316 lines
7.1 KiB
C
316 lines
7.1 KiB
C
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/*
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* Copyright (c) 2008 Travis Geiselbrecht
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files
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* (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge,
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* publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <debug.h>
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#include <err.h>
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#include <reg.h>
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#include <string.h>
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#include <platform.h>
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#include <platform/omap3.h>
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#define LOCAL_TRACE 0
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#define I2C_TIMEOUT 200
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static const addr_t i2c_reg_base[] = {
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I2C1_BASE,
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I2C2_BASE,
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I2C3_BASE,
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};
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#define I2C_REG_ADDR(bus, reg) (i2c_reg_base[bus] + (reg))
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#define I2C_REG(bus, reg) (*REG16(I2C_REG_ADDR(bus, reg)))
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#define I2C_RMW_REG(bus, reg, startbit, width, val) RMWREG16(I2C_REG_ADDR(bus, reg), startbit, width, val)
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static void i2c_dump_bus(int bus)
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{
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hexdump((void *)i2c_reg_base[bus], 128);
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}
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static void i2c_reset_bus(int bus)
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{
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I2C_REG(bus, I2C_CON) &= ~(1<<15); // make sure the bus is disabled
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/* reset the bus */
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I2C_REG(bus, I2C_SYSC) = (1<<1);
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I2C_REG(bus, I2C_CON) = (1<<15); // enable the bus
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while ((I2C_REG(bus, I2C_SYSS) & 1) == 0)
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;
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/* disable the bus again and set up some internals */
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I2C_REG(bus, I2C_CON) &= ~(1<<15); // make sure the bus is disabled
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/* set up the clock */
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I2C_REG(bus, I2C_PSC) = 23; // 96Mhz / 23 == 4Mhz
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I2C_REG(bus, I2C_SCLL) = 13;
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I2C_REG(bus, I2C_SCLH) = 15; // 4Mhz / combined divider of 40 (13+7 + 15+5) == 100khz
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/* slave address */
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I2C_REG(bus, I2C_OA0) = 1; // XXX made this up
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/* fifo is set to 1 byte trigger */
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I2C_REG(bus, I2C_BUF) = 0;
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/* disable all interrupts */
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I2C_REG(bus, I2C_IE) = 0;
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/* enable the bus */
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I2C_REG(bus, I2C_CON) = (1<<15)|(1<<10)|(1<<9); // enable, master, transmitter mode
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}
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static void i2c_wait_for_bb(int bus)
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{
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I2C_REG(bus, I2C_STAT) = 0xffff; // clear whatever is pending
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while (I2C_REG(bus, I2C_STAT) & (1<<12)) {
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I2C_REG(bus, I2C_STAT) = 0xffff; // clear whatever is pending
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}
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I2C_REG(bus, I2C_STAT) = 0xffff; // clear whatever is pending
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}
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int i2c_transmit(int bus, uint8_t address, const void *buf, size_t count)
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{
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int err;
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LTRACEF("bus %d, address 0x%hhx, buf %p, count %zd\n", bus, address, buf, count);
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i2c_wait_for_bb(bus);
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I2C_REG(bus, I2C_SA) = address;
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I2C_REG(bus, I2C_CNT) = count;
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I2C_REG(bus, I2C_CON) = (1<<15)|(1<<10)|(1<<9)|(1<<1)|(1<<0); // enable, master, transmit, STP, STT
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time_t t = current_time();
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const uint8_t *ptr = (const uint8_t *)buf;
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for(;;) {
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uint16_t stat = I2C_REG(bus, I2C_STAT);
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if (stat & (1<<1)) {
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// NACK
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// printf("NACK\n");
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err = -1;
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goto out;
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}
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if (stat & (1<<0)) {
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// AL (arbitration lost)
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// printf("arbitration lost!\n");
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err = -1;
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goto out;
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}
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if (stat & (1<<2)) {
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// ARDY
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// printf("ARDY, completed\n");
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break;
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}
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if (stat & (1<<4)) {
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// RRDY
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// printf("XRDY\n");
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// transmit a byte
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*REG8(I2C_REG_ADDR(bus, I2C_DATA)) = *ptr;
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ptr++;
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}
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I2C_REG(bus, I2C_STAT) = stat;
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if (current_time() - t > I2C_TIMEOUT) {
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// printf("i2c timeout\n");
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err = ERR_TIMED_OUT;
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goto out;
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}
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}
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err = 0;
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out:
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I2C_REG(bus, I2C_STAT) = 0xffff;
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I2C_REG(bus, I2C_CNT) = 0;
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return err;
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}
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int i2c_receive(int bus, uint8_t address, void *buf, size_t count)
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{
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int err;
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LTRACEF("bus %d, address 0x%hhx, buf %p, count %zd\n", bus, address, buf, count);
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i2c_wait_for_bb(bus);
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I2C_REG(bus, I2C_SA) = address;
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I2C_REG(bus, I2C_CNT) = count;
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I2C_REG(bus, I2C_CON) = (1<<15)|(1<<10)|(1<<1)|(1<<0); // enable, master, STP, STT
