[deliverable/linux.git] / drivers / w1 / masters / ds2482.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"

/**
 * 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 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ds2482_id);

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)
		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;
}

module_i2c_driver(ds2482_driver);

MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
MODULE_DESCRIPTION("DS2482 driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
baf12ae2 EP	1	/**
	2	* ds2482.c - provides i2c to w1-master bridge(s)
	3	* Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
	4	*
	5	* The DS2482 is a sensor chip made by Dallas Semiconductor (Maxim).
	6	* It is a I2C to 1-wire bridge.
	7	* There are two variations: -100 and -800, which have 1 or 8 1-wire ports.
	8	* The complete datasheet can be obtained from MAXIM's website at:
	9	* http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4382
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License as published by
	13	* the Free Software Foundation; version 2 of the License.
	14	*/
	15
	16	#include <linux/module.h>
	17	#include <linux/init.h>
	18	#include <linux/slab.h>
	19	#include <linux/i2c.h>
	20	#include <linux/delay.h>
	21	#include <asm/delay.h>
	22
	23	#include "../w1.h"
	24	#include "../w1_int.h"
	25
baf12ae2 EP	26	/**
	27	* The DS2482 registers - there are 3 registers that are addressed by a read
	28	* pointer. The read pointer is set by the last command executed.
	29	*
	30	* To read the data, issue a register read for any address
	31	*/
	32	#define DS2482_CMD_RESET 0xF0 /* No param */
	33	#define DS2482_CMD_SET_READ_PTR 0xE1 /* Param: DS2482_PTR_CODE_xxx */
	34	#define DS2482_CMD_CHANNEL_SELECT 0xC3 /* Param: Channel byte - DS2482-800 only */
	35	#define DS2482_CMD_WRITE_CONFIG 0xD2 /* Param: Config byte */
	36	#define DS2482_CMD_1WIRE_RESET 0xB4 /* Param: None */
	37	#define DS2482_CMD_1WIRE_SINGLE_BIT 0x87 /* Param: Bit byte (bit7) */
	38	#define DS2482_CMD_1WIRE_WRITE_BYTE 0xA5 /* Param: Data byte */
	39	#define DS2482_CMD_1WIRE_READ_BYTE 0x96 /* Param: None */
	40	/* Note to read the byte, Set the ReadPtr to Data then read (any addr) */
	41	#define DS2482_CMD_1WIRE_TRIPLET 0x78 /* Param: Dir byte (bit7) */
	42
	43	/* Values for DS2482_CMD_SET_READ_PTR */
	44	#define DS2482_PTR_CODE_STATUS 0xF0
	45	#define DS2482_PTR_CODE_DATA 0xE1
	46	#define DS2482_PTR_CODE_CHANNEL 0xD2 /* DS2482-800 only */
	47	#define DS2482_PTR_CODE_CONFIG 0xC3
	48
	49	/**
	50	* Configure Register bit definitions
	51	* The top 4 bits always read 0.
	52	* To write, the top nibble must be the 1's compl. of the low nibble.
	53	*/
9c95bb6f MA	54	#define DS2482_REG_CFG_1WS 0x08 /* 1-wire speed */
	55	#define DS2482_REG_CFG_SPU 0x04 /* strong pull-up */
	56	#define DS2482_REG_CFG_PPM 0x02 /* presence pulse masking */
	57	#define DS2482_REG_CFG_APU 0x01 /* active pull-up */
baf12ae2 EP	58
	59
	60	/**
	61	* Write and verify codes for the CHANNEL_SELECT command (DS2482-800 only).
	62	* To set the channel, write the value at the index of the channel.
	63	* Read and compare against the corresponding value to verify the change.
