diff options
Diffstat (limited to 'drivers/i2c/chips/ds1337.c')
| -rw-r--r-- | drivers/i2c/chips/ds1337.c | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/drivers/i2c/chips/ds1337.c b/drivers/i2c/chips/ds1337.c new file mode 100644 index 000000000000..07f16c3fb084 --- /dev/null +++ b/drivers/i2c/chips/ds1337.c @@ -0,0 +1,402 @@ +/* + * linux/drivers/i2c/chips/ds1337.c + * + * Copyright (C) 2005 James Chapman <jchapman@katalix.com> + * + * based on linux/drivers/acron/char/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 Dallas Semiconductor DS1337 real time clock chip + */ + +#include <linux/config.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/i2c.h> +#include <linux/i2c-sensor.h> +#include <linux/string.h> +#include <linux/rtc.h> /* get the user-level API */ +#include <linux/bcd.h> +#include <linux/list.h> + +/* Device registers */ +#define DS1337_REG_HOUR 2 +#define DS1337_REG_DAY 3 +#define DS1337_REG_DATE 4 +#define DS1337_REG_MONTH 5 +#define DS1337_REG_CONTROL 14 +#define DS1337_REG_STATUS 15 + +/* FIXME - how do we export these interface constants? */ +#define DS1337_GET_DATE 0 +#define DS1337_SET_DATE 1 + +/* + * Functions declaration + */ +static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END }; +static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END }; + +SENSORS_INSMOD_1(ds1337); + +static int ds1337_attach_adapter(struct i2c_adapter *adapter); +static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind); +static void ds1337_init_client(struct i2c_client *client); +static int ds1337_detach_client(struct i2c_client *client); +static int ds1337_command(struct i2c_client *client, unsigned int cmd, + void *arg); + +/* + * Driver data (common to all clients) + */ +static struct i2c_driver ds1337_driver = { + .owner = THIS_MODULE, + .name = "ds1337", + .flags = I2C_DF_NOTIFY, + .attach_adapter = ds1337_attach_adapter, + .detach_client = ds1337_detach_client, + .command = ds1337_command, +}; + +/* + * Client data (each client gets its own) + */ +struct ds1337_data { + struct i2c_client client; + struct list_head list; + int id; +}; + +/* + * Internal variables + */ +static int ds1337_id; +static LIST_HEAD(ds1337_clients); + +static inline int ds1337_read(struct i2c_client *client, u8 reg, u8 *value) +{ + s32 tmp = i2c_smbus_read_byte_data(client, reg); + + if (tmp < 0) + return -EIO; + + *value = tmp; + + return 0; +} + +/* + * Chip access functions + */ +static int ds1337_get_datetime(struct i2c_client *client, struct rtc_time *dt) +{ + struct ds1337_data *data = i2c_get_clientdata(client); + int result; + u8 buf[7]; + u8 val; + struct i2c_msg msg[2]; + u8 offs = 0; + + if (!dt) { + dev_dbg(&client->adapter->dev, "%s: EINVAL: dt=NULL\n", + __FUNCTION__); + + return -EINVAL; + } + + msg[0].addr = client->addr; + msg[0].flags = 0; + msg[0].len = 1; + msg[0].buf = &offs; + + msg[1].addr = client->addr; + msg[1].flags = I2C_M_RD; + msg[1].len = sizeof(buf); + msg[1].buf = &buf[0]; + + result = client->adapter->algo->master_xfer(client->adapter, + &msg[0], 2); + + dev_dbg(&client->adapter->dev, + "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n", + __FUNCTION__, result, buf[0], buf[1], buf[2], buf[3], + buf[4], buf[5], buf[6]); + + if (result >= 0) { + dt->tm_sec = BCD_TO_BIN(buf[0]); + dt->tm_min = BCD_TO_BIN(buf[1]); + val = buf[2] & 0x3f; + dt->tm_hour = BCD_TO_BIN(val); + dt->tm_wday = BCD_TO_BIN(buf[3]) - 1; + dt->tm_mday = BCD_TO_BIN(buf[4]); + val = buf[5] & 0x7f; + dt->tm_mon = BCD_TO_BIN(val); + dt->tm_year = 1900 + BCD_TO_BIN(buf[6]); + if (buf[5] & 0x80) + dt->tm_year += 100; + + dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, " + "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", + __FUNCTION__, dt->tm_sec, dt->tm_min, + dt->tm_hour, dt->tm_mday, + dt->tm_mon, dt->tm_year, dt->tm_wday); + } else { + dev_err(&client->adapter->dev, "ds1337[%d]: error reading " + "data! %d\n", data->id, result); + result = -EIO; + } + + return result; +} + +static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *dt) +{ + struct ds1337_data *data = i2c_get_clientdata(client); + int result; + u8 buf[8]; + u8 val; + struct i2c_msg msg[1]; + + if (!dt) { + dev_dbg(&client->adapter->dev, "%s: EINVAL: dt=NULL\n", + __FUNCTION__); + + return -EINVAL; + } + + dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, hours=%d, " + "mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__, + dt->tm_sec, dt->tm_min, dt->tm_hour, + dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday); + + buf[0] = 0; /* reg offset */ + buf[1] = BIN_TO_BCD(dt->tm_sec); + buf[2] = BIN_TO_BCD(dt->tm_min); + buf[3] = BIN_TO_BCD(dt->tm_hour) | (1 << 6); + buf[4] = BIN_TO_BCD(dt->tm_wday) + 1; + buf[5] = BIN_TO_BCD(dt->tm_mday); + buf[6] = BIN_TO_BCD(dt->tm_mon); + if (dt->tm_year >= 2000) { + val = dt->tm_year - 2000; + buf[6] |= (1 << 7); + } else { + val = dt->tm_year - 1900; + } + buf[7] = BIN_TO_BCD(val); + + msg[0].addr = client->addr; + msg[0].flags = 0; + msg[0].len = sizeof(buf); + msg[0].buf = &buf[0]; + + result = client->adapter->algo->master_xfer(client->adapter, + &msg[0], 1); + if (result < 