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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: Alexandre Belloni <alexandre.belloni@bootlin.com>
hifive-unleashed-5.1
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;