diff options
Diffstat (limited to 'drivers/i2c/chips/x1205.c')
| -rw-r--r-- | drivers/i2c/chips/x1205.c | 698 |
1 files changed, 698 insertions, 0 deletions
diff --git a/drivers/i2c/chips/x1205.c b/drivers/i2c/chips/x1205.c new file mode 100644 index 0000000..7da366c --- /dev/null +++ b/drivers/i2c/chips/x1205.c @@ -0,0 +1,698 @@ +/* + * x1205.c - An i2c driver for the Xicor X1205 RTC + * Copyright 2004 Karen Spearel + * Copyright 2005 Alessandro Zummo + * + * please send all reports to: + * kas11 at tampabay dot rr dot com + * a dot zummo at towertech dot it + * + * based on the other drivers in this same directory. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/i2c.h> +#include <linux/string.h> +#include <linux/bcd.h> +#include <linux/rtc.h> +#include <linux/list.h> + +#include <linux/x1205.h> + +#define DRV_VERSION "0.9.9" + +/* Addresses to scan: none. This chip is located at + * 0x6f and uses a two bytes register addressing. + * Two bytes need to be written to read a single register, + * while most other chips just require one and take the second + * one as the data to be written. To prevent corrupting + * unknown chips, the user must explicitely set the probe parameter. + */ + +static unsigned short normal_i2c[] = { I2C_CLIENT_END }; + +/* Insmod parameters */ +I2C_CLIENT_INSMOD; +I2C_CLIENT_MODULE_PARM(hctosys, + "Set the system time from the hardware clock upon initialization"); + +/* offsets into CCR area */ + +#define CCR_SEC 0 +#define CCR_MIN 1 +#define CCR_HOUR 2 +#define CCR_MDAY 3 +#define CCR_MONTH 4 +#define CCR_YEAR 5 +#define CCR_WDAY 6 +#define CCR_Y2K 7 + +#define X1205_REG_SR 0x3F /* status register */ +#define X1205_REG_Y2K 0x37 +#define X1205_REG_DW 0x36 +#define X1205_REG_YR 0x35 +#define X1205_REG_MO 0x34 +#define X1205_REG_DT 0x33 +#define X1205_REG_HR 0x32 +#define X1205_REG_MN 0x31 +#define X1205_REG_SC 0x30 +#define X1205_REG_DTR 0x13 +#define X1205_REG_ATR 0x12 +#define X1205_REG_INT 0x11 +#define X1205_REG_0 0x10 +#define X1205_REG_Y2K1 0x0F +#define X1205_REG_DWA1 0x0E +#define X1205_REG_YRA1 0x0D +#define X1205_REG_MOA1 0x0C +#define X1205_REG_DTA1 0x0B +#define X1205_REG_HRA1 0x0A +#define X1205_REG_MNA1 0x09 +#define X1205_REG_SCA1 0x08 +#define X1205_REG_Y2K0 0x07 +#define X1205_REG_DWA0 0x06 +#define X1205_REG_YRA0 0x05 +#define X1205_REG_MOA0 0x04 +#define X1205_REG_DTA0 0x03 +#define X1205_REG_HRA0 0x02 +#define X1205_REG_MNA0 0x01 +#define X1205_REG_SCA0 0x00 + +#define X1205_CCR_BASE 0x30 /* Base address of CCR */ +#define X1205_ALM0_BASE 0x00 /* Base address of ALARM0 */ + +#define X1205_SR_RTCF 0x01 /* Clock failure */ +#define X1205_SR_WEL 0x02 /* Write Enable Latch */ +#define X1205_SR_RWEL 0x04 /* Register Write Enable */ + +#define X1205_DTR_DTR0 0x01 +#define X1205_DTR_DTR1 0x02 +#define X1205_DTR_DTR2 0x04 + +#define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */ + +/* Prototypes */ +static int x1205_attach(struct i2c_adapter *adapter); +static int x1205_detach(struct i2c_client *client); +static int x1205_probe(struct i2c_adapter *adapter, int address, int kind); +static int x1205_command(struct i2c_client *client, unsigned int cmd, + void *arg); + +static struct i2c_driver x1205_driver = { + .owner = THIS_MODULE, + .name = "x1205", + .flags = I2C_DF_NOTIFY, + .attach_adapter = &x1205_attach, + .detach_client = &x1205_detach, +}; + +struct x1205_data { + struct i2c_client client; + struct list_head list; + unsigned int epoch; +}; + +static const unsigned char