diff options
Diffstat (limited to 'drivers/nxp/i2c/i2c.c')
| -rw-r--r-- | drivers/nxp/i2c/i2c.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/drivers/nxp/i2c/i2c.c b/drivers/nxp/i2c/i2c.c new file mode 100644 index 0000000..9281409 --- /dev/null +++ b/drivers/nxp/i2c/i2c.c @@ -0,0 +1,257 @@ +/* + * Copyright 2016-2020 NXP + * + * SPDX-License-Identifier: BSD-3-Clause + * + */ + +#include <errno.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> + +#include <common/debug.h> +#include <drivers/delay_timer.h> +#include "i2c.h" +#include <nxp_timer.h> + +static uintptr_t g_nxp_i2c_addr; + +void i2c_init(uintptr_t nxp_i2c_addr) +{ + struct ls_i2c *ccsr_i2c = (void *)nxp_i2c_addr; + + g_nxp_i2c_addr = nxp_i2c_addr; + /* Presume workaround for erratum a009203 applied */ + i2c_out(&ccsr_i2c->cr, I2C_CR_DIS); + i2c_out(&ccsr_i2c->fd, I2C_FD_CONSERV); + i2c_out(&ccsr_i2c->sr, I2C_SR_RST); + i2c_out(&ccsr_i2c->cr, I2C_CR_EN); +} + +static int wait_for_state(struct ls_i2c *ccsr_i2c, + unsigned char state, unsigned char mask) +{ + unsigned char sr; + uint64_t start_time = get_timer_val(0); + uint64_t timer; + + do { + sr = i2c_in(&ccsr_i2c->sr); + if (sr & I2C_SR_AL) { + i2c_out(&ccsr_i2c->sr, sr); + WARN("I2C arbitration lost\n"); + return -EIO; + } + if ((sr & mask) == state) { + return (int)sr; + } + + timer = get_timer_val(start_time); + if (timer > I2C_TIMEOUT) + break; + mdelay(1); + } while (1); + WARN("I2C: Timeout waiting for state 0x%x, sr = 0x%x\n", state, sr); + + return -ETIMEDOUT; +} + +static int tx_byte(struct ls_i2c *ccsr_i2c, unsigned char c) +{ + int ret; + + i2c_out(&ccsr_i2c->sr, I2C_SR_IF); + i2c_out(&ccsr_i2c->dr, c); + ret = wait_for_state(ccsr_i2c, I2C_SR_IF, I2C_SR_IF); + if (ret < 0) { + WARN("%s: state error\n", __func__); + return ret; + } + if (ret & I2C_SR_RX_NAK) { + WARN("%s: nodev\n", __func__); + return -ENODEV; + } + + return 0; +} + +static int gen_stop(struct ls_i2c *ccsr_i2c) +{ + unsigned char cr; + int ret; + + cr = i2c_in(&ccsr_i2c->cr); + cr &= ~(I2C_CR_MA | I2C_CR_TX); + i2c_out(&ccsr_i2c->cr, cr); + ret = wait_for_state(ccsr_i2c, I2C_SR_IDLE, I2C_SR_BB); + if (ret < 0) { + WARN("I2C: Generating stop failed.\n"); + } + return ret; +} + +static int i2c_write_addr(struct ls_i2c *ccsr_i2c, unsigned char chip, + int addr, int alen) +{ + int ret; + unsigned char cr; + + if (alen != 1) { + WARN("I2C: Unsupported address len [%d]\n", alen); + return -EIO; + } + + if (i2c_in(&ccsr_i2c->ad) == (chip << 1)) { + WARN("I2C: slave address same as self\n"); + return -ENODEV; + } + i2c_out(&ccsr_i2c->sr, I2C_SR_IF); + ret = wait_for_state(ccsr_i2c, I2C_SR_IDLE, I2C_SR_BB); + if (ret < 0) { + return ret; + } + + cr = i2c_in(&ccsr_i2c->cr); + cr |= I2C_CR_MA; + i2c_out(&ccsr_i2c->cr, cr); + ret = wait_for_state(ccsr_i2c, I2C_SR_BB, I2C_SR_BB); + if (ret < 0) { + return ret; + } + + VERBOSE("Before writing chip %d\n", chip); + cr |= I2C_CR_TX | I2C_CR_TX_NAK; + i2c_out(&ccsr_i2c->cr, cr); + ret = tx_byte(ccsr_i2c, chip << 1); + if (ret < 0) { + gen_stop(ccsr_i2c); + return ret; + } + + VERBOSE("Before writing addr\n"); + while (alen--) { + ret = tx_byte(ccsr_i2c, (addr >> (alen << 3)) & 0xff); + if (ret < 0) { + gen_stop(ccsr_i2c); + return ret; + } + } + + return 0; +} + +static int read_data(struct ls_i2c *ccsr_i2c, unsigned char chip, + unsigned char *buf, int len) +{ + int i; + int ret; + unsigned char cr; + + cr = i2c_in(&ccsr_i2c->cr); + cr &= ~(I2C_CR_TX | I2C_CR_TX_NAK); + if (len == 1) { + cr |= I2C_CR_TX_NAK; + } + i2c_out(&ccsr_i2c->cr, cr); + i2c_out(&ccsr_i2c->sr, I2C_SR_IF); + i2c_in(&ccsr_i2c->dr); /* dummy read */ + for (i = 0; i < len; i++) { + ret = wait_for_state(ccsr_i2c, I2C_SR_IF, I2C_SR_IF); + if (ret < 0) { + gen_stop(ccsr_i2c); + return ret; + } + if (i == (len - 1)) { + gen_stop(ccsr_i2c); + } else if (i == (len - 2)) { + /* Updating the command to send + * No ACK. + */ + cr = i2c_in(&ccsr_i2c->cr); + cr |= I2C_CR_TX_NAK; + i2c_out(&ccsr_i2c->cr, cr); + } + i2c_out(&ccsr_i2c->sr, I2C_SR_IF); + buf[i] = i2c_in(&ccsr_i2c->dr); + } + + return 0; +} + +static int write_data(struct ls_i2c *ccsr_i2c, unsigned char chip, + const unsigned char *buf, int len) +{ + int i; + int ret; + + for (i = 0; i < len; i++) { + ret = tx_byte(ccsr_i2c, buf[i]); + if (ret < 0) { + break; + } + } + ret = gen_stop(ccsr_i2c); + + return ret; +} + + +int i2c_read(unsigned char chip, int addr, int alen, + unsigned char *buf, int len) +{ + int ret; + unsigned char cr; + struct ls_i2c *ccsr_i2c = (void *)g_nxp_i2c_addr; + + ret = i2c_write_addr(ccsr_i2c, chip, addr, alen); + if (ret < 0) { + gen_stop(ccsr_i2c); + return ret; + } + + cr = i2c_in(&ccsr_i2c->cr); + cr |= I2C_CR_RSTA; + i2c_out(&ccsr_i2c->cr, cr); + + ret = tx_byte(ccsr_i2c, (chip << 1) | 1); + if (ret < 0) { + gen_stop(ccsr_i2c); + return ret; + } + + return read_data(ccsr_i2c, chip, buf, len); +} + +int i2c_write(unsigned char chip, int addr, int alen, + const unsigned char *buf, int len) +{ + int ret; + struct ls_i2c *ccsr_i2c = (void *)g_nxp_i2c_addr; + + ret = i2c_write_addr(ccsr_i2c, chip, addr, alen); + if (ret < 0) { + return ret; + } + + return write_data(ccsr_i2c, chip, buf, len); +} + +int i2c_probe_chip(unsigned char chip) +{ + int ret; + struct ls_i2c *ccsr_i2c = (void *)g_nxp_i2c_addr; + + ret = i2c_write_addr(ccsr_i2c, chip, 0, 0); + if (ret < 0) { + WARN("write addr failed\n"); + return ret; + } + + ret = gen_stop(ccsr_i2c); + if (ret < 0) { + WARN("I2C: Probe not complete.\n"); + } + + return ret; +} |