https://github.com/torvalds/linux
Tip revision: a7904a538933c525096ca2ccde1e60d0ee62c08e authored by Linus Torvalds on 19 December 2021, 22:14:33 UTC
Linux 5.16-rc6
Linux 5.16-rc6
Tip revision: a7904a5
i2c-owl.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Actions Semiconductor Owl SoC's I2C driver
*
* Copyright (c) 2014 Actions Semi Inc.
* Author: David Liu <liuwei@actions-semi.com>
*
* Copyright (c) 2018 Linaro Ltd.
* Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of_device.h>
/* I2C registers */
#define OWL_I2C_REG_CTL 0x0000
#define OWL_I2C_REG_CLKDIV 0x0004
#define OWL_I2C_REG_STAT 0x0008
#define OWL_I2C_REG_ADDR 0x000C
#define OWL_I2C_REG_TXDAT 0x0010
#define OWL_I2C_REG_RXDAT 0x0014
#define OWL_I2C_REG_CMD 0x0018
#define OWL_I2C_REG_FIFOCTL 0x001C
#define OWL_I2C_REG_FIFOSTAT 0x0020
#define OWL_I2C_REG_DATCNT 0x0024
#define OWL_I2C_REG_RCNT 0x0028
/* I2Cx_CTL Bit Mask */
#define OWL_I2C_CTL_RB BIT(1)
#define OWL_I2C_CTL_GBCC(x) (((x) & 0x3) << 2)
#define OWL_I2C_CTL_GBCC_NONE OWL_I2C_CTL_GBCC(0)
#define OWL_I2C_CTL_GBCC_START OWL_I2C_CTL_GBCC(1)
#define OWL_I2C_CTL_GBCC_STOP OWL_I2C_CTL_GBCC(2)
#define OWL_I2C_CTL_GBCC_RSTART OWL_I2C_CTL_GBCC(3)
#define OWL_I2C_CTL_IRQE BIT(5)
#define OWL_I2C_CTL_EN BIT(7)
#define OWL_I2C_CTL_AE BIT(8)
#define OWL_I2C_CTL_SHSM BIT(10)
#define OWL_I2C_DIV_FACTOR(x) ((x) & 0xff)
/* I2Cx_STAT Bit Mask */
#define OWL_I2C_STAT_RACK BIT(0)
#define OWL_I2C_STAT_BEB BIT(1)
#define OWL_I2C_STAT_IRQP BIT(2)
#define OWL_I2C_STAT_LAB BIT(3)
#define OWL_I2C_STAT_STPD BIT(4)
#define OWL_I2C_STAT_STAD BIT(5)
#define OWL_I2C_STAT_BBB BIT(6)
#define OWL_I2C_STAT_TCB BIT(7)
#define OWL_I2C_STAT_LBST BIT(8)
#define OWL_I2C_STAT_SAMB BIT(9)
#define OWL_I2C_STAT_SRGC BIT(10)
/* I2Cx_CMD Bit Mask */
#define OWL_I2C_CMD_SBE BIT(0)
#define OWL_I2C_CMD_RBE BIT(4)
#define OWL_I2C_CMD_DE BIT(8)
#define OWL_I2C_CMD_NS BIT(9)
#define OWL_I2C_CMD_SE BIT(10)
#define OWL_I2C_CMD_MSS BIT(11)
#define OWL_I2C_CMD_WRS BIT(12)
#define OWL_I2C_CMD_SECL BIT(15)
#define OWL_I2C_CMD_AS(x) (((x) & 0x7) << 1)
#define OWL_I2C_CMD_SAS(x) (((x) & 0x7) << 5)
/* I2Cx_FIFOCTL Bit Mask */
#define OWL_I2C_FIFOCTL_NIB BIT(0)
#define OWL_I2C_FIFOCTL_RFR BIT(1)
#define OWL_I2C_FIFOCTL_TFR BIT(2)
/* I2Cc_FIFOSTAT Bit Mask */
#define OWL_I2C_FIFOSTAT_CECB BIT(0)
#define OWL_I2C_FIFOSTAT_RNB BIT(1)
#define OWL_I2C_FIFOSTAT_RFE BIT(2)
#define OWL_I2C_FIFOSTAT_TFF BIT(5)
#define OWL_I2C_FIFOSTAT_TFD GENMASK(23, 16)
#define OWL_I2C_FIFOSTAT_RFD GENMASK(15, 8)
/* I2C bus timeout */
#define OWL_I2C_TIMEOUT_MS (4 * 1000)
#define OWL_I2C_TIMEOUT msecs_to_jiffies(OWL_I2C_TIMEOUT_MS)
#define OWL_I2C_MAX_RETRIES 50
struct owl_i2c_dev {
struct i2c_adapter adap;
struct i2c_msg *msg;
struct completion msg_complete;
struct clk *clk;
spinlock_t lock;
void __iomem *base;
unsigned long clk_rate;
u32 bus_freq;
u32 msg_ptr;
int err;
};
static void owl_i2c_update_reg(void __iomem *reg, unsigned int val, bool state)
{
unsigned int regval;
regval = readl(reg);
if (state)
regval |= val;
else
regval &= ~val;
writel(regval, reg);
}
static void owl_i2c_reset(struct owl_i2c_dev *i2c_dev)
{
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
OWL_I2C_CTL_EN, false);
mdelay(1);
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
OWL_I2C_CTL_EN, true);
