- 根目录:
- drivers
- i2c
- busses
- i2c-xlp9xx.c
/*
* Copyright (c) 2003-2015 Broadcom Corporation
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/completion.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#define XLP9XX_I2C_DIV 0x0
#define XLP9XX_I2C_CTRL 0x1
#define XLP9XX_I2C_CMD 0x2
#define XLP9XX_I2C_STATUS 0x3
#define XLP9XX_I2C_MTXFIFO 0x4
#define XLP9XX_I2C_MRXFIFO 0x5
#define XLP9XX_I2C_MFIFOCTRL 0x6
#define XLP9XX_I2C_STXFIFO 0x7
#define XLP9XX_I2C_SRXFIFO 0x8
#define XLP9XX_I2C_SFIFOCTRL 0x9
#define XLP9XX_I2C_SLAVEADDR 0xA
#define XLP9XX_I2C_OWNADDR 0xB
#define XLP9XX_I2C_FIFOWCNT 0xC
#define XLP9XX_I2C_INTEN 0xD
#define XLP9XX_I2C_INTST 0xE
#define XLP9XX_I2C_WAITCNT 0xF
#define XLP9XX_I2C_TIMEOUT 0X10
#define XLP9XX_I2C_GENCALLADDR 0x11
#define XLP9XX_I2C_CMD_START BIT(7)
#define XLP9XX_I2C_CMD_STOP BIT(6)
#define XLP9XX_I2C_CMD_READ BIT(5)
#define XLP9XX_I2C_CMD_WRITE BIT(4)
#define XLP9XX_I2C_CMD_ACK BIT(3)
#define XLP9XX_I2C_CTRL_MCTLEN_SHIFT 16
#define XLP9XX_I2C_CTRL_MCTLEN_MASK 0xffff0000
#define XLP9XX_I2C_CTRL_RST BIT(8)
#define XLP9XX_I2C_CTRL_EN BIT(6)
#define XLP9XX_I2C_CTRL_MASTER BIT(4)
#define XLP9XX_I2C_CTRL_FIFORD BIT(1)
#define XLP9XX_I2C_CTRL_ADDMODE BIT(0)
#define XLP9XX_I2C_INTEN_NACKADDR BIT(25)
#define XLP9XX_I2C_INTEN_SADDR BIT(13)
#define XLP9XX_I2C_INTEN_DATADONE BIT(12)
#define XLP9XX_I2C_INTEN_ARLOST BIT(11)
#define XLP9XX_I2C_INTEN_MFIFOFULL BIT(4)
#define XLP9XX_I2C_INTEN_MFIFOEMTY BIT(3)
#define XLP9XX_I2C_INTEN_MFIFOHI BIT(2)
#define XLP9XX_I2C_INTEN_BUSERR BIT(0)
#define XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT 8
#define XLP9XX_I2C_MFIFOCTRL_LOTH_SHIFT 0
#define XLP9XX_I2C_MFIFOCTRL_RST BIT(16)
#define XLP9XX_I2C_SLAVEADDR_RW BIT(0)
#define XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT 1
#define XLP9XX_I2C_IP_CLK_FREQ 133000000UL
#define XLP9XX_I2C_DEFAULT_FREQ 100000
#define XLP9XX_I2C_HIGH_FREQ 400000
#define XLP9XX_I2C_FIFO_SIZE 0x80U
#define XLP9XX_I2C_TIMEOUT_MS 1000
#define XLP9XX_I2C_FIFO_WCNT_MASK 0xff
#define XLP9XX_I2C_STATUS_ERRMASK (XLP9XX_I2C_INTEN_ARLOST | \
XLP9XX_I2C_INTEN_NACKADDR | XLP9XX_I2C_INTEN_BUSERR)
struct xlp9xx_i2c_dev {
struct device *dev;
struct i2c_adapter adapter;
struct completion msg_complete;
int irq;
bool msg_read;
u32 __iomem *base;
u32 msg_buf_remaining;
u32 msg_len;
u32 clk_hz;
u32 msg_err;
u8 *msg_buf;
};
static inline void xlp9xx_write_i2c_reg(struct xlp9xx_i2c_dev *priv,
unsigned long reg, u32 val)
{
writel(val, priv->base + reg);
}
static inline u32 xlp9xx_read_i2c_reg(struct xlp9xx_i2c_dev *priv,
unsigned long reg)
{
return readl(priv->base + reg);
}
static void xlp9xx_i2c_mask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
{
u32 inten;
inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) & ~mask;
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
}
static void xlp9xx_i2c_unmask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
{
u32 inten;
inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) | mask;
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
}
static void xlp9xx_i2c_update_rx_fifo_thres(struct xlp9xx_i2c_dev *priv)
{
u32 thres;
thres = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
thres << XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT);
}
static void xlp9xx_i2c_fill_tx_fifo(struct xlp9xx_i2c_dev *priv)
{
u32 len, i;
u8 *buf = priv->msg_buf;
len = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
for (i = 0; i < len; i++)
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MTXFIFO, buf[i]);
priv->msg_buf_remaining -= len;
priv->msg_buf += len;
}
static void xlp9xx_i2c_drain_rx_fifo(struct xlp9xx_i2c_dev *priv)
{
u32 len, i;
