565 lines
14 KiB
C
565 lines
14 KiB
C
/**
|
|
* ds2482.c - provides i2c to w1-master bridge(s)
|
|
* Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
|
|
*
|
|
* The DS2482 is a sensor chip made by Dallas Semiconductor (Maxim).
|
|
* It is a I2C to 1-wire bridge.
|
|
* There are two variations: -100 and -800, which have 1 or 8 1-wire ports.
|
|
* The complete datasheet can be obtained from MAXIM's website at:
|
|
* http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4382
|
|
*
|
|
* 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; version 2 of the License.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/delay.h>
|
|
#include <asm/delay.h>
|
|
|
|
#include "../w1.h"
|
|
#include "../w1_int.h"
|
|
|
|
/**
|
|
* Address is selected using 2 pins, resulting in 4 possible addresses.
|
|
* 0x18, 0x19, 0x1a, 0x1b
|
|
* However, the chip cannot be detected without doing an i2c write,
|
|
* so use the force module parameter.
|
|
*/
|
|
static unsigned short normal_i2c[] = {I2C_CLIENT_END};
|
|
|
|
/**
|
|
* Insmod parameters
|
|
*/
|
|
I2C_CLIENT_INSMOD_1(ds2482);
|
|
|
|
/**
|
|
* The DS2482 registers - there are 3 registers that are addressed by a read
|
|
* pointer. The read pointer is set by the last command executed.
|
|
*
|
|
* To read the data, issue a register read for any address
|
|
*/
|
|
#define DS2482_CMD_RESET 0xF0 /* No param */
|
|
#define DS2482_CMD_SET_READ_PTR 0xE1 /* Param: DS2482_PTR_CODE_xxx */
|
|
#define DS2482_CMD_CHANNEL_SELECT 0xC3 /* Param: Channel byte - DS2482-800 only */
|
|
#define DS2482_CMD_WRITE_CONFIG 0xD2 /* Param: Config byte */
|
|
#define DS2482_CMD_1WIRE_RESET 0xB4 /* Param: None */
|
|
#define DS2482_CMD_1WIRE_SINGLE_BIT 0x87 /* Param: Bit byte (bit7) */
|
|
#define DS2482_CMD_1WIRE_WRITE_BYTE 0xA5 /* Param: Data byte */
|
|
#define DS2482_CMD_1WIRE_READ_BYTE 0x96 /* Param: None */
|
|
/* Note to read the byte, Set the ReadPtr to Data then read (any addr) */
|
|
#define DS2482_CMD_1WIRE_TRIPLET 0x78 /* Param: Dir byte (bit7) */
|
|
|
|
/* Values for DS2482_CMD_SET_READ_PTR */
|
|
#define DS2482_PTR_CODE_STATUS 0xF0
|
|
#define DS2482_PTR_CODE_DATA 0xE1
|
|
#define DS2482_PTR_CODE_CHANNEL 0xD2 /* DS2482-800 only */
|
|
#define DS2482_PTR_CODE_CONFIG 0xC3
|
|
|
|
/**
|
|
* Configure Register bit definitions
|
|
* The top 4 bits always read 0.
|
|
* To write, the top nibble must be the 1's compl. of the low nibble.
|
|
*/
|
|
#define DS2482_REG_CFG_1WS 0x08
|
|
#define DS2482_REG_CFG_SPU 0x04
|
|
#define DS2482_REG_CFG_PPM 0x02
|
|
#define DS2482_REG_CFG_APU 0x01
|
|
|
|
|
|
/**
|
|
* Write and verify codes for the CHANNEL_SELECT command (DS2482-800 only).
|
|
* To set the channel, write the value at the index of the channel.
|
|
* Read and compare against the corresponding value to verify the change.