	64	*/
	65	static const u8 ds2482_chan_wr[8] =
	66	{ 0xF0, 0xE1, 0xD2, 0xC3, 0xB4, 0xA5, 0x96, 0x87 };
	67	static const u8 ds2482_chan_rd[8] =
	68	{ 0xB8, 0xB1, 0xAA, 0xA3, 0x9C, 0x95, 0x8E, 0x87 };
	69
	70
	71	/**
	72	* Status Register bit definitions (read only)
	73	*/
	74	#define DS2482_REG_STS_DIR 0x80
	75	#define DS2482_REG_STS_TSB 0x40
	76	#define DS2482_REG_STS_SBR 0x20
	77	#define DS2482_REG_STS_RST 0x10
	78	#define DS2482_REG_STS_LL 0x08
	79	#define DS2482_REG_STS_SD 0x04
	80	#define DS2482_REG_STS_PPD 0x02
	81	#define DS2482_REG_STS_1WB 0x01
	82
	83
61c91f7d JD	84	static int ds2482_probe(struct i2c_client *client,
61c91f7d JD	85	const struct i2c_device_id *id);
61c91f7d	86	static int ds2482_remove(struct i2c_client *client);
baf12ae2 EP	87
	88
	89	/**
	90	* Driver data (common to all clients)
	91	*/
61c91f7d JD	92	static const struct i2c_device_id ds2482_id[] = {
	93	{ "ds2482", 0 },
	94	{ }
	95	};
0dcacd76	96	MODULE_DEVICE_TABLE(i2c, ds2482_id);
61c91f7d	97
baf12ae2 EP	98	static struct i2c_driver ds2482_driver = {
	99	.driver = {
	100	.owner = THIS_MODULE,
	101	.name = "ds2482",
	102	},
61c91f7d JD	103	.probe = ds2482_probe,
	104	.remove = ds2482_remove,
	105	.id_table = ds2482_id,
baf12ae2 EP	106	};
	107
	108	/*
	109	* Client data (each client gets its own)
	110	*/
	111
	112	struct ds2482_data;
	113
	114	struct ds2482_w1_chan {
	115	struct ds2482_data *pdev;
	116	u8 channel;
	117	struct w1_bus_master w1_bm;
	118	};
	119
	120	struct ds2482_data {
61c91f7d	121	struct i2c_client *client;
abd52a13	122	struct mutex access_lock;
baf12ae2 EP	123
	124	/* 1-wire interface(s) */
	125	int w1_count; /* 1 or 8 */
	126	struct ds2482_w1_chan w1_ch[8];
	127
	128	/* per-device values */
	129	u8 channel;
	130	u8 read_prt; /* see DS2482_PTR_CODE_xxx */
	131	u8 reg_config;
	132	};
	133
	134
9c95bb6f MA	135	/**
	136	* Helper to calculate values for configuration register
	137	* @param conf the raw config value
	138	* @return the value w/ complements that can be written to register
	139	*/
	140	static inline u8 ds2482_calculate_config(u8 conf)
	141	{
	142	return conf \| ((~conf & 0x0f) << 4);
	143	}
	144
	145
baf12ae2 EP	146	/**
	147	* Sets the read pointer.
