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rtc: rs5c348: report error when time is invalid

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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: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Alexandre Belloni 2018-09-24 17:05:09 +02:00
parent 2d7be4ed7a
commit 1654a2b06b
1 changed files with 21 additions and 22 deletions
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43
drivers/rtc/rtc-rs5c348.c
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@ -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;