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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.c476
1 files changed, 476 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf2123.c b/drivers/rtc/rtc-pcf2123.c
new file mode 100644
index 000000000..e13b5e695
--- /dev/null
+++ b/drivers/rtc/rtc-pcf2123.c
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * An SPI driver for the Philips PCF2123 RTC
+ * Copyright 2009 Cyber Switching, Inc.
+ *
+ * Author: Chris Verges <chrisv@cyberswitching.com>
+ * Maintainers: http://www.cyberswitching.com
+ *
+ * based on the RS5C348 driver in this same directory.
+ *
+ * Thanks to Christian Pellegrin <chripell@fsfe.org> for
+ * the sysfs contributions to this driver.
+ *
+ * Please note that the CS is active high, so platform data
+ * should look something like:
+ *
+ * static struct spi_board_info ek_spi_devices[] = {
+ * ...
+ * {
+ * .modalias = "rtc-pcf2123",
+ * .chip_select = 1,
+ * .controller_data = (void *)AT91_PIN_PA10,
+ * .max_speed_hz = 1000 * 1000,
+ * .mode = SPI_CS_HIGH,
+ * .bus_num = 0,
+ * },
+ * ...
+ *};
+ */
+
+#include <linux/bcd.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+/* REGISTERS */
+#define PCF2123_REG_CTRL1 (0x00) /* Control Register 1 */
+#define PCF2123_REG_CTRL2 (0x01) /* Control Register 2 */
+#define PCF2123_REG_SC (0x02) /* datetime */
+#define PCF2123_REG_MN (0x03)
+#define PCF2123_REG_HR (0x04)
+#define PCF2123_REG_DM (0x05)
+#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_DISABLE BIT(7) /* MN, HR, DM, or DW alarm matching */
+
+/* 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 6 /* 2's complement sign bit */
+#define OFFSET_COARSE BIT(7) /* Coarse mode offset */
+#define OFFSET_STEP (2170) /* Offset step in parts per billion */
+#define OFFSET_MASK GENMASK(6, 0) /* Offset value */
+
+/* READ/WRITE ADDRESS BITS */
+#define PCF2123_WRITE BIT(4)
+#define PCF2123_READ (BIT(4) | BIT(7))
+
+
+static struct spi_driver pcf2123_driver;
+
+struct pcf2123_data {
+ struct rtc_device *rtc;
+ struct regmap *map;
+};
+
+static const struct regmap_config pcf2123_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .read_flag_mask = PCF2123_READ,
+ .write_flag_mask = PCF2123_WRITE,
+ .max_register = PCF2123_REG_CTDWN_TMR,
+};
+
+static int pcf2123_read_offset(struct device *dev, long *offset)
+{
+ struct pcf2123_data *pcf2123 = dev_get_drvdata(dev);
+ int ret, val;
+ unsigned int reg;
+
+ ret = regmap_read(pcf2123->map, PCF2123_REG_OFFSET, &reg);
+ if (ret)
+ return ret;
+
+ val = sign_extend32((reg & OFFSET_MASK), OFFSET_SIGN_BIT);
+
+ if (reg & OFFSET_COARSE)
+ val *= 2;
+
+ *offset = ((long)val) * 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)
+{
+ struct pcf2123_data *pcf2123 = dev_get_drvdata(dev);
+ s8 reg;
+
+ if (offset > OFFSET_STEP * 127)
+ reg = 127;
+ else if (offset < OFFSET_STEP * -128)
+ reg = -128;
+ else
+ reg = DIV_ROUND_CLOSEST(offset, 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 regmap_write(pcf2123->map, PCF2123_REG_OFFSET, (unsigned int)reg);
+}
+
+static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct pcf2123_data *pcf2123 = dev_get_drvdata(dev);
+ u8 rxbuf[7];
+ int ret;
+
+ ret = regmap_bulk_read(pcf2123->map, PCF2123_REG_SC, rxbuf,
+ sizeof(rxbuf));
+ if (ret)
+ return ret;
+
+ 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);
+ tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */
+ tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F);