	148	* @param pdev The ds2482 client pointer
	149	* @param read_ptr see DS2482_PTR_CODE_xxx above
	150	* @return -1 on failure, 0 on success
	151	*/
	152	static inline int ds2482_select_register(struct ds2482_data *pdev, u8 read_ptr)
	153	{
	154	if (pdev->read_prt != read_ptr) {
61c91f7d	155	if (i2c_smbus_write_byte_data(pdev->client,
baf12ae2 EP	156	DS2482_CMD_SET_READ_PTR,
	157	read_ptr) < 0)
	158	return -1;
	159
	160	pdev->read_prt = read_ptr;
	161	}
	162	return 0;
	163	}
	164
	165	/**
	166	* Sends a command without a parameter
	167	* @param pdev The ds2482 client pointer
	168	* @param cmd DS2482_CMD_RESET,
	169	* DS2482_CMD_1WIRE_RESET,
	170	* DS2482_CMD_1WIRE_READ_BYTE
	171	* @return -1 on failure, 0 on success
	172	*/
	173	static inline int ds2482_send_cmd(struct ds2482_data *pdev, u8 cmd)
	174	{
61c91f7d	175	if (i2c_smbus_write_byte(pdev->client, cmd) < 0)
baf12ae2 EP	176	return -1;
	177
	178	pdev->read_prt = DS2482_PTR_CODE_STATUS;
	179	return 0;
	180	}
	181
	182	/**
	183	* Sends a command with a parameter
	184	* @param pdev The ds2482 client pointer
	185	* @param cmd DS2482_CMD_WRITE_CONFIG,
	186	* DS2482_CMD_1WIRE_SINGLE_BIT,
	187	* DS2482_CMD_1WIRE_WRITE_BYTE,
	188	* DS2482_CMD_1WIRE_TRIPLET
	189	* @param byte The data to send
	190	* @return -1 on failure, 0 on success
	191	*/
	192	static inline int ds2482_send_cmd_data(struct ds2482_data *pdev,
	193	u8 cmd, u8 byte)
	194	{
61c91f7d	195	if (i2c_smbus_write_byte_data(pdev->client, cmd, byte) < 0)
baf12ae2 EP	196	return -1;
	197
	198	/* all cmds leave in STATUS, except CONFIG */
	199	pdev->read_prt = (cmd != DS2482_CMD_WRITE_CONFIG) ?
	200	DS2482_PTR_CODE_STATUS : DS2482_PTR_CODE_CONFIG;
	201	return 0;
	202	}
	203
	204
	205	/*
	206	* 1-Wire interface code
	207	*/
	208
	209	#define DS2482_WAIT_IDLE_TIMEOUT 100
	210
	211	/**
	212	* Waits until the 1-wire interface is idle (not busy)
	213	*
	214	* @param pdev Pointer to the device structure
	215	* @return the last value read from status or -1 (failure)
	216	*/
	217	static int ds2482_wait_1wire_idle(struct ds2482_data *pdev)
	218	{
	219	int temp = -1;
	220	int retries = 0;
	221
	222	if (!ds2482_select_register(pdev, DS2482_PTR_CODE_STATUS)) {
	223	do {
61c91f7d	224	temp = i2c_smbus_read_byte(pdev->client);
baf12ae2	225	} while ((temp >= 0) && (temp & DS2482_REG_STS_1WB) &&
b4786f18	226	(++retries < DS2482_WAIT_IDLE_TIMEOUT));
baf12ae2 EP	227	}
baf12ae2 EP	228
67860739	229	if (retries >= DS2482_WAIT_IDLE_TIMEOUT)
1fda5690	230	pr_err("%s: timeout on channel %d\n",
baf12ae2 EP	231	__func__, pdev->channel);
	232
	233	return temp;
	234	}
	235
	236	/**
	237	* Selects a w1 channel.
	238	* The 1-wire interface must be idle before calling this function.
	239	*
	240	* @param pdev The ds2482 client pointer
	241	* @param channel 0-7
	242	* @return -1 (failure) or 0 (success)
	243	*/
	244	static int ds2482_set_channel(struct ds2482_data *pdev, u8 channel)
	245	{
61c91f7d	246	if (i2c_smbus_write_byte_data(pdev->client, DS2482_CMD_CHANNEL_SELECT,
baf12ae2 EP	247	ds2482_chan_wr[channel]) < 0)
	248	return -1;
	249
	250	pdev->read_prt = DS2482_PTR_CODE_CHANNEL;
	251	pdev->channel = -1;
61c91f7d	252	if (i2c_smbus_read_byte(pdev->client) == ds2482_chan_rd[channel]) {
baf12ae2 EP	253	pdev->channel = channel;
	254	return 0;
	255	}
	256	return -1;
	257	}
	258
	259
	260	/**
	261	* Performs the touch-bit function, which writes a 0 or 1 and reads the level.
