linux/drivers/i2c/busses/i2c-zx2967.c

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/*
* Copyright (C) 2017 Sanechips Technology Co., Ltd.
* Copyright 2017 Linaro Ltd.
*
* Author: Baoyou Xie <baoyou.xie@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#define REG_CMD 0x04
#define REG_DEVADDR_H 0x0C
#define REG_DEVADDR_L 0x10
#define REG_CLK_DIV_FS 0x14
#define REG_CLK_DIV_HS 0x18
#define REG_WRCONF 0x1C
#define REG_RDCONF 0x20
#define REG_DATA 0x24
#define REG_STAT 0x28
#define I2C_STOP 0
#define I2C_MASTER BIT(0)
#define I2C_ADDR_MODE_TEN BIT(1)
#define I2C_IRQ_MSK_ENABLE BIT(3)
#define I2C_RW_READ BIT(4)
#define I2C_CMB_RW_EN BIT(5)
#define I2C_START BIT(6)
#define I2C_ADDR_LOW_MASK GENMASK(6, 0)
#define I2C_ADDR_LOW_SHIFT 0
#define I2C_ADDR_HI_MASK GENMASK(2, 0)
#define I2C_ADDR_HI_SHIFT 7
#define I2C_WFIFO_RESET BIT(7)
#define I2C_RFIFO_RESET BIT(7)
#define I2C_IRQ_ACK_CLEAR BIT(7)
#define I2C_INT_MASK GENMASK(6, 0)
#define I2C_TRANS_DONE BIT(0)
#define I2C_SR_EDEVICE BIT(1)
#define I2C_SR_EDATA BIT(2)
#define I2C_FIFO_MAX 16
#define I2C_TIMEOUT msecs_to_jiffies(1000)
#define DEV(i2c) ((i2c)->adap.dev.parent)
struct zx2967_i2c {
struct i2c_adapter adap;
struct clk *clk;
struct completion complete;
u32 clk_freq;
void __iomem *reg_base;
size_t residue;
int irq;
int msg_rd;
u8 *cur_trans;
u8 access_cnt;
bool is_suspended;
int error;
};
static void zx2967_i2c_writel(struct zx2967_i2c *i2c,
u32 val, unsigned long reg)
{
writel_relaxed(val, i2c->reg_base + reg);
}
static u32 zx2967_i2c_readl(struct zx2967_i2c *i2c, unsigned long reg)
{
return readl_relaxed(i2c->reg_base + reg);
}
static void zx2967_i2c_writesb(struct zx2967_i2c *i2c,
void *data, unsigned long reg, int len)
{
writesb(i2c->reg_base + reg, data, len);
}
static void zx2967_i2c_readsb(struct zx2967_i2c *i2c,
void *data, unsigned long reg, int len)
{
readsb(i2c->reg_base + reg, data, len);
}
static void zx2967_i2c_start_ctrl(struct zx2967_i2c *i2c)
{
u32 status;
u32 ctl;
status = zx2967_i2c_readl(i2c, REG_STAT);
status |= I2C_IRQ_ACK_CLEAR;
zx2967_i2c_writel(i2c, status, REG_STAT);
ctl = zx2967_i2c_readl(i2c, REG_CMD);
if (i2c->msg_rd)
ctl |= I2C_RW_READ;
else
ctl &= ~I2C_RW_READ;
ctl &= ~I2C_CMB_RW_EN;
ctl |= I2C_START;
zx2967_i2c_writel(i2c, ctl, REG_CMD);
}
static void zx2967_i2c_flush_fifos(struct zx2967_i2c *i2c)
{
u32 offset;
u32 val;
if (i2c->msg_rd) {
offset = REG_RDCONF;
val = I2C_RFIFO_RESET;
} else {
offset = REG_WRCONF;
val = I2C_WFIFO_RESET;
}
val |= zx2967_i2c_readl(i2c, offset);
zx2967_i2c_writel(i2c, val, offset);
}
static int zx2967_i2c_empty_rx_fifo(struct zx2967_i2c *i2c, u32 size)
{
u8 val[I2C_FIFO_MAX] = {0};
int i;
if (size > I2C_FIFO_MAX) {
dev_err(DEV(i2c), "fifo size %d over the max value %d\n",
size, I2C_FIFO_MAX);
return -EINVAL;
}
zx2967_i2c_readsb(i2c, val, REG_DATA, size);
for (i = 0; i < size; i++) {
*i2c->cur_trans++ = val[i];
i2c->residue--;
}
barrier();
return 0;
}
static int zx2967_i2c_fill_tx_fifo(struct zx2967_i2c *i2c)
{
size_t residue = i2c->residue;
u8 *buf = i2c->cur_trans;
if (residue == 0) {