/* Clear status registers */
writel(0, i2c_dev->base + OWL_I2C_REG_STAT);
}
static int owl_i2c_reset_fifo(struct owl_i2c_dev *i2c_dev)
{
unsigned int val, timeout = 0;
/* Reset FIFO */
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL,
OWL_I2C_FIFOCTL_RFR | OWL_I2C_FIFOCTL_TFR,
true);
/* Wait 50ms for FIFO reset complete */
do {
val = readl(i2c_dev->base + OWL_I2C_REG_FIFOCTL);
if (!(val & (OWL_I2C_FIFOCTL_RFR | OWL_I2C_FIFOCTL_TFR)))
break;
usleep_range(500, 1000);
} while (timeout++ < OWL_I2C_MAX_RETRIES);
if (timeout > OWL_I2C_MAX_RETRIES) {
dev_err(&i2c_dev->adap.dev, "FIFO reset timeout\n");
return -ETIMEDOUT;
}
return 0;
}
static void owl_i2c_set_freq(struct owl_i2c_dev *i2c_dev)
{
unsigned int val;
val = DIV_ROUND_UP(i2c_dev->clk_rate, i2c_dev->bus_freq * 16);
/* Set clock divider factor */
writel(OWL_I2C_DIV_FACTOR(val), i2c_dev->base + OWL_I2C_REG_CLKDIV);
}
static void owl_i2c_xfer_data(struct owl_i2c_dev *i2c_dev)
{
struct i2c_msg *msg = i2c_dev->msg;
unsigned int stat, fifostat;
i2c_dev->err = 0;
/* Handle NACK from slave */
fifostat = readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT);
if (fifostat & OWL_I2C_FIFOSTAT_RNB) {
i2c_dev->err = -ENXIO;
/* Clear NACK error bit by writing "1" */
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOSTAT,
OWL_I2C_FIFOSTAT_RNB, true);
return;
}
/* Handle bus error */
stat = readl(i2c_dev->base + OWL_I2C_REG_STAT);
if (stat & OWL_I2C_STAT_BEB) {
i2c_dev->err = -EIO;
/* Clear BUS error bit by writing "1" */
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_STAT,
OWL_I2C_STAT_BEB, true);
return;
}
/* Handle FIFO read */
if (msg->flags & I2C_M_RD) {
while ((readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) &
OWL_I2C_FIFOSTAT_RFE) && i2c_dev->msg_ptr < msg->len) {
msg->buf[i2c_dev->msg_ptr++] = readl(i2c_dev->base +
OWL_I2C_REG_RXDAT);
}
} else {
/* Handle the remaining bytes which were not sent */
while (!(readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) &
OWL_I2C_FIFOSTAT_TFF) && i2c_dev->msg_ptr < msg->len) {
writel(msg->buf[i2c_dev->msg_ptr++],
i2c_dev->base + OWL_I2C_REG_TXDAT);
}
}
}
static irqreturn_t owl_i2c_interrupt(int irq, void *_dev)
{
struct owl_i2c_dev *i2c_dev = _dev;
spin_lock(&i2c_dev->lock);
owl_i2c_xfer_data(i2c_dev);
/* Clear pending interrupts */
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_STAT,
OWL_I2C_STAT_IRQP, true);
complete_all(&i2c_dev->msg_complete);
spin_unlock(&i2c_dev->lock);
return IRQ_HANDLED;
}
static u32 owl_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static int owl_i2c_check_bus_busy(struct i2c_adapter *adap)
{
struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
unsigned long timeout;
/* Check for Bus busy */
timeout = jiffies + OWL_I2C_TIMEOUT;
while (readl(i2c_dev->base + OWL_I2C_REG_STAT) & OWL_I2C_STAT_BBB) {
if (time_after(jiffies, timeout)) {
dev_err(&adap->dev, "Bus busy timeout\n");
return -ETIMEDOUT;
}
}
return 0;
}
static int owl_i2c_xfer_common(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num, bool atomic)
{
struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
struct i2c_msg *msg;
unsigned long time_left, flags;
unsigned int i2c_cmd, val;
unsigned int addr;
int ret, idx;
spin_lock_irqsave(&i2c_dev->lock, flags);
/* Reset I2C controller */
owl_i2c_reset(i2c_dev);
