forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
566 lines
15 KiB
566 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* ds2482.c - provides i2c to w1-master bridge(s) |
|
* Copyright (C) 2005 Ben Gardner <[email protected]> |
|
* |
|
* 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 |
|
*/ |
|
|
|
#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 <linux/w1.h> |
|
|
|
/* |
|
* Allow the active pullup to be disabled, default is enabled. |
|
* |
|
* Note from the DS2482 datasheet: |
|
* The APU bit controls whether an active pullup (controlled slew-rate |
|
* transistor) or a passive pullup (Rwpu resistor) will be used to drive |
|
* a 1-Wire line from low to high. When APU = 0, active pullup is disabled |
|
* (resistor mode). Active Pullup should always be selected unless there is |
|
* only a single slave on the 1-Wire line. |
|
*/ |
|
static int ds2482_active_pullup = 1; |
|
module_param_named(active_pullup, ds2482_active_pullup, int, 0644); |
|
MODULE_PARM_DESC(active_pullup, "Active pullup (apply to all buses): " \ |
|
"0-disable, 1-enable (default)"); |
|
|
|
/* extra configurations - e.g. 1WS */ |
|
static int extra_config; |
|
module_param(extra_config, int, S_IRUGO | S_IWUSR); |
|
MODULE_PARM_DESC(extra_config, "Extra Configuration settings 1=APU,2=PPM,3=SPU,8=1WS"); |
|
|
|
/* |
|
* 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 /* 1-wire speed */ |
|
#define DS2482_REG_CFG_SPU 0x04 /* strong pull-up */ |
|
#define DS2482_REG_CFG_PPM 0x02 /* presence pulse masking */ |
|
#define DS2482_REG_CFG_APU 0x01 /* active pull-up */ |
|
|
|
|
|
/* |
|
* 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 |
|
|
|
/* |
|
* 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; |
|
}; |
|
|
|
|
|
/** |
|
* ds2482_calculate_config - Helper to calculate values for configuration register |
|
* @conf: the raw config value |
|
* Return: the value w/ complements that can be written to register |
|
*/ |
|
static inline u8 ds2482_calculate_config(u8 conf) |
|
{ |
|
conf |= extra_config; |
|
|
|
if (ds2482_active_pullup) |
|
conf |= DS2482_REG_CFG_APU; |
|
|
|
return conf | ((~conf & 0x0f) << 4); |
|
} |
|
|
|
|
|
/** |
|
* ds2482_select_register - Sets the read pointer. |
|
* @pdev: The ds2482 client pointer |
|
* @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; |
|
} |
|
|
|
/** |
|
* ds2482_send_cmd - Sends a command without a parameter |
|
* @pdev: The ds2482 client pointer |
|
* @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; |
|
} |
|
|
|
/** |
|
* ds2482_send_cmd_data - Sends a command with a parameter |
|
* @pdev: The ds2482 client pointer |
|
* @cmd: DS2482_CMD_WRITE_CONFIG, |
|
* DS2482_CMD_1WIRE_SINGLE_BIT, |
|
* DS2482_CMD_1WIRE_WRITE_BYTE, |
|
* DS2482_CMD_1WIRE_TRIPLET |
|
* @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 |
|
|
|
/** |
|
* ds2482_wait_1wire_idle - Waits until the 1-wire interface is idle (not busy) |
|
* |
|
* @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) |
|
pr_err("%s: timeout on channel %d\n", |
|
__func__, pdev->channel); |
|
|
|
return temp; |
|
} |
|
|
|
/** |
|
* ds2482_set_channel - Selects a w1 channel. |
|
* The 1-wire interface must be idle before calling this function. |
|
* |
|
* @pdev: The ds2482 client pointer |
|
* @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; |
|
} |
|
|
|
|
|
/** |
|
* ds2482_w1_touch_bit - Performs the touch-bit function, which writes a 0 or 1 and reads the level. |
|
* |
|
* @data: The ds2482 channel pointer |
|
* @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; |
|
} |
|
|
|
/** |
|
* ds2482_w1_triplet - 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 |
|
* |
|
* @data: The ds2482 channel pointer |
|
* @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); |
|
} |
|
|
|
/** |
|
* ds2482_w1_write_byte - Performs the write byte function. |
|
* |
|
* @data: The ds2482 channel pointer |
|
* @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); |
|
} |
|
|
|
/** |
|
* ds2482_w1_read_byte - Performs the read byte function. |
|
* |
|
* @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; |
|
} |
|
|
|
|
|
/** |
|
* ds2482_w1_reset_bus - Sends a reset on the 1-wire interface |
|
* |
|
* @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, |
|
ds2482_calculate_config(0x00)); |
|
} |
|
|
|
mutex_unlock(&pdev->access_lock); |
|
|
|
return retval; |
|
} |
|
|
|
static u8 ds2482_w1_set_pullup(void *data, int delay) |
|
{ |
|
struct ds2482_w1_chan *pchan = data; |
|
struct ds2482_data *pdev = pchan->pdev; |
|
u8 retval = 1; |
|
|
|
/* if delay is non-zero activate the pullup, |
|
* the strong pullup will be automatically deactivated |
|
* by the master, so do not explicitly deactive it |
|
*/ |
|
if (delay) { |
|
/* both waits are crucial, otherwise devices might not be |
|
* powered long enough, causing e.g. a w1_therm sensor to |
|
* provide wrong conversion results |
|
*/ |
|
ds2482_wait_1wire_idle(pdev); |
|
/* note: it seems like both SPU and APU have to be set! */ |
|
retval = ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG, |
|
ds2482_calculate_config(DS2482_REG_CFG_SPU | |
|
DS2482_REG_CFG_APU)); |
|
ds2482_wait_1wire_idle(pdev); |
|
} |
|
|
|
return retval; |
|
} |
|
|
|
|
|
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 (!i2c_check_functionality(client->adapter, |
|
I2C_FUNC_SMBUS_WRITE_BYTE_DATA | |
|
I2C_FUNC_SMBUS_BYTE)) |
|
return -ENODEV; |
|
|
|
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, |
|
ds2482_calculate_config(0x00)); |
|
|
|
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; |
|
data->w1_ch[idx].w1_bm.set_pullup = ds2482_w1_set_pullup; |
|
|
|
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; |
|
} |
|
|
|
/* |
|
* Driver data (common to all clients) |
|
*/ |
|
static const struct i2c_device_id ds2482_id[] = { |
|
{ "ds2482", 0 }, |
|
{ } |
|
}; |
|
MODULE_DEVICE_TABLE(i2c, ds2482_id); |
|
|
|
static struct i2c_driver ds2482_driver = { |
|
.driver = { |
|
.name = "ds2482", |
|
}, |
|
.probe = ds2482_probe, |
|
.remove = ds2482_remove, |
|
.id_table = ds2482_id, |
|
}; |
|
module_i2c_driver(ds2482_driver); |
|
|
|
MODULE_AUTHOR("Ben Gardner <[email protected]>"); |
|
MODULE_DESCRIPTION("DS2482 driver"); |
|
|
|
MODULE_LICENSE("GPL");
|
|
|