+++ /dev/null
-/*
- * i2c.c - driver for ADI TWI/I2C
- *
- * Copyright (c) 2006-2013 Analog Devices Inc.
- *
- * Licensed under the GPL-2 or later.
- */
-
-#include <common.h>
-#include <i2c.h>
-
-#include <asm/clock.h>
-#include <asm/twi.h>
-#include <asm/io.h>
-
-/* Every register is 32bit aligned, but only 16bits in size */
-#define ureg(name) u16 name; u16 __pad_##name;
-struct twi_regs {
- ureg(clkdiv);
- ureg(control);
- ureg(slave_ctl);
- ureg(slave_stat);
- ureg(slave_addr);
- ureg(master_ctl);
- ureg(master_stat);
- ureg(master_addr);
- ureg(int_stat);
- ureg(int_mask);
- ureg(fifo_ctl);
- ureg(fifo_stat);
- char __pad[0x50];
- ureg(xmt_data8);
- ureg(xmt_data16);
- ureg(rcv_data8);
- ureg(rcv_data16);
-};
-#undef ureg
-
-/* U-Boot I2C framework allows only one active device at a time. */
-#ifdef TWI_CLKDIV
-#define TWI0_CLKDIV TWI_CLKDIV
-#endif
-static struct twi_regs *twi = (void *)TWI0_CLKDIV;
-
-#ifdef DEBUG
-# define dmemset(s, c, n) memset(s, c, n)
-#else
-# define dmemset(s, c, n)
-#endif
-#define debugi(fmt, args...) \
- debug( \
- "MSTAT:0x%03x FSTAT:0x%x ISTAT:0x%02x\t%-20s:%-3i: " fmt "\n", \
- twi->master_stat, twi->fifo_stat, twi->int_stat, \
- __func__, __LINE__, ## args)
-
-#ifdef CONFIG_TWICLK_KHZ
-# error do not define CONFIG_TWICLK_KHZ ... use CONFIG_SYS_I2C_SPEED
-#endif
-
-/*
- * The way speed is changed into duty often results in integer truncation
- * with 50% duty, so we'll force rounding up to the next duty by adding 1
- * to the max. In practice this will get us a speed of something like
- * 385 KHz. The other limit is easy to handle as it is only 8 bits.
- */
-#define I2C_SPEED_MAX 400000
-#define I2C_SPEED_TO_DUTY(speed) (5000000 / (speed))
-#define I2C_DUTY_MAX (I2C_SPEED_TO_DUTY(I2C_SPEED_MAX) + 1)
-#define I2C_DUTY_MIN 0xff /* 8 bit limited */
-#define SYS_I2C_DUTY I2C_SPEED_TO_DUTY(CONFIG_SYS_I2C_SPEED)
-/* Note: duty is inverse of speed, so the comparisons below are correct */
-#if SYS_I2C_DUTY < I2C_DUTY_MAX || SYS_I2C_DUTY > I2C_DUTY_MIN
-# error "The Blackfin I2C hardware can only operate 20KHz - 400KHz"
-#endif
-
-/* All transfers are described by this data structure */
-struct i2c_msg {
- u8 flags;
-#define I2C_M_COMBO 0x4
-#define I2C_M_STOP 0x2
-#define I2C_M_READ 0x1
- int len; /* msg length */
- u8 *buf; /* pointer to msg data */
- int alen; /* addr length */
- u8 *abuf; /* addr buffer */
-};
-
-/* Allow msec timeout per ~byte transfer */
-#define I2C_TIMEOUT 10
-
-/**
- * wait_for_completion - manage the actual i2c transfer
- * @msg: the i2c msg
- */
-static int wait_for_completion(struct i2c_msg *msg)
-{
- u16 int_stat, ctl;
- ulong timebase = get_timer(0);
-
- do {
- int_stat = readw(&twi->int_stat);
-
- if (int_stat & XMTSERV) {
- debugi("processing XMTSERV");
- writew(XMTSERV, &twi->int_stat);
- if (msg->alen) {
- writew(*(msg->abuf++), &twi->xmt_data8);
- --msg->alen;
- } else if (!(msg->flags & I2C_M_COMBO) && msg->len) {
- writew(*(msg->buf++), &twi->xmt_data8);
- --msg->len;
- } else {
- ctl = readw(&twi->master_ctl);
- if (msg->flags & I2C_M_COMBO)
- writew(ctl | RSTART | MDIR,
- &twi->master_ctl);
- else
- writew(ctl | STOP, &twi->master_ctl);
- }
- }
- if (int_stat & RCVSERV) {
- debugi("processing RCVSERV");
- writew(RCVSERV, &twi->int_stat);
- if (msg->len) {
- *(msg->buf++) = readw(&twi->rcv_data8);
- --msg->len;
- } else if (msg->flags & I2C_M_STOP) {
- ctl = readw(&twi->master_ctl);
- writew(ctl | STOP, &twi->master_ctl);
- }
- }
- if (int_stat & MERR) {
- debugi("processing MERR");
- writew(MERR, &twi->int_stat);
