On Fri, Dec 02, 2005 at 09:34:22AM -0600, Ben Gardner (gardner.ben at gmail.com) wrote: > This patch adds support for the Maxim DS2482-100 and DS2482-800 chips, > which are i2c devices that provide 1 or 8 1-wire masters. Groovy. But there are couple of indentification nitpicks. > I put the code under drivers/i2c/chips, but perhaps it should go under > drivers/w1. > > Signed-off-by: Ben Gardner <bgardner at wabtec.com> > drivers/i2c/chips/Kconfig | 12 > drivers/i2c/chips/Makefile | 1 > drivers/i2c/chips/ds2482.c | 557 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 570 insertions(+) > > Index: linux-2.6.15-rc3-mm1/drivers/i2c/chips/Makefile > =================================================================== > --- linux-2.6.15-rc3-mm1.orig/drivers/i2c/chips/Makefile > +++ linux-2.6.15-rc3-mm1/drivers/i2c/chips/Makefile > @@ -12,6 +12,7 @@ obj-$(CONFIG_SENSORS_PCF8574) += pcf8574 > obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o > obj-$(CONFIG_SENSORS_RTC8564) += rtc8564.o > obj-$(CONFIG_ISP1301_OMAP) += isp1301_omap.o > +obj-$(CONFIG_SENSORS_DS2482) += ds2482.o > obj-$(CONFIG_TPS65010) += tps65010.o > obj-$(CONFIG_RTC_X1205_I2C) += x1205.o > > Index: linux-2.6.15-rc3-mm1/drivers/i2c/chips/ds2482.c > =================================================================== > --- /dev/null > +++ linux-2.6.15-rc3-mm1/drivers/i2c/chips/ds2482.c > @@ -0,0 +1,557 @@ > +/** > + * ds2482.c - provides i2c to w1-master bridge(s) > + * Copyright (C) 2005 Ben Gardner <bgardner at wabtec.com> > + * > + * The DS2482 is a sensor chip made by Dallis 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 > + * > + * 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 <asm/delay.h> > + > +#include "../../w1/w1.h" > +#include "../../w1/w1_int.h" > + > +/** > + * Address is selected using 2 pins, resulting in 4 possible addresses. > + * 0x18, 0x19, 0x1a, 0x1b > + * However, this chip is rare and should not be detected, so use the force > + * module parameter. > + */ > +static 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_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 Indent. > +#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) */ > + > +/** > + * 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) */ > +static u8 ds2482_chan_wr[8] = { 0xF0, 0xE1, 0xD2, 0xC3, 0xB4, 0xA5, 0x96, 0x87}; > +static 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_attach_adapter(struct i2c_adapter *adapter); > +static int ds2482_detect(struct i2c_adapter *adapter, int address, int kind); > +static int ds2482_detach_client(struct i2c_client *client); > + > + > +/** > + * Driver data (common to all clients) > + */ > +static struct i2c_driver ds2482_driver = { > + .owner = THIS_MODULE, > + .name = "ds2482", > + .flags = I2C_DF_NOTIFY, > + .attach_adapter = ds2482_attach_adapter, > + .detach_client = ds2482_detach_client, > +}; > + > +/* > + * 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_bus_master; > +}; > + > +struct ds2482_data { > + struct i2c_client client; > + struct semaphore 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); > + } Indent. I do not know about return(-1), but people will scream when they found if () { only one operator inside the {} block } And if you like return(-1), it is better to use it in all places, not mixing with 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 > + */ > + > + > +/** > + * 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 inline int ds2482_wait_1wire_idle(struct ds2482_data *pdev) > +{ > + int temp = -1; > + 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) ); > + } > + return(temp); > +} Do you really want to read it indefenitely, if there are bus/ds2482 problems? > +/** > + * 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 inline int ds2482_set_channel(struct ds2482_data *pdev, u8 channel) > +{ > + if (channel >= 8) > + return -1; > + > + 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(unsigned long data, u8 bit) > +{ > + struct ds2482_w1_chan *pchan = (struct ds2482_w1_chan *)data; > + struct ds2482_data *pdev = pchan->pdev; > + int status = -1; > + > + down(&pdev->access_lock); > + > + /* Select the channel */ > + ds2482_wait_1wire_idle(pdev); > + if (pdev->w1_count > 1) { > + ds2482_set_channel(pdev, pchan->channel); > + } > + > + if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_SINGLE_BIT, > + bit ? 0xFF : 0)) { > + /* Wait until 1WB == 0, return the status */ > + status = ds2482_wait_1wire_idle(pdev); > + } > + up(&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(unsigned long data, u8 dbit) > +{ > + struct ds2482_w1_chan *pchan = (struct ds2482_w1_chan *)data; > + struct ds2482_data *pdev = pchan->pdev; > + int status=3, result; > + > + down(&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 */ > + if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_TRIPLET, > + dbit ? 