u8 *buf = priv->msg_buf;
len = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_FIFOWCNT) &
XLP9XX_I2C_FIFO_WCNT_MASK;
len = min(priv->msg_buf_remaining, len);
for (i = 0; i < len; i++, buf++)
*buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
priv->msg_buf_remaining -= len;
priv->msg_buf = buf;
if (priv->msg_buf_remaining)
xlp9xx_i2c_update_rx_fifo_thres(priv);
}
static irqreturn_t xlp9xx_i2c_isr(int irq, void *dev_id)
{
struct xlp9xx_i2c_dev *priv = dev_id;
u32 status;
status = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTST);
if (status == 0)
return IRQ_NONE;
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTST, status);
if (status & XLP9XX_I2C_STATUS_ERRMASK) {
priv->msg_err = status;
goto xfer_done;
}
/* SADDR ACK for SMBUS_QUICK */
if ((status & XLP9XX_I2C_INTEN_SADDR) && (priv->msg_len == 0))
goto xfer_done;
if (!priv->msg_read) {
if (status & XLP9XX_I2C_INTEN_MFIFOEMTY) {
/* TX FIFO got empty, fill it up again */
if (priv->msg_buf_remaining)
xlp9xx_i2c_fill_tx_fifo(priv);
else
xlp9xx_i2c_mask_irq(priv,
XLP9XX_I2C_INTEN_MFIFOEMTY);
}
} else {
if (status & (XLP9XX_I2C_INTEN_DATADONE |
XLP9XX_I2C_INTEN_MFIFOHI)) {
/* data is in FIFO, read it */
if (priv->msg_buf_remaining)
xlp9xx_i2c_drain_rx_fifo(priv);
}
}
/* Transfer complete */
if (status & XLP9XX_I2C_INTEN_DATADONE)
goto xfer_done;
return IRQ_HANDLED;
xfer_done:
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
complete(&priv->msg_complete);
return IRQ_HANDLED;
}
static int xlp9xx_i2c_init(struct xlp9xx_i2c_dev *priv)
{
u32 prescale;
/*
* The controller uses 5 * SCL clock internally.
* So prescale value should be divided by 5.
*/
prescale = DIV_ROUND_UP(XLP9XX_I2C_IP_CLK_FREQ, priv->clk_hz);
prescale = ((prescale - 8) / 5) - 1;
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_RST);
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_EN |
XLP9XX_I2C_CTRL_MASTER);
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_DIV, prescale);
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
return 0;
}
static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg,
int last_msg)
{
unsigned long timeleft;
u32 intr_mask, cmd, val;
priv->msg_buf = msg->buf;
priv->msg_buf_remaining = priv->msg_len = msg->len;
priv->msg_err = 0;
priv->msg_read = (msg->flags & I2C_M_RD);
reinit_completion(&priv->msg_complete);
/* Reset FIFO */
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
XLP9XX_I2C_MFIFOCTRL_RST);
/* set FIFO threshold if reading */
if (priv->msg_read)
xlp9xx_i2c_update_rx_fifo_thres(priv);
/* set slave addr */
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_SLAVEADDR,
(msg->addr << XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT) |
(priv->msg_read ? XLP9XX_I2C_SLAVEADDR_RW : 0));
/* Build control word for transfer */
val = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_CTRL);
if (!priv->msg_read)
val &= ~XLP9XX_I2C_CTRL_FIFORD;
else
val |= XLP9XX_I2C_CTRL_FIFORD; /* read */
if (msg->flags & I2C_M_TEN)
val |= XLP9XX_I2C_CTRL_ADDMODE; /* 10-bit address mode*/
else
val &= ~XLP9XX_I2C_CTRL_ADDMODE;
/* set data length to be transferred */
val = (val & ~XLP9XX_I2C_CTRL_MCTLEN_MASK) |
(msg->len << XLP9XX_I2C_CTRL_MCTLEN_SHIFT);
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, val);
/* fill fifo during tx */
if (!priv->msg_read)
xlp9xx_i2c_fill_tx_fifo(priv);
/* set interrupt mask */
intr_mask = (XLP9XX_I2C_INTEN_ARLOST | XLP9XX_I2C_INTEN_BUSERR |
XLP9XX_I2C_INTEN_NACKADDR | XLP9XX_I2C_INTEN_DATADONE);
if (priv->msg_read) {
intr_mask |= XLP9XX_I2C_INTEN_MFIFOHI;
if (msg->len == 0)
intr_mask |= XLP9XX_I2C_INTEN_SADDR;
} else {
if (msg->len == 0)
intr_mask |= XLP9XX_I2C_INTEN_SADDR;
else
