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path: root/drivers/rtc/rtc-pcf2123.c
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Diffstat (limited to 'drivers/rtc/rtc-pcf2123.c')
-rw-r--r--drivers/rtc/rtc-pcf2123.c271
1 files changed, 194 insertions, 77 deletions
diff --git a/drivers/rtc/rtc-pcf2123.c b/drivers/rtc/rtc-pcf2123.c
index ea8a31c91641..da27738b1242 100644
--- a/drivers/rtc/rtc-pcf2123.c
+++ b/drivers/rtc/rtc-pcf2123.c
@@ -48,6 +48,7 @@
#define DRV_VERSION "0.6"
+/* REGISTERS */
#define PCF2123_REG_CTRL1 (0x00) /* Control Register 1 */
#define PCF2123_REG_CTRL2 (0x01) /* Control Register 2 */
#define PCF2123_REG_SC (0x02) /* datetime */
@@ -57,10 +58,54 @@
#define PCF2123_REG_DW (0x06)
#define PCF2123_REG_MO (0x07)
#define PCF2123_REG_YR (0x08)
+#define PCF2123_REG_ALRM_MN (0x09) /* Alarm Registers */
+#define PCF2123_REG_ALRM_HR (0x0a)
+#define PCF2123_REG_ALRM_DM (0x0b)
+#define PCF2123_REG_ALRM_DW (0x0c)
+#define PCF2123_REG_OFFSET (0x0d) /* Clock Rate Offset Register */
+#define PCF2123_REG_TMR_CLKOUT (0x0e) /* Timer Registers */
+#define PCF2123_REG_CTDWN_TMR (0x0f)
+
+/* PCF2123_REG_CTRL1 BITS */
+#define CTRL1_CLEAR (0) /* Clear */
+#define CTRL1_CORR_INT BIT(1) /* Correction irq enable */
+#define CTRL1_12_HOUR BIT(2) /* 12 hour time */
+#define CTRL1_SW_RESET (BIT(3) | BIT(4) | BIT(6)) /* Software reset */
+#define CTRL1_STOP BIT(5) /* Stop the clock */
+#define CTRL1_EXT_TEST BIT(7) /* External clock test mode */
+
+/* PCF2123_REG_CTRL2 BITS */
+#define CTRL2_TIE BIT(0) /* Countdown timer irq enable */
+#define CTRL2_AIE BIT(1) /* Alarm irq enable */
+#define CTRL2_TF BIT(2) /* Countdown timer flag */
+#define CTRL2_AF BIT(3) /* Alarm flag */
+#define CTRL2_TI_TP BIT(4) /* Irq pin generates pulse */
+#define CTRL2_MSF BIT(5) /* Minute or second irq flag */
+#define CTRL2_SI BIT(6) /* Second irq enable */
+#define CTRL2_MI BIT(7) /* Minute irq enable */
+
+/* PCF2123_REG_SC BITS */
+#define OSC_HAS_STOPPED BIT(7) /* Clock has been stopped */
+
+/* PCF2123_REG_ALRM_XX BITS */
+#define ALRM_ENABLE BIT(7) /* MN, HR, DM, or DW alarm enable */
+
+/* PCF2123_REG_TMR_CLKOUT BITS */
+#define CD_TMR_4096KHZ (0) /* 4096 KHz countdown timer */
+#define CD_TMR_64HZ (1) /* 64 Hz countdown timer */
+#define CD_TMR_1HZ (2) /* 1 Hz countdown timer */
+#define CD_TMR_60th_HZ (3) /* 60th Hz countdown timer */
+#define CD_TMR_TE BIT(3) /* Countdown timer enable */
+
+/* PCF2123_REG_OFFSET BITS */
+#define OFFSET_SIGN_BIT BIT(6) /* 2's complement sign bit */
+#define OFFSET_COARSE BIT(7) /* Coarse mode offset */
+#define OFFSET_STEP (2170) /* Offset step in parts per billion */
+
+/* READ/WRITE ADDRESS BITS */
+#define PCF2123_WRITE BIT(4)
+#define PCF2123_READ (BIT(4) | BIT(7))
-#define PCF2123_SUBADDR (1 << 4)
-#define PCF2123_WRITE ((0 << 7) | PCF2123_SUBADDR)
-#define PCF2123_READ ((1 << 7) | PCF2123_SUBADDR)
static struct spi_driver pcf2123_driver;
@@ -84,12 +129,44 @@ static inline void pcf2123_delay_trec(void)
ndelay(30);
}
+static int pcf2123_read(struct device *dev, u8 reg, u8 *rxbuf, size_t size)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ int ret;
+
+ reg |= PCF2123_READ;
+ ret = spi_write_then_read(spi, &reg, 1, rxbuf, size);
+ pcf2123_delay_trec();
+
+ return ret;
+}
+
+static int pcf2123_write(struct device *dev, u8 *txbuf, size_t size)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ int ret;
+
+ txbuf[0] |= PCF2123_WRITE;
+ ret = spi_write(spi, txbuf, size);
+ pcf2123_delay_trec();
+
+ return ret;
+}
+
+static int pcf2123_write_reg(struct device *dev, u8 reg, u8 val)
+{
+ u8 txbuf[2];
+
+ txbuf[0] = reg;
+ txbuf[1] = val;
+ return pcf2123_write(dev, txbuf, sizeof(txbuf));
+}
+
static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr,
char *buffer)
{
- struct spi_device *spi = to_spi_device(dev);