|
|
*/
|
|
static const u8 ds2482_chan_wr[8] =
|
|
{ 0xF0, 0xE1, 0xD2, 0xC3, 0xB4, 0xA5, 0x96, 0x87 };
|
|
static const u8 ds2482_chan_rd[8] =
|
|
{ 0xB8, 0xB1, 0xAA, 0xA3, 0x9C, 0x95, 0x8E, 0x87 };
|
|
|
|
|
|
/**
|
|
* Status Register bit definitions (read only)
|
|
*/
|
|
#define DS2482_REG_STS_DIR 0x80
|
|
#define DS2482_REG_STS_TSB 0x40
|
|
#define DS2482_REG_STS_SBR 0x20
|
|
#define DS2482_REG_STS_RST 0x10
|
|
#define DS2482_REG_STS_LL 0x08
|
|
#define DS2482_REG_STS_SD 0x04
|
|
#define DS2482_REG_STS_PPD 0x02
|
|
#define DS2482_REG_STS_1WB 0x01
|
|
|
|
|
|
static int ds2482_attach_adapter(struct i2c_adapter *adapter);
|
|
static int ds2482_detect(struct i2c_adapter *adapter, int address, int kind);
|
|
static int ds2482_detach_client(struct i2c_client *client);
|
|
|
|
|
|
/**
|
|
* Driver data (common to all clients)
|
|
*/
|
|
static struct i2c_driver ds2482_driver = {
|
|
.driver = {
|
|
.owner = THIS_MODULE,
|
|
.name = "ds2482",
|
|
},
|
|
.attach_adapter = ds2482_attach_adapter,
|
|
.detach_client = ds2482_detach_client,
|
|
};
|
|
|
|
/*
|
|
* Client data (each client gets its own)
|
|
*/
|
|
|
|
struct ds2482_data;
|
|
|
|
struct ds2482_w1_chan {
|
|
struct ds2482_data *pdev;
|
|
u8 channel;
|
|
struct w1_bus_master w1_bm;
|
|
};
|
|
|
|
struct ds2482_data {
|
|
struct i2c_client client;
|
|
struct mutex access_lock;
|
|
|
|
/* 1-wire interface(s) */
|
|
int w1_count; /* 1 or 8 */
|
|
struct ds2482_w1_chan w1_ch[8];
|
|
|
|
/* per-device values */
|
|
u8 channel;
|
|
u8 read_prt; /* see DS2482_PTR_CODE_xxx */
|
|
u8 reg_config;
|
|
};
|
|
|
|
|
|
/**
|
|
* Sets the read pointer.
|
|
* @param pdev The ds2482 client pointer
|
|
* @param read_ptr see DS2482_PTR_CODE_xxx above
|
|
* @return -1 on failure, 0 on success
|
|
*/
|
|
static inline int ds2482_select_register(struct ds2482_data *pdev, u8 read_ptr)
|
|
{
|
|
if (pdev->read_prt != read_ptr) {
|
|
if (i2c_smbus_write_byte_data(&pdev->client,
|
|
DS2482_CMD_SET_READ_PTR,
|
|
read_ptr) < 0)
|
|
return -1;
|
|
|
|
pdev->read_prt = read_ptr;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Sends a command without a parameter
|
|
* @param pdev The ds2482 client pointer
|
|
* @param cmd DS2482_CMD_RESET,
|
|
* DS2482_CMD_1WIRE_RESET,
|
|
* DS2482_CMD_1WIRE_READ_BYTE
|
|
* @return -1 on failure, 0 on success
|
|
*/
|
|
static inline int ds2482_send_cmd(struct ds2482_data *pdev, u8 cmd)
|
|
{
|
|
if (i2c_smbus_write_byte(&pdev->client, cmd) < 0)
|
|
return -1;
|
|
|
|
pdev->read_prt = DS2482_PTR_CODE_STATUS;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Sends a command with a parameter
|
|
* @param pdev The ds2482 client pointer
|
|
* @param cmd DS2482_CMD_WRITE_CONFIG,
|
|
* DS2482_CMD_1WIRE_SINGLE_BIT,
|
|
* DS2482_CMD_1WIRE_WRITE_BYTE,
|
|
* DS2482_CMD_1WIRE_TRIPLET
|
|
* @param byte The data to send
|
|
* @return -1 on failure, 0 on success
|
|
*/
|
|
static inline int ds2482_send_cmd_data(struct ds2482_data *pdev,
|
|
u8 cmd, u8 byte)
|
|
{
|
|
if (i2c_smbus_write_byte_data(&pdev->client, cmd, byte) < 0)
|
|
return -1;
|
|
|
|
/* all cmds leave in STATUS, except CONFIG */
|
|
pdev->read_prt = (cmd != DS2482_CMD_WRITE_CONFIG) ?
