
static int rv3029c2_rtc_i2c_set_alarm(struct i2c_client *client,
struct rtc_wkalrm *alarm)
{
struct rtc_time *const tm = &alarm->time;
int ret;
u8 regs[8];
/*
* The clock has an 8 bit wide bcd-coded register (they never learn)
* for the year. tm_year is an offset from 1900 and we are interested
* in the 2000-2099 range, so any value less than 100 is invalid.
*/
if (tm->tm_year < 100)
return -EINVAL;
ret = rv3029c2_i2c_get_sr(client, regs);
if (ret < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return -EIO;
}
regs[RV3029C2_A_SC-RV3029C2_A_SC] = bin2bcd(tm->tm_sec & 0x7f);
regs[RV3029C2_A_MN-RV3029C2_A_SC] = bin2bcd(tm->tm_min & 0x7f);
regs[RV3029C2_A_HR-RV3029C2_A_SC] = bin2bcd(tm->tm_hour & 0x3f);
regs[RV3029C2_A_DT-RV3029C2_A_SC] = bin2bcd(tm->tm_mday & 0x3f);
regs[RV3029C2_A_MO-RV3029C2_A_SC] = bin2bcd((tm->tm_mon & 0x1f) - 1);
regs[RV3029C2_A_DW-RV3029C2_A_SC] = bin2bcd((tm->tm_wday & 7) - 1);
regs[RV3029C2_A_YR-RV3029C2_A_SC] = bin2bcd((tm->tm_year & 0x7f) - 100);
ret = rv3029c2_i2c_write_regs(client, RV3029C2_A_SC, regs,
RV3029C2_ALARM_SECTION_LEN);
if (ret < 0)
return ret;
if (alarm->enabled) {
u8 buf[1];
/* clear AF flag */
ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_FLAGS,
buf, 1);
if (ret < 0) {
dev_err(&client->dev, "can't read alarm flag\n");
return ret;
}
buf[0] &= ~RV3029C2_IRQ_FLAGS_AF;
ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_FLAGS,
buf, 1);
if (ret < 0) {
dev_err(&client->dev, "can't set alarm flag\n");
return ret;
}
/* enable AIE irq */
ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
if (ret)
return ret;
dev_dbg(&client->dev, "alarm IRQ armed\n");
} else {
/* disable AIE irq */
ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 0);
if (ret)
return ret;
dev_dbg(&client->dev, "alarm IRQ disabled\n");
}
return 0;
}
static int rv3029c2_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
return rv3029c2_rtc_i2c_set_alarm(to_i2c_client(dev), alarm);
}
static int
rv3029c2_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
{
u8 regs[8];
int ret;
/*
* The clock has an 8 bit wide bcd-coded register (they never learn)
* for the year. tm_year is an offset from 1900 and we are interested
* in the 2000-2099 range, so any value less than 100 is invalid.
*/
if (tm->tm_year < 100)
return -EINVAL;
regs[RV3029C2_W_SEC-RV3029C2_W_SEC] = bin2bcd(tm->tm_sec);
regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC] = bin2bcd(tm->tm_min);
regs[RV3029C2_W_HOURS-RV3029C2_W_SEC] = bin2bcd(tm->tm_hour);
regs[RV3029C2_W_DATE-RV3029C2_W_SEC] = bin2bcd(tm->tm_mday);
regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC] = bin2bcd(tm->tm_mon+1);
regs[RV3029C2_W_DAYS-RV3029C2_W_SEC] = bin2bcd((tm->tm_wday & 7)+1);
regs[RV3029C2_W_YEARS-RV3029C2_W_SEC] = bin2bcd(tm->tm_year - 100);
ret = rv3029c2_i2c_write_regs(client, RV3029C2_W_SEC, regs,
RV3029C2_WATCH_SECTION_LEN);
if (ret < 0)
return ret;
ret = rv3029c2_i2c_get_sr(client, regs);
if (ret < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return ret;
}
/* clear PON bit */
ret = rv3029c2_i2c_set_sr(client, (regs[0] & ~RV3029C2_STATUS_PON));
if (ret < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return ret;
}
return 0;
}
static int rv3029c2_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return rv3029c2_i2c_set_time(to_i2c_client(dev), tm);
}
static const struct rtc_class_ops rv3029c2_rtc_ops = {
.read_time = rv3029c2_rtc_read_time,
.set_time = rv3029c2_rtc_set_time,
.read_alarm = rv3029c2_rtc_read_alarm,
.set_alarm = rv3029c2_rtc_set_alarm,
};
static struct i2c_device_id rv3029c2_id[] = {
{ "rv3029c2", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, rv3029c2_id);
static int rv3029c2_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct rtc_device *rtc;
int rc = 0;
u8 buf[1];
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_EMUL))
return -ENODEV;
rc = rv3029c2_i2c_get_sr(client, buf);
if (rc < 0) {
dev_err(&client->dev, "reading status failed\n");
return rc;
}
rtc = devm_rtc_device_register(&client->dev, client->name,
&rv3029c2_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
i2c_set_clientdata(client, rtc);
return 0;
}
static struct i2c_driver rv3029c2_driver = {
.driver = {
.name = "rtc-rv3029c2",
},
.probe = rv3029c2_probe,
.id_table = rv3029c2_id,
};
module_i2c_driver(rv3029c2_driver);
MODULE_AUTHOR("Gregory Hermant <gregory.hermant@calao-systems.com>");
MODULE_DESCRIPTION("Micro Crystal RV3029C2 RTC driver");
MODULE_LICENSE("GPL");
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