338 lines
8.9 KiB
C
338 lines
8.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* An I2C driver for the Epson RX8581 RTC
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*
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* Author: Martyn Welch <martyn.welch@ge.com>
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* Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
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*
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* Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
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* Copyright 2005-06 Tower Technologies
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/bcd.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/regmap.h>
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#include <linux/rtc.h>
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#include <linux/log2.h>
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#define RX8581_REG_SC 0x00 /* Second in BCD */
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#define RX8581_REG_MN 0x01 /* Minute in BCD */
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#define RX8581_REG_HR 0x02 /* Hour in BCD */
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#define RX8581_REG_DW 0x03 /* Day of Week */
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#define RX8581_REG_DM 0x04 /* Day of Month in BCD */
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#define RX8581_REG_MO 0x05 /* Month in BCD */
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#define RX8581_REG_YR 0x06 /* Year in BCD */
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#define RX8581_REG_RAM 0x07 /* RAM */
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#define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/
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#define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */
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#define RX8581_REG_ADM 0x0A
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#define RX8581_REG_ADW 0x0A
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#define RX8581_REG_TMR0 0x0B
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#define RX8581_REG_TMR1 0x0C
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#define RX8581_REG_EXT 0x0D /* Extension Register */
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#define RX8581_REG_FLAG 0x0E /* Flag Register */
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#define RX8581_REG_CTRL 0x0F /* Control Register */
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/* Flag Register bit definitions */
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#define RX8581_FLAG_UF 0x20 /* Update */
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#define RX8581_FLAG_TF 0x10 /* Timer */
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#define RX8581_FLAG_AF 0x08 /* Alarm */
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#define RX8581_FLAG_VLF 0x02 /* Voltage Low */
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/* Control Register bit definitions */
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#define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */
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#define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */
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#define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */
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#define RX8581_CTRL_STOP 0x02 /* STOP bit */
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#define RX8581_CTRL_RESET 0x01 /* RESET bit */
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#define RX8571_USER_RAM 0x10
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#define RX8571_NVRAM_SIZE 0x10
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struct rx8581 {
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struct regmap *regmap;
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struct rtc_device *rtc;
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};
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struct rx85x1_config {
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struct regmap_config regmap;
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unsigned int num_nvram;
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};
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/*
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* In the routines that deal directly with the rx8581 hardware, we use
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* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
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*/
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static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct i2c_client *client = to_i2c_client(dev);
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unsigned char date[7];
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unsigned int data;
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int err;
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struct rx8581 *rx8581 = i2c_get_clientdata(client);
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/* First we ensure that the "update flag" is not set, we read the
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* time and date then re-read the "update flag". If the update flag
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* has been set, we know that the time has changed during the read so
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* we repeat the whole process again.
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*/
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err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
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if (err < 0)
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return err;
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if (data & RX8581_FLAG_VLF) {
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dev_warn(dev,
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"low voltage detected, date/time is not reliable.\n");
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return -EINVAL;
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}
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do {
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/* If update flag set, clear it */
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if (data & RX8581_FLAG_UF) {
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err = regmap_write(rx8581->regmap, RX8581_REG_FLAG,
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data & ~RX8581_FLAG_UF);
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if (err < 0)
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return err;
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}
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/* Now read time and date */
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err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date,
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sizeof(date));
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if (err < 0)
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return err;
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/* Check flag register */
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err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
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if (err < 0)
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return err;
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} while (data & RX8581_FLAG_UF);
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dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
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"wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
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__func__,
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date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
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tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
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tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
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tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
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tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
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tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
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tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
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tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100;
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dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
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"mday=%d, mon=%d, year=%d, wday=%d\n",
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__func__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
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return 0;
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}
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static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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struct i2c_client *client = to_i2c_client(dev);
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int err;
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unsigned char buf[7];
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struct rx8581 *rx8581 = i2c_get_clientdata(client);
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dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
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"mday=%d, mon=%d, year=%d, wday=%d\n",
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__func__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
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/* hours, minutes and seconds */
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buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
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buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
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buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
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buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
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/* month, 1 - 12 */
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buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
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/* year and century */
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buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100);
