u-boot/drivers/i2c/nx_i2c.c
Simon Glass 8b85dfc675 dm: Avoid accessing seq directly
At present various drivers etc. access the device's 'seq' member directly.
This makes it harder to change the meaning of that member. Change access
to go through a function instead.

The drivers/i2c/lpc32xx_i2c.c file is left unchanged for now.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-12-18 20:32:21 -07:00

626 lines
14 KiB
C

#include <common.h>
#include <errno.h>
#include <dm.h>
#include <i2c.h>
#include <log.h>
#include <asm/arch/nexell.h>
#include <asm/arch/reset.h>
#include <asm/arch/clk.h>
#include <asm/arch/nx_gpio.h>
#include <linux/delay.h>
#define I2C_WRITE 0
#define I2C_READ 1
#define I2CSTAT_MTM 0xC0 /* Master Transmit Mode */
#define I2CSTAT_MRM 0x80 /* Master Receive Mode */
#define I2CSTAT_BSY 0x20 /* Read: Bus Busy */
#define I2CSTAT_SS 0x20 /* Write: START (1) / STOP (0) */
#define I2CSTAT_RXTXEN 0x10 /* Rx/Tx enable */
#define I2CSTAT_ABT 0x08 /* Arbitration bit */
#define I2CSTAT_NACK 0x01 /* Nack bit */
#define I2CCON_IRCLR 0x100 /* Interrupt Clear bit */
#define I2CCON_ACKGEN 0x80 /* Acknowledge generation */
#define I2CCON_TCP256 0x40 /* Tx-clock prescaler: 16 (0) / 256 (1) */
#define I2CCON_IRENB 0x20 /* Interrupt Enable bit */
#define I2CCON_IRPND 0x10 /* Interrupt pending bit */
#define I2CCON_TCDMSK 0x0F /* I2C-bus transmit clock divider bit mask */
#ifdef CONFIG_ARCH_S5P6818
#define SDADLY_CLKSTEP 5 /* SDA delay: Reg. val. is multiple of 5 clks */
#define SDADLY_MAX 3 /* SDA delay: Max. reg. value is 3 */
#define I2CLC_FILTER 0x04 /* SDA filter on */
#else
#define STOPCON_CLR 0x01 /* Clock Line Release */
#define STOPCON_DLR 0x02 /* Data Line Release */
#define STOPCON_NAG 0x04 /* not-ackn. generation and data shift cont. */
#endif
#define I2C_TIMEOUT_MS 10 /* 10 ms */
#define I2C_M_NOSTOP 0x100
#define MAX_I2C_NUM 3
#define DEFAULT_SPEED 100000 /* default I2C speed [Hz] */
DECLARE_GLOBAL_DATA_PTR;
struct nx_i2c_regs {
uint iiccon;
uint iicstat;
uint iicadd;
uint iicds;
#ifdef CONFIG_ARCH_S5P6818
/* S5P6818: Offset 0x10 is Line Control Register (SDA-delay, Filter) */
uint iiclc;
#else
/* S5P4418: Offset 0x10 is Stop Control Register */
uint iicstopcon;
#endif
};
struct nx_i2c_bus {
uint bus_num;
struct nx_i2c_regs *regs;
uint speed;
uint target_speed;
#ifdef CONFIG_ARCH_S5P6818
uint sda_delay;
#else
/* setup time for Stop condition [us] */
uint tsu_stop;
#endif
};
/* s5pxx18 i2c must be reset before enabled */
static void i2c_reset(int ch)
{
int rst_id = RESET_ID_I2C0 + ch;
nx_rstcon_setrst(rst_id, 0);
nx_rstcon_setrst(rst_id, 1);
}
static uint i2c_get_clkrate(struct nx_i2c_bus *bus)
{
struct clk *clk;
int index = bus->bus_num;
char name[50] = {0, };
sprintf(name, "%s.%d", DEV_NAME_I2C, index);
clk = clk_get((const char *)name);
if (!clk)
return -1;
