static int pcf8523_rtc_check_oscillator(struct i2c_client *client)
{
u8 value;
int err;
err = pcf8523_read(client, REG_SECONDS, &value);
if (err < 0)
return err;
if (value & REG_SECONDS_OS) {
/*
* If the oscillator was stopped, try to clear the flag. Upon
* power-up the flag is always set, but if we cannot clear it
* the oscillator isn't running properly for some reason. The
* sensible thing therefore is to return an error, signalling
* that the clock cannot be assumed to be correct.
*/
value &= ~REG_SECONDS_OS;
err = pcf8523_write(client, REG_SECONDS, value);
if (err < 0)
return err;
err = pcf8523_read(client, REG_SECONDS, &value);
if (err < 0)
return err;
if (value & REG_SECONDS_OS)
return -EAGAIN;
}
return 0;
}
static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
u8 start = REG_SECONDS, regs[7];
struct i2c_msg msgs[2];
int err;
msgs[0].addr = client->addr;
msgs[0].flags = 0;
msgs[0].len = 1;
msgs[0].buf = &start;
msgs[1].addr = client->addr;
msgs[1].flags = I2C_M_RD;
msgs[1].len = sizeof(regs);
msgs[1].buf = regs;
err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (err < 0)
return err;
if (regs[0] & REG_SECONDS_OS) {
/*
* If the oscillator was stopped, try to clear the flag. Upon
* power-up the flag is always set, but if we cannot clear it
* the oscillator isn't running properly for some reason. The
* sensible thing therefore is to return an error, signalling
* that the clock cannot be assumed to be correct.
*/
regs[0] &= ~REG_SECONDS_OS;
err = pcf8523_write(client, REG_SECONDS, regs[0]);
if (err < 0)
return err;
err = pcf8523_read(client, REG_SECONDS, ®s[0]);
if (err < 0)
return err;
if (regs[0] & REG_SECONDS_OS)
return -EAGAIN;
}
tm->tm_sec = bcd2bin(regs[0] & 0x7f);
tm->tm_min = bcd2bin(regs[1] & 0x7f);
tm->tm_hour = bcd2bin(regs[2] & 0x3f);
tm->tm_mday = bcd2bin(regs[3] & 0x3f);
tm->tm_wday = regs[4] & 0x7;
tm->tm_mon = bcd2bin(regs[5] & 0x1f);
tm->tm_year = bcd2bin(regs[6]) + 100;
return rtc_valid_tm(tm);
}
static int pcf8523_switch_capacitance(struct i2c_client *client)
{
u8 value;
int err;
err = pcf8523_read(client, REG_CONTROL1, &value);
if (err < 0)
goto out;
value ^= REG_CONTROL1_CAP_SEL;
err = pcf8523_write(client, REG_CONTROL1, value);
out:
return err;
}
static int pcf8523_start_rtc(struct i2c_client *client)
{
u8 value;
int err;
err = pcf8523_read(client, REG_CONTROL1, &value);
if (err < 0)
return err;
value &= ~REG_CONTROL1_STOP;
err = pcf8523_write(client, REG_CONTROL1, value);
if (err < 0)
return err;
return 0;
}
static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
{
u8 value;
int err;
err = pcf8523_read(client, REG_CONTROL3, &value);
if (err < 0)
return err;
value = (value & ~REG_CONTROL3_PM_MASK) | pm;
err = pcf8523_write(client, REG_CONTROL3, value);
if (err < 0)
return err;
return 0;
}
static int pcf8523_select_capacitance(struct i2c_client *client, bool high)
{
u8 value;
int err;
err = pcf8523_read(client, REG_CONTROL1, &value);
if (err < 0)
return err;
if (!high)
value &= ~REG_CONTROL1_CAP_SEL;
else
value |= REG_CONTROL1_CAP_SEL;
err = pcf8523_write(client, REG_CONTROL1, value);
if (err < 0)
return err;
return err;
}
static int pcf8523_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pcf8523 *pcf;
u8 value;
int err;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL);
if (!pcf)
return -ENOMEM;
/* Check whether the RTC reports battery low */
err = pcf8523_read(client, REG_CONTROL3, &value);
if (err < 0)
return err;
if (value & REG_CONTROL3_BLF)
dev_warn(&client->dev, "RTC reports battery is low\n");
err = pcf8523_enable_oscillator(client);
if (err < 0) {
dev_warn(&client->dev, "RTC reports oscillator is not running\n");
return err;
}
err = pcf8523_set_pm(client, 0);
if (err < 0)
return err;
pcf->rtc = devm_rtc_device_register(&client->dev, DRIVER_NAME,
&pcf8523_rtc_ops, THIS_MODULE);
if (IS_ERR(pcf->rtc))
return PTR_ERR(pcf->rtc);
i2c_set_clientdata(client, pcf);
return 0;
}
static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
unsigned long arg)
{
struct i2c_client *client = to_i2c_client(dev);
u8 value;
int ret = 0, err;
switch (cmd) {
case RTC_VL_READ:
err = pcf8523_read(client, REG_CONTROL3, &value);
if (err < 0)
return err;
if (value & REG_CONTROL3_BLF)
ret = 1;
if (copy_to_user((void __user *)arg, &ret, sizeof(int)))
return -EFAULT;
return 0;
default:
return -ENOIOCTLCMD;
}
}