struct pcf2123_sysfs_reg *r;
- u8 txbuf[1], rxbuf[1];
+ u8 rxbuf[1];
unsigned long reg;
int ret;
@@ -99,19 +176,16 @@ static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr,
if (ret)
return ret;
- txbuf[0] = PCF2123_READ | reg;
- ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
+ ret = pcf2123_read(dev, reg, rxbuf, 1);
if (ret < 0)
return -EIO;
- pcf2123_delay_trec();
+
return sprintf(buffer, "0x%x\n", rxbuf[0]);
}
static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr,
const char *buffer, size_t count) {
- struct spi_device *spi = to_spi_device(dev);
struct pcf2123_sysfs_reg *r;
- u8 txbuf[2];
unsigned long reg;
unsigned long val;
@@ -127,27 +201,78 @@ static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr,
if (ret)
return ret;
- txbuf[0] = PCF2123_WRITE | reg;
- txbuf[1] = val;
- ret = spi_write(spi, txbuf, sizeof(txbuf));
+ pcf2123_write_reg(dev, reg, val);
if (ret < 0)
return -EIO;
- pcf2123_delay_trec();
return count;
}
+static int pcf2123_read_offset(struct device *dev, long *offset)
+{
+ int ret;
+ s8 reg;
+
+ ret = pcf2123_read(dev, PCF2123_REG_OFFSET, &reg, 1);
+ if (ret < 0)
+ return ret;
+
+ if (reg & OFFSET_COARSE)
+ reg <<= 1; /* multiply by 2 and sign extend */
+ else
+ reg |= (reg & OFFSET_SIGN_BIT) << 1; /* sign extend only */
+
+ *offset = ((long)reg) * OFFSET_STEP;
+
+ return 0;
+}
+
+/*
+ * The offset register is a 7 bit signed value with a coarse bit in bit 7.
+ * The main difference between the two is normal offset adjusts the first
+ * second of n minutes every other hour, with 61, 62 and 63 being shoved
+ * into the 60th minute.
+ * The coarse adjustment does the same, but every hour.
+ * the two overlap, with every even normal offset value corresponding
+ * to a coarse offset. Based on this algorithm, it seems that despite the
+ * name, coarse offset is a better fit for overlapping values.
+ */
+static int pcf2123_set_offset(struct device *dev, long offset)
+{
+ s8 reg;
+
+ if (offset > OFFSET_STEP * 127)
+ reg = 127;
+ else if (offset < OFFSET_STEP * -128)
+ reg = -128;
+ else
+ reg = (s8)((offset + (OFFSET_STEP >> 1)) / OFFSET_STEP);
+
+ /* choose fine offset only for odd values in the normal range */
+ if (reg & 1 && reg <= 63 && reg >= -64) {
+ /* Normal offset. Clear the coarse bit */
+ reg &= ~OFFSET_COARSE;
+ } else {
+ /* Coarse offset. Divide by 2 and set the coarse bit */
+ reg >>= 1;
+ reg |= OFFSET_COARSE;
+ }
+
+ return pcf2123_write_reg(dev, PCF2123_REG_OFFSET, reg);
+}
+
static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
- struct spi_device *spi = to_spi_device(dev);
- u8 txbuf[1], rxbuf[7];
+ u8 rxbuf[7];
int ret;
- txbuf[0] = PCF2123_READ | PCF2123_REG_SC;
- ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
- rxbuf, sizeof(rxbuf));
+ ret = pcf2123_read(dev, PCF2123_REG_SC, rxbuf, sizeof(rxbuf));
if (ret < 0)
return ret;
- pcf2123_delay_trec();
+
+ if (rxbuf[0] & OSC_HAS_STOPPED) {
+ dev_info(dev, "clock was stopped. Time is not valid\n");
+ return -EINVAL;
+ }
tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F);
tm->tm_min = bcd2bin(rxbuf[1] & 0x7F);
@@ -170,7 +295,6 @@ static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)
static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
- struct spi_device *spi = to_spi_device(dev);
u8 txbuf[8];
int ret;
@@ -181,15 +305,12 @@ static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
/* Stop the counter first */
- txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
- txbuf[1] = 0x20;
- ret = spi_write(spi, txbuf, 2);
+ ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_STOP);
if (ret < 0)
return ret;
- pcf2123_delay_trec();
/* Set the new time */
- txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC;
+ txbuf[0] = PCF2123_REG_SC;
txbuf[1] = bin2bcd(tm->tm_sec & 0x7F);
txbuf[2] = bin2bcd(tm->tm_min & 0x7F);
