/*
* I2C bus driver for CSR SiRFprimaII
*
* Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
*
* Licensed under GPLv2 or later.
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#define SIRFSOC_I2C_CLK_CTRL 0x00
#define SIRFSOC_I2C_STATUS 0x0C
#define SIRFSOC_I2C_CTRL 0x10
#define SIRFSOC_I2C_IO_CTRL 0x14
#define SIRFSOC_I2C_SDA_DELAY 0x18
#define SIRFSOC_I2C_CMD_START 0x1C
#define SIRFSOC_I2C_CMD_BUF 0x30
#define SIRFSOC_I2C_DATA_BUF 0x80
#define SIRFSOC_I2C_CMD_BUF_MAX 16
#define SIRFSOC_I2C_DATA_BUF_MAX 16
#define SIRFSOC_I2C_CMD(x) (SIRFSOC_I2C_CMD_BUF + (x)*0x04)
#define SIRFSOC_I2C_DATA_MASK(x) (0xFF<<(((x)&3)*8))
#define SIRFSOC_I2C_DATA_SHIFT(x) (((x)&3)*8)
#define SIRFSOC_I2C_DIV_MASK (0xFFFF)
/* I2C status flags */
#define SIRFSOC_I2C_STAT_BUSY BIT(0)
#define SIRFSOC_I2C_STAT_TIP BIT(1)
#define SIRFSOC_I2C_STAT_NACK BIT(2)
#define SIRFSOC_I2C_STAT_TR_INT BIT(4)
#define SIRFSOC_I2C_STAT_STOP BIT(6)
#define SIRFSOC_I2C_STAT_CMD_DONE BIT(8)
#define SIRFSOC_I2C_STAT_ERR BIT(9)
#define SIRFSOC_I2C_CMD_INDEX (0x1F<<16)
/* I2C control flags */
#define SIRFSOC_I2C_RESET BIT(0)
#define SIRFSOC_I2C_CORE_EN BIT(1)
#define SIRFSOC_I2C_MASTER_MODE BIT(2)
#define SIRFSOC_I2C_CMD_DONE_EN BIT(11)
#define SIRFSOC_I2C_ERR_INT_EN BIT(12)
#define SIRFSOC_I2C_SDA_DELAY_MASK (0xFF)
#define SIRFSOC_I2C_SCLF_FILTER (3<<8)
#define SIRFSOC_I2C_START_CMD BIT(0)
#define SIRFSOC_I2C_CMD_RP(x) ((x)&0x7)
#define SIRFSOC_I2C_NACK BIT(3)
#define SIRFSOC_I2C_WRITE BIT(4)
#define SIRFSOC_I2C_READ BIT(5)
#define SIRFSOC_I2C_STOP BIT(6)
#define SIRFSOC_I2C_START BIT(7)
#define SIRFSOC_I2C_DEFAULT_SPEED 100000
#define SIRFSOC_I2C_ERR_NOACK 1
#define SIRFSOC_I2C_ERR_TIMEOUT 2
struct sirfsoc_i2c {
void __iomem *base;
struct clk *clk;
u32 cmd_ptr; /* Current position in CMD buffer */
u8 *buf; /* Buffer passed by user */
u32 msg_len; /* Message length */
u32 finished_len; /* number of bytes read/written */
u32 read_cmd_len; /* number of read cmd sent */
int msg_read; /* 1 indicates a read message */
int err_status; /* 1 indicates an error on bus */
u32 sda_delay; /* For suspend/resume */
u32 clk_div;
int last; /* Last message in transfer, STOP cmd can be sent */
struct completion done; /* indicates completion of message transfer */
struct i2c_adapter adapter;
};
static void i2c_sirfsoc_read_data(struct sirfsoc_i2c *siic)
{
u32 data = 0;
int i;
for (i = 0; i < siic->read_cmd_len; i++) {
if (!(i & 0x3))
data = readl(siic->base + SIRFSOC_I2C_DATA_BUF + i);
siic->buf[siic->finished_len++] =
(u8)((data & SIRFSOC_I2C_DATA_MASK(i)) >>
SIRFSOC_I2C_DATA_SHIFT(i));
}
}
static void i2c_sirfsoc_queue_cmd(struct sirfsoc_i2c *siic)
{
u32 regval;
int i = 0;
if (siic->msg_read) {
while (((siic->finished_len + i) < siic->msg_len)
&& (siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX)) {
regval = SIRFSOC_I2C_READ | SIRFSOC_I2C_CMD_RP(0);
if (((siic->finished_len + i) ==
(siic->msg_len - 1)) && siic->last)
regval |= SIRFSOC_I2C_STOP | SIRFSOC_I2C_NACK;
writel(regval,
siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
i++;
}
siic->read_cmd_len = i;
} else {
while ((siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX - 1)
&& (siic->finished_len < siic->msg_len)) {
regval = SIRFSOC_I2C_WRITE | SIRFSOC_I2C_CMD_RP(0);
if ((siic->finished_len == (siic->msg_len - 1))
&& siic->last)
regval |= SIRFSOC_I2C_STOP;
writel(regval,
siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
writel(siic->buf[siic->finished_len++],
siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
}
}
siic->cmd_ptr = 0;
/* Trigger the transfer */
writel(SIRFSOC_I2C_START_CMD, siic->base + SIRFSOC_I2C_CMD_START);
}
static irqreturn_t i2c_sirfsoc_irq(int irq, void *dev_id)
{
struct sirfsoc_i2c *siic = (struct sirfsoc_i2c *)dev_id;