0xFF : 0)) { > + /* Wait until 1WB == 0, grab the status */ > + status = ds2482_wait_1wire_idle(pdev); > + } > + up(&pdev->access_lock); > + > + /* Decode the status */ > + result = (status >> 5); > + return(result); > +} > + > +/** > + * Performs the write byte function. > + * > + * @param data The ds2482 channel pointer > + * @param byte The value to write > + */ > +static void ds2482_w1_write_byte(unsigned long data, u8 byte) > +{ > + struct ds2482_w1_chan *pchan = (struct ds2482_w1_chan *)data; > + struct ds2482_data *pdev = pchan->pdev; > + > + down(&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); > + > + up(&pdev->access_lock); > +} > + > +/** > + * Performs the read byte function. > + * > + * @param data The ds2482 channel pointer > + * @return The value read > + */ > +static u8 ds2482_w1_read_byte(unsigned long data) > +{ > + struct ds2482_w1_chan *pchan = (struct ds2482_w1_chan *)data; > + struct ds2482_data *pdev = pchan->pdev; > + int result; > + > + down(&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); > + > + up(&pdev->access_lock); > + > + return((u8)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(unsigned long data) > +{ > + struct ds2482_w1_chan *pchan = (struct ds2482_w1_chan *)data; > + struct ds2482_data *pdev = pchan->pdev; > + int err; > + u8 retval = 1; > + > + down(&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) ? 0 : 1; > + > + /* 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); > + } > + } > + > + up(&pdev->access_lock); > + > + return(retval); > +} > + > + > +/** > + * Called to see if the device exists on an i2c bus. > + */ > +static int ds2482_attach_adapter(struct i2c_adapter *adapter) > +{ > + return(i2c_probe(adapter, &addr_data, ds2482_detect)); > +} > + > + > +/* > + * The following function does more than just detection. If detection > + * succeeds, it also registers the new chip. > + */ > +static int ds2482_detect(struct i2c_adapter *adapter, int address, int kind) > +{ > + struct ds2482_data *data; > + struct i2c_client *new_client; > + int err = 0; > + int temp1; > + int idx; > + > + if ( !i2c_check_functionality(adapter, > + I2C_FUNC_SMBUS_BYTE_DATA | > + I2C_FUNC_SMBUS_BYTE) ) { > + goto exit; > + } > + > + if ( !(data = kmalloc(sizeof(struct ds2482_data), GFP_KERNEL)) ) { > + err = -ENOMEM; > + goto exit; > + } > + memset(data, 0, sizeof(struct ds2482_data)); > + > + new_client = &data->client; > + i2c_set_clientdata(new_client, data); > + new_client->addr = address; > + new_client->adapter = adapter; > + new_client->driver = &ds2482_driver; > + new_client->flags = 0; > + > + /* Reset the device (sets the read_ptr to status) */ > + if ( ds2482_send_cmd(data, DS2482_CMD_RESET) < 0 ) { > + dev_dbg(&adapter->dev, "DS2482 reset failed at 0x%02x.\n", > + address); > + goto exit_free; > + } > + > + /* Sleep at least 525ns to allow the reset to complete */ > + ndelay(525); > + > + /* Read the status byte - expect reset bit and line to be set */ > + temp1 = i2c_smbus_read_byte(new_client); > + if (temp1 != (DS2482_REG_STS_LL | DS2482_REG_STS_RST)) { > + dev_dbg(&adapter->dev, "DS2482 (0x%02x) reset status " > + "0x%02X - not a DS2482\n", address, 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); > + > + /* We can fill in the remaining client fields */ > + sprintf(new_client->name, "ds2482-%d00", data->w1_count); > + > + init_MUTEX(&data->access_lock); > + > + /* Tell the I2C layer a new client has arrived */ > + if ( (err = i2c_attach_client(new_client)) ) > + goto exit_free; > + > + /* 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_bus_master.data = (unsigned long)&data->w1_ch[idx]; > + data->w1_ch[idx].w1_bus_master.read_byte = ds2482_w1_read_byte; > + data->w1_ch[idx].w1_bus_master.write_byte = ds2482_w1_write_byte; > + data->w1_ch[idx].w1_bus_master.touch_bit = ds2482_w1_touch_bit; > + data->w1_ch[idx].w1_bus_master.triplet = ds2482_w1_triplet; > + data->w1_ch[idx].w1_bus_master.reset_bus = ds2482_w1_reset_bus; > + > + err = w1_add_master_device(&data->w1_ch[idx].w1_bus_master); > + 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_bus_master); > + } > + } > +exit_free: > + kfree(data); > +exit: > + return(err); > +} > + > +static int ds2482_detach_client(struct i2c_client *client) > +{ > + struct ds2482_data *data = i2c_get_clientdata(client); > + int err, 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_bus_master); > + } > + } > + > + /* Detach the i2c device */ > + if ( (err = i2c_detach_client(client)) ) { > + dev_err(&client->dev, > + "Client deregistration failed, client not detached.\n"); > + return(err); > + } > + > + /* 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 at wabtec.com>"); > +MODULE_DESCRIPTION("DS2482 driver"); > +MODULE_LICENSE("GPL"); > + > +module_init(sensors_ds2482_init); > +module_exit(sensors_ds2482_exit); > Index: linux-2.6.15-rc3-mm1/drivers/i2c/chips/Kconfig > =================================================================== > --- linux-2.6.15-rc3-mm1.orig/drivers/i2c/chips/Kconfig > +++ linux-2.6.15-rc3-mm1/drivers/i2c/chips/Kconfig > @@ -135,4 +135,16 @@ config RTC_X1205_I2C > This driver can also be built as a module. If so, the module > will be called x1205. > > +config SENSORS_DS2482 > + tristate "Maxim DS2482 I2C to 1-Wire bridge" > + depends on I2C && EXPERIMENTAL > + select W1 "select" is for very small and commond code pathes. You need here depends on I2C && W1 && EXPERIMENTAL > + help > + If you say yes here you get support for the Maxim DS2482 > + I2C to 1-Wire bridge. > + This, obviously, requires the 1-Wire subsystem (W1) > + > + This driver can also be built as a module. If so, the module > + will be called ds2482. > + > endmenu > > > > -- Evgeniy Polyakov
