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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2021 Nuvoton Technology Corp.
*/
#include <clk.h>
#include <dm.h>
#include <i2c.h>
#include <asm/io.h>
#include <linux/iopoll.h>
#include <asm/arch/gcr.h>
#define I2C_FREQ_100K 100000
#define NPCM_I2C_TIMEOUT_MS 10
#define NPCM7XX_I2CSEGCTL_INIT_VAL 0x0333F000
#define NPCM8XX_I2CSEGCTL_INIT_VAL 0x9333F000
/* SCLFRQ min/max field values */
#define SCLFRQ_MIN 10
#define SCLFRQ_MAX 511
/* SMBCTL1 */
#define SMBCTL1_START BIT(0)
#define SMBCTL1_STOP BIT(1)
#define SMBCTL1_INTEN BIT(2)
#define SMBCTL1_ACK BIT(4)
#define SMBCTL1_STASTRE BIT(7)
/* SMBCTL2 */
#define SMBCTL2_ENABLE BIT(0)
/* SMBCTL3 */
#define SMBCTL3_SCL_LVL BIT(7)
#define SMBCTL3_SDA_LVL BIT(6)
/* SMBCST */
#define SMBCST_BB BIT(1)
#define SMBCST_TGSCL BIT(5)
/* SMBST */
#define SMBST_XMIT BIT(0)
#define SMBST_MASTER BIT(1)
#define SMBST_STASTR BIT(3)
#define SMBST_NEGACK BIT(4)
#define SMBST_BER BIT(5)
#define SMBST_SDAST BIT(6)
/* SMBCST3 in bank0 */
#define SMBCST3_EO_BUSY BIT(7)
/* SMBFIF_CTS in bank1 */
#define SMBFIF_CTS_CLR_FIFO BIT(6)
#define SMBFIF_CTL_FIFO_EN BIT(4)
#define SMBCTL3_BNK_SEL BIT(5)
enum {
I2C_ERR_NACK = 1,
I2C_ERR_BER,
I2C_ERR_TIMEOUT,
};
struct smb_bank0_regs {
u8 addr3;
u8 addr7;
u8 addr4;
u8 addr8;
u16 addr5;
u16 addr6;
u8 cst2;
u8 cst3;
u8 ctl4;
u8 ctl5;
u8 scllt;
u8 fif_ctl;
u8 sclht;
};
struct smb_bank1_regs {
u8 fif_cts;
u8 fair_per;
u16 txf_ctl;
u32 t_out;
u8 cst2;
u8 cst3;
u16 txf_sts;
u16 rxf_sts;
u8 rxf_ctl;
};
struct npcm_i2c_regs {
u16 sda;
u16 st;
u16 cst;
u16 ctl1;
u16 addr;
u16 ctl2;
u16 addr2;
u16 ctl3;
union {
struct smb_bank0_regs bank0;
struct smb_bank1_regs bank1;
};
};
struct npcm_i2c_bus {
struct npcm_i2c_regs *reg;
int num;
u32 apb_clk;
u32 freq;
bool started;
};
static void npcm_dump_regs(struct npcm_i2c_bus *bus)
{
struct npcm_i2c_regs *reg = bus->reg;
printf("\n");
printf("SMBST=0x%x\n", readb(&reg->st));
printf("SMBCST=0x%x\n", readb(&reg->cst));
printf("SMBCTL1=0x%x\n", readb(&reg->ctl1));
printf("\n");
}
static int npcm_i2c_check_sda(struct npcm_i2c_bus *bus)
{
struct npcm_i2c_regs *reg = bus->reg;
ulong start_time;
int err = I2C_ERR_TIMEOUT;
u8 val;
start_time = get_timer(0);
/* wait SDAST to be 1 */
while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
val = readb(&reg->st);
if (val & SMBST_NEGACK) {
err = I2C_ERR_NACK;
break;
}
if (val & SMBST_BER) {
err = I2C_ERR_BER;
break;
}
if (val & SMBST_SDAST) {
err = 0;
break;
}
}
if (err)
printf("%s: err %d\n", __func__, err);
return err;
}
static int npcm_i2c_send_start(struct npcm_i2c_bus *bus)
{
struct npcm_i2c_regs *reg = bus->reg;
ulong start_time;
int err = I2C_ERR_TIMEOUT;
/* Generate START condition */
setbits_8(&reg->ctl1, SMBCTL1_START);
start_time = get_timer(0);
while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
if (readb(&reg->st) & SMBST_BER)
return I2C_ERR_BER;
if (readb(&reg->st) & SMBST_MASTER) {
err = 0;
break;
}
}
bus->started = true;
return err;
}
static int npcm_i2c_send_stop(struct npcm_i2c_bus *bus, bool wait)
{
struct npcm_i2c_regs *reg = bus->reg;
ulong start_time;
int err = I2C_ERR_TIMEOUT;
setbits_8(&reg->ctl1, SMBCTL1_STOP);
/* Clear NEGACK, STASTR and BER bits */
writeb(SMBST_STASTR | SMBST_NEGACK | SMBST_BER, &reg->st);
bus->started = false;
