bb71f99f8d
Replace the I2C bus address, as per drivers/acorn/char/pcf8583.c. Also, since this driver also contains Acorn RiscPC specific code for obtaining the current year from the SRAM (and updating the platform specific checksum when writing new data back) this is NOT a platform independent driver. Document it as such, and update the dependencies to reflect this fact. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
395 lines
7.9 KiB
C
395 lines
7.9 KiB
C
/*
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* drivers/rtc/rtc-pcf8583.c
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*
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* Copyright (C) 2000 Russell King
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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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* Driver for PCF8583 RTC & RAM chip
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*
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* Converted to the generic RTC susbsystem by G. Liakhovetski (2006)
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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/slab.h>
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#include <linux/string.h>
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#include <linux/mc146818rtc.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/bcd.h>
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struct rtc_mem {
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unsigned int loc;
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unsigned int nr;
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unsigned char *data;
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};
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struct pcf8583 {
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struct i2c_client client;
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struct rtc_device *rtc;
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unsigned char ctrl;
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};
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#define CTRL_STOP 0x80
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#define CTRL_HOLD 0x40
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#define CTRL_32KHZ 0x00
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#define CTRL_MASK 0x08
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#define CTRL_ALARMEN 0x04
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#define CTRL_ALARM 0x02
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#define CTRL_TIMER 0x01
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static unsigned short normal_i2c[] = { 0x50, I2C_CLIENT_END };
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/* Module parameters */
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I2C_CLIENT_INSMOD;
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static struct i2c_driver pcf8583_driver;
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#define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl
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#define set_ctrl(x, v) get_ctrl(x) = v
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#define CMOS_YEAR (64 + 128)
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#define CMOS_CHECKSUM (63)
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static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt)
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{
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unsigned char buf[8], addr[1] = { 1 };
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struct i2c_msg msgs[2] = {
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{
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.addr = client->addr,
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.flags = 0,
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.len = 1,
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.buf = addr,
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}, {
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.addr = client->addr,
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.flags = I2C_M_RD,
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.len = 6,
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.buf = buf,
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}
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};
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int ret;
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memset(buf, 0, sizeof(buf));
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ret = i2c_transfer(client->adapter, msgs, 2);
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if (ret == 2) {
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dt->tm_year = buf[4] >> 6;
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dt->tm_wday = buf[5] >> 5;
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buf[4] &= 0x3f;
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buf[5] &= 0x1f;
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dt->tm_sec = BCD2BIN(buf[1]);
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dt->tm_min = BCD2BIN(buf[2]);
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dt->tm_hour = BCD2BIN(buf[3]);
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dt->tm_mday = BCD2BIN(buf[4]);
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dt->tm_mon = BCD2BIN(buf[5]) - 1;
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}
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return ret == 2 ? 0 : -EIO;
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}
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static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo)
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{
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unsigned char buf[8];
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int ret, len = 6;
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buf[0] = 0;
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buf[1] = get_ctrl(client) | 0x80;
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buf[2] = 0;
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buf[3] = BIN2BCD(dt->tm_sec);
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buf[4] = BIN2BCD(dt->tm_min);
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buf[5] = BIN2BCD(dt->tm_hour);
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if (datetoo) {
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len = 8;
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buf[6] = BIN2BCD(dt->tm_mday) | (dt->tm_year << 6);
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buf[7] = BIN2BCD(dt->tm_mon + 1) | (dt->tm_wday << 5);
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}
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ret = i2c_master_send(client, (char *)buf, len);
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if (ret != len)
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return -EIO;
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buf[1] = get_ctrl(client);
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ret = i2c_master_send(client, (char *)buf, 2);
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return ret == 2 ? 0 : -EIO;
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}
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static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
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{
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*ctrl = get_ctrl(client);
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return 0;
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}
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static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)
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{
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unsigned char buf[2];
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buf[0] = 0;
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buf[1] = *ctrl;
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set_ctrl(client, *ctrl);
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return i2c_master_send(client, (char *)buf, 2);
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}
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static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem)
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{
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unsigned char addr[1];
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struct i2c_msg msgs[2] = {
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{
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.addr = client->addr,
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.flags = 0,
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.len = 1,
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.buf = addr,
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}, {
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.addr = client->addr,
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.flags = I2C_M_RD,
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.len = mem->nr,
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.buf = mem->data,
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}
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};
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if (mem->loc < 8)
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return -EINVAL;
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addr[0] = mem->loc;
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return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
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}
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static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem)
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{
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unsigned char addr[1];
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struct i2c_msg msgs[2] = {
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{
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.addr = client->addr,
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.flags = 0,
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.len = 1,
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.buf = addr,
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}, {
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.addr = client->addr,
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.flags = I2C_M_NOSTART,
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.len = mem->nr,
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.buf = mem->data,
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}
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};
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if (mem->loc < 8)
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return -EINVAL;
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addr[0] = mem->loc;
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return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
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}
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static int pcf8583_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 ctrl, year[2];
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struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year };
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int real_year, year_offset, err;
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/*
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* Ensure that the RTC is running.