0) { + dev_err(&client->adapter->dev, "ds1337[%d]: error " + "writing data! %d\n", data->id, result); + result = -EIO; + } else { + result = 0; + } + + return result; +} + +static int ds1337_command(struct i2c_client *client, unsigned int cmd, + void *arg) +{ + dev_dbg(&client->adapter->dev, "%s: cmd=%d\n", __FUNCTION__, cmd); + + switch (cmd) { + case DS1337_GET_DATE: + return ds1337_get_datetime(client, arg); + + case DS1337_SET_DATE: + return ds1337_set_datetime(client, arg); + + default: + return -EINVAL; + } +} + +/* + * Public API for access to specific device. Useful for low-level + * RTC access from kernel code. + */ +int ds1337_do_command(int id, int cmd, void *arg) +{ + struct list_head *walk; + struct list_head *tmp; + struct ds1337_data *data; + + list_for_each_safe(walk, tmp, &ds1337_clients) { + data = list_entry(walk, struct ds1337_data, list); + if (data->id == id) + return ds1337_command(&data->client, cmd, arg); + } + + return -ENODEV; +} + +static int ds1337_attach_adapter(struct i2c_adapter *adapter) +{ + return i2c_detect(adapter, &addr_data, ds1337_detect); +} + +/* + * The following function does more than just detection. If detection + * succeeds, it also registers the new chip. + */ +static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind) +{ + struct i2c_client *new_client; + struct ds1337_data *data; + int err = 0; + const char *name = ""; + + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_I2C)) + goto exit; + + if (!(data = kmalloc(sizeof(struct ds1337_data), GFP_KERNEL))) { + err = -ENOMEM; + goto exit; + } + memset(data, 0, sizeof(struct ds1337_data)); + INIT_LIST_HEAD(&data->list); + + /* The common I2C client data is placed right before the + * DS1337-specific data. + */ + new_client = &data->client; + i2c_set_clientdata(new_client, data); + new_client->addr = address; + new_client->adapter = adapter; + new_client->driver = &ds1337_driver; + new_client->flags = 0; + + /* + * Now we do the remaining detection. A negative kind means that + * the driver was loaded with no force parameter (default), so we + * must both detect and identify the chip. A zero kind means that + * the driver was loaded with the force parameter, the detection + * step shall be skipped. A positive kind means that the driver + * was loaded with the force parameter and a given kind of chip is + * requested, so both the detection and the identification steps + * are skipped. + * + * For detection, we read registers that are most likely to cause + * detection failure, i.e. those that have more bits with fixed + * or reserved values. + */ + + /* Default to an DS1337 if forced */ + if (kind == 0) + kind = ds1337; + + if (kind < 0) { /* detection and identification */ + u8 data; + + /* Check that status register bits 6-2 are zero */ + if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) || + (data & 0x7c)) + goto exit_free; + + /* Check for a valid day register value */ + if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) || + (data == 0) || (data & 0xf8)) + goto exit_free; + + /* Check for a valid date register value */ + if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) || + (data == 0) || (data & 0xc0) || ((data & 0x0f) > 9) || + (data >= 0x32)) + goto exit_free; + + /* Check for a valid month register value */ + if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) || + (data == 0) || (data & 0x60) || ((data & 0x0f) > 9) || + ((data >= 0x13) && (data <= 0x19))) + goto exit_free; + + /* Check that control register bits 6-5 are zero */ + if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) || + (data & 0x60)) + goto exit_free; + + kind = ds1337; + } + + if (kind == ds1337) + name = "ds1337"; + + /* We can fill in the remaining client fields */ + strlcpy(new_client->name, name, I2C_NAME_SIZE); + + /* Tell the I2C layer a new client has arrived */ + if ((err = i2c_attach_client(new_client))) + goto exit_free; + + /* Initialize the DS1337 chip */ + ds1337_init_client(new_client); + + /* Add client to local list */ + data->id = ds1337_id++; + list_add(&data->list, &ds1337_clients); + + return 0; + +exit_free: + kfree(data); +exit: + return err; +} + +static void ds1337_init_client(struct i2c_client *client) +{ + s32 val; + + /* Ensure that device is set in 24-hour mode */ + val = i2c_smbus_read_byte_data(client, DS1337_REG_HOUR); + if ((val >= 0) && (val & (1 << 6)) == 0) + i2c_smbus_write_byte_data(client, DS1337_REG_HOUR, + val | (1 << 6)); +} + +static int ds1337_detach_client(struct i2c_client *client) +{ + int err; + struct ds1337_data *data = i2c_get_clientdata(client); + + if ((err = i2c_detach_client(client))) { + dev_err(&client->dev, "Client deregistration failed, " + "client not detached.\n"); + return err; + } + + list_del(&data->list); + kfree(data); + return 0; +} + +static int __init ds1337_init(void) +{ + return i2c_add_driver(&ds1337_driver); +} + +static void __exit ds1337_exit(void) +{ + i2c_del_driver(&ds1337_driver); +} + +MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); +MODULE_DESCRIPTION("DS1337 RTC driver"); +MODULE_LICENSE("GPL"); + +module_init(ds1337_init); +module_exit(ds1337_exit); |
