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linux/drivers/rtc/rtc-isl1208.c
Chris Elston cc6c2ca300 rtc: rtc-isl1208: reject invalid dates 
This patch for the rtc-isl1208 driver makes it reject invalid dates.

Signed-off-by: Chris Elston <celston@katalix.com>
[a.zummo@towertech.it: added comment explaining the check]
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: Hebert Valerio Riedel <hvr@gnu.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-23 15:58:21 -08:00

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/*
* Intersil ISL1208 rtc class driver
*
* Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#define DRV_VERSION "0.3"
/* Register map */
/* rtc section */
#define ISL1208_REG_SC 0x00
#define ISL1208_REG_MN 0x01
#define ISL1208_REG_HR 0x02
#define ISL1208_REG_HR_MIL (1<<7) /* 24h/12h mode */
#define ISL1208_REG_HR_PM (1<<5) /* PM/AM bit in 12h mode */
#define ISL1208_REG_DT 0x03
#define ISL1208_REG_MO 0x04
#define ISL1208_REG_YR 0x05
#define ISL1208_REG_DW 0x06
#define ISL1208_RTC_SECTION_LEN 7
/* control/status section */
#define ISL1208_REG_SR 0x07
#define ISL1208_REG_SR_ARST (1<<7) /* auto reset */
#define ISL1208_REG_SR_XTOSCB (1<<6) /* crystal oscillator */
#define ISL1208_REG_SR_WRTC (1<<4) /* write rtc */
#define ISL1208_REG_SR_ALM (1<<2) /* alarm */
#define ISL1208_REG_SR_BAT (1<<1) /* battery */
#define ISL1208_REG_SR_RTCF (1<<0) /* rtc fail */
#define ISL1208_REG_INT 0x08
#define ISL1208_REG_09 0x09 /* reserved */
#define ISL1208_REG_ATR 0x0a
#define ISL1208_REG_DTR 0x0b
/* alarm section */
#define ISL1208_REG_SCA 0x0c
#define ISL1208_REG_MNA 0x0d
#define ISL1208_REG_HRA 0x0e
#define ISL1208_REG_DTA 0x0f
#define ISL1208_REG_MOA 0x10
#define ISL1208_REG_DWA 0x11
#define ISL1208_ALARM_SECTION_LEN 6
/* user section */
#define ISL1208_REG_USR1 0x12
#define ISL1208_REG_USR2 0x13
#define ISL1208_USR_SECTION_LEN 2
static struct i2c_driver isl1208_driver;
/* block read */
static int
isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
unsigned len)
{
u8 reg_addr[1] = { reg };
struct i2c_msg msgs[2] = {
{client->addr, 0, sizeof(reg_addr), reg_addr}
,
{client->addr, I2C_M_RD, len, buf}
};
int ret;
BUG_ON(reg > ISL1208_REG_USR2);
BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
ret = i2c_transfer(client->adapter, msgs, 2);
if (ret > 0)
ret = 0;
return ret;
}
/* block write */
static int
isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
unsigned len)
{
u8 i2c_buf[ISL1208_REG_USR2 + 2];
struct i2c_msg msgs[1] = {
{client->addr, 0, len + 1, i2c_buf}
};
int ret;
BUG_ON(reg > ISL1208_REG_USR2);
BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
i2c_buf[0] = reg;
memcpy(&i2c_buf[1], &buf[0], len);
ret = i2c_transfer(client->adapter, msgs, 1);
if (ret > 0)
ret = 0;
return ret;
}
/* simple check to see wether we have a isl1208 */
static int
isl1208_i2c_validate_client(struct i2c_client *client)
{
u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
};
int i;
int ret;
ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
if (ret < 0)
return ret;
for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
if (regs[i] & zero_mask[i]) /* check if bits are cleared */
return -ENODEV;
}
return 0;
}
static int
isl1208_i2c_get_sr(struct i2c_client *client)
{
int sr = i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
if (sr < 0)
return -EIO;
return sr;
}
static int
isl1208_i2c_get_atr(struct i2c_client *client)
{
int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
if (atr < 0)
return atr;
/* The 6bit value in the ATR register controls the load
* capacitance C_load * in steps of 0.25pF
*
* bit (1<<5) of the ATR register is inverted
*
* C_load(ATR=0x20) = 4.50pF
* C_load(ATR=0x00) = 12.50pF
* C_load(ATR=0x1f) = 20.25pF
*
*/
atr &= 0x3f; /* mask out lsb */
atr ^= 1 << 5; /* invert 6th bit */
atr += 2 * 9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
return atr;
}
static int
isl1208_i2c_get_dtr(struct i2c_client *client)
{
int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
if (dtr < 0)
return -EIO;
/* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
dtr = ((dtr & 0x3) * 20) * (dtr & (1 << 2) ? -1 : 1);
return dtr;
}
static int
isl1208_i2c_get_usr(struct i2c_client *client)
{
u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
int ret;
ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