+ tm->tm_wday = rxbuf[4] & 0x07;
+ tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */
+ tm->tm_year = bcd2bin(rxbuf[6]) + 100;
+
+ dev_dbg(dev, "%s: tm is %ptR\n", __func__, tm);
+
+ return 0;
+}
+
+static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct pcf2123_data *pcf2123 = dev_get_drvdata(dev);
+ u8 txbuf[7];
+ int ret;
+
+ dev_dbg(dev, "%s: tm is %ptR\n", __func__, tm);
+
+ /* Stop the counter first */
+ ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_STOP);
+ if (ret)
+ return ret;
+
+ /* Set the new time */
+ txbuf[0] = bin2bcd(tm->tm_sec & 0x7F);
+ txbuf[1] = bin2bcd(tm->tm_min & 0x7F);
+ txbuf[2] = bin2bcd(tm->tm_hour & 0x3F);
+ txbuf[3] = bin2bcd(tm->tm_mday & 0x3F);
+ txbuf[4] = tm->tm_wday & 0x07;
+ txbuf[5] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */
+ txbuf[6] = bin2bcd(tm->tm_year - 100);
+
+ ret = regmap_bulk_write(pcf2123->map, PCF2123_REG_SC, txbuf,
+ sizeof(txbuf));
+ if (ret)
+ return ret;
+
+ /* Start the counter */
+ ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_CLEAR);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int pcf2123_rtc_alarm_irq_enable(struct device *dev, unsigned int en)
+{
+ struct pcf2123_data *pcf2123 = dev_get_drvdata(dev);
+
+ return regmap_update_bits(pcf2123->map, PCF2123_REG_CTRL2, CTRL2_AIE,
+ en ? CTRL2_AIE : 0);
+}
+
+static int pcf2123_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+ struct pcf2123_data *pcf2123 = dev_get_drvdata(dev);
+ u8 rxbuf[4];
+ int ret;
+ unsigned int val = 0;
+
+ ret = regmap_bulk_read(pcf2123->map, PCF2123_REG_ALRM_MN, rxbuf,
+ sizeof(rxbuf));
+ if (ret)
+ return ret;
+
+ alm->time.tm_min = bcd2bin(rxbuf[0] & 0x7F);
+ alm->time.tm_hour = bcd2bin(rxbuf[1] & 0x3F);
+ alm->time.tm_mday = bcd2bin(rxbuf[2] & 0x3F);
+ alm->time.tm_wday = bcd2bin(rxbuf[3] & 0x07);
+
+ dev_dbg(dev, "%s: alm is %ptR\n", __func__, &alm->time);
+
+ ret = regmap_read(pcf2123->map, PCF2123_REG_CTRL2, &val);
+ if (ret)
+ return ret;
+
+ alm->enabled = !!(val & CTRL2_AIE);
+
+ return 0;
+}
+
+static int pcf2123_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+ struct pcf2123_data *pcf2123 = dev_get_drvdata(dev);
+ u8 txbuf[4];
+ int ret;
+
+ dev_dbg(dev, "%s: alm is %ptR\n", __func__, &alm->time);
+
+ /* Disable alarm interrupt */
+ ret = regmap_update_bits(pcf2123->map, PCF2123_REG_CTRL2, CTRL2_AIE, 0);
+ if (ret)
+ return ret;
+
+ /* Ensure alarm flag is clear */
+ ret = regmap_update_bits(pcf2123->map, PCF2123_REG_CTRL2, CTRL2_AF, 0);
+ if (ret)
+ return ret;
+
+ /* Set new alarm */
+ txbuf[0] = bin2bcd(alm->time.tm_min & 0x7F);
+ txbuf[1] = bin2bcd(alm->time.tm_hour & 0x3F);
+ txbuf[2] = bin2bcd(alm->time.tm_mday & 0x3F);
+ txbuf[3] = ALRM_DISABLE;
+
+ ret = regmap_bulk_write(pcf2123->map, PCF2123_REG_ALRM_MN, txbuf,
+ sizeof(txbuf));
+ if (ret)
+ return ret;
+
+ return pcf2123_rtc_alarm_irq_enable(dev, alm->enabled);
+}
+
+static irqreturn_t pcf2123_rtc_irq(int irq, void *dev)
+{
+ struct pcf2123_data *pcf2123 = dev_get_drvdata(dev);
+ unsigned int val = 0;
+ int ret = IRQ_NONE;
+
+ rtc_lock(pcf2123->rtc);
+ regmap_read(pcf2123->map, PCF2123_REG_CTRL2, &val);
+
+ /* Alarm? */
+ if (val & CTRL2_AF) {
+ ret = IRQ_HANDLED;
+
+ /* Clear alarm flag */
+ regmap_update_bits(pcf2123->map, PCF2123_REG_CTRL2, CTRL2_AF, 0);
+
+ rtc_update_irq(pcf2123->rtc, 1, RTC_IRQF | RTC_AF);
+ }
+
+ rtc_unlock(pcf2123->rtc);
+
+ return ret;
+}
+
+static int pcf2123_reset(struct device *dev)
+{
