From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- arch/cris/arch-v10/drivers/i2c.c | 730 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 730 insertions(+) create mode 100644 arch/cris/arch-v10/drivers/i2c.c (limited to 'arch/cris/arch-v10/drivers/i2c.c') diff --git a/arch/cris/arch-v10/drivers/i2c.c b/arch/cris/arch-v10/drivers/i2c.c new file mode 100644 index 00000000000..8bbe233ba7b --- /dev/null +++ b/arch/cris/arch-v10/drivers/i2c.c @@ -0,0 +1,730 @@ +/*!*************************************************************************** +*! +*! FILE NAME : i2c.c +*! +*! DESCRIPTION: implements an interface for IIC/I2C, both directly from other +*! kernel modules (i2c_writereg/readreg) and from userspace using +*! ioctl()'s +*! +*! Nov 30 1998 Torbjorn Eliasson Initial version. +*! Bjorn Wesen Elinux kernel version. +*! Jan 14 2000 Johan Adolfsson Fixed PB shadow register stuff - +*! don't use PB_I2C if DS1302 uses same bits, +*! use PB. +*! $Log: i2c.c,v $ +*! Revision 1.9 2004/08/24 06:49:14 starvik +*! Whitespace cleanup +*! +*! Revision 1.8 2004/06/08 08:48:26 starvik +*! Removed unused code +*! +*! Revision 1.7 2004/05/28 09:26:59 starvik +*! Modified I2C initialization to work in 2.6. +*! +*! Revision 1.6 2004/05/14 07:58:03 starvik +*! Merge of changes from 2.4 +*! +*! Revision 1.4 2002/12/11 13:13:57 starvik +*! Added arch/ to v10 specific includes +*! Added fix from Linux 2.4 in serial.c (flush_to_flip_buffer) +*! +*! Revision 1.3 2002/11/20 11:56:11 starvik +*! Merge of Linux 2.5.48 +*! +*! Revision 1.2 2002/11/18 13:16:06 starvik +*! Linux 2.5 port of latest 2.4 drivers +*! +*! Revision 1.9 2002/10/31 15:32:26 starvik +*! Update Port B register and shadow even when running with hardware support +*! to avoid glitches when reading bits +*! Never set direction to out in i2c_inbyte +*! Removed incorrect clock togling at end of i2c_inbyte +*! +*! Revision 1.8 2002/08/13 06:31:53 starvik +*! Made SDA and SCL line configurable +*! Modified i2c_inbyte to work with PCF8563 +*! +*! Revision 1.7 2001/04/04 13:11:36 markusl +*! Updated according to review remarks +*! +*! Revision 1.6 2001/03/19 12:43:00 markusl +*! Made some symbols unstatic (used by the eeprom driver) +*! +*! Revision 1.5 2001/02/27 13:52:48 bjornw +*! malloc.h -> slab.h +*! +*! Revision 1.4 2001/02/15 07:17:40 starvik +*! Corrected usage if port_pb_i2c_shadow +*! +*! Revision 1.3 2001/01/26 17:55:13 bjornw +*! * Made I2C_USES_PB_NOT_PB_I2C a CONFIG option instead of assigning it +*! magically. Config.in needs to set it for the options that need it, like +*! Dallas 1302 support. Actually, it should be default since it screws up +*! the PB bits even if you don't use I2C.. +*! * Include linux/config.h to get the above +*! +*! Revision 1.2 2001/01/18 15:49:30 bjornw +*! 2.4 port of I2C including some cleanups (untested of course) +*! +*! Revision 1.1 2001/01/18 15:35:25 bjornw +*! Verbatim copy of the Etrax i2c driver, 2.0 elinux version +*! +*! +*! --------------------------------------------------------------------------- +*! +*! (C) Copyright 1999-2002 Axis Communications AB, LUND, SWEDEN +*! +*!