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u-boot/drivers/i2c/imx_lpi2c.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style 
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2016 Freescale Semiconductors, Inc.
*/
#include <common.h>
#include <errno.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#include <asm/arch/imx-regs.h>
#include <asm/arch/imx_lpi2c.h>
#include <asm/arch/sys_proto.h>
#include <dm.h>
#include <fdtdec.h>
#include <i2c.h>
#define LPI2C_FIFO_SIZE 4
#define LPI2C_TIMEOUT_MS 100
/* Weak linked function for overridden by some SoC power function */
int __weak init_i2c_power(unsigned i2c_num)
{
return 0;
}
static int imx_lpci2c_check_busy_bus(const struct imx_lpi2c_reg *regs)
{
lpi2c_status_t result = LPI2C_SUCESS;
u32 status;
status = readl(&regs->msr);
if ((status & LPI2C_MSR_BBF_MASK) && !(status & LPI2C_MSR_MBF_MASK))
result = LPI2C_BUSY;
return result;
}
static int imx_lpci2c_check_clear_error(struct imx_lpi2c_reg *regs)
{
lpi2c_status_t result = LPI2C_SUCESS;
u32 val, status;
status = readl(&regs->msr);
/* errors to check for */
status &= LPI2C_MSR_NDF_MASK | LPI2C_MSR_ALF_MASK |
LPI2C_MSR_FEF_MASK | LPI2C_MSR_PLTF_MASK;
if (status) {
if (status & LPI2C_MSR_PLTF_MASK)
result = LPI2C_PIN_LOW_TIMEOUT_ERR;
else if (status & LPI2C_MSR_ALF_MASK)
result = LPI2C_ARB_LOST_ERR;
else if (status & LPI2C_MSR_NDF_MASK)
result = LPI2C_NAK_ERR;
else if (status & LPI2C_MSR_FEF_MASK)
result = LPI2C_FIFO_ERR;
/* clear status flags */
writel(0x7f00, &regs->msr);
/* reset fifos */
val = readl(&regs->mcr);
val |= LPI2C_MCR_RRF_MASK | LPI2C_MCR_RTF_MASK;
writel(val, &regs->mcr);
}
return result;
}
static int bus_i2c_wait_for_tx_ready(struct imx_lpi2c_reg *regs)
{
lpi2c_status_t result = LPI2C_SUCESS;
u32 txcount = 0;
ulong start_time = get_timer(0);
do {
txcount = LPI2C_MFSR_TXCOUNT(readl(&regs->mfsr));
txcount = LPI2C_FIFO_SIZE - txcount;
result = imx_lpci2c_check_clear_error(regs);
if (result) {
debug("i2c: wait for tx ready: result 0x%x\n", result);
return result;
}
if (get_timer(start_time) > LPI2C_TIMEOUT_MS) {
debug("i2c: wait for tx ready: timeout\n");
return -1;
}
} while (!txcount);
return result;
}
static int bus_i2c_send(struct imx_lpi2c_reg *regs, u8 *txbuf, int len)
{
lpi2c_status_t result = LPI2C_SUCESS;
/* empty tx */
if (!len)
return result;
while (len--) {
result = bus_i2c_wait_for_tx_ready(regs);
if (result) {
debug("i2c: send wait fot tx ready: %d\n", result);
return result;
}
writel(*txbuf++, &regs->mtdr);
}
return result;
}
static int bus_i2c_receive(struct imx_lpi2c_reg *regs, u8 *rxbuf, int len)
{
lpi2c_status_t result = LPI2C_SUCESS;
u32 val;
ulong start_time = get_timer(0);
/* empty read */
if (!len)
return result;
result = bus_i2c_wait_for_tx_ready(regs);
if (result) {
debug("i2c: receive wait fot tx ready: %d\n", result);
return result;
}
/* clear all status flags */
writel(0x7f00, &regs->msr);
/* send receive command */
val = LPI2C_MTDR_CMD(0x1) | LPI2C_MTDR_DATA(len - 1);
writel(val, &regs->mtdr);
while (len--) {
do {
result = imx_lpci2c_check_clear_error(regs);
if (result) {
debug("i2c: receive check clear error: %d\n",
result);
return result;
}
if (get_timer(start_time) > LPI2C_TIMEOUT_MS) {
debug("i2c: receive mrdr: timeout\n");
return -1;
}
val = readl(&regs->mrdr);
} while (val & LPI2C_MRDR_RXEMPTY_MASK);
*rxbuf++ = LPI2C_MRDR_DATA(val);
}
return result;
}
static int bus_i2c_start(struct imx_lpi2c_reg *regs, u8 addr, u8 dir)