days_in_mo[] = + { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; + +static LIST_HEAD(x1205_clients); + +/* Workaround until the I2C subsytem will allow to send + * commands to a specific client. This function will send the command + * to the first client. + */ +int x1205_do_command(unsigned int cmd, void *arg) +{ + struct list_head *walk; + struct list_head *tmp; + struct x1205_data *data; + + list_for_each_safe(walk, tmp, &x1205_clients) { + data = list_entry(walk, struct x1205_data, list); + return x1205_command(&data->client, cmd, arg); + } + + return -ENODEV; +} + +#define is_leap(year) \ + ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0)) + +/* make sure the rtc_time values are in bounds */ +static int x1205_validate_tm(struct rtc_time *tm) +{ + int year = tm->tm_year + 1900; + + if ((tm->tm_year < 70) || (tm->tm_year > 255)) + return -EINVAL; + + if ((tm->tm_mon > 11) || (tm->tm_mday == 0)) + return -EINVAL; + + if (tm->tm_mday > days_in_mo[tm->tm_mon] + + ((tm->tm_mon == 1) && is_leap(year))) + return -EINVAL; + + if ((tm->tm_hour >= 24) || (tm->tm_min >= 60) || (tm->tm_sec >= 60)) + return -EINVAL; + + return 0; +} + +/* + * In the routines that deal directly with the x1205 hardware, we use + * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch + * Epoch is initialized as 2000. Time is set to UTC. + */ +static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm, + u8 reg_base) +{ + unsigned char dt_addr[2] = { 0, reg_base }; + static unsigned char sr_addr[2] = { 0, X1205_REG_SR }; + + unsigned char buf[8], sr; + + struct i2c_msg msgs[] = { + { client->addr, 0, 2, sr_addr }, /* setup read ptr */ + { client->addr, I2C_M_RD, 1, &sr }, /* read status */ + { client->addr, 0, 2, dt_addr }, /* setup read ptr */ + { client->addr, I2C_M_RD, 8, buf }, /* read date */ + }; + + struct x1205_data *data = i2c_get_clientdata(client); + + /* read status register */ + if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { + dev_err(&client->dev, "%s: read error\n", __FUNCTION__); + return -EIO; + } + + /* check for battery failure */ + if (sr & X1205_SR_RTCF) { + dev_warn(&client->dev, + "Clock had a power failure, you must set the date.\n"); + return -EINVAL; + } + + /* read date registers */ + if ((i2c_transfer(client->adapter, &msgs[2], 2)) != 2) { + dev_err(&client->dev, "%s: read error\n", __FUNCTION__); + return -EIO; + } + + dev_dbg(&client->dev, + "%s: raw read data - sec=%02x, min=%02x, hr=%02x, " + "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n", + __FUNCTION__, + buf[0], buf[1], buf[2], buf[3], + buf[4], buf[5], buf[6], buf[7]); + + tm->tm_sec = BCD2BIN(buf[CCR_SEC]); + tm->tm_min = BCD2BIN(buf[CCR_MIN]); + tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */ + tm->tm_mday = BCD2BIN(buf[CCR_MDAY]); + tm->tm_mon = BCD2BIN(buf[CCR_MONTH]); + data->epoch = BCD2BIN(buf[CCR_Y2K]) * 100; + tm->tm_year = BCD2BIN(buf[CCR_YEAR]) + data->epoch - 1900; + tm->tm_wday = buf[CCR_WDAY]; + + dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " + "mday=%d, mon=%d, year=%d, wday=%d\n", + __FUNCTION__, + tm->tm_sec, tm->tm_min, tm->tm_hour, + tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); + + return 0; +} + +static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, + int datetoo, u8 reg_base) +{ + int i, err, xfer; + + unsigned char buf[8]; + + static const unsigned char wel[3] = { 0, X1205_REG_SR, + X1205_SR_WEL }; + + static const unsigned char rwel[3] = { 0, X1205_REG_SR, + X1205_SR_WEL | X1205_SR_RWEL }; + + static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 }; + + struct x1205_data *data = i2c_get_clientdata(client); + + /* check if all values in the tm struct are correct */ + if ((err = x1205_validate_tm(tm)) < 0) + return err; + + dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " + "mday=%d, mon=%d, year=%d, wday=%d\n", + __FUNCTION__, + tm->tm_sec, tm->tm_min, tm->tm_hour, + tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); + + buf[CCR_SEC] = BIN2BCD(tm->tm_sec); + buf[CCR_MIN] = BIN2BCD(tm->tm_min); + + /* set hour and 24hr bit */ + buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL; + + /* should we also set the date? */ + if (datetoo) { + buf[CCR_MDAY] = BIN2BCD(tm->tm_mday); + + /* month, 0 - 11 */ + buf[CCR_MONTH] = BIN2BCD(tm->tm_mon); + + /* year, since 1900 */ + buf[CCR_YEAR] = BIN2BCD(tm->tm_year + 1900 - data->epoch); + buf[CCR_WDAY] = tm->tm_wday & 0x07; + buf[CCR_Y2K] = BIN2BCD(data->epoch / 100); + } + + /* this sequence is required to unlock the chip */ + xfer = i2c_master_send(client, wel, 3); + if (xfer != 3) { + dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer); + return -EIO; + } + + xfer = i2c_master_send(client, rwel, 3); + if (xfer != 3) { + dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer); + return -EIO; + } + + /* write register's data */ + for (i = 0; i < (datetoo ? 8 : 3); i++) { + unsigned char rdata[3] = { 0, reg_base + i, buf[i] }; + + xfer = i2c_master_send(client, rdata, 3); + if (xfer != 3) { + dev_err(&client->dev, + "%s: xfer=%d addr=%02x, data=%02x\n", + __FUNCTION__, + xfer, rdata[1], rdata[2]); + return -EIO; + } + }; + + /* disable further writes */ + xfer = i2c_master_send(client, diswe, 3); + if (xfer != 3) { + dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer); + return -EIO; + } + + return 0; +} + +static int x1205_get_dtrim(struct i2c_client *client, int *trim) +{ + unsigned char dtr; + static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR }; + + struct i2c_msg msgs[] = { + { client->addr, 0, 2, dtr_addr }, /* setup read ptr */ + { client->addr, I2C_M_RD, 1, &dtr }, /* read dtr */ + }; + + /* read dtr register */ + if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { + dev_err(&client->dev, "%s: read error\n", __FUNCTION__); + return -EIO; + } + + dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr); + + *trim = 0; + + if (dtr & X1205_DTR_DTR0) + *trim += 20; + + if (dtr & X1205_DTR_DTR1) + *trim += 10; + + if (dtr & X1205_DTR_DTR2) + *trim = -*trim; + + return 0; +} + +static int x1205_get_atrim(struct i2c_client *client, int *trim) +{ + s8 atr; + static unsigned char atr_addr[2] = { 0, X1205_REG_ATR }; + + struct i2c_msg msgs[] = { + { client->addr, 0, 2, atr_addr }, /* setup read ptr */ + { client->addr, I2C_M_RD, 1, &atr }, /* read atr */ + }; + + /* read atr register */ + if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { + dev_err(&client->dev, "%s: read error\n", __FUNCTION__); + return -EIO; + } + + dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr); + + /* atr is a two's complement value on 6 bits, + * perform sign extension. The formula is + * Catr = (atr * 0.25pF) + 11.00pF. + */ + if (atr & 0x20) + atr |= 0xC0; + + dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr); + + *trim = (atr * 250) + 11000; + + dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim); + + return 0; +} + +static int x1205_hctosys(struct i2c_client *client) +{ + int err; + + struct rtc_time tm; + struct timespec tv; + + err = x1205_command(client, X1205_CMD_GETDATETIME, &tm); + + if (err) { + dev_err(&client->dev, + "Unable to set the system clock\n"); + return err; + } + + /* IMPORTANT: the RTC only stores whole seconds. It is arbitrary + * whether it stores the most close value or the value with partial + * seconds truncated. However, it is important that we use it to store + * the truncated value. This is because otherwise it is necessary, + * in an rtc sync function, to read both xtime.tv_sec and + * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read + * of >32bits is not possible. So storing the most close value would + * slow down the sync API. So here we have the truncated value and + * the best guess is to add 0.5s. + */ + + tv.tv_nsec = NSEC_PER_SEC >> 1; + + /* WARNING: this is not the C library 'mktime' call, it is a built in + * inline function from include/linux/time.h. It expects (requires) + * the month to be in the range 1-12 + */ + + tv.tv_sec = mktime(tm.tm_year + 1900, tm.tm_mon + 1, + tm.tm_mday, tm.tm_hour, + tm.tm_min, tm.tm_sec); + + do_settimeofday(&tv); + + dev_info(&client->dev, + "setting the system clock to %d-%d-%d %d:%d:%d\n", + tm.tm_year + 1900, tm.tm_mon + 1, + tm.tm_mday, tm.tm_hour, tm.tm_min, + tm.tm_sec); + + return 0; +} + +struct x1205_limit +{ + unsigned char reg; + unsigned char mask; + unsigned char min; + unsigned char max; +}; + +static int x1205_validate_client(struct i2c_client *client) +{ + int i, xfer; + + /* Probe array. We will read the register at the specified + * address and check if the given bits are zero. + */ + static const unsigned char probe_zero_pattern[] = { + /* register, mask */ + X1205_REG_SR, 0x18, + X1205_REG_DTR, 0xF8, + X1205_REG_ATR, 0xC0, + X1205_REG_INT, 0x18, + X1205_REG_0, 0xFF, + }; + + static const struct x1205_limit probe_limits_pattern[] = { + /* register, mask, min, max */ + { X1205_REG_Y2K, 0xFF, 19, 20 }, + { X1205_REG_DW, 0xFF, 0, 6 }, + { X1205_REG_YR, 0xFF, 0, 99 }, + { X1205_REG_MO, 0xFF, 0, 12 }, + { X1205_REG_DT, 0xFF, 0, 31 }, + { X1205_REG_HR, 0x7F, 0, 23 }, + { X1205_REG_MN, 0xFF, 0, 59 }, + { X1205_REG_SC, 0xFF, 0, 59 }, + { X1205_REG_Y2K1, 0xFF, 19, 20 }, + { X1205_REG_Y2K0, 0xFF, 19, 20 }, + }; + + /* check that registers have bits a 0 where expected */ + for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) { + unsigned char buf; + + unsigned char addr[2] = { 0, probe_zero_pattern[i] }; + + struct i2c_msg msgs[2] = { + { client->addr, 0, 2, addr }, + { client->addr, I2C_M_RD, 1, &buf }, + }; + + xfer = i2c_transfer(client->adapter, msgs, 2); + if (xfer != 2) { + dev_err(&client->adapter->dev, + "%s: could not read register %x\n", + __FUNCTION__, addr[1]); + + return -EIO; + } + + if ((buf & probe_zero_pattern[i+1]) != 0) { + dev_err(&client->adapter->dev, + "%s: register=%02x, zero pattern=%d, value=%x\n", + __FUNCTION__, addr[1], i, buf); + + return -ENODEV; + } + } + + /* check limits (only registers with bcd values) */ + for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) { + unsigned char reg, value; + + unsigned char addr[2] = { 0, probe_limits_pattern[i].reg }; + + struct i2c_msg msgs[2] = { + { client->addr, 0, 2, addr }, + { client->addr, I2C_M_RD, 1, ® }, + }; + + xfer = i2c_transfer(client->adapter, msgs, 2); + + if (xfer != 2) { + dev_err(&client->adapter->dev, + "%s: could not read register %x\n", + __FUNCTION__, addr[1]); + + return -EIO; + } + + value = BCD2BIN(reg & probe_limits_pattern[i].mask); + + if (value > probe_limits_pattern[i].max || + value < probe_limits_pattern[i].min) { + dev_dbg(&client->adapter->dev, + "%s: