/** * ds2482.c - provides i2c to w1-master bridge(s) * Copyright (C) 2005 Ben Gardner * * 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 #include #include #include #include #include #include "../w1.h" #include "../w1_int.h" /** * 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 static int ds2482_probe(struct i2c_client *client, const struct i2c_device_id *id); 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, }; /* * 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) { 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) 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, 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; } module_i2c_driver(ds2482_driver); MODULE_AUTHOR("Ben Gardner "); MODULE_DESCRIPTION("DS2482 driver"); MODULE_LICENSE("GPL");