|
|
DS2482_PTR_CODE_STATUS : DS2482_PTR_CODE_CONFIG;
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* 1-Wire interface code
|
|
*/
|
|
|
|
#define DS2482_WAIT_IDLE_TIMEOUT 100
|
|
|
|
/**
|
|
* Waits until the 1-wire interface is idle (not busy)
|
|
*
|
|
* @param pdev Pointer to the device structure
|
|
* @return the last value read from status or -1 (failure)
|
|
*/
|
|
static int ds2482_wait_1wire_idle(struct ds2482_data *pdev)
|
|
{
|
|
int temp = -1;
|
|
int retries = 0;
|
|
|
|
if (!ds2482_select_register(pdev, DS2482_PTR_CODE_STATUS)) {
|
|
do {
|
|
temp = i2c_smbus_read_byte(&pdev->client);
|
|
} while ((temp >= 0) && (temp & DS2482_REG_STS_1WB) &&
|
|
(++retries > DS2482_WAIT_IDLE_TIMEOUT));
|
|
}
|
|
|
|
if (retries > DS2482_WAIT_IDLE_TIMEOUT)
|
|
printk(KERN_ERR "%s: timeout on channel %d\n",
|
|
__func__, pdev->channel);
|
|
|
|
return temp;
|
|
}
|
|
|
|
/**
|
|
* Selects a w1 channel.
|
|
* The 1-wire interface must be idle before calling this function.
|
|
*
|
|
* @param pdev The ds2482 client pointer
|
|
* @param channel 0-7
|
|
* @return -1 (failure) or 0 (success)
|
|
*/
|
|
static int ds2482_set_channel(struct ds2482_data *pdev, u8 channel)
|
|
{
|
|
if (i2c_smbus_write_byte_data(&pdev->client, DS2482_CMD_CHANNEL_SELECT,
|
|
ds2482_chan_wr[channel]) < 0)
|
|
return -1;
|
|
|
|
pdev->read_prt = DS2482_PTR_CODE_CHANNEL;
|
|
pdev->channel = -1;
|
|
if (i2c_smbus_read_byte(&pdev->client) == ds2482_chan_rd[channel]) {
|
|
pdev->channel = channel;
|
|
return 0;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
|
|
/**
|
|
* Performs the touch-bit function, which writes a 0 or 1 and reads the level.
|
|
*
|
|
* @param data The ds2482 channel pointer
|
|
* @param bit The level to write: 0 or non-zero
|
|
* @return The level read: 0 or 1
|
|
*/
|
|
static u8 ds2482_w1_touch_bit(void *data, u8 bit)
|
|
{
|
|
struct ds2482_w1_chan *pchan = data;
|
|
struct ds2482_data *pdev = pchan->pdev;
|
|
int status = -1;
|
|
|
|
mutex_lock(&pdev->access_lock);
|
|
|
|
/* Select the channel */
|
|
ds2482_wait_1wire_idle(pdev);
|
|
if (pdev->w1_count > 1)
|
|
ds2482_set_channel(pdev, pchan->channel);
|
|
|
|
/* Send the touch command, wait until 1WB == 0, return the status */
|
|
if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_SINGLE_BIT,
|
|
bit ? 0xFF : 0))
|
|
status = ds2482_wait_1wire_idle(pdev);
|
|
|
|
mutex_unlock(&pdev->access_lock);
|
|
|
|
return (status & DS2482_REG_STS_SBR) ? 1 : 0;
|
|
}
|
|
|
|
/**
|
|
* Performs the triplet function, which reads two bits and writes a bit.
|
|
* The bit written is determined by the two reads:
|
|
* 00 => dbit, 01 => 0, 10 => 1
|
|
*
|
|
* @param data The ds2482 channel pointer
|
|
* @param dbit The direction to choose if both branches are valid
|
|
* @return b0=read1 b1=read2 b3=bit written
|
|
*/
|
|
static u8 ds2482_w1_triplet(void *data, u8 dbit)
|
|
{
|
|
struct ds2482_w1_chan *pchan = data;
|
|
struct ds2482_data *pdev = pchan->pdev;
|
|
int status = (3 << 5);
|
|
|
|
mutex_lock(&pdev->access_lock);
|
|
|
|
/* Select the channel */
|
|
ds2482_wait_1wire_idle(pdev);
|
|
if (pdev->w1_count > 1)
|
|
ds2482_set_channel(pdev, pchan->channel);
|
|
|
|
/* Send the triplet command, wait until 1WB == 0, return the status */
|
|
if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_TRIPLET,
|
|
dbit ? 0xFF : 0))
|
|
status = ds2482_wait_1wire_idle(pdev);
|
|
|
|
mutex_unlock(&pdev->access_lock);
|
|
|
|
/* Decode the status */
|
|
return (status >> 5);
|
|
}
|
|
|
|
/**
|
|
* Performs the write byte function.