return clk_get_rate(clk);
}
static uint i2c_set_clk(struct nx_i2c_bus *bus, uint enb)
{
struct clk *clk;
char name[50];
sprintf(name, "%s.%d", DEV_NAME_I2C, bus->bus_num);
clk = clk_get((const char *)name);
if (!clk) {
debug("%s(): clk_get(%s) error!\n",
__func__, (const char *)name);
return -EINVAL;
}
clk_disable(clk);
if (enb)
clk_enable(clk);
return 0;
}
#ifdef CONFIG_ARCH_S5P6818
/* Set SDA line delay, not available at S5P4418 */
static int nx_i2c_set_sda_delay(struct nx_i2c_bus *bus)
{
struct nx_i2c_regs *i2c = bus->regs;
uint pclk = 0;
uint t_pclk = 0;
uint delay = 0;
/* get input clock of the I2C-controller */
pclk = i2c_get_clkrate(bus);
if (bus->sda_delay) {
/* t_pclk = period time of one pclk [ns] */
t_pclk = DIV_ROUND_UP(1000, pclk / 1000000);
/* delay = number of pclks required for sda_delay [ns] */
delay = DIV_ROUND_UP(bus->sda_delay, t_pclk);
/* delay = register value (step of 5 clocks) */
delay = DIV_ROUND_UP(delay, SDADLY_CLKSTEP);
/* max. possible register value = 3 */
if (delay > SDADLY_MAX) {
delay = SDADLY_MAX;
debug("%s(): sda-delay des.: %dns, sat. to max.: %dns (granularity: %dns)\n",
__func__, bus->sda_delay, t_pclk * delay * SDADLY_CLKSTEP,
t_pclk * SDADLY_CLKSTEP);
} else {
debug("%s(): sda-delay des.: %dns, act.: %dns (granularity: %dns)\n",
__func__, bus->sda_delay, t_pclk * delay * SDADLY_CLKSTEP,
t_pclk * SDADLY_CLKSTEP);
}
delay |= I2CLC_FILTER;
} else {
delay = 0;
debug("%s(): sda-delay = 0\n", __func__);
}
delay &= 0x7;
writel(delay, &i2c->iiclc);
return 0;
}
#endif
static int nx_i2c_set_bus_speed(struct udevice *dev, uint speed)
{
struct nx_i2c_bus *bus = dev_get_priv(dev);
struct nx_i2c_regs *i2c = bus->regs;
unsigned long pclk, pres = 16, div;
if (i2c_set_clk(bus, 1))
return -EINVAL;
/* get input clock of the I2C-controller */
pclk = i2c_get_clkrate(bus);
/* calculate prescaler and divisor values */
if ((pclk / pres / (16 + 1)) > speed)
/* prescaler value 16 is too less --> set to 256 */
pres = 256;
div = 0;
/* actual divider = div + 1 */
while ((pclk / pres / (div + 1)) > speed)
div++;
if (div > 0xF) {
debug("%s(): pres==%ld, div==0x%lx is saturated to 0xF !)\n",
__func__, pres, div);
div = 0xF;
} else {
debug("%s(): pres==%ld, div==0x%lx)\n", __func__, pres, div);
}
/* set Tx-clock divisor and prescaler values */
writel((div & I2CCON_TCDMSK) | ((pres == 256) ? I2CCON_TCP256 : 0),
&i2c->iiccon);
/* init to SLAVE REVEIVE and set slaveaddr */
writel(0, &i2c->iicstat);
writel(0x00, &i2c->iicadd);
/* program Master Transmit (and implicit STOP) */
writel(I2CSTAT_MTM | I2CSTAT_RXTXEN, &i2c->iicstat);
/* calculate actual I2C speed [Hz] */
bus->speed = pclk / ((div + 1) * pres);
debug("%s(): speed des.: %dHz, act.: %dHz\n",
__func__, speed, bus->speed);
#ifdef CONFIG_ARCH_S5P6818
nx_i2c_set_sda_delay(bus);
#else
/* setup time for Stop condition [us], min. 4us @ 100kHz I2C-clock */