if (!wait)
return 0;
start_time = get_timer(0);
while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
if ((readb(&reg->ctl1) & SMBCTL1_STOP) == 0) {
err = 0;
break;
}
}
if (err) {
printf("%s: err %d\n", __func__, err);
npcm_dump_regs(bus);
}
return err;
}
static void npcm_i2c_reset(struct npcm_i2c_bus *bus)
{
struct npcm_i2c_regs *reg = bus->reg;
debug("%s: module %d\n", __func__, bus->num);
/* disable & enable SMB moudle */
clrbits_8(&reg->ctl2, SMBCTL2_ENABLE);
setbits_8(&reg->ctl2, SMBCTL2_ENABLE);
/* clear BB and status */
writeb(SMBCST_BB, &reg->cst);
writeb(0xff, &reg->st);
/* select bank 1 */
setbits_8(&reg->ctl3, SMBCTL3_BNK_SEL);
/* Clear all fifo bits */
writeb(SMBFIF_CTS_CLR_FIFO, &reg->bank1.fif_cts);
/* select bank 0 */
clrbits_8(&reg->ctl3, SMBCTL3_BNK_SEL);
/* clear EOB bit */
writeb(SMBCST3_EO_BUSY, &reg->bank0.cst3);
/* single byte mode */
clrbits_8(&reg->bank0.fif_ctl, SMBFIF_CTL_FIFO_EN);
/* set POLL mode */
writeb(0, &reg->ctl1);
}
static void npcm_i2c_recovery(struct npcm_i2c_bus *bus, u32 addr)
{
u8 val;
int iter = 27;
struct npcm_i2c_regs *reg = bus->reg;
int err;
val = readb(&reg->ctl3);
/* Skip recovery, bus not stucked */
if ((val & SMBCTL3_SCL_LVL) && (val & SMBCTL3_SDA_LVL))
return;
printf("Performing I2C bus %d recovery...\n", bus->num);
/* SCL/SDA are not releaed, perform recovery */
while (1) {
/* toggle SCL line */
writeb(SMBCST_TGSCL, &reg->cst);
udelay(20);
val = readb(&reg->ctl3);
if (val & SMBCTL3_SDA_LVL)
break;
if (iter-- == 0)
break;
}
if (val & SMBCTL3_SDA_LVL) {
writeb((u8)((addr << 1) & 0xff), &reg->sda);
err = npcm_i2c_send_start(bus);
if (!err) {
udelay(20);
npcm_i2c_send_stop(bus, false);
udelay(200);
printf("I2C bus %d recovery completed\n",
bus->num);
} else {
printf("%s: send START err %d\n", __func__, err);
}
} else {
printf("Fail to recover I2C bus %d\n", bus->num);
}
npcm_i2c_reset(bus);
}
static int npcm_i2c_send_address(struct npcm_i2c_bus *bus, u8 addr,
bool stall)
{
struct npcm_i2c_regs *reg = bus->reg;
ulong start_time;
u8 val;
/* Stall After Start Enable */
if (stall)
setbits_8(&reg->ctl1, SMBCTL1_STASTRE);
writeb(addr, &reg->sda);
if (stall) {
start_time = get_timer(0);
while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
if (readb(&reg->st) & SMBST_STASTR)
break;
if (readb(&reg->st) & SMBST_BER) {
clrbits_8(&reg->ctl1, SMBCTL1_STASTRE);
return I2C_ERR_BER;
}
}
}
/* check ACK */
val = readb(&reg->st);
if (val & SMBST_NEGACK) {
debug("NACK on addr 0x%x\n", addr >> 1);
/* After a Stop condition, writing 1 to NEGACK clears it */
return I2C_ERR_NACK;
}
if (val & SMBST_BER)
return I2C_ERR_BER;
return 0;
}
static int npcm_i2c_read_bytes(struct npcm_i2c_bus *bus, u8 *data, int len)
{
struct npcm_i2c_regs *reg = bus->reg;
u8 val;
int i;
int err = 0;
if (len == 1) {
/* bus should be stalled before receiving last byte */
setbits_8(&reg->ctl1, SMBCTL1_ACK);
/* clear STASTRE if it is set */
if (readb(&reg->ctl1) & SMBCTL1_STASTRE) {
writeb(SMBST_STASTR, &reg->st);
clrbits_8(&reg->ctl1, SMBCTL1_STASTRE);
}
npcm_i2c_check_sda(bus);
npcm_i2c_send_stop(bus, false);
*data = readb(&reg->sda);
/* this must be done to generate STOP condition */
writeb(SMBST_NEGACK, &reg->st);
} else {
for (i = 0; i < len; i++) {
/*
* When NEGACK bit is set to 1 after the transmission of a byte,
* SDAST is not set to 1.