u32 i2c_stat = readl(siic->base + SIRFSOC_I2C_STATUS);
if (i2c_stat & SIRFSOC_I2C_STAT_ERR) {
/* Error conditions */
siic->err_status = SIRFSOC_I2C_ERR_NOACK;
writel(SIRFSOC_I2C_STAT_ERR, siic->base + SIRFSOC_I2C_STATUS);
if (i2c_stat & SIRFSOC_I2C_STAT_NACK)
dev_dbg(&siic->adapter.dev, "ACK not received\n");
else
dev_err(&siic->adapter.dev, "I2C error\n");
/*
* Due to hardware ANOMALY, we need to reset I2C earlier after
* we get NOACK while accessing non-existing clients, otherwise
* we will get errors even we access existing clients later
*/
writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET,
siic->base + SIRFSOC_I2C_CTRL);
while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
cpu_relax();
complete(&siic->done);
} else if (i2c_stat & SIRFSOC_I2C_STAT_CMD_DONE) {
/* CMD buffer execution complete */
if (siic->msg_read)
i2c_sirfsoc_read_data(siic);
if (siic->finished_len == siic->msg_len)
complete(&siic->done);
else /* Fill a new CMD buffer for left data */
i2c_sirfsoc_queue_cmd(siic);
writel(SIRFSOC_I2C_STAT_CMD_DONE, siic->base + SIRFSOC_I2C_STATUS);
}
return IRQ_HANDLED;
}
static void i2c_sirfsoc_set_address(struct sirfsoc_i2c *siic,
struct i2c_msg *msg)
{
unsigned char addr;
u32 regval = SIRFSOC_I2C_START | SIRFSOC_I2C_CMD_RP(0) | SIRFSOC_I2C_WRITE;
/* no data and last message -> add STOP */
if (siic->last && (msg->len == 0))
regval |= SIRFSOC_I2C_STOP;
writel(regval, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
addr = msg->addr << 1; /* Generate address */
if (msg->flags & I2C_M_RD)
addr |= 1;
/* Reverse direction bit */
if (msg->flags & I2C_M_REV_DIR_ADDR)
addr ^= 1;
writel(addr, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
}
static int i2c_sirfsoc_xfer_msg(struct sirfsoc_i2c *siic, struct i2c_msg *msg)
{
u32 regval = readl(siic->base + SIRFSOC_I2C_CTRL);
/* timeout waiting for the xfer to finish or fail */
int timeout = msecs_to_jiffies((msg->len + 1) * 50);
i2c_sirfsoc_set_address(siic, msg);
writel(regval | SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN,
siic->base + SIRFSOC_I2C_CTRL);
i2c_sirfsoc_queue_cmd(siic);
if (wait_for_completion_timeout(&siic->done, timeout) == 0) {
siic->err_status = SIRFSOC_I2C_ERR_TIMEOUT;
dev_err(&siic->adapter.dev, "Transfer timeout\n");
}
writel(regval & ~(SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN),
siic->base + SIRFSOC_I2C_CTRL);
writel(0, siic->base + SIRFSOC_I2C_CMD_START);
/* i2c control doesn't response, reset it */
if (siic->err_status == SIRFSOC_I2C_ERR_TIMEOUT) {
writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET,
siic->base + SIRFSOC_I2C_CTRL);
while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
cpu_relax();
}
return siic->err_status ? -EAGAIN : 0;
}
static u32 i2c_sirfsoc_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static int i2c_sirfsoc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
struct sirfsoc_i2c *siic = adap->algo_data;
int i, ret;
clk_enable(siic->clk);
for (i = 0; i < num; i++) {
siic->buf = msgs[i].buf;
siic->msg_len = msgs[i].len;
siic->msg_read = !!(msgs[i].flags & I2C_M_RD);
siic->err_status = 0;
siic->cmd_ptr = 0;
siic->finished_len = 0;
siic->last = (i == (num - 1));
ret = i2c_sirfsoc_xfer_msg(siic, &msgs[i]);
if (ret) {
clk_disable(siic->clk);
return ret;
}
}
clk_disable(siic->clk);
return num;
}
/* I2C algorithms associated with this master controller driver */
static const struct i2c_algorithm i2c_sirfsoc_algo = {
.master_xfer = i2c_sirfsoc_xfer,
.functionality = i2c_sirfsoc_func,
};
static int i2c_sirfsoc_probe(struct platform_device *pdev)
{
struct sirfsoc_i2c *siic;
struct i2c_adapter *adap;
struct resource *mem_res;
struct clk *clk;
int bitrate;
int ctrl_speed;
int irq;
int e