***************************************************************************/ +/* $Id: i2c.c,v 1.9 2004/08/24 06:49:14 starvik Exp $ */ + +/****************** INCLUDE FILES SECTION ***********************************/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include +#include +#include + +#include "i2c.h" + +/****************** I2C DEFINITION SECTION *************************/ + +#define D(x) + +#define I2C_MAJOR 123 /* LOCAL/EXPERIMENTAL */ +static const char i2c_name[] = "i2c"; + +#define CLOCK_LOW_TIME 8 +#define CLOCK_HIGH_TIME 8 +#define START_CONDITION_HOLD_TIME 8 +#define STOP_CONDITION_HOLD_TIME 8 +#define ENABLE_OUTPUT 0x01 +#define ENABLE_INPUT 0x00 +#define I2C_CLOCK_HIGH 1 +#define I2C_CLOCK_LOW 0 +#define I2C_DATA_HIGH 1 +#define I2C_DATA_LOW 0 + +#ifdef CONFIG_ETRAX_I2C_USES_PB_NOT_PB_I2C +/* Use PB and not PB_I2C */ +#ifndef CONFIG_ETRAX_I2C_DATA_PORT +#define CONFIG_ETRAX_I2C_DATA_PORT 0 +#endif +#ifndef CONFIG_ETRAX_I2C_CLK_PORT +#define CONFIG_ETRAX_I2C_CLK_PORT 1 +#endif + +#define SDABIT CONFIG_ETRAX_I2C_DATA_PORT +#define SCLBIT CONFIG_ETRAX_I2C_CLK_PORT +#define i2c_enable() +#define i2c_disable() + +/* enable or disable output-enable, to select output or input on the i2c bus */ + +#define i2c_dir_out() \ + REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, SDABIT, 1) +#define i2c_dir_in() \ + REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, SDABIT, 0) + +/* control the i2c clock and data signals */ + +#define i2c_clk(x) \ + REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, SCLBIT, x) +#define i2c_data(x) \ + REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, SDABIT, x) + +/* read a bit from the i2c interface */ + +#define i2c_getbit() (((*R_PORT_PB_READ & (1 << SDABIT))) >> SDABIT) + +#else +/* enable or disable the i2c interface */ + +#define i2c_enable() *R_PORT_PB_I2C = (port_pb_i2c_shadow |= IO_MASK(R_PORT_PB_I2C, i2c_en)) +#define i2c_disable() *R_PORT_PB_I2C = (port_pb_i2c_shadow &= ~IO_MASK(R_PORT_PB_I2C, i2c_en)) + +/* enable or disable output-enable, to select output or input on the i2c bus */ + +#define i2c_dir_out() \ + *R_PORT_PB_I2C = (port_pb_i2c_shadow &= ~IO_MASK(R_PORT_PB_I2C, i2c_oe_)); \ + REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, 0, 1); +#define i2c_dir_in() \ + *R_PORT_PB_I2C = (port_pb_i2c_shadow |= IO_MASK(R_PORT_PB_I2C, i2c_oe_)); \ + REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, 0, 0); + +/* control the i2c clock and data signals */ + +#define i2c_clk(x) \ + *R_PORT_PB_I2C = (port_pb_i2c_shadow = (port_pb_i2c_shadow & \ + ~IO_MASK(R_PORT_PB_I2C, i2c_clk)) | IO_FIELD(R_PORT_PB_I2C, i2c_clk, (x))); \ + REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, 1, x); + +#define i2c_data(x) \ + *R_PORT_PB_I2C = (port_pb_i2c_shadow = (port_pb_i2c_shadow & \ + ~IO_MASK(R_PORT_PB_I2C, i2c_d)) | IO_FIELD(R_PORT_PB_I2C, i2c_d, (x))); \ + REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, 0, x); + +/* read a bit from the i2c interface */ + +#define i2c_getbit() (*R_PORT_PB_READ & 0x1) +#endif + +/* use the kernels delay routine */ + +#define i2c_delay(usecs) udelay(usecs) + + +/****************** FUNCTION DEFINITION SECTION *************************/ + + +/* generate i2c start condition */ + +void +i2c_start(void) +{ + /* + * SCL=1 