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Commit f97cfddc authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Alexandre Belloni
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rtc: pcf2127: fix reading uninitialized value on RTC_READ_VL ioctl 



The flag reported on the RTC_READ_VL ioctl is only initialized when the
date is read out. So the voltage low value doesn't represent reality but
the status at the time the date was read (or 0 if the date was not read
yet).

Moreover when userspace requests a value via an ioctl there is no added
benefit to also make a prosa representation of this (and other) values
appear in the kernel log so remove the calls to dev_info and the driver
data members to track their state.

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent 24417829

drivers/rtc/rtc-pcf2127.c

+22 −18
Original line number Diff line number Diff line
@@ -24,7 +24,10 @@ 


#define PCF2127_REG_CTRL1       (0x00)  /* Control Register 1 */

#define PCF2127_REG_CTRL2       (0x01)  /* Control Register 2 */



#define PCF2127_REG_CTRL3       (0x02)  /* Control Register 3 */

#define PCF2127_REG_CTRL3_BLF		BIT(2)



#define PCF2127_REG_SC          (0x03)  /* datetime */

#define PCF2127_REG_MN          (0x04)

#define PCF2127_REG_HR          (0x05)
@@ -39,8 +42,6 @@ static struct i2c_driver pcf2127_driver; 


struct pcf2127 {

	struct rtc_device *rtc;

	int voltage_low; /* indicates if a low_voltage was detected */

	int oscillator_failed; /* OSF was detected and date is unreliable */

};



/*
@@ -49,7 +50,6 @@ struct pcf2127 { 
 */

static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm)

{

	struct pcf2127 *pcf2127 = i2c_get_clientdata(client);

	unsigned char buf[10] = { PCF2127_REG_CTRL1 };



	/* read registers */
@@ -59,18 +59,15 @@ static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm) 
		return -EIO;

	}



	if (buf[PCF2127_REG_CTRL3] & 0x04) {

		pcf2127->voltage_low = 1;

	if (buf[PCF2127_REG_CTRL3] & PCF2127_REG_CTRL3_BLF)

		dev_info(&client->dev,

			"low voltage detected, check/replace RTC battery.\n");

	}



	if (buf[PCF2127_REG_SC] & PCF2127_OSF) {

		/*

		 * no need clear the flag here,

		 * it will be cleared once the new date is saved

		 */

		pcf2127->oscillator_failed = 1;

		dev_warn(&client->dev,

			 "oscillator stop detected, date/time is not reliable\n");

		return -EINVAL;
@@ -107,7 +104,6 @@ static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm) 


static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm)

{

	struct pcf2127 *pcf2127 = i2c_get_clientdata(client);

	unsigned char buf[8];

	int i = 0, err;
@@ -141,9 +137,6 @@ static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm) 
		return -EIO;

	}



	/* clear OSF flag in client data */

	pcf2127->oscillator_failed = 0;



	return 0;

}
@@ -151,17 +144,28 @@ static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm) 
static int pcf2127_rtc_ioctl(struct device *dev,

				unsigned int cmd, unsigned long arg)

{

	struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev));

	struct i2c_client *client = to_i2c_client(dev);

	unsigned char buf = PCF2127_REG_CTRL3;

	int touser;

	int ret;



	switch (cmd) {

	case RTC_VL_READ:

		if (pcf2127->voltage_low)

			dev_info(dev, "low voltage detected, check/replace battery\n");

		if (pcf2127->oscillator_failed)

			dev_info(dev, "oscillator stop detected, date/time is not reliable\n");

		ret = i2c_master_send(client, &buf, 1);

		if (!ret)

			ret = -EIO;

		if (ret < 0)

			return ret;



		ret = i2c_master_recv(client, &buf, 1);

		if (!ret)

			ret = -EIO;

		if (ret < 0)

			return ret;



		touser = buf & PCF2127_REG_CTRL3_BLF ? 1 : 0;



		if (copy_to_user((void __user *)arg, &pcf2127->voltage_low,

					sizeof(int)))

		if (copy_to_user((void __user *)arg, &touser, sizeof(int)))

			return -EFAULT;

		return 0;

	default: