/* * drivers/rtc/rtc-pcf8583.c * * Copyright (C) 2000 Russell King * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Driver for PCF8583 RTC & RAM chip * * Converted to the generic RTC susbsystem by G. Liakhovetski (2006) */ #include <linux/module.h> #include <linux/i2c.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/mc146818rtc.h> #include <linux/init.h> #include <linux/errno.h> #include <linux/bcd.h> struct rtc_mem { unsigned int loc; unsigned int nr; unsigned char *data; }; struct pcf8583 { struct i2c_client client; struct rtc_device *rtc; unsigned char ctrl; }; #define CTRL_STOP 0x80 #define CTRL_HOLD 0x40 #define CTRL_32KHZ 0x00 #define CTRL_MASK 0x08 #define CTRL_ALARMEN 0x04 #define CTRL_ALARM 0x02 #define CTRL_TIMER 0x01 static unsigned short normal_i2c[] = { I2C_CLIENT_END }; /* Module parameters */ I2C_CLIENT_INSMOD; static struct i2c_driver pcf8583_driver; #define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl #define set_ctrl(x, v) get_ctrl(x) = v #define CMOS_YEAR (64 + 128) #define CMOS_CHECKSUM (63) static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt) { unsigned char buf[8], addr[1] = { 1 }; struct i2c_msg msgs[2] = { { .addr = client->addr, .flags = 0, .len = 1, .buf = addr, }, { .addr = client->addr, .flags = I2C_M_RD, .len = 6, .buf = buf, } }; int ret; memset(buf, 0, sizeof(buf)); ret = i2c_transfer(client->adapter, msgs, 2); if (ret == 2) { dt->tm_year = buf[4] >> 6; dt->tm_wday = buf[5] >> 5; buf[4] &= 0x3f; buf[5] &= 0x1f; dt->tm_sec = BCD_TO_BIN(buf[1]); dt->tm_min = BCD_TO_BIN(buf[2]); dt->tm_hour = BCD_TO_BIN(buf[3]); dt->tm_mday = BCD_TO_BIN(buf[4]); dt->tm_mon = BCD_TO_BIN(buf[5]); } return ret == 2 ? 0 : -EIO; } static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo) { unsigned char buf[8]; int ret, len = 6; buf[0] = 0; buf[1] = get_ctrl(client) | 0x80; buf[2] = 0; buf[3] = BIN_TO_BCD(dt->tm_sec); buf[4] = BIN_TO_BCD(dt->tm_min); buf[5] = BIN_TO_BCD(dt->tm_hour); if (datetoo) { len = 8; buf[6] = BIN_TO_BCD(dt->tm_mday) | (dt->tm_year << 6); buf[7] = BIN_TO_BCD(dt->tm_mon) | (dt->tm_wday << 5); } ret = i2c_master_send(client, (char *)buf, len); if (ret != len) return -EIO; buf[1] = get_ctrl(client); ret = i2c_master_send(client, (char *)buf, 2); return ret == 2 ? 0 : -EIO; } static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl) { *ctrl = get_ctrl(client); return 0; } static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl) { unsigned char buf[2]; buf[0] = 0; buf[1] = *ctrl; set_ctrl(client, *ctrl); return i2c_master_send(client, (char *)buf, 2); } static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem) { unsigned char addr[1]; struct i2c_msg msgs[2] = { { .addr = client->addr, .flags = 0, .len = 1, .buf = addr, }, { .addr = client->addr, .flags = I2C_M_RD, .len = mem->nr, .buf = mem->data, } }; if (mem->loc < 8) return -EINVAL; addr[0] = mem->loc; return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO; } static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem) { unsigned char addr[1]; struct i2c_msg msgs[2] = { { .addr = client->addr, .flags = 0, .len = 1, .buf = addr, }, { .addr = client->addr, .flags = I2C_M_NOSTART, .len = mem->nr, .buf = mem->data, } }; if (mem->loc < 8) return -EINVAL; addr[0] = mem->loc; return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO; } static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); unsigned char ctrl, year[2]; struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year }; int real_year, year_offset, err; /* * Ensure that the RTC is running. */ pcf8583_get_ctrl(client, &ctrl); if (ctrl & (CTRL_STOP | CTRL_HOLD)) { unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD); printk(KERN_WARNING "RTC: resetting control %02x -> %02x\n", ctrl, new_ctrl); if ((err = pcf8583_set_ctrl(client, &new_ctrl)) < 0) return err; } if (pcf8583_get_datetime(client, tm) || pcf8583_read_mem(client, &mem)) return -EIO; real_year = year[0]; /* * The RTC year holds the LSB two bits of the current * year, which should reflect the LSB two bits of the * CMOS copy of the year. Any difference indicates * that we have to correct the CMOS version. */ year_offset = tm->tm_year - (real_year & 3); if (year_offset < 0) /* * RTC year wrapped. Adjust it appropriately. */ year_offset += 4; tm->tm_year = real_year + year_offset + year[1] * 100; return 0; } static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); unsigned char year[2], chk; struct rtc_mem cmos_year = { CMOS_YEAR, sizeof(year), year }; struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk }; int ret; /* * The RTC's own 2-bit year must reflect the least * significant two bits of the CMOS year. */ ret = pcf8583_set_datetime(client, tm, 1); if (ret) return ret; ret = pcf8583_read_mem(client, &cmos_check); if (ret) return ret; ret = pcf8583_read_mem(client, &cmos_year); if (ret) return ret; chk -= year[1] + year[0]; year[1] = tm->tm_year / 100; year[0] = tm->tm_year % 100; chk += year[1] + year[0]; ret = pcf8583_write_mem(client, &cmos_year); if (ret) return ret; ret = pcf8583_write_mem(client, &cmos_check); return ret; } static const struct rtc_class_ops pcf8583_rtc_ops = { .read_time = pcf8583_rtc_read_time, .set_time = pcf8583_rtc_set_time, }; static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind); static int pcf8583_attach(struct i2c_adapter *adap) { return i2c_probe(adap, &addr_data, pcf8583_probe); } static int pcf8583_detach(struct i2c_client *client) { int err; struct pcf8583 *pcf = i2c_get_clientdata(client); struct rtc_device *rtc = pcf->rtc; if (rtc) rtc_device_unregister(rtc); if ((err = i2c_detach_client(client))) return err; kfree(pcf); return 0; } static struct i2c_driver pcf8583_driver = { .driver = { .name = "pcf8583", }, .id = I2C_DRIVERID_PCF8583, .attach_adapter = pcf8583_attach, .detach_client = pcf8583_detach, }; static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind) { struct pcf8583 *pcf; struct i2c_client *client; struct rtc_device *rtc; unsigned char buf[1], ad[1] = { 0 }; int err; struct i2c_msg msgs[2] = { { .addr = addr, .flags = 0, .len = 1, .buf = ad, }, { .addr = addr, .flags = I2C_M_RD, .len = 1, .buf = buf, } }; pcf = kzalloc(sizeof(*pcf), GFP_KERNEL); if (!pcf) return -ENOMEM; client = &pcf->client; client->addr = addr; client->adapter = adap; client->driver = &pcf8583_driver; strlcpy(client->name, pcf8583_driver.driver.name, I2C_NAME_SIZE); if (i2c_transfer(client->adapter, msgs, 2) != 2) { err = -EIO; goto exit_kfree; } err = i2c_attach_client(client); if (err) goto exit_kfree; rtc = rtc_device_register(pcf8583_driver.driver.name, &client->dev, &pcf8583_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) { err = PTR_ERR(rtc); goto exit_detach; } pcf->rtc = rtc; i2c_set_clientdata(client, pcf); set_ctrl(client, buf[0]); return 0; exit_detach: i2c_detach_client(client); exit_kfree: kfree(pcf); return err; } static __init int pcf8583_init(void) { return i2c_add_driver(&pcf8583_driver); } static __exit void pcf8583_exit(void) { i2c_del_driver(&pcf8583_driver); } module_init(pcf8583_init); module_exit(pcf8583_exit); MODULE_AUTHOR("Russell King"); MODULE_DESCRIPTION("PCF8583 I2C RTC driver"); MODULE_LICENSE("GPL");