|
|
*
|
|
* @param data The ds2482 channel pointer
|
|
* @param byte The value to write
|
|
*/
|
|
static void ds2482_w1_write_byte(void *data, u8 byte)
|
|
{
|
|
struct ds2482_w1_chan *pchan = data;
|
|
struct ds2482_data *pdev = pchan->pdev;
|
|
|
|
mutex_lock(&pdev->access_lock);
|
|
|
|
/* Select the channel */
|
|
ds2482_wait_1wire_idle(pdev);
|
|
if (pdev->w1_count > 1)
|
|
ds2482_set_channel(pdev, pchan->channel);
|
|
|
|
/* Send the write byte command */
|
|
ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_WRITE_BYTE, byte);
|
|
|
|
mutex_unlock(&pdev->access_lock);
|
|
}
|
|
|
|
/**
|
|
* Performs the read byte function.
|
|
*
|
|
* @param data The ds2482 channel pointer
|
|
* @return The value read
|
|
*/
|
|
static u8 ds2482_w1_read_byte(void *data)
|
|
{
|
|
struct ds2482_w1_chan *pchan = data;
|
|
struct ds2482_data *pdev = pchan->pdev;
|
|
int result;
|
|
|
|
mutex_lock(&pdev->access_lock);
|
|
|
|
/* Select the channel */
|
|
ds2482_wait_1wire_idle(pdev);
|
|
if (pdev->w1_count > 1)
|
|
ds2482_set_channel(pdev, pchan->channel);
|
|
|
|
/* Send the read byte command */
|
|
ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_READ_BYTE);
|
|
|
|
/* Wait until 1WB == 0 */
|
|
ds2482_wait_1wire_idle(pdev);
|
|
|
|
/* Select the data register */
|
|
ds2482_select_register(pdev, DS2482_PTR_CODE_DATA);
|
|
|
|
/* Read the data byte */
|
|
result = i2c_smbus_read_byte(&pdev->client);
|
|
|
|
mutex_unlock(&pdev->access_lock);
|
|
|
|
return result;
|
|
}
|
|
|
|
|
|
/**
|
|
* Sends a reset on the 1-wire interface
|
|
*
|
|
* @param data The ds2482 channel pointer
|
|
* @return 0=Device present, 1=No device present or error
|
|
*/
|
|
static u8 ds2482_w1_reset_bus(void *data)
|
|
{
|
|
struct ds2482_w1_chan *pchan = data;
|
|
struct ds2482_data *pdev = pchan->pdev;
|
|
int err;
|
|
u8 retval = 1;
|
|
|
|
mutex_lock(&pdev->access_lock);
|
|
|
|
/* Select the channel */
|
|
ds2482_wait_1wire_idle(pdev);
|
|
if (pdev->w1_count > 1)
|
|
ds2482_set_channel(pdev, pchan->channel);
|
|
|
|
/* Send the reset command */
|
|
err = ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_RESET);
|
|
if (err >= 0) {
|
|
/* Wait until the reset is complete */
|
|
err = ds2482_wait_1wire_idle(pdev);
|
|
retval = !(err & DS2482_REG_STS_PPD);
|
|
|
|
/* If the chip did reset since detect, re-config it */
|
|
if (err & DS2482_REG_STS_RST)
|
|
ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
|
|
0xF0);
|
|
}
|
|
|
|
mutex_unlock(&pdev->access_lock);
|
|
|
|
return retval;
|
|
}
|
|
|
|
|
|
/**
|
|
* Called to see if the device exists on an i2c bus.
|
|
*/
|
|
static int ds2482_attach_adapter(struct i2c_adapter *adapter)
|
|
{
|
|
return i2c_probe(adapter, &addr_data, ds2482_detect);
|
|
}
|
|
|
|
|
|
/*
|
|
* The following function does more than just detection. If detection
|
|
* succeeds, it also registers the new chip.