	262	*
	263	* @param data The ds2482 channel pointer
	264	* @param bit The level to write: 0 or non-zero
	265	* @return The level read: 0 or 1
	266	*/
	267	static u8 ds2482_w1_touch_bit(void *data, u8 bit)
	268	{
	269	struct ds2482_w1_chan *pchan = data;
	270	struct ds2482_data *pdev = pchan->pdev;
	271	int status = -1;
	272
abd52a13	273	mutex_lock(&pdev->access_lock);
baf12ae2 EP	274
	275	/* Select the channel */
	276	ds2482_wait_1wire_idle(pdev);
	277	if (pdev->w1_count > 1)
	278	ds2482_set_channel(pdev, pchan->channel);
	279
	280	/* Send the touch command, wait until 1WB == 0, return the status */
	281	if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_SINGLE_BIT,
	282	bit ? 0xFF : 0))
	283	status = ds2482_wait_1wire_idle(pdev);
	284
abd52a13	285	mutex_unlock(&pdev->access_lock);
baf12ae2 EP	286
	287	return (status & DS2482_REG_STS_SBR) ? 1 : 0;
	288	}
	289
	290	/**
	291	* Performs the triplet function, which reads two bits and writes a bit.
	292	* The bit written is determined by the two reads:
	293	* 00 => dbit, 01 => 0, 10 => 1
	294	*
	295	* @param data The ds2482 channel pointer
	296	* @param dbit The direction to choose if both branches are valid
	297	* @return b0=read1 b1=read2 b3=bit written
	298	*/
	299	static u8 ds2482_w1_triplet(void *data, u8 dbit)
	300	{
	301	struct ds2482_w1_chan *pchan = data;
	302	struct ds2482_data *pdev = pchan->pdev;
	303	int status = (3 << 5);
	304
abd52a13	305	mutex_lock(&pdev->access_lock);
baf12ae2 EP	306
	307	/* Select the channel */
	308	ds2482_wait_1wire_idle(pdev);
	309	if (pdev->w1_count > 1)
	310	ds2482_set_channel(pdev, pchan->channel);
	311
	312	/* Send the triplet command, wait until 1WB == 0, return the status */
	313	if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_TRIPLET,
	314	dbit ? 0xFF : 0))
	315	status = ds2482_wait_1wire_idle(pdev);
	316
abd52a13	317	mutex_unlock(&pdev->access_lock);
baf12ae2 EP	318
	319	/* Decode the status */
	320	return (status >> 5);
	321	}
	322
	323	/**
	324	* Performs the write byte function.
	325	*
	326	* @param data The ds2482 channel pointer
	327	* @param byte The value to write
	328	*/
	329	static void ds2482_w1_write_byte(void *data, u8 byte)
	330	{
	331	struct ds2482_w1_chan *pchan = data;
	332	struct ds2482_data *pdev = pchan->pdev;
	333
abd52a13	334	mutex_lock(&pdev->access_lock);
baf12ae2 EP	335
	336	/* Select the channel */
	337	ds2482_wait_1wire_idle(pdev);
	338	if (pdev->w1_count > 1)
	339	ds2482_set_channel(pdev, pchan->channel);
	340
	341	/* Send the write byte command */
	342	ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_WRITE_BYTE, byte);
	343
abd52a13	344	mutex_unlock(&pdev->access_lock);
baf12ae2 EP	345	}
	346
	347	/**
	348	* Performs the read byte function.