ISL1208_USR_SECTION_LEN);
if (ret < 0)
return ret;
return (buf[1] << 8) | buf[0];
}
static int
isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
{
u8 buf[ISL1208_USR_SECTION_LEN];
buf[0] = usr & 0xff;
buf[1] = (usr >> 8) & 0xff;
return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
ISL1208_USR_SECTION_LEN);
}
static int
isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
{
struct i2c_client *const client = to_i2c_client(dev);
int sr, dtr, atr, usr;
sr = isl1208_i2c_get_sr(client);
if (sr < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return sr;
}
seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
(sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
(sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
(sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
(sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
(sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
(sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);
seq_printf(seq, "batt_status\t: %s\n",
(sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
dtr = isl1208_i2c_get_dtr(client);
if (dtr >= 0 - 1)
seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);
atr = isl1208_i2c_get_atr(client);
if (atr >= 0)
seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
atr >> 2, (atr & 0x3) * 25);
usr = isl1208_i2c_get_usr(client);
if (usr >= 0)
seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
return 0;
}
static int
isl1208_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
{
int sr;
u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
sr = isl1208_i2c_get_sr(client);
if (sr < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return -EIO;
}
sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
if (sr < 0) {
dev_err(&client->dev, "%s: reading RTC section failed\n",
__func__);
return sr;
}
tm->tm_sec = bcd2bin(regs[ISL1208_REG_SC]);
tm->tm_min = bcd2bin(regs[ISL1208_REG_MN]);
/* HR field has a more complex interpretation */
{
const u8 _hr = regs[ISL1208_REG_HR];
if (_hr & ISL1208_REG_HR_MIL) /* 24h format */
tm->tm_hour = bcd2bin(_hr & 0x3f);
else {
/* 12h format */
tm->tm_hour = bcd2bin(_hr & 0x1f);
if (_hr & ISL1208_REG_HR_PM) /* PM flag set */
tm->tm_hour += 12;
}
}
tm->tm_mday = bcd2bin(regs[ISL1208_REG_DT]);
tm->tm_mon = bcd2bin(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
tm->tm_year = bcd2bin(regs[ISL1208_REG_YR]) + 100;
tm->tm_wday = bcd2bin(regs[ISL1208_REG_DW]);
return 0;
}
static int
isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
{
struct rtc_time *const tm = &alarm->time;
u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
int sr;
sr = isl1208_i2c_get_sr(client);
if (sr < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return sr;
}
sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
ISL1208_ALARM_SECTION_LEN);
if (sr < 0) {
dev_err(&client->dev, "%s: reading alarm section failed\n",
__func__);
return sr;
}
/* MSB of each alarm register is an enable bit */
tm->tm_sec = bcd2bin(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
tm->tm_min = bcd2bin(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
tm->tm_hour = bcd2bin(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
tm->tm_mday = bcd2bin(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
tm->tm_mon =
bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
return 0;
}
static int
isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return isl1208_i2c_read_time(to_i2c_client(dev), tm);
}
static int
isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
{
int sr;
u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
/* 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[ISL1208_REG_SC] = bin2bcd(tm->tm_sec);
regs[ISL1208_REG_MN] = bin2bcd(tm->tm_min);
regs[ISL1208_REG_HR] = bin2bcd(tm->tm_hour) | ISL1208_REG_HR_MIL;
regs[ISL1208_REG_DT] = bin2bcd(tm->tm_mday);
regs[ISL1208_REG_MO] = bin2bcd(tm->tm_mon + 1);
regs[ISL1208_REG_YR] = bin2bcd(tm->tm_year - 100);
regs[ISL1208_REG_DW] = bin2bcd(tm->tm_wday & 7);
sr = isl1208_i2c_get_sr(client);
if (sr < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return sr;
}
/* set WRTC */
sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
sr | ISL1208_REG_SR_WRTC);
if (sr < 0) {
dev_err(&client->dev, "%s: writing SR failed\n", __func__);
return sr;
}
