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/*
* Copyright (C) ST-Ericsson SA 2010
*
* Basic U-Boot I2C interface for STn8500/DB8500
* Author: Michael Brandt <Michael.Brandt@stericsson.com> for ST-Ericsson
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Only 7-bit I2C device addresses are supported.
*/
#include <common.h>
#include <i2c.h>
#include "u8500_i2c.h"
#include <asm/io.h>
#include <asm/arch/clock.h>
#define U8500_I2C_ENDAD_COUNTER (CONFIG_SYS_HZ/100) /* I2C bus timeout */
#define U8500_I2C_FIFO_FLUSH_COUNTER 500000 /* flush "timeout" */
#define U8500_I2C_SCL_FREQ 100000 /* I2C bus clock freq */
#define U8500_I2C_INPUT_FREQ 48000000 /* Input clock freq */
#define TX_FIFO_THRESHOLD 0x4
#define RX_FIFO_THRESHOLD 0x4
#define SLAVE_SETUP_TIME 14 /* Slave data setup time, 250ns for 48MHz i2c_clk */
#define WRITE_FIELD(var, mask, shift, value) \
(var = ((var & ~(mask)) | ((value) << (shift))))
static unsigned int bus_initialized[CONFIG_SYS_U8500_I2C_BUS_MAX];
static unsigned int i2c_bus_num;
static unsigned int i2c_bus_speed[] = {
CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SPEED,
CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SPEED
};
static struct u8500_i2c_regs *i2c_dev[] = {
(struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C0_BASE,
(struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C1_BASE,
(struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C2_BASE,
(struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C3_BASE,
};
static struct {
int periph;
int pcken;
int kcken;
} i2c_clock_bits[] = {
{3, 3, 3}, /* I2C0 */
{1, 2, 2}, /* I2C1 */
{1, 6, 6}, /* I2C2 */
{2, 0, 0}, /* I2C3 */
};
static void i2c_set_bit(void *reg, u32 mask)
{
writel(readl(reg) | mask, reg);
}
static void i2c_clr_bit(void *reg, u32 mask)
{
writel(readl(reg) & ~mask, reg);
}
static void i2c_write_field(void *reg, u32 mask, uint shift, u32 value)
{
writel((readl(reg) & ~mask) | (value << shift), reg);
}
static int __i2c_set_bus_speed(unsigned int speed)
{
u32 value;
struct u8500_i2c_regs *i2c_regs;
i2c_regs = i2c_dev[i2c_bus_num];
/* Select standard (100 kbps) speed mode */
i2c_write_field(&i2c_regs->cr, U8500_I2C_CR_SM,
U8500_I2C_CR_SHIFT_SM, 0x0);
/*
* Set the Baud Rate Counter 2 value
* Baud rate (standard) = fi2cclk / ( (BRCNT2 x 2) + Foncycle )
* Foncycle = 0 (no digital filtering)
*/
value = (u32) (U8500_I2C_INPUT_FREQ / (speed * 2));
i2c_write_field(&i2c_regs->brcr, U8500_I2C_BRCR_BRCNT2,
U8500_I2C_BRCR_SHIFT_BRCNT2, value);
/* ensure that BRCNT value is zero */
i2c_write_field(&i2c_regs->brcr, U8500_I2C_BRCR_BRCNT1,
U8500_I2C_BRCR_SHIFT_BRCNT1, 0);
return U8500_I2C_INPUT_FREQ/(value * 2);
}
/*
* i2c_init - initialize the i2c bus
*
* speed: bus speed (in HZ)
* slaveaddr: address of device in slave mode
*
* Slave mode is not implemented.
*/
void i2c_init(int speed, int slaveaddr)
{
struct u8500_i2c_regs *i2c_regs;
debug("i2c_init bus %d, speed %d\n", i2c_bus_num, speed);
u8500_clock_enable(i2c_clock_bits[i2c_bus_num].periph,
i2c_clock_bits[i2c_bus_num].pcken,
i2c_clock_bits[i2c_bus_num].kcken);
i2c_regs = i2c_dev[i2c_bus_num];
/* Disable the controller */
i2c_clr_bit(&i2c_regs->cr, U8500_I2C_CR_PE);
/* Clear registers */
writel(0, &i2c_regs->cr);
writel(0, &i2c_regs->scr);
writel(0, &i2c_regs->hsmcr);
writel(0, &i2c_regs->tftr);
writel(0, &i2c_regs->rftr);
writel(0, &i2c_regs->dmar);
i2c_bus_speed[i2c_bus_num] = __i2c_set_bus_speed(speed);
/*
* Set our own address.