	349	*
	350	* @param data The ds2482 channel pointer
	351	* @return The value read
	352	*/
	353	static u8 ds2482_w1_read_byte(void *data)
	354	{
	355	struct ds2482_w1_chan *pchan = data;
	356	struct ds2482_data *pdev = pchan->pdev;
	357	int result;
	358
abd52a13	359	mutex_lock(&pdev->access_lock);
baf12ae2 EP	360
	361	/* Select the channel */
	362	ds2482_wait_1wire_idle(pdev);
	363	if (pdev->w1_count > 1)
	364	ds2482_set_channel(pdev, pchan->channel);
	365
	366	/* Send the read byte command */
	367	ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_READ_BYTE);
	368
	369	/* Wait until 1WB == 0 */
	370	ds2482_wait_1wire_idle(pdev);
	371
	372	/* Select the data register */
	373	ds2482_select_register(pdev, DS2482_PTR_CODE_DATA);
	374
	375	/* Read the data byte */
61c91f7d	376	result = i2c_smbus_read_byte(pdev->client);
baf12ae2	377
abd52a13	378	mutex_unlock(&pdev->access_lock);
baf12ae2 EP	379
	380	return result;
	381	}
	382
	383
	384	/**
	385	* Sends a reset on the 1-wire interface
	386	*
	387	* @param data The ds2482 channel pointer
	388	* @return 0=Device present, 1=No device present or error
	389	*/
	390	static u8 ds2482_w1_reset_bus(void *data)
	391	{
	392	struct ds2482_w1_chan *pchan = data;
	393	struct ds2482_data *pdev = pchan->pdev;
	394	int err;
	395	u8 retval = 1;
	396
abd52a13	397	mutex_lock(&pdev->access_lock);
baf12ae2 EP	398
	399	/* Select the channel */
	400	ds2482_wait_1wire_idle(pdev);
	401	if (pdev->w1_count > 1)
	402	ds2482_set_channel(pdev, pchan->channel);
	403
	404	/* Send the reset command */
	405	err = ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_RESET);
	406	if (err >= 0) {
	407	/* Wait until the reset is complete */
	408	err = ds2482_wait_1wire_idle(pdev);
	409	retval = !(err & DS2482_REG_STS_PPD);
	410
	411	/* If the chip did reset since detect, re-config it */
	412	if (err & DS2482_REG_STS_RST)
	413	ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
9c95bb6f	414	ds2482_calculate_config(0x00));
baf12ae2 EP	415	}
baf12ae2 EP	416
abd52a13	417	mutex_unlock(&pdev->access_lock);
baf12ae2 EP	418
	419	return retval;
	420	}
	421
9c95bb6f MA	422	static u8 ds2482_w1_set_pullup(void *data, int delay)
	423	{
	424	struct ds2482_w1_chan *pchan = data;
	425	struct ds2482_data *pdev = pchan->pdev;
	426	u8 retval = 1;
	427
	428	/* if delay is non-zero activate the pullup,
	429	* the strong pullup will be automatically deactivated
	430	* by the master, so do not explicitly deactive it
	431	*/
	432	if (delay) {
	433	/* both waits are crucial, otherwise devices might not be
	434	* powered long enough, causing e.g. a w1_therm sensor to
	435	* provide wrong conversion results
	436	*/
	437	ds2482_wait_1wire_idle(pdev);
	438	/* note: it seems like both SPU and APU have to be set! */
	439	retval = ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
	440	ds2482_calculate_config(DS2482_REG_CFG_SPU \|
	441	DS2482_REG_CFG_APU));
	442	ds2482_wait_1wire_idle(pdev);
	443	}
	444
	445	return retval;
	446	}
	447
baf12ae2	448
61c91f7d JD	449	static int ds2482_probe(struct i2c_client *client,
61c91f7d JD	450	const struct i2c_device_id *id)
baf12ae2 EP	451	{
baf12ae2 EP	452	struct ds2482_data *data;
61c91f7d	453	int err = -ENODEV;
baf12ae2 EP	454	int temp1;