SDA=1 + */ + i2c_dir_out(); + i2c_delay(CLOCK_HIGH_TIME/6); + i2c_data(I2C_DATA_HIGH); + i2c_clk(I2C_CLOCK_HIGH); + i2c_delay(CLOCK_HIGH_TIME); + /* + * SCL=1 SDA=0 + */ + i2c_data(I2C_DATA_LOW); + i2c_delay(START_CONDITION_HOLD_TIME); + /* + * SCL=0 SDA=0 + */ + i2c_clk(I2C_CLOCK_LOW); + i2c_delay(CLOCK_LOW_TIME); +} + +/* generate i2c stop condition */ + +void +i2c_stop(void) +{ + i2c_dir_out(); + + /* + * SCL=0 SDA=0 + */ + i2c_clk(I2C_CLOCK_LOW); + i2c_data(I2C_DATA_LOW); + i2c_delay(CLOCK_LOW_TIME*2); + /* + * SCL=1 SDA=0 + */ + i2c_clk(I2C_CLOCK_HIGH); + i2c_delay(CLOCK_HIGH_TIME*2); + /* + * SCL=1 SDA=1 + */ + i2c_data(I2C_DATA_HIGH); + i2c_delay(STOP_CONDITION_HOLD_TIME); + + i2c_dir_in(); +} + +/* write a byte to the i2c interface */ + +void +i2c_outbyte(unsigned char x) +{ + int i; + + i2c_dir_out(); + + for (i = 0; i < 8; i++) { + if (x & 0x80) { + i2c_data(I2C_DATA_HIGH); + } else { + i2c_data(I2C_DATA_LOW); + } + + i2c_delay(CLOCK_LOW_TIME/2); + i2c_clk(I2C_CLOCK_HIGH); + i2c_delay(CLOCK_HIGH_TIME); + i2c_clk(I2C_CLOCK_LOW); + i2c_delay(CLOCK_LOW_TIME/2); + x <<= 1; + } + i2c_data(I2C_DATA_LOW); + i2c_delay(CLOCK_LOW_TIME/2); + + /* + * enable input + */ + i2c_dir_in(); +} + +/* read a byte from the i2c interface */ + +unsigned char +i2c_inbyte(void) +{ + unsigned char aBitByte = 0; + int i; + + /* Switch off I2C to get bit */ + i2c_disable(); + i2c_dir_in(); + i2c_delay(CLOCK_HIGH_TIME/2); + + /* Get bit */ + aBitByte |= i2c_getbit(); + + /* Enable I2C */ + i2c_enable(); + i2c_delay(CLOCK_LOW_TIME/2); + + for (i = 1; i < 8; i++) { + aBitByte <<= 1; + /* Clock pulse */ + i2c_clk(I2C_CLOCK_HIGH); + i2c_delay(CLOCK_HIGH_TIME); + i2c_clk(I2C_CLOCK_LOW); + i2c_delay(CLOCK_LOW_TIME); + + /* Switch off I2C to get bit */ + i2c_disable(); + i2c_dir_in(); + i2c_delay(CLOCK_HIGH_TIME/2); + + /* Get bit */ + aBitByte |= i2c_getbit(); + + /* Enable I2C */ + i2c_enable(); + i2c_delay(CLOCK_LOW_TIME/2); + } + i2c_clk(I2C_CLOCK_HIGH); + i2c_delay(CLOCK_HIGH_TIME); + + /* + * we leave the clock low, getbyte is usually followed + * by sendack/nack, they assume the clock to be low + */ + i2c_clk(I2C_CLOCK_LOW); + return aBitByte; +} + +/*#--------------------------------------------------------------------------- +*# +*# FUNCTION NAME: i2c_getack +*# +*# DESCRIPTION : checks if ack was received from ic2 +*# +*#--------------------------------------------------------------------------*/ + +int +i2c_getack(void) +{ + int ack = 1; + /* + * enable output + */ + i2c_dir_out(); + /* + * Release data bus by setting + * data high + */ + i2c_data(I2C_DATA_HIGH); + /* + * enable input + */ + i2c_dir_in(); + i2c_delay(CLOCK_HIGH_TIME/4); + /* + * generate ACK clock pulse + */ + i2c_clk(I2C_CLOCK_HIGH); + /* + * Use PORT PB instead of I2C + * for input. (I2C not working) + */ + i2c_clk(1); + i2c_data(1); + /* + * switch off I2C + */ + i2c_data(1); + i2c_disable(); + i2c_dir_in(); + /* + * now wait for ack + */ + i2c_delay(CLOCK_HIGH_TIME/2); + /* + * check for ack + */ + if(i2c_getbit()) + ack = 0; + i2c_delay(CLOCK_HIGH_TIME/2); + if(!ack){ + if(!i2c_getbit()) /* receiver pulld SDA low */ + ack = 1; + i2c_delay(CLOCK_HIGH_TIME/2); + } + + /* + * our clock is high now, make