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![Simon Glass](/assets/img/avatar_default.png)
Make the driver model I2C API available always, even if driver model is not enabled. This allows for a 'soft' switch-over, where drivers can use the new structures in code which is compiled but not yet used. This makes migration easier in some cases. Fix up the existing drivers which define their own 'struct i2c_msg'. Signed-off-by: Simon Glass <sjg@chromium.org> Acked-by: Heiko Schocher <hs@denx.de>
306 lines
7.3 KiB
C
306 lines
7.3 KiB
C
/*
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* i2c.c - driver for ADI TWI/I2C
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*
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* Copyright (c) 2006-2014 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later.
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*/
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#include <common.h>
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#include <i2c.h>
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#include <asm/clock.h>
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#include <asm/twi.h>
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#include <asm/io.h>
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static struct twi_regs *i2c_get_base(struct i2c_adapter *adap);
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/* Every register is 32bit aligned, but only 16bits in size */
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#define ureg(name) u16 name; u16 __pad_##name;
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struct twi_regs {
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ureg(clkdiv);
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ureg(control);
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ureg(slave_ctl);
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ureg(slave_stat);
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ureg(slave_addr);
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ureg(master_ctl);
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ureg(master_stat);
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ureg(master_addr);
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ureg(int_stat);
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ureg(int_mask);
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ureg(fifo_ctl);
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ureg(fifo_stat);
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char __pad[0x50];
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ureg(xmt_data8);
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ureg(xmt_data16);
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ureg(rcv_data8);
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ureg(rcv_data16);
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};
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#undef ureg
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#ifdef TWI_CLKDIV
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#define TWI0_CLKDIV TWI_CLKDIV
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# ifdef CONFIG_SYS_MAX_I2C_BUS
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# undef CONFIG_SYS_MAX_I2C_BUS
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# endif
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#define CONFIG_SYS_MAX_I2C_BUS 1
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#endif
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/*
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* The way speed is changed into duty often results in integer truncation
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* with 50% duty, so we'll force rounding up to the next duty by adding 1
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* to the max. In practice this will get us a speed of something like
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* 385 KHz. The other limit is easy to handle as it is only 8 bits.
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*/
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#define I2C_SPEED_MAX 400000
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#define I2C_SPEED_TO_DUTY(speed) (5000000 / (speed))
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#define I2C_DUTY_MAX (I2C_SPEED_TO_DUTY(I2C_SPEED_MAX) + 1)
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#define I2C_DUTY_MIN 0xff /* 8 bit limited */
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#define SYS_I2C_DUTY I2C_SPEED_TO_DUTY(CONFIG_SYS_I2C_SPEED)
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/* Note: duty is inverse of speed, so the comparisons below are correct */
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#if SYS_I2C_DUTY < I2C_DUTY_MAX || SYS_I2C_DUTY > I2C_DUTY_MIN
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# error "The I2C hardware can only operate 20KHz - 400KHz"
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#endif
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/* All transfers are described by this data structure */
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struct adi_i2c_msg {
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u8 flags;
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#define I2C_M_COMBO 0x4
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#define I2C_M_STOP 0x2
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#define I2C_M_READ 0x1
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int len; /* msg length */
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u8 *buf; /* pointer to msg data */
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int alen; /* addr length */
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u8 *abuf; /* addr buffer */
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};
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/* Allow msec timeout per ~byte transfer */
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#define I2C_TIMEOUT 10
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/**
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* wait_for_completion - manage the actual i2c transfer
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* @msg: the i2c msg
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*/
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static int wait_for_completion(struct twi_regs *twi, struct adi_i2c_msg *msg)
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{
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u16 int_stat, ctl;
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ulong timebase = get_timer(0);
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do {
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int_stat = readw(&twi->int_stat);
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if (int_stat & XMTSERV) {
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writew(XMTSERV, &twi->int_stat);
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if (msg->alen) {
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writew(*(msg->abuf++), &twi->xmt_data8);
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--msg->alen;
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} else if (!(msg->flags & I2C_M_COMBO) && msg->len) {
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writew(*(msg->buf++), &twi->xmt_data8);
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--msg->len;
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} else {
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ctl = readw(&twi->master_ctl);
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if (msg->flags & I2C_M_COMBO)
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writew(ctl | RSTART | MDIR,
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&twi->master_ctl);
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else
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writew(ctl | STOP, &twi->master_ctl);
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}
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}
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if (int_stat & RCVSERV) {
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writew(RCVSERV, &twi->int_stat);
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if (msg->len) {
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*(msg->buf++) = readw(&twi->rcv_data8);
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--msg->len;
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} else if (msg->flags & I2C_M_STOP) {
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ctl = readw(&twi->master_ctl);
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writew(ctl | STOP, &twi->master_ctl);
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}
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}
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if (int_stat & MERR) {
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writew(MERR, &twi->int_stat);
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return msg->len;
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}
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if (int_stat & MCOMP) {
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writew(MCOMP, &twi->int_stat);
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if (msg->flags & I2C_M_COMBO && msg->len) {
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ctl = readw(&twi->master_ctl);
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ctl = (ctl & ~RSTART) |
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(min(msg->len, 0xff) << 6) | MEN | MDIR;
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writew(ctl, &twi->master_ctl);
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} else
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break;
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}
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/* If we were able to do something, reset timeout */
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if (int_stat)
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timebase = get_timer(0);
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} while (get_timer(timebase) < I2C_TIMEOUT);
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return msg->len;
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}
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static int i2c_transfer(struct i2c_adapter *adap, uint8_t chip, uint addr,
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int alen, uint8_t *buffer, int len, uint8_t flags)
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{