{
lpi2c_status_t result;
u32 val;
result = imx_lpci2c_check_busy_bus(regs);
if (result) {
debug("i2c: start check busy bus: 0x%x\n", result);
return result;
}
/* clear all status flags */
writel(0x7f00, &regs->msr);
/* turn off auto-stop condition */
val = readl(&regs->mcfgr1) & ~LPI2C_MCFGR1_AUTOSTOP_MASK;
writel(val, &regs->mcfgr1);
/* wait tx fifo ready */
result = bus_i2c_wait_for_tx_ready(regs);
if (result) {
debug("i2c: start wait for tx ready: 0x%x\n", result);
return result;
}
/* issue start command */
val = LPI2C_MTDR_CMD(0x4) | (addr << 0x1) | dir;
writel(val, &regs->mtdr);
return result;
}
static int bus_i2c_stop(struct imx_lpi2c_reg *regs)
{
lpi2c_status_t result;
u32 status;
result = bus_i2c_wait_for_tx_ready(regs);
if (result) {
debug("i2c: stop wait for tx ready: 0x%x\n", result);
return result;
}
/* send stop command */
writel(LPI2C_MTDR_CMD(0x2), &regs->mtdr);
while (result == LPI2C_SUCESS) {
status = readl(&regs->msr);
result = imx_lpci2c_check_clear_error(regs);
/* stop detect flag */
if (status & LPI2C_MSR_SDF_MASK) {
/* clear stop flag */
status &= LPI2C_MSR_SDF_MASK;
writel(status, &regs->msr);
break;
}
}
return result;
}
static int bus_i2c_read(struct imx_lpi2c_reg *regs, u32 chip, u8 *buf, int len)
{
lpi2c_status_t result;
result = bus_i2c_start(regs, chip, 1);
if (result)
return result;
result = bus_i2c_receive(regs, buf, len);
if (result)
return result;
result = bus_i2c_stop(regs);
if (result)
return result;
return result;
}
static int bus_i2c_write(struct imx_lpi2c_reg *regs, u32 chip, u8 *buf, int len)
{
lpi2c_status_t result;
result = bus_i2c_start(regs, chip, 0);
if (result)
return result;
result = bus_i2c_send(regs, buf, len);
if (result)
return result;
result = bus_i2c_stop(regs);
if (result)
return result;
return result;
}
static int bus_i2c_set_bus_speed(struct udevice *bus, int speed)
{
struct imx_lpi2c_reg *regs;
u32 val;
u32 preescale = 0, best_pre = 0, clkhi = 0;
u32 best_clkhi = 0, abs_error = 0, rate;
u32 error = 0xffffffff;
u32 clock_rate;
bool mode;
int i;
regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
clock_rate = imx_get_i2cclk(bus->seq);
if (!clock_rate)
return -EPERM;
mode = (readl(&regs->mcr) & LPI2C_MCR_MEN_MASK) >> LPI2C_MCR_MEN_SHIFT;
/* disable master mode */
val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
writel(val | LPI2C_MCR_MEN(0), &regs->mcr);
for (preescale = 1; (preescale <= 128) &&
(error != 0); preescale = 2 * preescale) {
for (clkhi = 1; clkhi < 32; clkhi++) {
if (clkhi == 1)
rate = (clock_rate / preescale) / (1 + 3 + 2 + 2 / preescale);
else
rate = (clock_rate / preescale / (3 * clkhi + 2 + 2 / preescale));
abs_error = speed > rate ? speed - rate : rate - speed;
if (abs_error < error) {
best_pre = preescale;
best_clkhi = clkhi;
error = abs_error;
if (abs_error == 0)
break;
}
}
}
/* Standard, fast, fast mode plus and ultra-fast transfers. */
val = LPI2C_MCCR0_CLKHI(best_clkhi);
if (best_clkhi < 2)
val |= LPI2C_MCCR0_CLKLO(3) | LPI2C_MCCR0_SETHOLD(2) | LPI2C_MCCR0_DATAVD(1);
else
val |= LPI2C_MCCR0_CLKLO(2 * best_clkhi) | LPI2C_MCCR0_SETHOLD(best_clkhi) |
LPI2C_MCCR0_DATAVD(best_clkhi / 2);
writel(val, &regs->mccr0);
for (i = 0; i < 8; i++) {
if (best_pre == (1 << i)) {
best_pre = i;
break;
}
}
val = readl(&regs->mcfgr1) & ~LPI2C_MCFGR1_PRESCALE_MASK;
writel(val | LPI2C_MCFGR1_PRESCALE(best_pre), &regs->mcfgr1);
if (mode) {
val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