- return msg->len;
- }
- if (int_stat & MCOMP) {
- debugi("processing MCOMP");
- writew(MCOMP, &twi->int_stat);
- if (msg->flags & I2C_M_COMBO && msg->len) {
- ctl = readw(&twi->master_ctl);
- ctl = (ctl & ~RSTART) |
- (min(msg->len, 0xff) << 6) | MEN | MDIR;
- writew(ctl, &twi->master_ctl);
- } else
- break;
- }
-
- /* If we were able to do something, reset timeout */
- if (int_stat)
- timebase = get_timer(0);
-
- } while (get_timer(timebase) < I2C_TIMEOUT);
-
- return msg->len;
-}
-
-/**
- * i2c_transfer - setup an i2c transfer
- * @return: 0 if things worked, non-0 if things failed
- *
- * Here we just get the i2c stuff all prepped and ready, and then tail off
- * into wait_for_completion() for all the bits to go.
- */
-static int i2c_transfer(uchar chip, uint addr, int alen, uchar *buffer,
- int len, u8 flags)
-{
- int ret;
- u16 ctl;
- uchar addr_buffer[] = {
- (addr >> 0),
- (addr >> 8),
- (addr >> 16),
- };
- struct i2c_msg msg = {
- .flags = flags | (len >= 0xff ? I2C_M_STOP : 0),
- .buf = buffer,
- .len = len,
- .abuf = addr_buffer,
- .alen = alen,
- };
-
- dmemset(buffer, 0xff, len);
- debugi("chip=0x%x addr=0x%02x alen=%i buf[0]=0x%02x len=%i ",
- chip, addr, alen, buffer[0], len);
- debugi("flags=0x%02x[%s] ", flags,
- (flags & I2C_M_READ ? "rd" : "wr"));
-
- /* wait for things to settle */
- while (readw(&twi->master_stat) & BUSBUSY)
- if (ctrlc())
- return 1;
-
- /* Set Transmit device address */
- writew(chip, &twi->master_addr);
-
- /* Clear the FIFO before starting things */
- writew(XMTFLUSH | RCVFLUSH, &twi->fifo_ctl);
- writew(0, &twi->fifo_ctl);
-
- /* prime the pump */
- if (msg.alen) {
- len = (msg.flags & I2C_M_COMBO) ? msg.alen : msg.alen + len;
- debugi("first byte=0x%02x", *msg.abuf);
- writew(*(msg.abuf++), &twi->xmt_data8);
- --msg.alen;
- } else if (!(msg.flags & I2C_M_READ) && msg.len) {
- debugi("first byte=0x%02x", *msg.buf);
- writew(*(msg.buf++), &twi->xmt_data8);
- --msg.len;
- }
-
- /* clear int stat */
- writew(-1, &twi->master_stat);
- writew(-1, &twi->int_stat);
- writew(0, &twi->int_mask);
-
- /* Master enable */
- ctl = readw(&twi->master_ctl);
- ctl = (ctl & FAST) | (min(len, 0xff) << 6) | MEN |
- ((msg.flags & I2C_M_READ) ? MDIR : 0);
- writew(ctl, &twi->master_ctl);
-
- /* process the rest */
- ret = wait_for_completion(&msg);
- debugi("ret=%d", ret);
-
- if (ret) {
- ctl = readw(&twi->master_ctl) & ~MEN;
- writew(ctl, &twi->master_ctl);
- ctl = readw(&twi->control) & ~TWI_ENA;
- writew(ctl, &twi->control);
- ctl = readw(&twi->control) | TWI_ENA;
- writew(ctl, &twi->control);
- }
-
- return ret;
-}
-
-/**
- * i2c_set_bus_speed - set i2c bus speed
- * @speed: bus speed (in HZ)
- */
-int i2c_set_bus_speed(unsigned int speed)
-{
- u16 clkdiv = I2C_SPEED_TO_DUTY(speed);
-
- /* Set TWI interface clock */
- if (clkdiv < I2C_DUTY_MAX || clkdiv > I2C_DUTY_MIN)
- return -1;
- clkdiv = (clkdiv << 8) | (clkdiv & 0xff);
- writew(clkdiv, &twi->clkdiv);
-
- /* Don't turn it on */
- writew(speed > 100000 ? FAST : 0, &twi->master_ctl);
-
- return 0;
-}
-
-/**
- * i2c_get_bus_speed - get i2c bus speed
- * @speed: bus speed (in HZ)
- */
-unsigned int i2c_get_bus_speed(void)
-{
- u16 clkdiv = readw(&twi->clkdiv) & 0xff;
- /* 10 MHz / (2 * CLKDIV) -> 5 MHz / CLKDIV */
- return 5000000 / clkdiv;
-}
-
-/**
- * i2c_init - initialize the i2c bus
- * @speed: bus speed (in HZ)
- * @slaveaddr: address of device in slave mode (0 - not slave)
- *
- * Slave mode isn't actually implemented. It'll stay that way until
- * we get a real request for it.