intr_mask |= XLP9XX_I2C_INTEN_MFIFOEMTY;
}
xlp9xx_i2c_unmask_irq(priv, intr_mask);
/* set cmd reg */
cmd = XLP9XX_I2C_CMD_START;
cmd |= (priv->msg_read ? XLP9XX_I2C_CMD_READ : XLP9XX_I2C_CMD_WRITE);
if (last_msg)
cmd |= XLP9XX_I2C_CMD_STOP;
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CMD, cmd);
timeleft = msecs_to_jiffies(XLP9XX_I2C_TIMEOUT_MS);
timeleft = wait_for_completion_timeout(&priv->msg_complete, timeleft);
if (priv->msg_err) {
dev_dbg(priv->dev, "transfer error %x!\n", priv->msg_err);
if (priv->msg_err & XLP9XX_I2C_INTEN_BUSERR)
xlp9xx_i2c_init(priv);
return -EIO;
}
if (timeleft == 0) {
dev_dbg(priv->dev, "i2c transfer timed out!\n");
xlp9xx_i2c_init(priv);
return -ETIMEDOUT;
}
return 0;
}
static int xlp9xx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
int i, ret;
struct xlp9xx_i2c_dev *priv = i2c_get_adapdata(adap);
for (i = 0; i < num; i++) {
ret = xlp9xx_i2c_xfer_msg(priv, &msgs[i], i == num - 1);
if (ret != 0)
return ret;
}
return num;
}
static u32 xlp9xx_i2c_functionality(struct i2c_adapter *adapter)
{
return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C |
I2C_FUNC_10BIT_ADDR;
}
static struct i2c_algorithm xlp9xx_i2c_algo = {
.master_xfer = xlp9xx_i2c_xfer,
.functionality = xlp9xx_i2c_functionality,
};
static int xlp9xx_i2c_get_frequency(struct platform_device *pdev,
struct xlp9xx_i2c_dev *priv)
{
struct device_node *np = pdev->dev.of_node;
u32 freq;
int err;
err = of_property_read_u32(np, "clock-frequency", &freq);
if (err) {
freq = XLP9XX_I2C_DEFAULT_FREQ;
dev_dbg(&pdev->dev, "using default frequency %u\n", freq);
} else if (freq == 0 || freq > XLP9XX_I2C_HIGH_FREQ) {
dev_warn(&pdev->dev, "invalid frequency %u, using default\n",
freq);
freq = XLP9XX_I2C_DEFAULT_FREQ;
}
priv->clk_hz = freq;
return 0;
}
static int xlp9xx_i2c_probe(struct platform_device *pdev)
{
struct xlp9xx_i2c_dev *priv;
struct resource *res;
int err = 0;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->base))
return PTR_ERR(priv->base);
priv->irq = platform_get_irq(pdev, 0);
if (priv->irq <= 0) {
dev_err(&pdev->dev, "invalid irq!\n");
return priv->irq;
}
xlp9xx_i2c_get_frequency(pdev, priv);
xlp9xx_i2c_init(priv);
err = devm_request_irq(&pdev->dev, priv->irq, xlp9xx_i2c_isr, 0,
pdev->name, priv);
if (err) {
dev_err(&pdev->dev, "IRQ request failed!\n");
return err;
}
init_completion(&priv->msg_complete);
priv->adapter.dev.parent = &pdev->dev;
priv->adapter.algo = &xlp9xx_i2c_algo;
priv->adapter.dev.of_node = pdev->dev.of_node;
priv->dev = &pdev->dev;
snprintf(priv->adapter.name, sizeof(priv->adapter.name), "xlp9xx-i2c");
i2c_set_adapdata(&priv->adapter, priv);
err = i2c_add_adapter(&priv->adapter);
if (err) {
dev_err(&pdev->dev, "failed to add I2C adapter!\n");
return err;
}
platform_set_drvdata(pdev, priv);
dev_dbg(&pdev->dev, "I2C bus:%d added\n", priv->adapter.nr);
return 0;
}
static int xlp9xx_i2c_remove(struct platform_device *pdev)
{
struct xlp9xx_i2c_dev *priv;
priv = platform_get_drvdata(pdev);
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
synchronize_irq(priv->irq);
i2c_del_adapter(&priv->adapter);
xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, 0);
return 0;
}
static const struct of_device_id xlp9xx_i2c_of_match[] = {
{ .compatible = "netlogic,xlp980-i2c", },
{ /* sentinel */ },
};
static struct platform_driver xlp9xx_i2c_driver = {
.probe = xlp9xx_i2c_probe,
.remove = xlp9xx_i2c_remove,
.driver = {
.name = "xlp9xx-i2c",
.of_match_table = xlp9xx_i2c_of_match,
},
};
module_platform_driver(xlp9xx_i2c_driver);
MODULE_AUTHOR("Subhendu Sekhar Behera <sbehera@broadcom.com>");
MODULE_DESCRIPTION("XLP9XX/5XX I2C Bus Controller Driver");
MODULE_LICENSE("GPL v2");