Commit 1654a2b0 authored by Alexandre Belloni's avatar Alexandre Belloni
Browse files

rtc: rs5c348: report error when time is invalid 



Instead of resetting the RTC to an bogus valid time, let userspace know
that the time is invalid when XSTP is set. Reset XSTP when setting the time
again.

Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 2d7be4ed

drivers/rtc/rtc-rs5c348.c

+21 −22
Original line number Diff line number Diff line
@@ -66,6 +66,17 @@ rs5c348_rtc_set_time(struct device *dev, struct rtc_time *tm) 
	u8 txbuf[5+7], *txp;

	int ret;



	ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));

	if (ret < 0)

		return ret;

	if (ret & RS5C348_BIT_XSTP) {

		txbuf[0] = RS5C348_CMD_W(RS5C348_REG_CTL2);

		txbuf[1] = 0;

		ret = spi_write_then_read(spi, txbuf, 2, NULL, 0);

		if (ret < 0)

			return ret;

	}



	/* Transfer 5 bytes before writing SEC.  This gives 31us for carry. */

	txp = txbuf;

	txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
@@ -102,6 +113,16 @@ rs5c348_rtc_read_time(struct device *dev, struct rtc_time *tm) 
	u8 txbuf[5], rxbuf[7];

	int ret;



	ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));

	if (ret < 0)

		return ret;

	if (ret & RS5C348_BIT_VDET)

		dev_warn(&spi->dev, "voltage-low detected.\n");

	if (ret & RS5C348_BIT_XSTP) {

		dev_warn(&spi->dev, "oscillator-stop detected.\n");

		return -EINVAL;

	}



	/* Transfer 5 byte befores reading SEC.  This gives 31us for carry. */

	txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */

	txbuf[1] = 0;	/* dummy */
@@ -165,28 +186,6 @@ static int rs5c348_probe(struct spi_device *spi) 
	dev_info(&spi->dev, "spiclk %u KHz.\n",

		 (spi->max_speed_hz + 500) / 1000);



	/* turn RTC on if it was not on */

	ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));

	if (ret < 0)

		return ret;

	if (ret & (RS5C348_BIT_XSTP | RS5C348_BIT_VDET)) {

		u8 buf[2];

		struct rtc_time tm;

		if (ret & RS5C348_BIT_VDET)

			dev_warn(&spi->dev, "voltage-low detected.\n");

		if (ret & RS5C348_BIT_XSTP)

			dev_warn(&spi->dev, "oscillator-stop detected.\n");

		rtc_time_to_tm(0, &tm);	/* 1970/1/1 */

		ret = rs5c348_rtc_set_time(&spi->dev, &tm);

		if (ret < 0)

			return ret;

		buf[0] = RS5C348_CMD_W(RS5C348_REG_CTL2);

		buf[1] = 0;

		ret = spi_write_then_read(spi, buf, sizeof(buf), NULL, 0);

		if (ret < 0)

			return ret;

	}



	ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL1));

	if (ret < 0)

		return ret;