register=%x, lim pattern=%d, value=%d\n", + __FUNCTION__, addr[1], i, value); + + return -ENODEV; + } + } + + return 0; +} + +static int x1205_attach(struct i2c_adapter *adapter) +{ + dev_dbg(&adapter->dev, "%s\n", __FUNCTION__); + + return i2c_probe(adapter, &addr_data, x1205_probe); +} + +int x1205_direct_attach(int adapter_id, + struct i2c_client_address_data *address_data) +{ + int err; + struct i2c_adapter *adapter = i2c_get_adapter(adapter_id); + + if (adapter) { + err = i2c_probe(adapter, + address_data, x1205_probe); + + i2c_put_adapter(adapter); + + return err; + } + + return -ENODEV; +} + +static int x1205_probe(struct i2c_adapter *adapter, int address, int kind) +{ + struct i2c_client *client; + struct x1205_data *data; + + int err = 0; + + dev_dbg(&adapter->dev, "%s\n", __FUNCTION__); + + if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) { + err = -ENODEV; + goto exit; + } + + if (!(data = kzalloc(sizeof(struct x1205_data), GFP_KERNEL))) { + err = -ENOMEM; + goto exit; + } + + /* Initialize our structures */ + data->epoch = 2000; + + client = &data->client; + client->addr = address; + client->driver = &x1205_driver; + client->adapter = adapter; + + strlcpy(client->name, "x1205", I2C_NAME_SIZE); + + i2c_set_clientdata(client, data); + + /* Verify the chip is really an X1205 */ + if (kind < 0) { + if (x1205_validate_client(client) < 0) { + err = -ENODEV; + goto exit_kfree; + } + } + + /* Inform the i2c layer */ + if ((err = i2c_attach_client(client))) + goto exit_kfree; + + list_add(&data->list, &x1205_clients); + + dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); + + /* If requested, set the system time */ + if (hctosys) + x1205_hctosys(client); + + return 0; + +exit_kfree: + kfree(data); + +exit: + return err; +} + +static int x1205_detach(struct i2c_client *client) +{ + int err; + struct x1205_data *data = i2c_get_clientdata(client); + + dev_dbg(&client->dev, "%s\n", __FUNCTION__); + + if ((err = i2c_detach_client(client))) + return err; + + list_del(&data->list); + + kfree(data); + + return 0; +} + +static int x1205_command(struct i2c_client *client, unsigned int cmd, + void *param) +{ + if (param == NULL) + return -EINVAL; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + dev_dbg(&client->dev, "%s: cmd=%d\n", __FUNCTION__, cmd); + + switch (cmd) { + case X1205_CMD_GETDATETIME: + return x1205_get_datetime(client, param, X1205_CCR_BASE); + + case X1205_CMD_SETTIME: + return x1205_set_datetime(client, param, 0, + X1205_CCR_BASE); + + case X1205_CMD_SETDATETIME: + return x1205_set_datetime(client, param, 1, + X1205_CCR_BASE); + + case X1205_CMD_GETALARM: + return x1205_get_datetime(client, param, X1205_ALM0_BASE); + + case X1205_CMD_SETALARM: + return x1205_set_datetime(client, param, 1, + X1205_ALM0_BASE); + + case X1205_CMD_GETDTRIM: + return x1205_get_dtrim(client, param); + + case X1205_CMD_GETATRIM: + return x1205_get_atrim(client, param); + + default: + return -EINVAL; + } +} + +static int __init x1205_init(void) +{ + return i2c_add_driver(&x1205_driver); +} + +static void __exit x1205_exit(void) +{ + i2c_del_driver(&x1205_driver); +} + +MODULE_AUTHOR( + "Karen Spearel <kas11@tampabay.rr.com>, " + "Alessandro Zummo <a.zummo@towertech.it>"); +MODULE_DESCRIPTION("Xicor X1205 RTC driver"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(DRV_VERSION); + +EXPORT_SYMBOL_GPL(x1205_do_command); +EXPORT_SYMBOL_GPL(x1205_direct_attach); + +module_init(x1205_init); +module_exit(x1205_exit); |