/* Set bus frequency */
owl_i2c_set_freq(i2c_dev);
/*
* Spinlock should be released before calling reset FIFO and
* bus busy check since those functions may sleep
*/
spin_unlock_irqrestore(&i2c_dev->lock, flags);
/* Reset FIFO */
ret = owl_i2c_reset_fifo(i2c_dev);
if (ret)
goto unlocked_err_exit;
/* Check for bus busy */
ret = owl_i2c_check_bus_busy(adap);
if (ret)
goto unlocked_err_exit;
spin_lock_irqsave(&i2c_dev->lock, flags);
/* Check for Arbitration lost */
val = readl(i2c_dev->base + OWL_I2C_REG_STAT);
if (val & OWL_I2C_STAT_LAB) {
val &= ~OWL_I2C_STAT_LAB;
writel(val, i2c_dev->base + OWL_I2C_REG_STAT);
ret = -EAGAIN;
goto err_exit;
}
if (!atomic)
reinit_completion(&i2c_dev->msg_complete);
/* Enable/disable I2C controller interrupt */
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
OWL_I2C_CTL_IRQE, !atomic);
/*
* Select: FIFO enable, Master mode, Stop enable, Data count enable,
* Send start bit
*/
i2c_cmd = OWL_I2C_CMD_SECL | OWL_I2C_CMD_MSS | OWL_I2C_CMD_SE |
OWL_I2C_CMD_NS | OWL_I2C_CMD_DE | OWL_I2C_CMD_SBE;
/* Handle repeated start condition */
if (num > 1) {
/* Set internal address length and enable repeated start */
i2c_cmd |= OWL_I2C_CMD_AS(msgs[0].len + 1) |
OWL_I2C_CMD_SAS(1) | OWL_I2C_CMD_RBE;
/* Write slave address */
addr = i2c_8bit_addr_from_msg(&msgs[0]);
writel(addr, i2c_dev->base + OWL_I2C_REG_TXDAT);
/* Write internal register address */
for (idx = 0; idx < msgs[0].len; idx++)
writel(msgs[0].buf[idx],
i2c_dev->base + OWL_I2C_REG_TXDAT);
msg = &msgs[1];
} else {
/* Set address length */
i2c_cmd |= OWL_I2C_CMD_AS(1);
msg = &msgs[0];
}
i2c_dev->msg = msg;
i2c_dev->msg_ptr = 0;
/* Set data count for the message */
writel(msg->len, i2c_dev->base + OWL_I2C_REG_DATCNT);
addr = i2c_8bit_addr_from_msg(msg);
writel(addr, i2c_dev->base + OWL_I2C_REG_TXDAT);
if (!(msg->flags & I2C_M_RD)) {
/* Write data to FIFO */
for (idx = 0; idx < msg->len; idx++) {
/* Check for FIFO full */
if (readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) &
OWL_I2C_FIFOSTAT_TFF)
break;
writel(msg->buf[idx],
i2c_dev->base + OWL_I2C_REG_TXDAT);
}
i2c_dev->msg_ptr = idx;
}
/* Ignore the NACK if needed */
if (msg->flags & I2C_M_IGNORE_NAK)
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL,
OWL_I2C_FIFOCTL_NIB, true);
else
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL,
OWL_I2C_FIFOCTL_NIB, false);
/* Start the transfer */
writel(i2c_cmd, i2c_dev->base + OWL_I2C_REG_CMD);
spin_unlock_irqrestore(&i2c_dev->lock, flags);
if (atomic) {
/* Wait for Command Execute Completed or NACK Error bits */
ret = readl_poll_timeout_atomic(i2c_dev->base + OWL_I2C_REG_FIFOSTAT,
val, val & (OWL_I2C_FIFOSTAT_CECB |
OWL_I2C_FIFOSTAT_RNB),
10, OWL_I2C_TIMEOUT_MS * 1000);
} else {
time_left = wait_for_completion_timeout(&i2c_dev->msg_complete,
adap->timeout);
if (!time_left)
ret = -ETIMEDOUT;
}
spin_lock_irqsave(&i2c_dev->lock, flags);
if (ret) {
dev_err(&adap->dev, "Transaction timed out\n");
/* Send stop condition and release the bus */
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
OWL_I2C_CTL_GBCC_STOP | OWL_I2C_CTL_RB,
true);
goto err_exit;
}
if (atomic)
owl_i2c_xfer_data(i2c_dev);
ret = i2c_dev->err < 0 ? i2c_dev->err : num;
err_exit:
spin_unlock_irqrestore(&i2c_dev->lock, flags);
unlocked_err_exit:
/* Disable I2C controller */
owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
OWL_I2C_CTL_EN, false);
return ret;
}
static int owl_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
return owl_i2c_xfer_common(adap, msgs, num, false);
}
static int owl_i2c_xfer_atomic(struct i2c_adapter *adap,
struct i2c_msg *msgs, int num)
{
return owl_i2c_xfer_common(adap, msgs, num, true);
}
static const struct i2c_algorithm owl_i2c_algorithm = {
.master_xfer = owl_i2c_xfer,
.master_xfer_atomic = owl_i2c_xfer_atomic,
.functionality = owl_i2c_func,
};
static const struct i2c_adapter_quirks owl_i2c_quirks = {
.flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST,
.max_read_len = 240,
.max_write_len = 240,
.max_comb_1st_msg_len = 6,
.max_comb_2nd_msg_len = 240,
};
static int owl_i2c_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct owl_i2c_dev *i2c_dev;
int ret, irq;
i2c_dev = devm_kzalloc(dev, sizeof(*i2c_dev), GFP_KERNEL);
if (!i2c_dev)
return -ENOMEM;
i2c_dev->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(i2c_dev->base))
return PTR_ERR(i2c_dev->base);
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
if (of_property_read_u32(dev->of_node, "clock-frequency",
&i2c_dev->bus_freq))
i2c_dev->bus_freq = I2C_MAX_STANDARD_MODE_FREQ;
/* We support only frequencies of 100k and 400k for now */
if (i2c_dev->bus_freq != I2C_MAX_STANDARD_MODE_FREQ &&
i2c_dev->bus_freq != I2C_MAX_FAST_MODE_FREQ) {
dev_err(dev, "invalid clock-frequency %d\n", i2c_dev->bus_freq);
return -EINVAL;
}
i2c_dev->clk = devm_clk_get(dev, NULL);
if (IS_ERR(i2c_dev->clk)) {
dev_err(dev, "failed to get clock\n");
return PTR_ERR(i2c_dev->clk);
}
ret = clk_prepare_enable(i2c_dev->clk);
if (ret)
return ret;
i2c_dev->clk_rate = clk_get_rate(i2c_dev->clk);
if (!i2c_dev->clk_rate) {
dev_err(dev, "input clock rate should not be zero\n");
ret = -EINVAL;
goto disable_clk;
}
init_completion(&i2c_dev->msg_complete);
spin_lock_init(&i2c_dev->lock);
i2c_dev->adap.owner = THIS_MODULE;
i2c_dev->adap.algo = &owl_i2c_algorithm;
i2c_dev->adap.timeout = OWL_I2C_TIMEOUT;
i2c_dev->adap.quirks = &owl_i2c_quirks;
i2c_dev->adap.dev.parent = dev;
i2c_dev->adap.dev.of_node = dev->of_node;
snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
"%s", "OWL I2C adapter");
i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
platform_set_drvdata(pdev, i2c_dev);
ret = devm_request_irq(dev, irq, owl_i2c_interrupt, 0, pdev->name,
i2c_dev);
if (ret) {
dev_err(dev, "failed to request irq %d\n", irq);
goto disable_clk;
}
return i2c_add_adapter(&i2c_dev->adap);
disable_clk:
clk_disable_unprepare(i2c_dev->clk);
return ret;
}
static const struct of_device_id owl_i2c_of_match[] = {
{ .compatible = "actions,s500-i2c" },
{ .compatible = "actions,s700-i2c" },
{ .compatible = "actions,s900-i2c" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, owl_i2c_of_match);
static struct platform_driver owl_i2c_driver = {
.probe = owl_i2c_probe,
.driver = {
.name = "owl-i2c",
.of_match_table = of_match_ptr(owl_i2c_of_match),
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
},
};
module_platform_driver(owl_i2c_driver);
MODULE_AUTHOR("David Liu <liuwei@actions-semi.com>");
MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
MODULE_DESCRIPTION("Actions Semiconductor Owl SoC's I2C driver");
MODULE_LICENSE("GPL");