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Diffstat (limited to 'arch/arm/cpu/pxa/i2c.c')
| -rw-r--r-- | arch/arm/cpu/pxa/i2c.c | 458 |
1 files changed, 458 insertions, 0 deletions
diff --git a/arch/arm/cpu/pxa/i2c.c b/arch/arm/cpu/pxa/i2c.c new file mode 100644 index 0000000..6b72ba1 --- /dev/null +++ b/arch/arm/cpu/pxa/i2c.c @@ -0,0 +1,458 @@ +/* + * (C) Copyright 2000 + * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it + * + * (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com> + * Marius Groeger <mgroeger@sysgo.de> + * + * (C) Copyright 2003 Pengutronix e.K. + * Robert Schwebel <r.schwebel@pengutronix.de> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + * + * Back ported to the 8xx platform (from the 8260 platform) by + * Murray.Jensen@cmst.csiro.au, 27-Jan-01. + */ + +/* FIXME: this file is PXA255 specific! What about other XScales? */ + +#include <common.h> + +#ifdef CONFIG_HARD_I2C + +/* + * - CONFIG_SYS_I2C_SPEED + * - I2C_PXA_SLAVE_ADDR + */ + +#include <asm/arch/hardware.h> +#include <asm/arch/pxa-regs.h> +#include <i2c.h> + +/*#define DEBUG_I2C 1 /###* activate local debugging output */ +#define I2C_PXA_SLAVE_ADDR 0x1 /* slave pxa unit address */ + +#if (CONFIG_SYS_I2C_SPEED == 400000) +#define I2C_ICR_INIT (ICR_FM | ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE) +#else +#define I2C_ICR_INIT (ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE) +#endif + +#define I2C_ISR_INIT 0x7FF + +#ifdef DEBUG_I2C +#define PRINTD(x) printf x +#else +#define PRINTD(x) +#endif + + +/* Shall the current transfer have a start/stop condition? */ +#define I2C_COND_NORMAL 0 +#define I2C_COND_START 1 +#define I2C_COND_STOP 2 + +/* Shall the current transfer be ack/nacked or being waited for it? */ +#define I2C_ACKNAK_WAITACK 1 +#define I2C_ACKNAK_SENDACK 2 +#define I2C_ACKNAK_SENDNAK 4 + +/* Specify who shall transfer the data (master or slave) */ +#define I2C_READ 0 +#define I2C_WRITE 1 + +/* All transfers are described by this data structure */ +struct i2c_msg { + u8 condition; + u8 acknack; + u8 direction; + u8 data; +}; + + +/** + * i2c_pxa_reset: - reset the host controller + * + */ + +static void i2c_reset( void ) +{ + ICR &= ~ICR_IUE; /* disable unit */ + ICR |= ICR_UR; /* reset the unit */ + udelay(100); + ICR &= ~ICR_IUE; /* disable unit */ +#ifdef CONFIG_CPU_MONAHANS + CKENB |= (CKENB_4_I2C); /* | CKENB_1_PWM1 | CKENB_0_PWM0); */ +#else /* CONFIG_CPU_MONAHANS */ + CKEN |= CKEN14_I2C; /* set the global I2C clock on */ +#endif + ISAR = I2C_PXA_SLAVE_ADDR; /* set our slave address */ + ICR = I2C_ICR_INIT; /* set control register values */ + ISR = I2C_ISR_INIT; /* set clear interrupt bits */ + ICR |= ICR_IUE; /* enable unit */ + udelay(100); +} + + +/** + * i2c_isr_set_cleared: - wait until certain bits of the I2C status register + * are set and cleared + * + * @return: 1 in case of success, 0 means timeout (no match within 10 ms). + */ +static int i2c_isr_set_cleared( unsigned long set_mask, unsigned long cleared_mask ) +{ + int timeout = 10000; + + while( ((ISR & set_mask)!=set_mask) || ((ISR & cleared_mask)!=0) ){ + udelay( 10 ); + if( timeout-- < 0 ) return 0; + } + + return 1; +} + + +/** + * i2c_transfer: - Transfer one byte over the i2c bus + * + * This function can tranfer a byte over the i2c bus in both directions. + * It is used by the public API functions. + * + * @return: 0: transfer successful + * -1: message is empty + * -2: transmit timeout + * -3: ACK missing + * -4: receive timeout + * -5: illegal parameters + * -6: bus is busy and couldn't be aquired + */ +int i2c_transfer(struct i2c_msg *msg) +{ + int ret; + + if (!msg) + goto transfer_error_msg_empty; + + switch(msg->direction) { + + case I2C_WRITE: + + /* check if bus is not busy */ + if (!i2c_isr_set_cleared(0,ISR_IBB)) + goto transfer_error_bus_busy; + + /* start