- */
-void i2c_init(int speed, int slaveaddr)
-{
- u16 prescale = ((get_i2c_clk() / 1000 / 1000 + 5) / 10) & 0x7F;
-
- /* Set TWI internal clock as 10MHz */
- writew(prescale, &twi->control);
-
- /* Set TWI interface clock as specified */
- i2c_set_bus_speed(speed);
-
- /* Enable it */
- writew(TWI_ENA | prescale, &twi->control);
-
- debugi("CONTROL:0x%04x CLKDIV:0x%04x", readw(&twi->control),
- readw(&twi->clkdiv));
-
-#if CONFIG_SYS_I2C_SLAVE
-# error I2C slave support not tested/supported
-#endif
-}
-
-/**
- * i2c_probe - test if a chip exists at a given i2c address
- * @chip: i2c chip addr to search for
- * @return: 0 if found, non-0 if not found
- */
-int i2c_probe(uchar chip)
-{
- u8 byte;
- return i2c_read(chip, 0, 0, &byte, 1);
-}
-
-/**
- * i2c_read - read data from an i2c device
- * @chip: i2c chip addr
- * @addr: memory (register) address in the chip
- * @alen: byte size of address
- * @buffer: buffer to store data read from chip
- * @len: how many bytes to read
- * @return: 0 on success, non-0 on failure
- */
-int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
-{
- return i2c_transfer(chip, addr, alen, buffer,
- len, (alen ? I2C_M_COMBO : I2C_M_READ));
-}
-
-/**
- * i2c_write - write data to an i2c device
- * @chip: i2c chip addr
- * @addr: memory (register) address in the chip
- * @alen: byte size of address
- * @buffer: buffer holding data to write to chip
- * @len: how many bytes to write
- * @return: 0 on success, non-0 on failure
- */
-int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
-{
- return i2c_transfer(chip, addr, alen, buffer, len, 0);
-}
-
-/**
- * i2c_set_bus_num - change active I2C bus
- * @bus: bus index, zero based
- * @returns: 0 on success, non-0 on failure
- */
-int i2c_set_bus_num(unsigned int bus)
-{
- switch (bus) {
-#if CONFIG_SYS_MAX_I2C_BUS > 0
- case 0:
- twi = (void *)TWI0_CLKDIV;
- return 0;
-#endif
-#if CONFIG_SYS_MAX_I2C_BUS > 1
- case 1:
- twi = (void *)TWI1_CLKDIV;
- return 0;
-#endif
-#if CONFIG_SYS_MAX_I2C_BUS > 2
- case 2:
- twi = (void *)TWI2_CLKDIV;
- return 0;
-#endif
- default: return -1;
- }
-}
-
-/**
- * i2c_get_bus_num - returns index of active I2C bus
- */
-unsigned int i2c_get_bus_num(void)
-{
- switch ((unsigned long)twi) {
-#if CONFIG_SYS_MAX_I2C_BUS > 0
- case TWI0_CLKDIV:
- return 0;
-#endif
-#if CONFIG_SYS_MAX_I2C_BUS > 1
- case TWI1_CLKDIV:
- return 1;
-#endif
-#if CONFIG_SYS_MAX_I2C_BUS > 2
- case TWI2_CLKDIV:
- return 2;
-#endif
- default: return -1;
- }
-}
projects / u-boot.git / commitdiff
