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/*
* LPC32xx I2C interface driver
*
* (C) Copyright 2014 DENX Software Engineering GmbH
* Written-by: Albert ARIBAUD - 3ADEV <albert.aribaud@3adev.fr>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/io.h>
#include <i2c.h>
#include <asm/errno.h>
#include <asm/arch/clk.h>
/*
* Provide default speed and slave if target did not
*/
#if !defined(CONFIG_SYS_I2C_LPC32XX_SPEED)
#define CONFIG_SYS_I2C_LPC32XX_SPEED 350000
#endif
#if !defined(CONFIG_SYS_I2C_LPC32XX_SLAVE)
#define CONFIG_SYS_I2C_LPC32XX_SLAVE 0
#endif
/* i2c register set */
struct lpc32xx_i2c_registers {
union {
u32 rx;
u32 tx;
};
u32 stat;
u32 ctrl;
u32 clk_hi;
u32 clk_lo;
u32 adr;
u32 rxfl;
u32 txfl;
u32 rxb;
u32 txb;
u32 stx;
u32 stxfl;
};
/* TX register fields */
#define LPC32XX_I2C_TX_START 0x00000100
#define LPC32XX_I2C_TX_STOP 0x00000200
/* Control register values */
#define LPC32XX_I2C_SOFT_RESET 0x00000100
/* Status register values */
#define LPC32XX_I2C_STAT_TFF 0x00000400
#define LPC32XX_I2C_STAT_RFE 0x00000200
#define LPC32XX_I2C_STAT_DRMI 0x00000008
#define LPC32XX_I2C_STAT_NAI 0x00000004
#define LPC32XX_I2C_STAT_TDI 0x00000001
static struct lpc32xx_i2c_registers *lpc32xx_i2c[] = {
(struct lpc32xx_i2c_registers *)I2C1_BASE,
(struct lpc32xx_i2c_registers *)I2C2_BASE
};
/* Set I2C bus speed */
static unsigned int lpc32xx_i2c_set_bus_speed(struct i2c_adapter *adap,
unsigned int speed)
{
int half_period;
if (speed == 0)
return -EINVAL;
half_period = (105000000 / speed) / 2;
if ((half_period > 255) || (half_period < 0))
return -EINVAL;
writel(half_period, &lpc32xx_i2c[adap->hwadapnr]->clk_hi);
writel(half_period, &lpc32xx_i2c[adap->hwadapnr]->clk_lo);
return 0;
}
/* I2C init called by cmd_i2c when doing 'i2c reset'. */
static void _i2c_init(struct i2c_adapter *adap,
int requested_speed, int slaveadd)
{
struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
/* soft reset (auto-clears) */
writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
/* set HI and LO periods for about 350 kHz */
lpc32xx_i2c_set_bus_speed(adap, requested_speed);
}
/* I2C probe called by cmd_i2c when doing 'i2c probe'. */
static int lpc32xx_i2c_probe(struct i2c_adapter *adap, u8 dev)
{
struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
int stat;
/* Soft-reset the controller */
writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
while (readl(&i2c->ctrl) & LPC32XX_I2C_SOFT_RESET)
;
/* Addre slave for write with start before and stop after */
writel((dev<<1) | LPC32XX_I2C_TX_START | LPC32XX_I2C_TX_STOP,
&i2c->tx);
/* wait for end of transation */
while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
;
/* was there no acknowledge? */
return (stat & LPC32XX_I2C_STAT_NAI) ? -1 : 0;
}
/*
* I2C read called by cmd_i2c when doing 'i2c read' and by cmd_eeprom.c
* Begin write, send address byte(s), begin read, receive data bytes, end.