* Set slave address mode to 7 bit addressing mode
*/
i2c_clr_bit(&i2c_regs->cr, U8500_I2C_CR_SAM);
i2c_write_field(&i2c_regs->scr, U8500_I2C_SCR_ADDR,
U8500_I2C_SCR_SHIFT_ADDR, slaveaddr);
/* Slave Data Set up Time */
i2c_write_field(&i2c_regs->scr, U8500_I2C_SCR_DATA_SETUP_TIME,
U8500_I2C_SCR_SHIFT_DATA_SETUP_TIME, SLAVE_SETUP_TIME);
/* Disable the DMA sync logic */
i2c_write_field(&i2c_regs->cr, U8500_I2C_CR_DMA_SLE,
U8500_I2C_CR_SHIFT_DMA_SLE, 0);
/* Disable interrupts */
writel(0, &i2c_regs->imscr);
/* Configure bus master mode */
i2c_write_field(&i2c_regs->cr, U8500_I2C_CR_OM, U8500_I2C_CR_SHIFT_OM,
U8500_I2C_BUS_MASTER_MODE);
/* Set FIFO threshold values */
writel(TX_FIFO_THRESHOLD, &i2c_regs->tftr);
writel(RX_FIFO_THRESHOLD, &i2c_regs->rftr);
/* Enable the I2C Controller */
i2c_set_bit(&i2c_regs->cr, U8500_I2C_CR_PE);
bus_initialized[i2c_bus_num] = 1;
}
/*
* loop_till_bit_clear - polls on a bit till it clears
* ioreg: register where you want to check status
* mask: bit mask for the bit you wish to check
* timeout: timeout in ticks/s
*/
static int loop_till_bit_clear(void *io_reg, u32 mask, unsigned long timeout)
{
unsigned long timebase = get_timer(0);
do {
if ((readl(io_reg) & mask) == 0x0UL)
return 0;
} while (get_timer(timebase) < timeout);
debug("loop_till_bit_clear timed out\n");
return -1;
}
/*
* loop_till_bit_set - polls on a bit till it is set.
* ioreg: register where you want to check status
* mask: bit mask for the bit you wish to check
* timeout: timeout in ticks/s
*/
static int loop_till_bit_set(void *io_reg, u32 mask, unsigned long timeout)
{
unsigned long timebase = get_timer(0);
do {
if ((readl(io_reg) & mask) != 0x0UL)
return 0;
} while (get_timer(timebase) < timeout);
debug("loop_till_bit_set timed out\n");
return -1;
}
/*
* flush_fifo - flush the I2C TX and RX FIFOs
*/
static void flush_fifo(struct u8500_i2c_regs *i2c_regs)
{
int counter = U8500_I2C_FIFO_FLUSH_COUNTER;
/* Flush Tx FIFO */
i2c_set_bit(&i2c_regs->cr, U8500_I2C_CR_FTX);
/* Flush Rx FIFO */
i2c_set_bit(&i2c_regs->cr, U8500_I2C_CR_FRX);
while (counter--) {
if (!(readl(&i2c_regs->cr) &
(U8500_I2C_CR_FTX | U8500_I2C_CR_FRX)))
break;
}
return;
}
#ifdef DEBUG
static void print_abort_reason(struct u8500_i2c_regs *i2c_regs)
{
int cause;
printf("abort: risr %08x, sr %08x\n", i2c_regs->risr, i2c_regs->sr);
cause = (readl(&i2c_regs->sr) & U8500_I2C_SR_CAUSE) >>
U8500_I2C_SR_SHIFT_CAUSE;
switch (cause) {
case U8500_I2C_NACK_ADDR:
printf("No Ack received after Slave Address xmission\n");
break;
case U8500_I2C_NACK_DATA:
printf("Valid for MASTER_WRITE: No Ack received "
"during data phase\n");
break;
case U8500_I2C_ACK_MCODE:
printf("Master recv ack after xmission of master code"
"in hs mode\n");
break;
case U8500_I2C_ARB_LOST:
printf("Master Lost arbitration\n");
break;
case U8500_I2C_BERR_START:
printf("Slave restarts\n");
break;
case U8500_I2C_BERR_STOP:
printf("Slave reset\n");
break;
case U8500_I2C_OVFL:
printf("Overflow\n");
break;
default:
printf("Unknown error type\n");
}
}
#endif
/*
* i2c_abort - called when a I2C transaction failed
*/
static void i2c_abort(struct u8500_i2c_regs *i2c_regs)
{
#ifdef DEBUG
print_abort_reason(i2c_regs);
#endif
/* flush RX and TX fifos */
flush_fifo(i2c_regs);
/* Acknowledge the Master Transaction Done */
i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
/* Acknowledge the Master Transaction Done Without Stop */
i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
i2c_init(i2c_bus_speed[i2c_bus_num], CONFIG_SYS_I2C_SLAVE);
}
/*
* write addr, alias index, to I2C bus.
