linux/drivers/w1/masters/ds2482.c
Jean Delvare 61c91f7ded w1/ds2482: Convert to a new-style driver
The new-style ds2482 driver implements the optional detect() callback
to cover the use cases of the legacy driver. I'm curious if anyone
really needs this though, so it might be removed in the feature.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-07-16 19:30:07 +02:00

548 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 const 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_probe(struct i2c_client *client,
const struct i2c_device_id *id);
static int ds2482_detect(struct i2c_client *client, int kind,
struct i2c_board_info *info);
static int ds2482_remove(struct i2c_client *client);
/**
* Driver data (common to all clients)
*/
static const struct i2c_device_id ds2482_id[] = {
{ "ds2482", 0 },
{ }
};
static struct i2c_driver ds2482_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "ds2482",
},
.probe = ds2482_probe,
.remove = ds2482_remove,
.id_table = ds2482_id,
.detect = ds2482_detect,
.address_data = &addr_data,
};
/*
* 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;
}
static int ds2482_detect(struct i2c_client *client, int kind,
struct i2c_board_info *info)
{
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
I2C_FUNC_SMBUS_BYTE))
return -ENODEV;
strlcpy(info->type, "ds2482", I2C_NAME_SIZE);
return 0;
}
static int ds2482_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds2482_data *data;
int err = -ENODEV;
int temp1;
int idx;
if (!(data = kzalloc(sizeof(struct ds2482_data), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
data->client = client;
i2c_set_clientdata(client, data);
/* Reset the device (sets the read_ptr to status) */
if (ds2482_send_cmd(data, DS2482_CMD_RESET) < 0) {
dev_warn(&client->dev, "DS2482 reset failed.\n");
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(client);
if (temp1 != (DS2482_REG_STS_LL | DS2482_REG_STS_RST)) {
dev_warn(&client->dev, "DS2482 reset status "
"0x%02X - not a DS2482\n", 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);
mutex_init(&data->access_lock);
/* 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:
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_remove(struct i2c_client *client)
{
struct ds2482_data *data = i2c_get_clientdata(client);
int 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);
}
/* 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);