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time_t t = current_time();
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uint8_t *ptr = (uint8_t *)buf;
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for(;;) {
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uint16_t stat = I2C_REG(bus, I2C_STAT);
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if (stat & (1<<1)) {
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// NACK
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// printf("NACK\n");
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err = -1;
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goto out;
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}
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if (stat & (1<<0)) {
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// AL (arbitration lost)
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// printf("arbitration lost!\n");
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err = -1;
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goto out;
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}
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if (stat & (1<<2)) {
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// ARDY
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// printf("ARDY, completed\n");
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break;
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}
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if (stat & (1<<3)) {
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// RRDY
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// printf("RRDY\n");
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// read a byte, since our fifo threshold is set to 1 byte
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*ptr = *REG8(I2C_REG_ADDR(bus, I2C_DATA));
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ptr++;
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}
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I2C_REG(bus, I2C_STAT) = stat;
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if (current_time() - t > I2C_TIMEOUT) {
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// printf("i2c timeout\n");
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err = ERR_TIMED_OUT;
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goto out;
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}
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}
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err = 0;
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out:
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I2C_REG(bus, I2C_STAT) = 0xffff;
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I2C_REG(bus, I2C_CNT) = 0;
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return err;
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}
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int i2c_write_reg(int bus, uint8_t address, uint8_t reg, uint8_t val)
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{
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uint8_t buf[2];
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buf[0] = reg;
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buf[1] = val;
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return i2c_transmit(bus, address, buf, 2);
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}
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int i2c_read_reg(int bus, uint8_t address, uint8_t reg, uint8_t *val)
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{
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int err = i2c_transmit(bus, address, ®, 1);
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if (err < 0)
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return err;
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return i2c_receive(bus, address, val, 1);
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}
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void i2c_init_early(void)
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{
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LTRACE_ENTRY;
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/* enable clocks on i2c 0-2 */
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RMWREG32(CM_FCLKEN1_CORE, 15, 3, 0x7),
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RMWREG32(CM_ICLKEN1_CORE, 15, 3, 0x7),
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i2c_reset_bus(0);
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i2c_reset_bus(1);
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i2c_reset_bus(2);
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#if 0
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// write something into a reg
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char buf[2];
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i2c_write_reg(0, 0x4b, 0x14, 0x99);
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i2c_write_reg(0, 0x4b, 0x15, 0x98);
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i2c_read_reg(0, 0x4b, 0x15, buf);
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printf("0x%hhx\n", buf[0]);
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i2c_read_reg(0, 0x4b, 0x14, buf);
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printf("0x%hhx\n", buf[0]);
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int i;
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for (i=0; i < 255; i++) {
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char buf[1];
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buf[0] = i;
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i2c_transmit(0, 0x4b, buf, 1);
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i2c_receive(0, 0x4b, buf, sizeof(buf));
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printf("0x%hhx\n", buf[0]);
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}
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#endif
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LTRACE_EXIT;
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}
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void i2c_init(void)
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{
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}
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#if WITH_LIB_CONSOLE
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#include <lib/console.h>
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static int cmd_i2c(int argc, const cmd_args *argv);
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STATIC_COMMAND_START
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{ "i2c", "i2c read/write commands", &cmd_i2c },
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STATIC_COMMAND_END(i2c);
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static int cmd_i2c(int argc, const cmd_args *argv)
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{
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int err;
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if (argc < 5) {
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printf("not enough arguments\n");
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usage:
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printf("%s read_reg <bus> <i2c address> <register>\n", argv[0].str);
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printf("%s write_reg <bus> <i2c address> <register> <val>\n", argv[0].str);
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return -1;
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}
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int bus = argv[2].u;
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uint8_t i2c_address = argv[3].u;
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if (!strcmp(argv[1].str, "read_reg")) {
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uint8_t reg = argv[4].u;
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uint8_t val;
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err = i2c_read_reg(bus, i2c_address, reg, &val);
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printf("i2c_read_reg err %d, val 0x%hhx\n", err, val);
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} else if (!strcmp(argv[1].str, "write_reg")) {
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uint8_t reg = argv[4].u;
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uint8_t val = argv[5].u;
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err = i2c_write_reg(bus, i2c_address, reg, val);
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printf("i2c_write_reg err %d\n", err);
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} else {
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printf("unrecognized subcommand\n");
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goto usage;
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}
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return 0;
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}
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#endif // WITH_APP_CONSOLE
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