txbuf[3] = bin2bcd(tm->tm_hour & 0x3F);
@@ -198,18 +319,48 @@ static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */
txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100);
- ret = spi_write(spi, txbuf, sizeof(txbuf));
+ ret = pcf2123_write(dev, txbuf, sizeof(txbuf));
if (ret < 0)
return ret;
- pcf2123_delay_trec();
/* Start the counter */
- txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
- txbuf[1] = 0x00;
- ret = spi_write(spi, txbuf, 2);
+ ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_CLEAR);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int pcf2123_reset(struct device *dev)
+{
+ int ret;
+ u8 rxbuf[2];
+
+ ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_SW_RESET);
+ if (ret < 0)
+ return ret;
+
+ /* Stop the counter */
+ dev_dbg(dev, "stopping RTC\n");
+ ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_STOP);
+ if (ret < 0)
+ return ret;
+
+ /* See if the counter was actually stopped */
+ dev_dbg(dev, "checking for presence of RTC\n");
+ ret = pcf2123_read(dev, PCF2123_REG_CTRL1, rxbuf, sizeof(rxbuf));
+ if (ret < 0)
+ return ret;
+
+ dev_dbg(dev, "received data from RTC (0x%02X 0x%02X)\n",
+ rxbuf[0], rxbuf[1]);
+ if (!(rxbuf[0] & CTRL1_STOP))
+ return -ENODEV;
+
+ /* Start the counter */
+ ret = pcf2123_write_reg(dev, PCF2123_REG_CTRL1, CTRL1_CLEAR);
if (ret < 0)
return ret;
- pcf2123_delay_trec();
return 0;
}
@@ -217,13 +368,16 @@ static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
static const struct rtc_class_ops pcf2123_rtc_ops = {
.read_time = pcf2123_rtc_read_time,
.set_time = pcf2123_rtc_set_time,
+ .read_offset = pcf2123_read_offset,
+ .set_offset = pcf2123_set_offset,
+
};
static int pcf2123_probe(struct spi_device *spi)
{
struct rtc_device *rtc;
+ struct rtc_time tm;
struct pcf2123_plat_data *pdata;
- u8 txbuf[2], rxbuf[2];
int ret, i;
pdata = devm_kzalloc(&spi->dev, sizeof(struct pcf2123_plat_data),
@@ -232,56 +386,19 @@ static int pcf2123_probe(struct spi_device *spi)
return -ENOMEM;
spi->dev.platform_data = pdata;
- /* Send a software reset command */
- txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
- txbuf[1] = 0x58;
- dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n",
- txbuf[0], txbuf[1]);
- ret = spi_write(spi, txbuf, 2 * sizeof(u8));
- if (ret < 0)
- goto kfree_exit;
- pcf2123_delay_trec();
-
- /* Stop the counter */
- txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
- txbuf[1] = 0x20;
- dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n",
- txbuf[0], txbuf[1]);
- ret = spi_write(spi, txbuf, 2 * sizeof(u8));
- if (ret < 0)
- goto kfree_exit;
- pcf2123_delay_trec();
-
- /* See if the counter was actually stopped */
- txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1;
- dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n",
- txbuf[0]);
- ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8),
- rxbuf, 2 * sizeof(u8));
- dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n",
- rxbuf[0], rxbuf[1]);
- if (ret < 0)
- goto kfree_exit;
- pcf2123_delay_trec();
-
- if (!(rxbuf[0] & 0x20)) {
- dev_err(&spi->dev, "chip not found\n");
- ret = -ENODEV;
- goto kfree_exit;
+ ret = pcf2123_rtc_read_time(&spi->dev, &tm);
+ if (ret < 0) {
+ ret = pcf2123_reset(&spi->dev);
+ if (ret < 0) {
+ dev_err(&spi->dev, "chip not found\n");
+ goto kfree_exit;
+ }
}
dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n");
dev_info(&spi->dev, "spiclk %u KHz.\n",
(spi->max_speed_hz + 500) / 1000);
- /* Start the counter */
- txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
- txbuf[1] = 0x00;
- ret = spi_write(spi, txbuf, sizeof(txbuf));
- if (ret < 0)
- goto kfree_exit;
- pcf2123_delay_trec();
-
/* Finalize the initialization */
rtc = devm_rtc_device_register(&spi->dev, pcf2123_driver.driver.name,
&pcf2123_rtc_ops, THIS_MODULE);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.