*/
static int i2c_write_addr(struct u8500_i2c_regs *i2c_regs, uint addr, int alen)
{
while (alen--) {
/* Wait until the Tx Fifo is not full */
if (loop_till_bit_clear((void *)&i2c_regs->risr,
U8500_I2C_INT_TXFF,
U8500_I2C_ENDAD_COUNTER)) {
i2c_abort(i2c_regs);
return -1;
}
/* MSB first */
writeb((addr >> (alen * 8)) & 0xff, &i2c_regs->tfr);
}
return 0;
}
/*
* Internal simplified read function:
* i2c_regs: Pointer to I2C registers for current bus
* chip: I2C chip address, range 0..127
* addr: Memory (register) address within the chip
* alen: Number of bytes to use for addr (typically 1, 2 for larger
* memories, 0 for register type devices with only one register)
* value: Where to put the data
*
* Returns: 0 on success, not 0 on failure
*/
static int i2c_read_byte(struct u8500_i2c_regs *i2c_regs, uchar chip,
uint addr, int alen, uchar *value)
{
u32 mcr = 0;
/* Set the address mode to 7 bit */
WRITE_FIELD(mcr, U8500_I2C_MCR_AM, U8500_I2C_MCR_SHIFT_AM, 1);
/* Store the slave address in the master control register */
WRITE_FIELD(mcr, U8500_I2C_MCR_A7, U8500_I2C_MCR_SHIFT_A7, chip);
if (alen != 0) {
/* Master write operation */
mcr &= ~(U8500_I2C_MCR_OP);
/* Configure the Frame length to one byte */
WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH,
U8500_I2C_MCR_SHIFT_LENGTH, 1);
/* Repeated start, no stop */
mcr &= ~(U8500_I2C_MCR_STOP);
/* Write Master Control Register */
writel(mcr, &i2c_regs->mcr);
/* send addr/index */
if (i2c_write_addr(i2c_regs, addr, alen) != 0)
return -1;
/* Check for the Master Transaction Done Without Stop */
if (loop_till_bit_set((void *)&i2c_regs->risr,
U8500_I2C_INT_MTDWS,
U8500_I2C_ENDAD_COUNTER)) {
return -1;
}
/* Acknowledge the Master Transaction Done Without Stop */
i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
}
/* Master control configuration for read operation */
mcr |= U8500_I2C_MCR_OP;
/* Configure the STOP condition, we read only one byte */
mcr |= U8500_I2C_MCR_STOP;
/* Set the frame length to one byte, we support only 1 byte reads */
WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH, U8500_I2C_MCR_SHIFT_LENGTH, 1);
i2c_write_field(&i2c_regs->mcr, U8500_I2C_MCR_LENGTH_STOP_OP,
U8500_I2C_MCR_SHIFT_LENGTH_STOP_OP, mcr);
/*
* receive_data_polling
*/
/* Wait until the Rx FIFO is not empty */
if (loop_till_bit_clear((void *)&i2c_regs->risr,
U8500_I2C_INT_RXFE,
U8500_I2C_ENDAD_COUNTER))
return -1;
/* Read the data byte from Rx FIFO */
*value = readb(&i2c_regs->rfr);
/* Wait until the work is done */
if (loop_till_bit_set((void *)&i2c_regs->risr, U8500_I2C_INT_MTD,
U8500_I2C_ENDAD_COUNTER))
return -1;
/* Acknowledge the Master Transaction Done */
i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
/* If MTD is set, Master Transaction Done Without Stop is set too */
i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
return 0;
}
/*
* Internal simplified write function:
* i2c_regs: Pointer to I2C registers for current bus
* chip: I2C chip address, range 0..127
* addr: Memory (register) address within the chip
* alen: Number of bytes to use for addr (typically 1, 2 for larger
* memories, 0 for register type devices with only one register)
* data: Where to read the data
* len: How many bytes to write
*
* Returns: 0 on success, not 0 on failure
*/
static int __i2c_write(struct u8500_i2c_regs *i2c_regs, u8 chip, uint addr,
int alen, u8 *data, int len)
{
int i;
u32 mcr = 0;
/* Set the address mode to 7 bit */
WRITE_FIELD(mcr, U8500_I2C_MCR_AM, U8500_I2C_MCR_SHIFT_AM, 1);
/* Store the slave address in the master control register */
WRITE_FIELD(mcr, U8500_I2C_MCR_A7, U8500_I2C_MCR_SHIFT_A7, chip);
/* Write operation */
mcr &= ~(U8500_I2C_MCR_OP);
/* Current transaction is terminated by STOP condition */
mcr |= U8500_I2C_MCR_STOP;
/* Frame length: addr byte + len */
WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH, U8500_I2C_MCR_SHIFT_LENGTH,
(alen + len));
/* Write MCR register */
writel(mcr, &i2c_regs->mcr);
if (i2c_write_addr(i2c_regs, addr, alen) != 0)
return -1;
for (i = 0; i < len; i++) {
/* Wait until the Tx FIFO is not full */
if (loop_till_bit_clear((void *)&i2c_regs->risr,
U8500_I2C_INT_TXFF,
U8500_I2C_ENDAD_COUNTER))
return -1;
/* it is a 32 bit register with upper 24 reserved R/O */
writeb(data[i], &i2c_regs->tfr);
}
/* Check for Master Transaction Done */
if (loop_till_bit_set((void *)&i2c_regs->risr,
U8500_I2C_INT_MTD,
U8500_I2C_ENDAD_COUNTER)) {
printf("i2c_write_byte error2: risr %08x\n",
i2c_regs->risr);
return -1;
}
/* Acknowledge Master Transaction Done */
i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
/* Acknowledge Master Transaction Done Without Stop */
i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
return 0;
}
/*
* Probe the given I2C chip address. Returns 0 if a chip responded,
* not 0 on failure.