dev_err(DEV(i2c), "residue is %d\n", (int)residue);
return -EINVAL;
}
if (residue <= I2C_FIFO_MAX) {
zx2967_i2c_writesb(i2c, buf, REG_DATA, residue);
/* Again update before writing to FIFO to make sure isr sees. */
i2c->residue = 0;
i2c->cur_trans = NULL;
} else {
zx2967_i2c_writesb(i2c, buf, REG_DATA, I2C_FIFO_MAX);
i2c->residue -= I2C_FIFO_MAX;
i2c->cur_trans += I2C_FIFO_MAX;
}
barrier();
return 0;
}
static int zx2967_i2c_reset_hardware(struct zx2967_i2c *i2c)
{
u32 val;
u32 clk_div;
val = I2C_MASTER | I2C_IRQ_MSK_ENABLE;
zx2967_i2c_writel(i2c, val, REG_CMD);
clk_div = clk_get_rate(i2c->clk) / i2c->clk_freq - 1;
zx2967_i2c_writel(i2c, clk_div, REG_CLK_DIV_FS);
zx2967_i2c_writel(i2c, clk_div, REG_CLK_DIV_HS);
zx2967_i2c_writel(i2c, I2C_FIFO_MAX - 1, REG_WRCONF);
zx2967_i2c_writel(i2c, I2C_FIFO_MAX - 1, REG_RDCONF);
zx2967_i2c_writel(i2c, 1, REG_RDCONF);
zx2967_i2c_flush_fifos(i2c);
return 0;
}
static void zx2967_i2c_isr_clr(struct zx2967_i2c *i2c)
{
u32 status;
status = zx2967_i2c_readl(i2c, REG_STAT);
status |= I2C_IRQ_ACK_CLEAR;
zx2967_i2c_writel(i2c, status, REG_STAT);
}
static irqreturn_t zx2967_i2c_isr(int irq, void *dev_id)
{
u32 status;
struct zx2967_i2c *i2c = (struct zx2967_i2c *)dev_id;
status = zx2967_i2c_readl(i2c, REG_STAT) & I2C_INT_MASK;
zx2967_i2c_isr_clr(i2c);
if (status & I2C_SR_EDEVICE)
i2c->error = -ENXIO;
else if (status & I2C_SR_EDATA)
i2c->error = -EIO;
else if (status & I2C_TRANS_DONE)
i2c->error = 0;
else
goto done;
complete(&i2c->complete);
done:
return IRQ_HANDLED;
}
static void zx2967_set_addr(struct zx2967_i2c *i2c, u16 addr)
{
u16 val;
val = (addr >> I2C_ADDR_LOW_SHIFT) & I2C_ADDR_LOW_MASK;
zx2967_i2c_writel(i2c, val, REG_DEVADDR_L);
val = (addr >> I2C_ADDR_HI_SHIFT) & I2C_ADDR_HI_MASK;
zx2967_i2c_writel(i2c, val, REG_DEVADDR_H);
if (val)
val = zx2967_i2c_readl(i2c, REG_CMD) | I2C_ADDR_MODE_TEN;
else
val = zx2967_i2c_readl(i2c, REG_CMD) & ~I2C_ADDR_MODE_TEN;
zx2967_i2c_writel(i2c, val, REG_CMD);
}
static int zx2967_i2c_xfer_bytes(struct zx2967_i2c *i2c, u32 bytes)
{
unsigned long time_left;
int rd = i2c->msg_rd;
int ret;
reinit_completion(&i2c->complete);
if (rd) {
zx2967_i2c_writel(i2c, bytes - 1, REG_RDCONF);
} else {
ret = zx2967_i2c_fill_tx_fifo(i2c);
if (ret)
return ret;
}
zx2967_i2c_start_ctrl(i2c);
time_left = wait_for_completion_timeout(&i2c->complete,
I2C_TIMEOUT);
if (time_left == 0)
return -ETIMEDOUT;
if (i2c->error)
return i2c->error;
return rd ? zx2967_i2c_empty_rx_fifo(i2c, bytes) : 0;
}
static int zx2967_i2c_xfer_msg(struct zx2967_i2c *i2c,
struct i2c_msg *msg)
{
int ret;
int i;
if (msg->len == 0)
return -EINVAL;
zx2967_i2c_flush_fifos(i2c);
i2c->cur_trans = msg->buf;
i2c->residue = msg->len;
i2c->access_cnt = msg->len / I2C_FIFO_MAX;
i2c->msg_rd = msg->flags & I2C_M_RD;
for (i = 0; i < i2c->access_cnt; i++) {
ret = zx2967_i2c_xfer_bytes(i2c, I2C_FIFO_MAX);
if (ret)
return ret;
}
if (i2c->residue > 0) {
ret = zx2967_i2c_xfer_bytes(i2c, i2c->residue);
if (ret)
return ret;
}
i2c->residue = 0;
i2c->access_cnt = 0;
return 0;
}
static int zx2967_i2c_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs, int num)