*/
static int lpc32xx_i2c_read(struct i2c_adapter *adap, u8 dev, uint addr,
int alen, u8 *data, int length)
{
struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
int stat, wlen;
/* Soft-reset the controller */
writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
while (readl(&i2c->ctrl) & LPC32XX_I2C_SOFT_RESET)
;
/* do we need to write an address at all? */
if (alen) {
/* Address slave in write mode */
writel((dev<<1) | LPC32XX_I2C_TX_START, &i2c->tx);
/* write address bytes */
while (alen--) {
/* compute address byte + stop for the last one */
int a = (addr >> (8 * alen)) & 0xff;
if (!alen)
a |= LPC32XX_I2C_TX_STOP;
/* Send address byte */
writel(a, &i2c->tx);
}
/* wait for end of transation */
while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
;
/* clear end-of-transaction flag */
writel(1, &i2c->stat);
}
/* do we have to read data at all? */
if (length) {
/* Address slave in read mode */
writel(1 | (dev<<1) | LPC32XX_I2C_TX_START, &i2c->tx);
wlen = length;
/* get data */
while (length | wlen) {
/* read status for TFF and RFE */
stat = readl(&i2c->stat);
/* must we, can we write a trigger byte? */
if ((wlen > 0)
& (!(stat & LPC32XX_I2C_STAT_TFF))) {
wlen--;
/* write trigger byte + stop if last */
writel(wlen ? 0 :
LPC32XX_I2C_TX_STOP, &i2c->tx);
}
/* must we, can we read a data byte? */
if ((length > 0)
& (!(stat & LPC32XX_I2C_STAT_RFE))) {
length--;
/* read byte */
*(data++) = readl(&i2c->rx);
}
}
}
/* wait for end of transation */
while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
;
/* clear end-of-transaction flag */
writel(1, &i2c->stat);
/* success */
return 0;
}
/*
* I2C write called by cmd_i2c when doing 'i2c write' and by cmd_eeprom.c
* Begin write, send address byte(s), send data bytes, end.
*/
static int lpc32xx_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr,
int alen, u8 *data, int length)
{
struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
int stat;
/* Soft-reset the controller */
writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
while (readl(&i2c->ctrl) & LPC32XX_I2C_SOFT_RESET)
;
/* do we need to write anything at all? */
if (alen | length)
/* Address slave in write mode */
writel((dev<<1) | LPC32XX_I2C_TX_START, &i2c->tx);
/* write address bytes */
while (alen) {
/* wait for transmit fifo not full */
stat = readl(&i2c->stat);
if (!(stat & LPC32XX_I2C_STAT_TFF)) {
alen--;
int a = (addr >> (8 * alen)) & 0xff;
if (!(alen | length))
a |= LPC32XX_I2C_TX_STOP;
/* Send address byte */
writel(a, &i2c->tx);
}
}
while (length) {
/* wait for transmit fifo not full */
stat = readl(&i2c->stat);
if (!(stat & LPC32XX_I2C_STAT_TFF)) {
/* compute data byte, add stop if length==0 */
length--;
int d = *(data++);
if (!length)
d |= LPC32XX_I2C_TX_STOP;
/* Send data byte */
writel(d, &i2c->tx);
}
}
/* wait for end of transation */
while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
;
/* clear end-of-transaction flag */
writel(1, &i2c->stat);
return 0;
}
U_BOOT_I2C_ADAP_COMPLETE(lpc32xx_0, _i2c_init, lpc32xx_i2c_probe,
lpc32xx_i2c_read, lpc32xx_i2c_write,
lpc32xx_i2c_set_bus_speed,
CONFIG_SYS_I2C_LPC32XX_SPEED,
CONFIG_SYS_I2C_LPC32XX_SLAVE,
0)
U_BOOT_I2C_ADAP_COMPLETE(lpc32xx_1, _i2c_init, lpc32xx_i2c_probe,
lpc32xx_i2c_read, lpc32xx_i2c_write,
lpc32xx_i2c_set_bus_speed,
CONFIG_SYS_I2C_LPC32XX_SPEED,
CONFIG_SYS_I2C_LPC32XX_SLAVE,
1)
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