bus->tsu_stop = DIV_ROUND_UP(400, bus->speed / 1000);
#endif
if (i2c_set_clk(bus, 0))
return -EINVAL;
return 0;
}
static void i2c_process_node(struct udevice *dev)
{
struct nx_i2c_bus *bus = dev_get_priv(dev);
bus->target_speed = dev_read_s32_default(dev, "clock-frequency",
DEFAULT_SPEED);
#ifdef CONFIG_ARCH_S5P6818
bus->sda_delay = dev_read_s32_default(dev, "i2c-sda-delay-ns", 0);
#endif
}
static int nx_i2c_probe(struct udevice *dev)
{
struct nx_i2c_bus *bus = dev_get_priv(dev);
fdt_addr_t addr;
/* get regs = i2c base address */
addr = devfdt_get_addr(dev);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
bus->regs = (struct nx_i2c_regs *)addr;
bus->bus_num = dev_seq(dev);
/* i2c node parsing */
i2c_process_node(dev);
if (!bus->target_speed)
return -ENODEV;
/* reset */
i2c_reset(bus->bus_num);
return 0;
}
/* i2c bus busy check */
static int i2c_is_busy(struct nx_i2c_regs *i2c)
{
ulong start_time;
start_time = get_timer(0);
while (readl(&i2c->iicstat) & I2CSTAT_BSY) {
if (get_timer(start_time) > I2C_TIMEOUT_MS) {
debug("Timeout\n");
return -EBUSY;
}
}
return 0;
}
/* irq enable/disable functions */
static void i2c_enable_irq(struct nx_i2c_regs *i2c)
{
unsigned int reg;
reg = readl(&i2c->iiccon);
reg |= I2CCON_IRENB;
writel(reg, &i2c->iiccon);
}
/* irq clear function */
static void i2c_clear_irq(struct nx_i2c_regs *i2c)
{
unsigned int reg;
reg = readl(&i2c->iiccon);
/* reset interrupt pending flag */
reg &= ~(I2CCON_IRPND);
/*
* Interrupt must also be cleared!
* Otherwise linux boot may hang after:
* [ 0.436000] NetLabel: unlabeled traffic allowed by default
* Next would be:
* [ 0.442000] clocksource: Switched to clocksource source timer
*/
reg |= I2CCON_IRCLR;
writel(reg, &i2c->iiccon);
}
/* ack enable functions */
static void i2c_enable_ack(struct nx_i2c_regs *i2c)
{
unsigned int reg;
reg = readl(&i2c->iiccon);
reg |= I2CCON_ACKGEN;
writel(reg, &i2c->iiccon);
}
static void i2c_send_stop(struct nx_i2c_bus *bus)
{
struct nx_i2c_regs *i2c = bus->regs;
if (IS_ENABLED(CONFIG_ARCH_S5P6818)) {
unsigned int reg;
reg = readl(&i2c->iicstat);
reg |= I2CSTAT_MRM | I2CSTAT_RXTXEN;
reg &= (~I2CSTAT_SS);
writel(reg, &i2c->iicstat);
i2c_clear_irq(i2c);
} else { /* S5P4418 */
writel(STOPCON_NAG, &i2c->iicstopcon);
i2c_clear_irq(i2c);
/*
* Clock Line Release --> SDC changes from Low to High and
* SDA from High to Low
*/
writel(STOPCON_CLR, &i2c->iicstopcon);
/* Hold SDA Low (Setup Time for Stop condition) */
udelay(bus->tsu_stop);
i2c_clear_irq(i2c);
/* Master Receive Mode Stop --> SDA becomes High */
writel(I2CSTAT_MRM, &i2c->iicstat);
}
}
static int wait_for_xfer(struct nx_i2c_regs *i2c)
{
unsigned long start_time = get_timer(0);
do {
if (readl(&i2c->iiccon) & I2CCON_IRPND)
/* return -EREMOTEIO if not Acknowledged, otherwise 0 */
return (readl(&i2c->iicstat) & I2CSTAT_NACK) ?