{
struct zx2967_i2c *i2c = i2c_get_adapdata(adap);
int ret;
int i;
if (i2c->is_suspended)
return -EBUSY;
zx2967_set_addr(i2c, msgs->addr);
for (i = 0; i < num; i++) {
ret = zx2967_i2c_xfer_msg(i2c, &msgs[i]);
if (ret)
return ret;
}
return num;
}
static void
zx2967_smbus_xfer_prepare(struct zx2967_i2c *i2c, u16 addr,
char read_write, u8 command, int size,
union i2c_smbus_data *data)
{
u32 val;
val = zx2967_i2c_readl(i2c, REG_RDCONF);
val |= I2C_RFIFO_RESET;
zx2967_i2c_writel(i2c, val, REG_RDCONF);
zx2967_set_addr(i2c, addr);
val = zx2967_i2c_readl(i2c, REG_CMD);
val &= ~I2C_RW_READ;
zx2967_i2c_writel(i2c, val, REG_CMD);
switch (size) {
case I2C_SMBUS_BYTE:
zx2967_i2c_writel(i2c, command, REG_DATA);
break;
case I2C_SMBUS_BYTE_DATA:
zx2967_i2c_writel(i2c, command, REG_DATA);
if (read_write == I2C_SMBUS_WRITE)
zx2967_i2c_writel(i2c, data->byte, REG_DATA);
break;
case I2C_SMBUS_WORD_DATA:
zx2967_i2c_writel(i2c, command, REG_DATA);
if (read_write == I2C_SMBUS_WRITE) {
zx2967_i2c_writel(i2c, (data->word >> 8), REG_DATA);
zx2967_i2c_writel(i2c, (data->word & 0xff),
REG_DATA);
}
break;
}
}
static int zx2967_smbus_xfer_read(struct zx2967_i2c *i2c, int size,
union i2c_smbus_data *data)
{
unsigned long time_left;
u8 buf[2];
u32 val;
reinit_completion(&i2c->complete);
val = zx2967_i2c_readl(i2c, REG_CMD);
val |= I2C_CMB_RW_EN;
zx2967_i2c_writel(i2c, val, REG_CMD);
val = zx2967_i2c_readl(i2c, REG_CMD);
val |= I2C_START;
zx2967_i2c_writel(i2c, val, REG_CMD);
time_left = wait_for_completion_timeout(&i2c->complete,
I2C_TIMEOUT);
if (time_left == 0)
return -ETIMEDOUT;
if (i2c->error)
return i2c->error;
switch (size) {
case I2C_SMBUS_BYTE:
case I2C_SMBUS_BYTE_DATA:
val = zx2967_i2c_readl(i2c, REG_DATA);
data->byte = val;
break;
case I2C_SMBUS_WORD_DATA:
case I2C_SMBUS_PROC_CALL:
buf[0] = zx2967_i2c_readl(i2c, REG_DATA);
buf[1] = zx2967_i2c_readl(i2c, REG_DATA);
data->word = (buf[0] << 8) | buf[1];
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static int zx2967_smbus_xfer_write(struct zx2967_i2c *i2c)
{
unsigned long time_left;
u32 val;
reinit_completion(&i2c->complete);
val = zx2967_i2c_readl(i2c, REG_CMD);
val |= I2C_START;
zx2967_i2c_writel(i2c, val, REG_CMD);
time_left = wait_for_completion_timeout(&i2c->complete,
I2C_TIMEOUT);
if (time_left == 0)
return -ETIMEDOUT;
if (i2c->error)
return i2c->error;
return 0;
}
static int zx2967_smbus_xfer(struct i2c_adapter *adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size, union i2c_smbus_data *data)
{
struct zx2967_i2c *i2c = i2c_get_adapdata(adap);
if (size == I2C_SMBUS_QUICK)
read_write = I2C_SMBUS_WRITE;
switch (size) {
case I2C_SMBUS_QUICK:
case I2C_SMBUS_BYTE:
case I2C_SMBUS_BYTE_DATA:
case I2C_SMBUS_WORD_DATA:
zx2967_smbus_xfer_prepare(i2c, addr, read_write,
command, size, data);
break;
default:
return -EOPNOTSUPP;
}
if (read_write == I2C_SMBUS_READ)
return zx2967_smbus_xfer_read(i2c, size, data);
return zx2967_smbus_xfer_write(i2c);
}
static u32 zx2967_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C |
I2C_FUNC_SMBUS_QUICK |