+ struct pcf2123_data *pcf2123 = dev_get_drvdata(dev);
+ int ret;
+ unsigned int val = 0;
+
+ ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_SW_RESET);
+ if (ret)
+ return ret;
+
+ /* Stop the counter */
+ dev_dbg(dev, "stopping RTC\n");
+ ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_STOP);
+ if (ret)
+ return ret;
+
+ /* See if the counter was actually stopped */
+ dev_dbg(dev, "checking for presence of RTC\n");
+ ret = regmap_read(pcf2123->map, PCF2123_REG_CTRL1, &val);
+ if (ret)
+ return ret;
+
+ dev_dbg(dev, "received data from RTC (0x%08X)\n", val);
+ if (!(val & CTRL1_STOP))
+ return -ENODEV;
+
+ /* Start the counter */
+ ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_CLEAR);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+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,
+ .read_alarm = pcf2123_rtc_read_alarm,
+ .set_alarm = pcf2123_rtc_set_alarm,
+ .alarm_irq_enable = pcf2123_rtc_alarm_irq_enable,
+};
+
+static int pcf2123_probe(struct spi_device *spi)
+{
+ struct rtc_device *rtc;
+ struct rtc_time tm;
+ struct pcf2123_data *pcf2123;
+ int ret = 0;
+
+ pcf2123 = devm_kzalloc(&spi->dev, sizeof(struct pcf2123_data),
+ GFP_KERNEL);
+ if (!pcf2123)
+ return -ENOMEM;
+
+ dev_set_drvdata(&spi->dev, pcf2123);
+
+ pcf2123->map = devm_regmap_init_spi(spi, &pcf2123_regmap_config);
+ if (IS_ERR(pcf2123->map)) {
+ dev_err(&spi->dev, "regmap init failed.\n");
+ return PTR_ERR(pcf2123->map);
+ }
+
+ 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");
+ return ret;
+ }
+ }
+
+ dev_info(&spi->dev, "spiclk %u KHz.\n",
+ (spi->max_speed_hz + 500) / 1000);
+
+ /* Finalize the initialization */
+ rtc = devm_rtc_allocate_device(&spi->dev);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ pcf2123->rtc = rtc;
+
+ /* Register alarm irq */
+ if (spi->irq > 0) {
+ ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
+ pcf2123_rtc_irq,
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+ pcf2123_driver.driver.name, &spi->dev);
+ if (!ret)
+ device_init_wakeup(&spi->dev, true);
+ else
+ dev_err(&spi->dev, "could not request irq.\n");
+ }
+
+ /* The PCF2123's alarm only has minute accuracy. Must add timer
+ * support to this driver to generate interrupts more than once
+ * per minute.
+ */
+ set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
+ clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
+ rtc->ops = &pcf2123_rtc_ops;
+ rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ rtc->range_max = RTC_TIMESTAMP_END_2099;
+ rtc->set_start_time = true;
+
+ ret = devm_rtc_register_device(rtc);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id pcf2123_dt_ids[] = {
+ { .compatible = "nxp,pcf2123", },
+ { .compatible = "microcrystal,rv2123", },
+ /* Deprecated, do not use */
+ { .compatible = "nxp,rtc-pcf2123", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pcf2123_dt_ids);
+#endif
+
+static const struct spi_device_id pcf2123_spi_ids[] = {
+ { .name = "pcf2123", },
+ { .name = "rv2123", },
+ { .name = "rtc-pcf2123", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(spi, pcf2123_spi_ids);
+
+static struct spi_driver pcf2123_driver = {
+ .driver = {
+ .name = "rtc-pcf2123",
+ .of_match_table = of_match_ptr(pcf2123_dt_ids),
+ },
+ .probe = pcf2123_probe,
+ .id_table = pcf2123_spi_ids,
+};
+
+module_spi_driver(pcf2123_driver);
+
+MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>");
+MODULE_DESCRIPTION("NXP PCF2123 RTC driver");
+MODULE_LICENSE("GPL");