// SPDX-License-Identifier: GPL-2.0-only
/*
* An SPI driver for the Philips PCF2123 RTC
* Copyright 2009 Cyber Switching, Inc.
*
* Author: Chris Verges <[email protected]>
* Maintainers: http://www.cyberswitching.com
*
* based on the RS5C348 driver in this same directory.
*
* Thanks to Christian Pellegrin <[email protected]> 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, ®);
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) {
unsigned long irqflags = IRQF_TRIGGER_LOW;
if (dev_fwnode(&spi->dev))
irqflags = 0;
ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
pcf2123_rtc_irq,
irqflags | 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 <[email protected]>");
MODULE_DESCRIPTION("NXP PCF2123 RTC driver");
MODULE_LICENSE("GPL");
Codebase Browser
linux