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buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
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/* Stop the clock */
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err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
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RX8581_CTRL_STOP, RX8581_CTRL_STOP);
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if (err < 0)
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return err;
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/* write register's data */
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err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC,
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buf, sizeof(buf));
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if (err < 0)
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return err;
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/* get VLF and clear it */
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err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG,
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RX8581_FLAG_VLF, 0);
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if (err < 0)
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return err;
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/* Restart the clock */
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return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
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RX8581_CTRL_STOP, 0);
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}
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static const struct rtc_class_ops rx8581_rtc_ops = {
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.read_time = rx8581_rtc_read_time,
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.set_time = rx8581_rtc_set_time,
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};
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static int rx8571_nvram_read(void *priv, unsigned int offset, void *val,
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size_t bytes)
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{
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struct rx8581 *rx8581 = priv;
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return regmap_bulk_read(rx8581->regmap, RX8571_USER_RAM + offset,
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val, bytes);
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}
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static int rx8571_nvram_write(void *priv, unsigned int offset, void *val,
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size_t bytes)
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{
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struct rx8581 *rx8581 = priv;
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return regmap_bulk_write(rx8581->regmap, RX8571_USER_RAM + offset,
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val, bytes);
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}
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static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val,
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size_t bytes)
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{
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struct rx8581 *rx8581 = priv;
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unsigned int tmp_val;
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int ret;
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ret = regmap_read(rx8581->regmap, RX8581_REG_RAM, &tmp_val);
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(*(unsigned char *)val) = (unsigned char) tmp_val;
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return ret;
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}
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static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val,
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size_t bytes)
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{
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struct rx8581 *rx8581 = priv;
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unsigned char tmp_val;
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tmp_val = *((unsigned char *)val);
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return regmap_write(rx8581->regmap, RX8581_REG_RAM,
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(unsigned int)tmp_val);
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}
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static const struct rx85x1_config rx8581_config = {
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.regmap = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = 0xf,
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},
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.num_nvram = 1
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};
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static const struct rx85x1_config rx8571_config = {
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.regmap = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = 0x1f,
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},
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.num_nvram = 2
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};
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static int rx8581_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct rx8581 *rx8581;
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const struct rx85x1_config *config = &rx8581_config;
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const void *data = of_device_get_match_data(&client->dev);
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static struct nvmem_config nvmem_cfg[] = {
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{
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.name = "rx85x1-",
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.word_size = 1,
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.stride = 1,
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.size = 1,
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.reg_read = rx85x1_nvram_read,
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.reg_write = rx85x1_nvram_write,
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}, {
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.name = "rx8571-",
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.word_size = 1,
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.stride = 1,
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.size = RX8571_NVRAM_SIZE,
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.reg_read = rx8571_nvram_read,
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.reg_write = rx8571_nvram_write,
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},
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};
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int ret, i;
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dev_dbg(&client->dev, "%s\n", __func__);
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if (data)
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config = data;
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rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
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if (!rx8581)
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return -ENOMEM;
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i2c_set_clientdata(client, rx8581);
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rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap);
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if (IS_ERR(rx8581->regmap))
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return PTR_ERR(rx8581->regmap);
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rx8581->rtc = devm_rtc_allocate_device(&client->dev);
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if (IS_ERR(rx8581->rtc))
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return PTR_ERR(rx8581->rtc);
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rx8581->rtc->ops = &rx8581_rtc_ops;
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rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
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rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099;
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rx8581->rtc->start_secs = 0;
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rx8581->rtc->set_start_time = true;
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ret = devm_rtc_register_device(rx8581->rtc);
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for (i = 0; i < config->num_nvram; i++) {
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nvmem_cfg[i].priv = rx8581;
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devm_rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]);
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}
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return ret;
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}
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static const struct i2c_device_id rx8581_id[] = {
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{ "rx8581", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, rx8581_id);
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static const __maybe_unused struct of_device_id rx8581_of_match[] = {
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{ .compatible = "epson,rx8571", .data = &rx8571_config },
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{ .compatible = "epson,rx8581", .data = &rx8581_config },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, rx8581_of_match);
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static struct i2c_driver rx8581_driver = {
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.driver = {
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.name = "rtc-rx8581",
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.of_match_table = of_match_ptr(rx8581_of_match),
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},
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.probe = rx8581_probe,
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.id_table = rx8581_id,
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};
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module_i2c_driver(rx8581_driver);
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MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
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MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver");
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MODULE_LICENSE("GPL");
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