transmission */ + ICR &= ~ICR_START; + ICR &= ~ICR_STOP; + IDBR = msg->data; + if (msg->condition == I2C_COND_START) ICR |= ICR_START; + if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP; + if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK; + if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK; + ICR &= ~ICR_ALDIE; + ICR |= ICR_TB; + + /* transmit register empty? */ + if (!i2c_isr_set_cleared(ISR_ITE,0)) + goto transfer_error_transmit_timeout; + + /* clear 'transmit empty' state */ + ISR |= ISR_ITE; + + /* wait for ACK from slave */ + if (msg->acknack == I2C_ACKNAK_WAITACK) + if (!i2c_isr_set_cleared(0,ISR_ACKNAK)) + goto transfer_error_ack_missing; + break; + + case I2C_READ: + + /* check if bus is not busy */ + if (!i2c_isr_set_cleared(0,ISR_IBB)) + goto transfer_error_bus_busy; + + /* start receive */ + ICR &= ~ICR_START; + ICR &= ~ICR_STOP; + if (msg->condition == I2C_COND_START) ICR |= ICR_START; + if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP; + if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK; + if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK; + ICR &= ~ICR_ALDIE; + ICR |= ICR_TB; + + /* receive register full? */ + if (!i2c_isr_set_cleared(ISR_IRF,0)) + goto transfer_error_receive_timeout; + + msg->data = IDBR; + + /* clear 'receive empty' state */ + ISR |= ISR_IRF; + + break; + + default: + + goto transfer_error_illegal_param; + + } + + return 0; + +transfer_error_msg_empty: + PRINTD(("i2c_transfer: error: 'msg' is empty\n")); + ret = -1; goto i2c_transfer_finish; + +transfer_error_transmit_timeout: + PRINTD(("i2c_transfer: error: transmit timeout\n")); + ret = -2; goto i2c_transfer_finish; + +transfer_error_ack_missing: + PRINTD(("i2c_transfer: error: ACK missing\n")); + ret = -3; goto i2c_transfer_finish; + +transfer_error_receive_timeout: + PRINTD(("i2c_transfer: error: receive timeout\n")); + ret = -4; goto i2c_transfer_finish; + +transfer_error_illegal_param: + PRINTD(("i2c_transfer: error: illegal parameters\n")); + ret = -5; goto i2c_transfer_finish; + +transfer_error_bus_busy: + PRINTD(("i2c_transfer: error: bus is busy\n")); + ret = -6; goto i2c_transfer_finish; + +i2c_transfer_finish: + PRINTD(("i2c_transfer: ISR: 0x%04x\n",ISR)); + i2c_reset(); + return ret; + +} + +/* ------------------------------------------------------------------------ */ +/* API Functions */ +/* ------------------------------------------------------------------------ */ + +void i2c_init(int speed, int slaveaddr) +{ +#ifdef CONFIG_SYS_I2C_INIT_BOARD + /* call board specific i2c bus reset routine before accessing the */ + /* environment, which might be in a chip on that bus. For details */ + /* about this problem see doc/I2C_Edge_Conditions. */ + i2c_init_board(); +#endif +} + + +/** + * i2c_probe: - Test if a chip answers for a given i2c address + * + * @chip: address of the chip which is searched for + * @return: 0 if a chip was found, -1 otherwhise + */ + +int i2c_probe(uchar chip) +{ + struct i2c_msg msg; + + i2c_reset(); + + msg.condition = I2C_COND_START; + msg.acknack = I2C_ACKNAK_WAITACK; + msg.direction = I2C_WRITE; + msg.data = (chip << 1) + 1; + if (i2c_transfer(&msg)) return -1; + + msg.condition = I2C_COND_STOP; + msg.acknack = I2C_ACKNAK_SENDNAK; + msg.direction = I2C_READ; + msg.data = 0x00; + if (i2c_transfer(&msg)) return -1; + + return 0; +} + + +/** + * i2c_read: - Read multiple bytes from an i2c device + * + * The higher level routines take into account that this function is only + * called with len < page length of the device (see configuration file) + * + * @chip: address of the chip which is to be read + * @addr: i2c data address within the chip + * @alen: length of the i2c data address (1..2 bytes) + * @buffer: where to write the data + * @len: how much byte do we want to read + * @return: 0 in case of success + */ + +int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len) +{ + struct i2c_msg msg; + u8 addr_bytes[3]; /* lowest...highest byte of data address */ + int ret; + + PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len)); + + i2c_reset(); + + /* dummy chip address write */ + PRINTD(("i2c_read: dummy chip address write\n")); + msg.condition = I2C_COND_START; + msg.acknack = I2C_ACKNAK_WAITACK; + msg.direction = I2C_WRITE; + msg.data = (chip << 1); + msg.data &= 0xFE; + if ((ret=i2c_transfer(&msg))) return -1; + + /* + * send memory address bytes; + * alen defines how much bytes we have to send. + */ + /*addr &= ((1 << CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)-1); */ + addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF); + addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF); + addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF); + + while (--alen >= 0) { + + PRINTD(("i2c_read: send memory word address byte %1d\n",alen)); + msg.condition = I2C_COND_NORMAL; + msg.acknack = I2C_ACKNAK_WAITACK; + msg.direction = I2C_WRITE; + msg.data = addr_bytes[alen]; + if ((ret=i2c_transfer(&msg))) return -1; + } + + + /* start read sequence */ + PRINTD(("i2c_read: start read sequence\n")); + msg.condition = I2C_COND_START; + msg.acknack = I2C_ACKNAK_WAITACK; + msg.direction = I2C_WRITE; + msg.data = (chip << 1); + msg.data |= 0x01; + if ((ret=i2c_transfer(&msg))) return -1; + + /* read bytes; send NACK at last byte */ + while (len--) { + + if (len==0) { + msg.condition = I2C_COND_STOP; + msg.acknack = I2C_ACKNAK_SENDNAK; + } else { + msg.condition = I2C_COND_NORMAL; + msg.acknack = I2C_ACKNAK_SENDACK; + } + + msg.direction = I2C_READ; + msg.data = 0x00; + if ((ret=i2c_transfer(&msg))) return -1; + + *buffer = msg.data; + PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer)); + buffer++; + + } + + i2c_reset(); + + return 0; +} + + +/** + * i2c_write: - Write multiple bytes to an i2c device + * + * The higher level routines take into account that this function is only + * called with len < page length of the device (see configuration file) + * + * @chip: address of the chip which is to be written + * @addr: i2c data address within the chip + * @alen: length of the i2c data address (1..2 bytes) + * @buffer: where to find the data to be written + * @len: how much byte do we want to read + * @return: 0 in case of success + */ + +int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len) +{ + struct i2c_msg msg; + u8 addr_bytes[3]; /* lowest...highest byte of data address */ + + PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len)); + + i2c_reset(); + + /* chip address write */ + PRINTD(("i2c_write: chip address write\n")); + msg.condition = I2C_COND_START; + msg.acknack = I2C_ACKNAK_WAITACK; + msg.direction = I2C_WRITE; + msg.data = (chip << 1); + msg.data &= 0xFE; + if (i2c_transfer(&msg)) return -1; + + /* + * send memory address bytes; + * alen defines how much bytes we have to send. + */ + addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF); + addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF); + addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF); + + while (--alen >= 0) { + + PRINTD(("i2c_write: send memory word address\n")); + msg.condition = I2C_COND_NORMAL; + msg.acknack = I2C_ACKNAK_WAITACK; + msg.direction = I2C_WRITE; + msg.data = addr_bytes[alen]; + if (i2c_transfer(&msg)) return -1; + } + + /* write bytes; send NACK at last byte */ + while (len--) { + + PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer)); + + if (len==0) + msg.condition = I2C_COND_STOP; + else + msg.condition = I2C_COND_NORMAL; + + msg.acknack = I2C_ACKNAK_WAITACK; + msg.direction = I2C_WRITE; + msg.data = *(buffer++); + + if (i2c_transfer(&msg)) return -1; + + } + + i2c_reset(); + + return 0; + +} + +#endif /* CONFIG_HARD_I2C */ |