sure data is low + * before we enable our output. If we keep data high + * and enable output, we would generate a stop condition. + */ + i2c_data(I2C_DATA_LOW); + + /* + * end clock pulse + */ + i2c_enable(); + i2c_dir_out(); + i2c_clk(I2C_CLOCK_LOW); + i2c_delay(CLOCK_HIGH_TIME/4); + /* + * enable output + */ + i2c_dir_out(); + /* + * remove ACK clock pulse + */ + i2c_data(I2C_DATA_HIGH); + i2c_delay(CLOCK_LOW_TIME/2); + return ack; +} + +/*#--------------------------------------------------------------------------- +*# +*# FUNCTION NAME: I2C::sendAck +*# +*# DESCRIPTION : Send ACK on received data +*# +*#--------------------------------------------------------------------------*/ +void +i2c_sendack(void) +{ + /* + * enable output + */ + i2c_delay(CLOCK_LOW_TIME); + i2c_dir_out(); + /* + * set ack pulse high + */ + i2c_data(I2C_DATA_LOW); + /* + * generate clock pulse + */ + i2c_delay(CLOCK_HIGH_TIME/6); + i2c_clk(I2C_CLOCK_HIGH); + i2c_delay(CLOCK_HIGH_TIME); + i2c_clk(I2C_CLOCK_LOW); + i2c_delay(CLOCK_LOW_TIME/6); + /* + * reset data out + */ + i2c_data(I2C_DATA_HIGH); + i2c_delay(CLOCK_LOW_TIME); + + i2c_dir_in(); +} + +/*#--------------------------------------------------------------------------- +*# +*# FUNCTION NAME: i2c_sendnack +*# +*# DESCRIPTION : Sends NACK on received data +*# +*#--------------------------------------------------------------------------*/ +void +i2c_sendnack(void) +{ + /* + * enable output + */ + i2c_delay(CLOCK_LOW_TIME); + i2c_dir_out(); + /* + * set data high + */ + i2c_data(I2C_DATA_HIGH); + /* + * generate clock pulse + */ + i2c_delay(CLOCK_HIGH_TIME/6); + i2c_clk(I2C_CLOCK_HIGH); + i2c_delay(CLOCK_HIGH_TIME); + i2c_clk(I2C_CLOCK_LOW); + i2c_delay(CLOCK_LOW_TIME); + + i2c_dir_in(); +} + +/*#--------------------------------------------------------------------------- +*# +*# FUNCTION NAME: i2c_writereg +*# +*# DESCRIPTION : Writes a value to an I2C device +*# +*#--------------------------------------------------------------------------*/ +int +i2c_writereg(unsigned char theSlave, unsigned char theReg, + unsigned char theValue) +{ + int error, cntr = 3; + unsigned long flags; + + do { + error = 0; + /* + * we don't like to be interrupted + */ + local_irq_save(flags); + local_irq_disable(); + + i2c_start(); + /* + * send slave address + */ + i2c_outbyte((theSlave & 0xfe)); + /* + * wait for ack + */ + if(!i2c_getack()) + error = 1; + /* + * now select register + */ + i2c_dir_out(); + i2c_outbyte(theReg); + /* + * now it's time to wait for ack + */ + if(!i2c_getack()) + error |= 2; + /* + * send register register data + */ + i2c_outbyte(theValue); + /* + * now it's time to wait for ack + */ + if(!i2c_getack()) + error |= 4; + /* + * end byte stream + */ + i2c_stop(); + /* + * enable interrupt again + */ + local_irq_restore(flags); + + } while(error && cntr--); + + i2c_delay(CLOCK_LOW_TIME); + + return -error; +} + +/*#--------------------------------------------------------------------------- +*# +*# FUNCTION NAME: i2c_readreg +*# +*# DESCRIPTION : Reads a value from the decoder registers. +*# +*#--------------------------------------------------------------------------*/ +unsigned char +i2c_readreg(unsigned char theSlave, unsigned