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329 lines
9.2 KiB
329 lines
9.2 KiB
/* |
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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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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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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/rtc.h> |
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#include <linux/log2.h> |
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#define DRV_VERSION "0.1" |
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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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struct rx8581 { |
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struct i2c_client *client; |
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struct rtc_device *rtc; |
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s32 (*read_block_data)(const struct i2c_client *client, u8 command, |
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u8 length, u8 *values); |
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s32 (*write_block_data)(const struct i2c_client *client, u8 command, |
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u8 length, const u8 *values); |
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}; |
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static struct i2c_driver rx8581_driver; |
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static int rx8581_read_block_data(const struct i2c_client *client, u8 command, |
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u8 length, u8 *values) |
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{ |
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s32 i, data; |
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for (i = 0; i < length; i++) { |
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data = i2c_smbus_read_byte_data(client, command + i); |
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if (data < 0) |
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return data; |
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values[i] = data; |
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} |
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return i; |
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} |
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static int rx8581_write_block_data(const struct i2c_client *client, u8 command, |
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u8 length, const u8 *values) |
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{ |
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s32 i, ret; |
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for (i = 0; i < length; i++) { |
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ret = i2c_smbus_write_byte_data(client, command + i, |
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values[i]); |
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if (ret < 0) |
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return ret; |
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} |
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return length; |
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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_get_datetime(struct i2c_client *client, struct rtc_time *tm) |
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{ |
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unsigned char date[7]; |
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int data, 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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data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); |
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if (data < 0) { |
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dev_err(&client->dev, "Unable to read device flags\n"); |
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return -EIO; |
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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 = i2c_smbus_write_byte_data(client, |
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RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF)); |
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if (err != 0) { |
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dev_err(&client->dev, "Unable to write device flags\n"); |
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return -EIO; |
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} |
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} |
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/* Now read time and date */ |
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err = rx8581->read_block_data(client, RX8581_REG_SC, |
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7, date); |
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if (err < 0) { |
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dev_err(&client->dev, "Unable to read date\n"); |
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return -EIO; |
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} |
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/* Check flag register */ |
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data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); |
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if (data < 0) { |
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dev_err(&client->dev, "Unable to read device flags\n"); |
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return -EIO; |
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} |
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} while (data & RX8581_FLAG_UF); |
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if (data & RX8581_FLAG_VLF) |
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dev_info(&client->dev, |
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"low voltage detected, date/time is not reliable.\n"); |
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dev_dbg(&client->dev, |
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"%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]); |
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if (tm->tm_year < 70) |
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tm->tm_year += 100; /* assume we are in 1970...2069 */ |
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dev_dbg(&client->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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err = rtc_valid_tm(tm); |
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if (err < 0) |
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dev_err(&client->dev, "retrieved date/time is not valid.\n"); |
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return err; |
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} |
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static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm) |
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{ |
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int data, 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(&client->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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data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); |
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if (data < 0) { |
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dev_err(&client->dev, "Unable to read control register\n"); |
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return -EIO; |
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} |
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err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL, |
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(data | RX8581_CTRL_STOP)); |
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if (err < 0) { |
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dev_err(&client->dev, "Unable to write control register\n"); |
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return -EIO; |
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} |
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/* write register's data */ |
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err = rx8581->write_block_data(client, RX8581_REG_SC, 7, buf); |
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if (err < 0) { |
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dev_err(&client->dev, "Unable to write to date registers\n"); |
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return -EIO; |
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} |
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/* get VLF and clear it */ |
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data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); |
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if (data < 0) { |
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dev_err(&client->dev, "Unable to read flag register\n"); |
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return -EIO; |
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} |
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err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG, |
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(data & ~(RX8581_FLAG_VLF))); |
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if (err != 0) { |
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dev_err(&client->dev, "Unable to write flag register\n"); |
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return -EIO; |
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} |
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/* Restart the clock */ |
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data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); |
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if (data < 0) { |
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dev_err(&client->dev, "Unable to read control register\n"); |
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return -EIO; |
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} |
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err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL, |
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(data & ~(RX8581_CTRL_STOP))); |
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if (err != 0) { |
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dev_err(&client->dev, "Unable to write control register\n"); |
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return -EIO; |
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} |
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return 0; |
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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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return rx8581_get_datetime(to_i2c_client(dev), tm); |
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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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return rx8581_set_datetime(to_i2c_client(dev), tm); |
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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 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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dev_dbg(&client->dev, "%s\n", __func__); |
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA) |
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&& !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) |
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return -EIO; |
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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->client = client; |
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if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) { |
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rx8581->read_block_data = i2c_smbus_read_i2c_block_data; |
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rx8581->write_block_data = i2c_smbus_write_i2c_block_data; |
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} else { |
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rx8581->read_block_data = rx8581_read_block_data; |
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rx8581->write_block_data = rx8581_write_block_data; |
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} |
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dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); |
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rx8581->rtc = devm_rtc_device_register(&client->dev, |
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rx8581_driver.driver.name, &rx8581_rtc_ops, THIS_MODULE); |
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if (IS_ERR(rx8581->rtc)) { |
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dev_err(&client->dev, |
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"unable to register the class device\n"); |
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return PTR_ERR(rx8581->rtc); |
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} |
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return 0; |
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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 struct i2c_driver rx8581_driver = { |
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.driver = { |
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.name = "rtc-rx8581", |
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.owner = THIS_MODULE, |
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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-8581 RTC driver"); |
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MODULE_LICENSE("GPL"); |
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MODULE_VERSION(DRV_VERSION);
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