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struct twi_regs *twi = i2c_get_base(adap);
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int ret;
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u16 ctl;
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uchar addr_buffer[] = {
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(addr >> 0),
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(addr >> 8),
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(addr >> 16),
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};
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struct adi_i2c_msg msg = {
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.flags = flags | (len >= 0xff ? I2C_M_STOP : 0),
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.buf = buffer,
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.len = len,
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.abuf = addr_buffer,
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.alen = alen,
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};
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/* wait for things to settle */
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while (readw(&twi->master_stat) & BUSBUSY)
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if (ctrlc())
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return 1;
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/* Set Transmit device address */
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writew(chip, &twi->master_addr);
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/* Clear the FIFO before starting things */
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writew(XMTFLUSH | RCVFLUSH, &twi->fifo_ctl);
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writew(0, &twi->fifo_ctl);
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/* prime the pump */
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if (msg.alen) {
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len = (msg.flags & I2C_M_COMBO) ? msg.alen : msg.alen + len;
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writew(*(msg.abuf++), &twi->xmt_data8);
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--msg.alen;
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} else if (!(msg.flags & I2C_M_READ) && msg.len) {
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writew(*(msg.buf++), &twi->xmt_data8);
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--msg.len;
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}
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/* clear int stat */
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writew(-1, &twi->master_stat);
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writew(-1, &twi->int_stat);
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writew(0, &twi->int_mask);
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/* Master enable */
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ctl = readw(&twi->master_ctl);
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ctl = (ctl & FAST) | (min(len, 0xff) << 6) | MEN |
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((msg.flags & I2C_M_READ) ? MDIR : 0);
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writew(ctl, &twi->master_ctl);
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/* process the rest */
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ret = wait_for_completion(twi, &msg);
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if (ret) {
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ctl = readw(&twi->master_ctl) & ~MEN;
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writew(ctl, &twi->master_ctl);
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ctl = readw(&twi->control) & ~TWI_ENA;
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writew(ctl, &twi->control);
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ctl = readw(&twi->control) | TWI_ENA;
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writew(ctl, &twi->control);
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}
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return ret;
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}
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static uint adi_i2c_setspeed(struct i2c_adapter *adap, uint speed)
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{
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struct twi_regs *twi = i2c_get_base(adap);
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u16 clkdiv = I2C_SPEED_TO_DUTY(speed);
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/* Set TWI interface clock */
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if (clkdiv < I2C_DUTY_MAX || clkdiv > I2C_DUTY_MIN)
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return -1;
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clkdiv = (clkdiv << 8) | (clkdiv & 0xff);
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writew(clkdiv, &twi->clkdiv);
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/* Don't turn it on */
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writew(speed > 100000 ? FAST : 0, &twi->master_ctl);
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return 0;
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}
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static void adi_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
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{
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struct twi_regs *twi = i2c_get_base(adap);
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u16 prescale = ((get_i2c_clk() / 1000 / 1000 + 5) / 10) & 0x7F;
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/* Set TWI internal clock as 10MHz */
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writew(prescale, &twi->control);
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/* Set TWI interface clock as specified */
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i2c_set_bus_speed(speed);
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/* Enable it */
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writew(TWI_ENA | prescale, &twi->control);
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}
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static int adi_i2c_read(struct i2c_adapter *adap, uint8_t chip,
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uint addr, int alen, uint8_t *buffer, int len)
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{
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return i2c_transfer(adap, chip, addr, alen, buffer,
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len, alen ? I2C_M_COMBO : I2C_M_READ);
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}
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static int adi_i2c_write(struct i2c_adapter *adap, uint8_t chip,
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uint addr, int alen, uint8_t *buffer, int len)
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{
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return i2c_transfer(adap, chip, addr, alen, buffer, len, 0);
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}
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static int adi_i2c_probe(struct i2c_adapter *adap, uint8_t chip)
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{
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u8 byte;
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return adi_i2c_read(adap, chip, 0, 0, &byte, 1);
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}
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static struct twi_regs *i2c_get_base(struct i2c_adapter *adap)
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{
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switch (adap->hwadapnr) {
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#if CONFIG_SYS_MAX_I2C_BUS > 2
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case 2:
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return (struct twi_regs *)TWI2_CLKDIV;
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#endif
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#if CONFIG_SYS_MAX_I2C_BUS > 1
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case 1:
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return (struct twi_regs *)TWI1_CLKDIV;
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#endif
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case 0:
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return (struct twi_regs *)TWI0_CLKDIV;
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default:
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printf("wrong hwadapnr: %d\n", adap->hwadapnr);
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}
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return NULL;
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}
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U_BOOT_I2C_ADAP_COMPLETE(adi_i2c0, adi_i2c_init, adi_i2c_probe,
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adi_i2c_read, adi_i2c_write,
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adi_i2c_setspeed,
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CONFIG_SYS_I2C_SPEED,
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0,
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0)
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#if CONFIG_SYS_MAX_I2C_BUS > 1
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U_BOOT_I2C_ADAP_COMPLETE(adi_i2c1, adi_i2c_init, adi_i2c_probe,
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adi_i2c_read, adi_i2c_write,
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adi_i2c_setspeed,
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CONFIG_SYS_I2C_SPEED,
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0,
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1)
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#endif
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#if CONFIG_SYS_MAX_I2C_BUS > 2
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U_BOOT_I2C_ADAP_COMPLETE(adi_i2c2, adi_i2c_init, adi_i2c_probe,
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adi_i2c_read, adi_i2c_write,
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adi_i2c_setspeed,
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CONFIG_SYS_I2C_SPEED,
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0,
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2)
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#endif
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