char theReg) +{ + unsigned char b = 0; + int error, cntr = 3; + unsigned long flags; + + do { + error = 0; + /* + * we don't like to be interrupted + */ + local_irq_save(flags); + local_irq_disable(); + /* + * generate start condition + */ + i2c_start(); + + /* + * send slave address + */ + i2c_outbyte((theSlave & 0xfe)); + /* + * wait for ack + */ + if(!i2c_getack()) + error = 1; + /* + * now select register + */ + i2c_dir_out(); + i2c_outbyte(theReg); + /* + * now it's time to wait for ack + */ + if(!i2c_getack()) + error = 1; + /* + * repeat start condition + */ + i2c_delay(CLOCK_LOW_TIME); + i2c_start(); + /* + * send slave address + */ + i2c_outbyte(theSlave | 0x01); + /* + * wait for ack + */ + if(!i2c_getack()) + error = 1; + /* + * fetch register + */ + b = i2c_inbyte(); + /* + * last received byte needs to be nacked + * instead of acked + */ + i2c_sendack(); + /* + * end sequence + */ + i2c_stop(); + /* + * enable interrupt again + */ + local_irq_restore(flags); + + } while(error && cntr--); + + return b; +} + +static int +i2c_open(struct inode *inode, struct file *filp) +{ + return 0; +} + +static int +i2c_release(struct inode *inode, struct file *filp) +{ + return 0; +} + +/* Main device API. ioctl's to write or read to/from i2c registers. + */ + +static int +i2c_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + if(_IOC_TYPE(cmd) != ETRAXI2C_IOCTYPE) { + return -EINVAL; + } + + switch (_IOC_NR(cmd)) { + case I2C_WRITEREG: + /* write to an i2c slave */ + D(printk("i2cw %d %d %d\n", + I2C_ARGSLAVE(arg), + I2C_ARGREG(arg), + I2C_ARGVALUE(arg))); + + return i2c_writereg(I2C_ARGSLAVE(arg), + I2C_ARGREG(arg), + I2C_ARGVALUE(arg)); + case I2C_READREG: + { + unsigned char val; + /* read from an i2c slave */ + D(printk("i2cr %d %d ", + I2C_ARGSLAVE(arg), + I2C_ARGREG(arg))); + val = i2c_readreg(I2C_ARGSLAVE(arg), I2C_ARGREG(arg)); + D(printk("= %d\n", val)); + return val; + } + default: + return -EINVAL; + + } + + return 0; +} + +static struct file_operations i2c_fops = { + .owner = THIS_MODULE, + .ioctl = i2c_ioctl, + .open = i2c_open, + .release = i2c_release, +}; + +int __init +i2c_init(void) +{ + /* Setup and enable the Port B I2C interface */ + +#ifndef CONFIG_ETRAX_I2C_USES_PB_NOT_PB_I2C + *R_PORT_PB_I2C = port_pb_i2c_shadow |= + IO_STATE(R_PORT_PB_I2C, i2c_en, on) | + IO_FIELD(R_PORT_PB_I2C, i2c_d, 1) | + IO_FIELD(R_PORT_PB_I2C, i2c_clk, 1) | + IO_STATE(R_PORT_PB_I2C, i2c_oe_, enable); +#endif + + port_pb_dir_shadow &= ~IO_MASK(R_PORT_PB_DIR, dir0); + port_pb_dir_shadow &= ~IO_MASK(R_PORT_PB_DIR, dir1); + + *R_PORT_PB_DIR = (port_pb_dir_shadow |= + IO_STATE(R_PORT_PB_DIR, dir0, input) | + IO_STATE(R_PORT_PB_DIR, dir1, output)); + + return 0; +} + +static int __init +i2c_register(void) +{ + int res; + + i2c_init(); + res = register_chrdev(I2C_MAJOR, i2c_name, &i2c_fops); + if(res < 0) { + printk(KERN_ERR "i2c: couldn't get a major number.\n"); + return res; + } + + printk(KERN_INFO "I2C driver v2.2, (c) 1999-2001 Axis Communications AB\n"); + + return 0; +} + +/* this makes sure that i2c_register is called during boot */ + +module_init(i2c_register); + +/****************** END OF FILE i2c.c ********************************/ -- cgit v1.2.3