*/
if (i != (len - 1)) {
err = npcm_i2c_check_sda(bus);
} else {
err = readb_poll_timeout(&reg->ctl1, val,
!(val & SMBCTL1_ACK), 100000);
if (err) {
printf("wait nack timeout\n");
err = I2C_ERR_TIMEOUT;
npcm_dump_regs(bus);
}
}
if (err && err != I2C_ERR_TIMEOUT)
break;
if (i == (len - 2)) {
/* set NACK before last byte */
setbits_8(&reg->ctl1, SMBCTL1_ACK);
}
if (i == (len - 1)) {
/* last byte, send STOP condition */
npcm_i2c_send_stop(bus, false);
*data = readb(&reg->sda);
writeb(SMBST_NEGACK, &reg->st);
break;
}
*data = readb(&reg->sda);
data++;
}
}
return err;
}
static int npcm_i2c_send_bytes(struct npcm_i2c_bus *bus, u8 *data, int len)
{
struct npcm_i2c_regs *reg = bus->reg;
u8 val;
int i;
int err = 0;
val = readb(&reg->st);
if (val & SMBST_NEGACK)
return I2C_ERR_NACK;
else if (val & SMBST_BER)
return I2C_ERR_BER;
/* clear STASTRE if it is set */
if (readb(&reg->ctl1) & SMBCTL1_STASTRE)
clrbits_8(&reg->ctl1, SMBCTL1_STASTRE);
for (i = 0; i < len; i++) {
err = npcm_i2c_check_sda(bus);
if (err)
break;
writeb(*data, &reg->sda);
data++;
}
npcm_i2c_check_sda(bus);
return err;
}
static int npcm_i2c_read(struct npcm_i2c_bus *bus, u32 addr, u8 *data,
u32 len)
{
struct npcm_i2c_regs *reg = bus->reg;
int err;
bool stall;
if (len <= 0)
return -EINVAL;
/* send START condition */
err = npcm_i2c_send_start(bus);
if (err) {
debug("%s: send START err %d\n", __func__, err);
return err;
}
stall = (len == 1) ? true : false;
/* send address byte */
err = npcm_i2c_send_address(bus, (u8)(addr << 1) | 0x1, stall);
if (!err && len)
npcm_i2c_read_bytes(bus, data, len);
if (err == I2C_ERR_NACK) {
/* clear NACK */
writeb(SMBST_NEGACK, &reg->st);
}
if (err)
debug("%s: err %d\n", __func__, err);
return err;
}
static int npcm_i2c_write(struct npcm_i2c_bus *bus, u32 addr, u8 *data,
u32 len)
{
struct npcm_i2c_regs *reg = bus->reg;
int err;
bool stall;
/* send START condition */
err = npcm_i2c_send_start(bus);
if (err) {
debug("%s: send START err %d\n", __func__, err);
return err;
}
stall = (len == 0) ? true : false;
/* send address byte */
err = npcm_i2c_send_address(bus, (u8)(addr << 1), stall);
if (!err && len)
err = npcm_i2c_send_bytes(bus, data, len);
/* clear STASTRE if it is set */
if (stall)
clrbits_8(&reg->ctl1, SMBCTL1_STASTRE);
if (err)
debug("%s: err %d\n", __func__, err);
return err;
}
static int npcm_i2c_xfer(struct udevice *dev,
struct i2c_msg *msg, int nmsgs)
{
struct npcm_i2c_bus *bus = dev_get_priv(dev);
struct npcm_i2c_regs *reg = bus->reg;
int ret = 0, err = 0;
if (nmsgs < 1 || nmsgs > 2) {
printf("%s: commands not support\n", __func__);
return -EREMOTEIO;
}
/* clear ST register */
writeb(0xFF, &reg->st);
for ( ; nmsgs > 0; nmsgs--, msg++) {
if (msg->flags & I2C_M_RD)
err = npcm_i2c_read(bus, msg->addr, msg->buf,
msg->len);
else