-EREMOTEIO : 0;
} while (get_timer(start_time) < I2C_TIMEOUT_MS);
return -ETIMEDOUT;
}
static int i2c_transfer(struct nx_i2c_regs *i2c,
uchar cmd_type,
uchar chip_addr,
uchar addr[],
uchar addr_len,
uchar data[],
unsigned short data_len,
uint seq)
{
uint status;
int i = 0, result;
/* Note: data_len = 0 is supported for "probe_chip" */
i2c_enable_irq(i2c);
i2c_enable_ack(i2c);
/* Get the slave chip address going */
/* Enable Rx/Tx */
writel(I2CSTAT_RXTXEN, &i2c->iicstat);
writel(chip_addr, &i2c->iicds);
status = I2CSTAT_RXTXEN | I2CSTAT_SS;
if (cmd_type == I2C_WRITE || (addr && addr_len))
status |= I2CSTAT_MTM;
else
status |= I2CSTAT_MRM;
writel(status, &i2c->iicstat);
if (seq)
i2c_clear_irq(i2c);
/* Wait for chip address to transmit. */
result = wait_for_xfer(i2c);
if (result) {
debug("%s: transmitting chip address failed\n", __func__);
goto bailout;
}
/* If register address needs to be transmitted - do it now. */
if (addr && addr_len) { /* register addr */
while ((i < addr_len) && !result) {
writel(addr[i++], &i2c->iicds);
i2c_clear_irq(i2c);
result = wait_for_xfer(i2c);
}
i = 0;
if (result) {
debug("%s: transmitting register address failed\n",
__func__);
goto bailout;
}
}
switch (cmd_type) {
case I2C_WRITE:
while ((i < data_len) && !result) {
writel(data[i++], &i2c->iicds);
i2c_clear_irq(i2c);
result = wait_for_xfer(i2c);
}
break;
case I2C_READ:
if (addr && addr_len) {
/*
* Register address has been sent, now send slave chip
* address again to start the actual read transaction.
*/
writel(chip_addr, &i2c->iicds);
/* Generate a re-START. */
writel(I2CSTAT_MRM | I2CSTAT_RXTXEN |
I2CSTAT_SS, &i2c->iicstat);
i2c_clear_irq(i2c);
result = wait_for_xfer(i2c);
if (result) {
debug("%s: I2C_READ: sending chip addr. failed\n",
__func__);
goto bailout;
}
}
while ((i < data_len) && !result) {
/* disable ACK for final READ */
if (i == data_len - 1)
clrbits_le32(&i2c->iiccon, I2CCON_ACKGEN);
i2c_clear_irq(i2c);
result = wait_for_xfer(i2c);
data[i++] = readb(&i2c->iicds);
}
if (result == -EREMOTEIO)
/* Not Acknowledged --> normal terminated read. */
result = 0;
else if (result == -ETIMEDOUT)
debug("%s: I2C_READ: time out\n", __func__);
else
debug("%s: I2C_READ: read not terminated with NACK\n",
__func__);
break;
default:
debug("%s: bad call\n", __func__);
result = -EINVAL;
break;
}
bailout:
return result;
}
static int nx_i2c_read(struct udevice *dev, uchar chip_addr, uint addr,
uint alen, uchar *buffer, uint len, uint seq)
{
struct nx_i2c_bus *i2c;
uchar xaddr[4];
int ret;
i2c = dev_get_priv(dev);
if (!i2c)
return -EFAULT;
if (alen > 4) {
debug("I2C read: addr len %d not supported\n", alen);
return -EADDRNOTAVAIL;
}
if (alen > 0)
xaddr[0] = (addr >> 24) & 0xFF;
if (alen > 0) {