|
|
*/
|
|
static int ds2482_detect(struct i2c_adapter *adapter, int address, int kind)
|
|
{
|
|
struct ds2482_data *data;
|
|
struct i2c_client *new_client;
|
|
int err = 0;
|
|
int temp1;
|
|
int idx;
|
|
|
|
if (!i2c_check_functionality(adapter,
|
|
I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
|
|
I2C_FUNC_SMBUS_BYTE))
|
|
goto exit;
|
|
|
|
if (!(data = kzalloc(sizeof(struct ds2482_data), GFP_KERNEL))) {
|
|
err = -ENOMEM;
|
|
goto exit;
|
|
}
|
|
|
|
new_client = &data->client;
|
|
i2c_set_clientdata(new_client, data);
|
|
new_client->addr = address;
|
|
new_client->driver = &ds2482_driver;
|
|
new_client->adapter = adapter;
|
|
|
|
/* Reset the device (sets the read_ptr to status) */
|
|
if (ds2482_send_cmd(data, DS2482_CMD_RESET) < 0) {
|
|
dev_dbg(&adapter->dev, "DS2482 reset failed at 0x%02x.\n",
|
|
address);
|
|
goto exit_free;
|
|
}
|
|
|
|
/* Sleep at least 525ns to allow the reset to complete */
|
|
ndelay(525);
|
|
|
|
/* Read the status byte - only reset bit and line should be set */
|
|
temp1 = i2c_smbus_read_byte(new_client);
|
|
if (temp1 != (DS2482_REG_STS_LL | DS2482_REG_STS_RST)) {
|
|
dev_dbg(&adapter->dev, "DS2482 (0x%02x) reset status "
|
|
"0x%02X - not a DS2482\n", address, temp1);
|
|
goto exit_free;
|
|
}
|
|
|
|
/* Detect the 8-port version */
|
|
data->w1_count = 1;
|
|
if (ds2482_set_channel(data, 7) == 0)
|
|
data->w1_count = 8;
|
|
|
|
/* Set all config items to 0 (off) */
|
|
ds2482_send_cmd_data(data, DS2482_CMD_WRITE_CONFIG, 0xF0);
|
|
|
|
/* We can fill in the remaining client fields */
|
|
snprintf(new_client->name, sizeof(new_client->name), "ds2482-%d00",
|
|
data->w1_count);
|
|
|
|
mutex_init(&data->access_lock);
|
|
|
|
/* Tell the I2C layer a new client has arrived */
|
|
if ((err = i2c_attach_client(new_client)))
|
|
goto exit_free;
|
|
|
|
/* Register 1-wire interface(s) */
|
|
for (idx = 0; idx < data->w1_count; idx++) {
|
|
data->w1_ch[idx].pdev = data;
|
|
data->w1_ch[idx].channel = idx;
|
|
|
|
/* Populate all the w1 bus master stuff */
|
|
data->w1_ch[idx].w1_bm.data = &data->w1_ch[idx];
|
|
data->w1_ch[idx].w1_bm.read_byte = ds2482_w1_read_byte;
|
|
data->w1_ch[idx].w1_bm.write_byte = ds2482_w1_write_byte;
|
|
data->w1_ch[idx].w1_bm.touch_bit = ds2482_w1_touch_bit;
|
|
data->w1_ch[idx].w1_bm.triplet = ds2482_w1_triplet;
|
|
data->w1_ch[idx].w1_bm.reset_bus = ds2482_w1_reset_bus;
|
|
|
|
err = w1_add_master_device(&data->w1_ch[idx].w1_bm);
|
|
if (err) {
|
|
data->w1_ch[idx].pdev = NULL;
|
|
goto exit_w1_remove;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
|
|
exit_w1_remove:
|
|
i2c_detach_client(new_client);
|
|
|
|
for (idx = 0; idx < data->w1_count; idx++) {
|
|
if (data->w1_ch[idx].pdev != NULL)
|
|
w1_remove_master_device(&data->w1_ch[idx].w1_bm);
|
|
}
|
|
exit_free:
|
|
kfree(data);
|
|
exit:
|
|
return err;
|
|
}
|
|
|
|
static int ds2482_detach_client(struct i2c_client *client)
|
|
{
|
|
struct ds2482_data *data = i2c_get_clientdata(client);
|
|
int err, idx;
|
|
|
|
/* Unregister the 1-wire bridge(s) */
|
|
for (idx = 0; idx < data->w1_count; idx++) {
|
|
if (data->w1_ch[idx].pdev != NULL)
|
|
w1_remove_master_device(&data->w1_ch[idx].w1_bm);
|
|
}
|
|
|
|
/* Detach the i2c device */
|
|
if ((err = i2c_detach_client(client))) {
|
|
dev_err(&client->dev,
|
|
"Deregistration failed, client not detached.\n");
|
|
return err;
|
|
}
|
|
|
|
/* Free the memory */
|
|
kfree(data);
|
|
return 0;
|
|
}
|
|
|
|
static int __init sensors_ds2482_init(void)
|
|
{
|
|
return i2c_add_driver(&ds2482_driver);
|
|
}
|
|
|
|
static void __exit sensors_ds2482_exit(void)
|
|
{
|
|
i2c_del_driver(&ds2482_driver);
|
|
}
|
|
|
|
MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
|
|
MODULE_DESCRIPTION("DS2482 driver");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
module_init(sensors_ds2482_init);
|
|
module_exit(sensors_ds2482_exit);
|