/* write RTC registers */
sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
if (sr < 0) {
dev_err(&client->dev, "%s: writing RTC section failed\n",
__func__);
return sr;
}
/* clear WRTC again */
sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
sr & ~ISL1208_REG_SR_WRTC);
if (sr < 0) {
dev_err(&client->dev, "%s: writing SR failed\n", __func__);
return sr;
}
return 0;
}
static int
isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return isl1208_i2c_set_time(to_i2c_client(dev), tm);
}
static int
isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
}
static const struct rtc_class_ops isl1208_rtc_ops = {
.proc = isl1208_rtc_proc,
.read_time = isl1208_rtc_read_time,
.set_time = isl1208_rtc_set_time,
.read_alarm = isl1208_rtc_read_alarm,
/*.set_alarm = isl1208_rtc_set_alarm, */
};
/* sysfs interface */
static ssize_t
isl1208_sysfs_show_atrim(struct device *dev,
struct device_attribute *attr, char *buf)
{
int atr = isl1208_i2c_get_atr(to_i2c_client(dev));
if (atr < 0)
return atr;
return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
}
static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
static ssize_t
isl1208_sysfs_show_dtrim(struct device *dev,
struct device_attribute *attr, char *buf)
{
int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
if (dtr < 0)
return dtr;
return sprintf(buf, "%d ppm\n", dtr);
}
static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
static ssize_t
isl1208_sysfs_show_usr(struct device *dev,
struct device_attribute *attr, char *buf)
{
int usr = isl1208_i2c_get_usr(to_i2c_client(dev));
if (usr < 0)
return usr;
return sprintf(buf, "0x%.4x\n", usr);
}
static ssize_t
isl1208_sysfs_store_usr(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int usr = -1;
if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
if (sscanf(buf, "%x", &usr) != 1)
return -EINVAL;
} else {
if (sscanf(buf, "%d", &usr) != 1)
return -EINVAL;
}
if (usr < 0 || usr > 0xffff)
return -EINVAL;
return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
}
static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
isl1208_sysfs_store_usr);
static int
isl1208_sysfs_register(struct device *dev)
{
int err;
err = device_create_file(dev, &dev_attr_atrim);
if (err)
return err;
err = device_create_file(dev, &dev_attr_dtrim);
if (err) {
device_remove_file(dev, &dev_attr_atrim);
return err;
}
err = device_create_file(dev, &dev_attr_usr);
if (err) {
device_remove_file(dev, &dev_attr_atrim);
device_remove_file(dev, &dev_attr_dtrim);
}
return 0;
}
static int
isl1208_sysfs_unregister(struct device *dev)
{
device_remove_file(dev, &dev_attr_dtrim);
device_remove_file(dev, &dev_attr_atrim);
device_remove_file(dev, &dev_attr_usr);
return 0;
}
static int
isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
int rc = 0;
struct rtc_device *rtc;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
if (isl1208_i2c_validate_client(client) < 0)
return -ENODEV;
dev_info(&client->dev,
"chip found, driver version " DRV_VERSION "\n");
rtc = rtc_device_register(isl1208_driver.driver.name,
&client->dev, &isl1208_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
i2c_set_clientdata(client, rtc);
rc = isl1208_i2c_get_sr(client);
if (rc < 0) {
dev_err(&client->dev, "reading status failed\n");
goto exit_unregister;
}
if (rc & ISL1208_REG_SR_RTCF)
dev_warn(&client->dev, "rtc power failure detected, "
"please set clock.\n");
rc = isl1208_sysfs_register(&client->dev);
if (rc)
goto exit_unregister;
return 0;
exit_unregister:
rtc_device_unregister(rtc);
return rc;
}
static int
isl1208_remove(struct i2c_client *client)
{
struct rtc_device *rtc = i2c_get_clientdata(client);
isl1208_sysfs_unregister(&client->dev);
rtc_device_unregister(rtc);
return 0;
}
static const struct i2c_device_id isl1208_id[] = {
{ "isl1208", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, isl1208_id);
static struct i2c_driver isl1208_driver = {
.driver = {
.name = "rtc-isl1208",
},
.probe = isl1208_probe,
.remove = isl1208_remove,
.id_table = isl1208_id,
};
static int __init
isl1208_init(void)
{
return i2c_add_driver(&isl1208_driver);
}
static void __exit
isl1208_exit(void)
{
i2c_del_driver(&isl1208_driver);
}
MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
module_init(isl1208_init);
module_exit(isl1208_exit);
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