I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_BLOCK_DATA |
I2C_FUNC_SMBUS_PROC_CALL |
I2C_FUNC_SMBUS_I2C_BLOCK;
}
static int __maybe_unused zx2967_i2c_suspend(struct device *dev)
{
struct zx2967_i2c *i2c = dev_get_drvdata(dev);
i2c->is_suspended = true;
clk_disable_unprepare(i2c->clk);
return 0;
}
static int __maybe_unused zx2967_i2c_resume(struct device *dev)
{
struct zx2967_i2c *i2c = dev_get_drvdata(dev);
i2c->is_suspended = false;
clk_prepare_enable(i2c->clk);
return 0;
}
static SIMPLE_DEV_PM_OPS(zx2967_i2c_dev_pm_ops,
zx2967_i2c_suspend, zx2967_i2c_resume);
static const struct i2c_algorithm zx2967_i2c_algo = {
.master_xfer = zx2967_i2c_xfer,
.smbus_xfer = zx2967_smbus_xfer,
.functionality = zx2967_i2c_func,
};
static const struct of_device_id zx2967_i2c_of_match[] = {
{ .compatible = "zte,zx296718-i2c", },
{ },
};
MODULE_DEVICE_TABLE(of, zx2967_i2c_of_match);
static int zx2967_i2c_probe(struct platform_device *pdev)
{
struct zx2967_i2c *i2c;
void __iomem *reg_base;
struct resource *res;
struct clk *clk;
int ret;
i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
if (!i2c)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
reg_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(reg_base))
return PTR_ERR(reg_base);
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "missing controller clock");
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret) {
dev_err(&pdev->dev, "failed to enable i2c_clk\n");
return ret;
}
ret = device_property_read_u32(&pdev->dev, "clock-frequency",
&i2c->clk_freq);
if (ret) {
dev_err(&pdev->dev, "missing clock-frequency");
return ret;
}
ret = platform_get_irq(pdev, 0);
if (ret < 0)
return ret;
i2c->irq = ret;
i2c->reg_base = reg_base;
i2c->clk = clk;
init_completion(&i2c->complete);
platform_set_drvdata(pdev, i2c);
ret = zx2967_i2c_reset_hardware(i2c);
if (ret) {
dev_err(&pdev->dev, "failed to initialize i2c controller\n");
goto err_clk_unprepare;
}
ret = devm_request_irq(&pdev->dev, i2c->irq,
zx2967_i2c_isr, 0, dev_name(&pdev->dev), i2c);
if (ret) {
dev_err(&pdev->dev, "failed to request irq %i\n", i2c->irq);
goto err_clk_unprepare;
}
i2c_set_adapdata(&i2c->adap, i2c);
strlcpy(i2c->adap.name, "zx2967 i2c adapter",
sizeof(i2c->adap.name));
i2c->adap.algo = &zx2967_i2c_algo;
i2c->adap.nr = pdev->id;
i2c->adap.dev.parent = &pdev->dev;
i2c->adap.dev.of_node = pdev->dev.of_node;
ret = i2c_add_numbered_adapter(&i2c->adap);
if (ret)
goto err_clk_unprepare;
return 0;
err_clk_unprepare:
clk_disable_unprepare(i2c->clk);
return ret;
}
static int zx2967_i2c_remove(struct platform_device *pdev)
{
struct zx2967_i2c *i2c = platform_get_drvdata(pdev);
i2c_del_adapter(&i2c->adap);
clk_disable_unprepare(i2c->clk);
return 0;
}
static struct platform_driver zx2967_i2c_driver = {
.probe = zx2967_i2c_probe,
.remove = zx2967_i2c_remove,
.driver = {
.name = "zx2967_i2c",
.of_match_table = zx2967_i2c_of_match,
.pm = &zx2967_i2c_dev_pm_ops,
},
};
module_platform_driver(zx2967_i2c_driver);
MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
MODULE_DESCRIPTION("ZTE ZX2967 I2C Bus Controller driver");
MODULE_LICENSE("GPL v2");