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Diffstat (limited to '')
| -rw-r--r-- | drivers/w1/masters/ds2482.c | 566 |
1 files changed, 566 insertions, 0 deletions
diff --git a/drivers/w1/masters/ds2482.c b/drivers/w1/masters/ds2482.c new file mode 100644 index 000000000..b471779c3 --- /dev/null +++ b/drivers/w1/masters/ds2482.c @@ -0,0 +1,566 @@ +// SPDX-License-Identifier: GPL-2.0-only +/** + * 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 + */ + +#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; +}; + + +/** + * Helper to calculate values for configuration register + * @param 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); +} + + +/** + * 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) + pr_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, + 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 <bgardner@wabtec.com>"); +MODULE_DESCRIPTION("DS2482 driver"); + +MODULE_LICENSE("GPL"); |