err = npcm_i2c_write(bus, msg->addr, msg->buf,
msg->len);
if (err) {
debug("i2c_xfer: error %d\n", err);
ret = -EREMOTEIO;
break;
}
}
if (bus->started)
npcm_i2c_send_stop(bus, true);
if (err)
npcm_i2c_recovery(bus, msg->addr);
return ret;
}
static int npcm_i2c_init_clk(struct npcm_i2c_bus *bus, u32 bus_freq)
{
struct npcm_i2c_regs *reg = bus->reg;
u32 freq = bus->apb_clk;
u32 sclfrq;
u8 hldt, val;
/* SCLFRQ = T(SCL)/4/T(CLK) = FREQ(CLK)/4/FREQ(SCL) */
sclfrq = freq / (bus_freq * 4);
if (sclfrq < SCLFRQ_MIN || sclfrq > SCLFRQ_MAX)
return -EINVAL;
if (freq >= 40000000)
hldt = 17;
else if (freq >= 12500000)
hldt = 15;
else
hldt = 7;
val = readb(&reg->ctl2) & 0x1;
val |= (sclfrq & 0x7F) << 1;
writeb(val, &reg->ctl2);
/* clear 400K_MODE bit */
val = readb(&reg->ctl3) & 0xc;
val |= (sclfrq >> 7) & 0x3;
writeb(val, &reg->ctl3);
writeb(hldt, &reg->bank0.ctl4);
return 0;
}
static int npcm_i2c_set_bus_speed(struct udevice *dev,
unsigned int speed)
{
struct npcm_i2c_bus *bus = dev_get_priv(dev);
return npcm_i2c_init_clk(bus, speed);
}
static int npcm_i2c_probe(struct udevice *dev)
{
struct npcm_i2c_bus *bus = dev_get_priv(dev);
struct npcm_gcr *gcr = (struct npcm_gcr *)NPCM_GCR_BA;
struct npcm_i2c_regs *reg;
u32 i2csegctl_val = dev_get_driver_data(dev);
struct clk clk;
int ret;
ret = clk_get_by_index(dev, 0, &clk);
if (ret) {
printf("%s: ret %d\n", __func__, ret);
return ret;
}
bus->apb_clk = clk_get_rate(&clk);
if (bus->apb_clk <= 0) {
printf("%s: fail to get rate\n", __func__);
return -EINVAL;
}
clk_free(&clk);
bus->num = dev->seq_;
bus->reg = dev_read_addr_ptr(dev);
bus->freq = dev_read_u32_default(dev, "clock-frequency", 100000);
bus->started = false;
reg = bus->reg;
if (npcm_i2c_init_clk(bus, bus->freq)) {
printf("%s: init_clk failed\n", __func__);
return -EINVAL;
}
/* set initial i2csegctl value */
writel(i2csegctl_val, &gcr->i2csegctl);
/* enable SMB module */
setbits_8(&reg->ctl2, SMBCTL2_ENABLE);
/* select register bank 0 */
clrbits_8(&reg->ctl3, SMBCTL3_BNK_SEL);
/* single byte mode */
clrbits_8(&reg->bank0.fif_ctl, SMBFIF_CTL_FIFO_EN);
/* set POLL mode */
writeb(0, &reg->ctl1);
printf("I2C bus %d ready. speed=%d, base=0x%x, apb=%u\n",
bus->num, bus->freq, (u32)(uintptr_t)bus->reg, bus->apb_clk);
return 0;
}
static const struct dm_i2c_ops nuvoton_i2c_ops = {
.xfer = npcm_i2c_xfer,
.set_bus_speed = npcm_i2c_set_bus_speed,
};
static const struct udevice_id nuvoton_i2c_of_match[] = {
{ .compatible = "nuvoton,npcm845-i2c", .data = NPCM8XX_I2CSEGCTL_INIT_VAL},
{ .compatible = "nuvoton,npcm750-i2c", .data = NPCM7XX_I2CSEGCTL_INIT_VAL},
{}
};
U_BOOT_DRIVER(npcm_i2c_bus) = {
.name = "npcm-i2c",
.id = UCLASS_I2C,
.of_match = nuvoton_i2c_of_match,
.probe = npcm_i2c_probe,
.priv_auto = sizeof(struct npcm_i2c_bus),
.ops = &nuvoton_i2c_ops,
};