*/
int i2c_probe(uchar chip)
{
u32 mcr = 0;
struct u8500_i2c_regs *i2c_regs;
if (chip == CONFIG_SYS_I2C_SLAVE)
return 1;
i2c_regs = i2c_dev[i2c_bus_num];
/* Set the address mode to 7 bit */
WRITE_FIELD(mcr, U8500_I2C_MCR_AM, U8500_I2C_MCR_SHIFT_AM, 1);
/* Store the slave address in the master control register */
WRITE_FIELD(mcr, U8500_I2C_MCR_A10, U8500_I2C_MCR_SHIFT_A7, chip);
/* Read operation */
mcr |= U8500_I2C_MCR_OP;
/* Set the frame length to one byte */
WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH, U8500_I2C_MCR_SHIFT_LENGTH, 1);
/* Current transaction is terminated by STOP condition */
mcr |= U8500_I2C_MCR_STOP;
/* Write MCR register */
writel(mcr, &i2c_regs->mcr);
/* Wait until the Rx Fifo is not empty */
if (loop_till_bit_clear((void *)&i2c_regs->risr,
U8500_I2C_INT_RXFE,
U8500_I2C_ENDAD_COUNTER)) {
i2c_abort(i2c_regs);
return -1;
}
flush_fifo(i2c_regs);
/* Acknowledge the Master Transaction Done */
i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
/* Acknowledge the Master Transaction Done Without Stop */
i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
return 0;
}
/*
* Read/Write interface:
* chip: I2C chip address, range 0..127
* addr: Memory (register) address within the chip
* alen: Number of bytes to use for addr (typically 1, 2 for larger
* memories, 0 for register type devices with only one
* register)
* buffer: Where to read/write the data
* len: How many bytes to read/write
*
* Returns: 0 on success, not 0 on failure
*/
int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
int i;
int rc;
struct u8500_i2c_regs *i2c_regs;
if (alen > 2) {
debug("I2C read: addr len %d not supported\n", alen);
return 1;
}
i2c_regs = i2c_dev[i2c_bus_num];
for (i = 0; i < len; i++) {
rc = i2c_read_byte(i2c_regs, chip, addr + i, alen, &buffer[i]);
if (rc != 0) {
debug("I2C read: I/O error: %d\n", rc);
i2c_abort(i2c_regs);
return rc;
}
}
return 0;
}
int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
int rc;
struct u8500_i2c_regs *i2c_regs;
i2c_regs = i2c_dev[i2c_bus_num];
rc = __i2c_write(i2c_regs, chip, addr, alen, buffer,
len);
if (rc != 0) {
debug("I2C write: I/O error\n");
i2c_abort(i2c_regs);
return rc;
}
return 0;
}
int i2c_set_bus_num(unsigned int bus)
{
if (bus > ARRAY_SIZE(i2c_dev) - 1) {
debug("i2c_set_bus_num: only up to bus %d supported\n",
ARRAY_SIZE(i2c_dev)-1);
return -1;
}
i2c_bus_num = bus;
if (!bus_initialized[i2c_bus_num])
i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
return 0;
}
int i2c_set_bus_speed(unsigned int speed)
{
if (speed > U8500_I2C_MAX_STANDARD_SCL) {
debug("i2c_set_bus_speed: only up to %d supported\n",
U8500_I2C_MAX_STANDARD_SCL);
return -1;
}
/* sets as side effect i2c_bus_speed[i2c_bus_num] */
i2c_init(speed, CONFIG_SYS_I2C_SLAVE);
return 0;
}
unsigned int i2c_get_bus_num(void)
{
return i2c_bus_num;
}
unsigned int i2c_get_bus_speed(void)
{
return i2c_bus_speed[i2c_bus_num];
}