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*/
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pcf8583_get_ctrl(client, &ctrl);
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if (ctrl & (CTRL_STOP | CTRL_HOLD)) {
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unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD);
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printk(KERN_WARNING "RTC: resetting control %02x -> %02x\n",
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ctrl, new_ctrl);
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if ((err = pcf8583_set_ctrl(client, &new_ctrl)) < 0)
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return err;
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}
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if (pcf8583_get_datetime(client, tm) ||
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pcf8583_read_mem(client, &mem))
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return -EIO;
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real_year = year[0];
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/*
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* The RTC year holds the LSB two bits of the current
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* year, which should reflect the LSB two bits of the
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* CMOS copy of the year. Any difference indicates
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* that we have to correct the CMOS version.
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*/
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year_offset = tm->tm_year - (real_year & 3);
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if (year_offset < 0)
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/*
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* RTC year wrapped. Adjust it appropriately.
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*/
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year_offset += 4;
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tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;
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return 0;
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}
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static int pcf8583_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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unsigned char year[2], chk;
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struct rtc_mem cmos_year = { CMOS_YEAR, sizeof(year), year };
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struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk };
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unsigned int proper_year = tm->tm_year + 1900;
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int ret;
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/*
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* The RTC's own 2-bit year must reflect the least
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* significant two bits of the CMOS year.
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*/
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ret = pcf8583_set_datetime(client, tm, 1);
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if (ret)
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return ret;
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ret = pcf8583_read_mem(client, &cmos_check);
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if (ret)
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return ret;
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ret = pcf8583_read_mem(client, &cmos_year);
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if (ret)
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return ret;
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chk -= year[1] + year[0];
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year[1] = proper_year / 100;
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year[0] = proper_year % 100;
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chk += year[1] + year[0];
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ret = pcf8583_write_mem(client, &cmos_year);
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if (ret)
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return ret;
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ret = pcf8583_write_mem(client, &cmos_check);
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return ret;
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}
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static const struct rtc_class_ops pcf8583_rtc_ops = {
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.read_time = pcf8583_rtc_read_time,
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.set_time = pcf8583_rtc_set_time,
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};
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static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind);
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static int pcf8583_attach(struct i2c_adapter *adap)
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{
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return i2c_probe(adap, &addr_data, pcf8583_probe);
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}
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static int pcf8583_detach(struct i2c_client *client)
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{
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int err;
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struct pcf8583 *pcf = i2c_get_clientdata(client);
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struct rtc_device *rtc = pcf->rtc;
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if (rtc)
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rtc_device_unregister(rtc);
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if ((err = i2c_detach_client(client)))
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return err;
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kfree(pcf);
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return 0;
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}
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static struct i2c_driver pcf8583_driver = {
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.driver = {
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.name = "pcf8583",
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},
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.id = I2C_DRIVERID_PCF8583,
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.attach_adapter = pcf8583_attach,
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.detach_client = pcf8583_detach,
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};
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static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind)
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{
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struct pcf8583 *pcf;
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struct i2c_client *client;
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struct rtc_device *rtc;
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unsigned char buf[1], ad[1] = { 0 };
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int err;
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struct i2c_msg msgs[2] = {
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{
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.addr = addr,
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.flags = 0,
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.len = 1,
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.buf = ad,
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}, {
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.addr = addr,
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.flags = I2C_M_RD,
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.len = 1,
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.buf = buf,
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}
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};
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pcf = kzalloc(sizeof(*pcf), GFP_KERNEL);
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if (!pcf)
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return -ENOMEM;
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client = &pcf->client;
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client->addr = addr;
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client->adapter = adap;
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client->driver = &pcf8583_driver;
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strlcpy(client->name, pcf8583_driver.driver.name, I2C_NAME_SIZE);
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if (i2c_transfer(client->adapter, msgs, 2) != 2) {
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err = -EIO;
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goto exit_kfree;
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}
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err = i2c_attach_client(client);
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if (err)
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goto exit_kfree;
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rtc = rtc_device_register(pcf8583_driver.driver.name, &client->dev,
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&pcf8583_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc)) {
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err = PTR_ERR(rtc);
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goto exit_detach;
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}
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pcf->rtc = rtc;
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i2c_set_clientdata(client, pcf);
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set_ctrl(client, buf[0]);
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return 0;
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exit_detach:
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i2c_detach_client(client);
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exit_kfree:
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kfree(pcf);
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return err;
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}
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static __init int pcf8583_init(void)
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{
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return i2c_add_driver(&pcf8583_driver);
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}
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static __exit void pcf8583_exit(void)
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{
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i2c_del_driver(&pcf8583_driver);
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}
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module_init(pcf8583_init);
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module_exit(pcf8583_exit);
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MODULE_AUTHOR("Russell King");
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MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
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MODULE_LICENSE("GPL");
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