	455	int idx;
	456
0314b020 JD	457	if (!i2c_check_functionality(client->adapter,
	458	I2C_FUNC_SMBUS_WRITE_BYTE_DATA \|
	459	I2C_FUNC_SMBUS_BYTE))
	460	return -ENODEV;
	461
baf12ae2 EP	462	if (!(data = kzalloc(sizeof(struct ds2482_data), GFP_KERNEL))) {
	463	err = -ENOMEM;
	464	goto exit;
	465	}
	466
61c91f7d JD	467	data->client = client;
61c91f7d JD	468	i2c_set_clientdata(client, data);
baf12ae2 EP	469
	470	/* Reset the device (sets the read_ptr to status) */
	471	if (ds2482_send_cmd(data, DS2482_CMD_RESET) < 0) {
61c91f7d	472	dev_warn(&client->dev, "DS2482 reset failed.\n");
baf12ae2 EP	473	goto exit_free;
	474	}
	475
	476	/* Sleep at least 525ns to allow the reset to complete */
	477	ndelay(525);
	478
	479	/* Read the status byte - only reset bit and line should be set */
61c91f7d	480	temp1 = i2c_smbus_read_byte(client);
baf12ae2	481	if (temp1 != (DS2482_REG_STS_LL \| DS2482_REG_STS_RST)) {
61c91f7d JD	482	dev_warn(&client->dev, "DS2482 reset status "
61c91f7d JD	483	"0x%02X - not a DS2482\n", temp1);
baf12ae2 EP	484	goto exit_free;
	485	}
	486
	487	/* Detect the 8-port version */
	488	data->w1_count = 1;
	489	if (ds2482_set_channel(data, 7) == 0)
	490	data->w1_count = 8;
	491
	492	/* Set all config items to 0 (off) */
9c95bb6f MA	493	ds2482_send_cmd_data(data, DS2482_CMD_WRITE_CONFIG,
9c95bb6f MA	494	ds2482_calculate_config(0x00));
baf12ae2	495
abd52a13	496	mutex_init(&data->access_lock);
baf12ae2	497
baf12ae2 EP	498	/* Register 1-wire interface(s) */
	499	for (idx = 0; idx < data->w1_count; idx++) {
	500	data->w1_ch[idx].pdev = data;
	501	data->w1_ch[idx].channel = idx;
	502
	503	/* Populate all the w1 bus master stuff */
	504	data->w1_ch[idx].w1_bm.data = &data->w1_ch[idx];
	505	data->w1_ch[idx].w1_bm.read_byte = ds2482_w1_read_byte;
	506	data->w1_ch[idx].w1_bm.write_byte = ds2482_w1_write_byte;
	507	data->w1_ch[idx].w1_bm.touch_bit = ds2482_w1_touch_bit;
	508	data->w1_ch[idx].w1_bm.triplet = ds2482_w1_triplet;
	509	data->w1_ch[idx].w1_bm.reset_bus = ds2482_w1_reset_bus;
9c95bb6f	510	data->w1_ch[idx].w1_bm.set_pullup = ds2482_w1_set_pullup;
baf12ae2 EP	511
	512	err = w1_add_master_device(&data->w1_ch[idx].w1_bm);
	513	if (err) {
	514	data->w1_ch[idx].pdev = NULL;
	515	goto exit_w1_remove;
	516	}
	517	}
	518
	519	return 0;
	520
	521	exit_w1_remove:
baf12ae2 EP	522	for (idx = 0; idx < data->w1_count; idx++) {
	523	if (data->w1_ch[idx].pdev != NULL)
	524	w1_remove_master_device(&data->w1_ch[idx].w1_bm);
	525	}
	526	exit_free:
	527	kfree(data);
	528	exit:
	529	return err;
	530	}
	531
61c91f7d	532	static int ds2482_remove(struct i2c_client *client)
baf12ae2 EP	533	{
baf12ae2 EP	534	struct ds2482_data *data = i2c_get_clientdata(client);
61c91f7d	535	int idx;
baf12ae2 EP	536
	537	/* Unregister the 1-wire bridge(s) */
	538	for (idx = 0; idx < data->w1_count; idx++) {
	539	if (data->w1_ch[idx].pdev != NULL)
	540	w1_remove_master_device(&data->w1_ch[idx].w1_bm);
	541	}
	542
baf12ae2 EP	543	/* Free the memory */
	544	kfree(data);
	545	return 0;
	546	}
	547
dbfd5ccc	548	module_i2c_driver(ds2482_driver);
baf12ae2 EP	549
	550	MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
	551	MODULE_DESCRIPTION("DS2482 driver");
	552	MODULE_LICENSE("GPL");