xaddr[0] = (addr >> 24) & 0xFF;
xaddr[1] = (addr >> 16) & 0xFF;
xaddr[2] = (addr >> 8) & 0xFF;
xaddr[3] = addr & 0xFF;
}
ret = i2c_transfer(i2c->regs, I2C_READ, chip_addr << 1,
&xaddr[4 - alen], alen, buffer, len, seq);
if (ret) {
debug("I2C read failed %d\n", ret);
return -EIO;
}
return 0;
}
static int nx_i2c_write(struct udevice *dev, uchar chip_addr, uint addr,
uint alen, uchar *buffer, uint len, uint seq)
{
struct nx_i2c_bus *i2c;
uchar xaddr[4];
int ret;
i2c = dev_get_priv(dev);
if (!i2c)
return -EFAULT;
if (alen > 4) {
debug("I2C write: addr len %d not supported\n", alen);
return -EINVAL;
}
if (alen > 0) {
xaddr[0] = (addr >> 24) & 0xFF;
xaddr[1] = (addr >> 16) & 0xFF;
xaddr[2] = (addr >> 8) & 0xFF;
xaddr[3] = addr & 0xFF;
}
ret = i2c_transfer(i2c->regs, I2C_WRITE, chip_addr << 1,
&xaddr[4 - alen], alen, buffer, len, seq);
if (ret) {
debug("I2C write failed %d\n", ret);
return -EIO;
}
return 0;
}
static int nx_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
{
struct nx_i2c_bus *bus = dev_get_priv(dev);
struct nx_i2c_regs *i2c = bus->regs;
int ret;
int i;
/* The power loss by the clock, only during on/off. */
ret = i2c_set_clk(bus, 1);
if (!ret)
/* Bus State(Busy) check */
ret = i2c_is_busy(i2c);
if (!ret) {
for (i = 0; i < nmsgs; msg++, i++) {
if (msg->flags & I2C_M_RD) {
ret = nx_i2c_read(dev, msg->addr, 0, 0,
msg->buf, msg->len, i);
} else {
ret = nx_i2c_write(dev, msg->addr, 0, 0,
msg->buf, msg->len, i);
}
if (ret) {
debug("i2c_xfer: error sending\n");
ret = -EREMOTEIO;
}
}
i2c_send_stop(bus);
if (i2c_set_clk(bus, 0))
ret = -EINVAL;
}
return ret;
};
static int nx_i2c_probe_chip(struct udevice *dev, u32 chip_addr,
u32 chip_flags)
{
int ret;
struct nx_i2c_bus *bus = dev_get_priv(dev);
ret = i2c_set_clk(bus, 1);
if (!ret) {
/*
* Send Chip Address only
* --> I2C transfer with data length and address length = 0.
* If there is a Slave, i2c_transfer() returns 0 (acknowledge
* transfer).
* I2C_WRITE must be used in order Master Transmit Mode is
* selected. Otherwise (in Master Receive Mode, I2C_READ)
* sending the stop condition below is not working (SDA does
* not transit to High).
*/
ret = i2c_transfer(bus->regs, I2C_WRITE, (uchar)chip_addr << 1,
NULL, 0, NULL, 0, 0);
i2c_send_stop(bus);
if (i2c_set_clk(bus, 0))
ret = -EINVAL;
}
return ret;
}
static const struct dm_i2c_ops nx_i2c_ops = {
.xfer = nx_i2c_xfer,
.probe_chip = nx_i2c_probe_chip,
.set_bus_speed = nx_i2c_set_bus_speed,
};
static const struct udevice_id nx_i2c_ids[] = {
{ .compatible = "nexell,s5pxx18-i2c" },
{ }
};
U_BOOT_DRIVER(i2c_nexell) = {
.name = "i2c_nexell",
.id = UCLASS_I2C,
.of_match = nx_i2c_ids,
.probe = nx_i2c_probe,
.priv_auto = sizeof(struct nx_i2c_bus),
.ops = &nx_i2c_ops,
};