writel(val | LPI2C_MCR_MEN(1), &regs->mcr);
}
return 0;
}
static int bus_i2c_init(struct udevice *bus, int speed)
{
struct imx_lpi2c_reg *regs;
u32 val;
int ret;
regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
/* reset peripheral */
writel(LPI2C_MCR_RST_MASK, &regs->mcr);
writel(0x0, &regs->mcr);
/* Disable Dozen mode */
writel(LPI2C_MCR_DBGEN(0) | LPI2C_MCR_DOZEN(1), &regs->mcr);
/* host request disable, active high, external pin */
val = readl(&regs->mcfgr0);
val &= (~(LPI2C_MCFGR0_HREN_MASK | LPI2C_MCFGR0_HRPOL_MASK |
LPI2C_MCFGR0_HRSEL_MASK));
val |= LPI2C_MCFGR0_HRPOL(0x1);
writel(val, &regs->mcfgr0);
/* pincfg and ignore ack */
val = readl(&regs->mcfgr1);
val &= ~(LPI2C_MCFGR1_PINCFG_MASK | LPI2C_MCFGR1_IGNACK_MASK);
val |= LPI2C_MCFGR1_PINCFG(0x0); /* 2 pin open drain */
val |= LPI2C_MCFGR1_IGNACK(0x0); /* ignore nack */
writel(val, &regs->mcfgr1);
ret = bus_i2c_set_bus_speed(bus, speed);
/* enable lpi2c in master mode */
val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
writel(val | LPI2C_MCR_MEN(1), &regs->mcr);
debug("i2c : controller bus %d, speed %d:\n", bus->seq, speed);
return ret;
}
static int imx_lpi2c_probe_chip(struct udevice *bus, u32 chip,
u32 chip_flags)
{
struct imx_lpi2c_reg *regs;
lpi2c_status_t result;
regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
result = bus_i2c_start(regs, chip, 0);
if (result) {
bus_i2c_stop(regs);
bus_i2c_init(bus, 100000);
return result;
}
result = bus_i2c_stop(regs);
if (result) {
bus_i2c_init(bus, 100000);
return -result;
}
return result;
}
static int imx_lpi2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
{
struct imx_lpi2c_reg *regs;
int ret = 0;
regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
for (; nmsgs > 0; nmsgs--, msg++) {
debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
if (msg->flags & I2C_M_RD)
ret = bus_i2c_read(regs, msg->addr, msg->buf, msg->len);
else {
ret = bus_i2c_write(regs, msg->addr, msg->buf,
msg->len);
if (ret)
break;
}
}
if (ret)
debug("i2c_write: error sending\n");
return ret;
}
static int imx_lpi2c_set_bus_speed(struct udevice *bus, unsigned int speed)
{
return bus_i2c_set_bus_speed(bus, speed);
}
static int imx_lpi2c_probe(struct udevice *bus)
{
struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
fdt_addr_t addr;
int ret;
i2c_bus->driver_data = dev_get_driver_data(bus);
addr = devfdt_get_addr(bus);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
i2c_bus->base = addr;
i2c_bus->index = bus->seq;
i2c_bus->bus = bus;
/* power up i2c resource */
ret = init_i2c_power(bus->seq);
if (ret) {
debug("init_i2c_power err = %d\n", ret);
return ret;
}
/* To i.MX7ULP, only i2c4-7 can be handled by A7 core */
ret = enable_i2c_clk(1, bus->seq);
if (ret < 0)
return ret;
ret = bus_i2c_init(bus, 100000);
if (ret < 0)
return ret;
debug("i2c : controller bus %d at %lu , speed %d: ",
bus->seq, i2c_bus->base,
i2c_bus->speed);
return 0;
}
static const struct dm_i2c_ops imx_lpi2c_ops = {
.xfer = imx_lpi2c_xfer,
.probe_chip = imx_lpi2c_probe_chip,
.set_bus_speed = imx_lpi2c_set_bus_speed,
};
static const struct udevice_id imx_lpi2c_ids[] = {
{ .compatible = "fsl,imx7ulp-lpi2c", },
{}
};
U_BOOT_DRIVER(imx_lpi2c) = {
.name = "imx_lpi2c",
.id = UCLASS_I2C,
.of_match = imx_lpi2c_ids,
.probe = imx_lpi2c_probe,
.priv_auto_alloc_size = sizeof(struct imx_lpi2c_bus),
.ops = &imx_lpi2c_ops,
};
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