- 根目录:
- drivers
- i2c
- busses
- i2c-rcar.c
/*
* Driver for the Renesas RCar I2C unit
*
* Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
*
* Copyright (C) 2012-14 Renesas Solutions Corp.
* Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
*
* This file is based on the drivers/i2c/busses/i2c-sh7760.c
* (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
*
* This file used out-of-tree driver i2c-rcar.c
* Copyright (C) 2011-2012 Renesas Electronics Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/i2c.h>
#include <linux/i2c/i2c-rcar.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
/* register offsets */
#define ICSCR 0x00 /* slave ctrl */
#define ICMCR 0x04 /* master ctrl */
#define ICSSR 0x08 /* slave status */
#define ICMSR 0x0C /* master status */
#define ICSIER 0x10 /* slave irq enable */
#define ICMIER 0x14 /* master irq enable */
#define ICCCR 0x18 /* clock dividers */
#define ICSAR 0x1C /* slave address */
#define ICMAR 0x20 /* master address */
#define ICRXTX 0x24 /* data port */
/* ICSCR */
#define SDBS (1 << 3) /* slave data buffer select */
#define SIE (1 << 2) /* slave interface enable */
#define GCAE (1 << 1) /* general call address enable */
#define FNA (1 << 0) /* forced non acknowledgment */
/* ICMCR */
#define MDBS (1 << 7) /* non-fifo mode switch */
#define FSCL (1 << 6) /* override SCL pin */
#define FSDA (1 << 5) /* override SDA pin */
#define OBPC (1 << 4) /* override pins */
#define MIE (1 << 3) /* master if enable */
#define TSBE (1 << 2)
#define FSB (1 << 1) /* force stop bit */
#define ESG (1 << 0) /* en startbit gen */
/* ICSSR (also for ICSIER) */
#define GCAR (1 << 6) /* general call received */
#define STM (1 << 5) /* slave transmit mode */
#define SSR (1 << 4) /* stop received */
#define SDE (1 << 3) /* slave data empty */
#define SDT (1 << 2) /* slave data transmitted */
#define SDR (1 << 1) /* slave data received */
#define SAR (1 << 0) /* slave addr received */
/* ICMSR (also for ICMIE) */
#define MNR (1 << 6) /* nack received */
#define MAL (1 << 5) /* arbitration lost */
#define MST (1 << 4) /* sent a stop */
#define MDE (1 << 3)
#define MDT (1 << 2)
#define MDR (1 << 1)
#define MAT (1 << 0) /* slave addr xfer done */
#define RCAR_BUS_PHASE_START (MDBS | MIE | ESG)
#define RCAR_BUS_PHASE_DATA (MDBS | MIE)
#define RCAR_BUS_PHASE_STOP (MDBS | MIE | FSB)
#define RCAR_IRQ_SEND (MNR | MAL | MST | MAT | MDE)
#define RCAR_IRQ_RECV (MNR | MAL | MST | MAT | MDR)
#define RCAR_IRQ_STOP (MST)
#define RCAR_IRQ_ACK_SEND (~(MAT | MDE) & 0xFF)
#define RCAR_IRQ_ACK_RECV (~(MAT | MDR) & 0xFF)
#define ID_LAST_MSG (1 << 0)
#define ID_IOERROR (1 << 1)
#define ID_DONE (1 << 2)
#define ID_ARBLOST (1 << 3)
#define ID_NACK (1 << 4)
enum rcar_i2c_type {
I2C_RCAR_GEN1,
I2C_RCAR_GEN2,
};
struct rcar_i2c_priv {
void __iomem *io;
struct i2c_adapter adap;
struct i2c_msg *msg;
struct clk *clk;
spinlock_t lock;
wait_queue_head_t wait;
int pos;
u32 icccr;
u32 flags;
enum rcar_i2c_type devtype;
struct i2c_client *slave;
};
#define rcar_i2c_priv_to_dev(p) ((p)->adap.dev.parent)
#define rcar_i2c_is_recv(p) ((p)->msg->flags & I2C_M_RD)
#define rcar_i2c_flags_set(p, f) ((p)->flags |= (f))
#define rcar_i2c_flags_has(p, f) ((p)->flags & (f))
#define LOOP_TIMEOUT 1024
static void rcar_i2c_write(struct rcar_i2c_priv *priv, int reg, u32 val)
{
writel(val, priv->io + reg);
}
static u32 rcar_i2c_read(struct rcar_i2c_priv *priv, int reg)
{
return readl(priv->io + reg);
}
static void rcar_i2c_init(struct rcar_i2c_priv *priv)
{
/* reset master mode */
rcar_i2c_write(priv, ICMIER, 0);
rcar_i2c_write(priv, ICMCR, 0);
rcar_i2c_write(priv, ICMSR, 0);
rcar_i2c_write(priv, ICMAR, 0);
}
static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
{
int i;
for (i = 0; i < LOOP_TIMEOUT; i++) {
/* make sure that bus is not busy */
if (!(rcar_i2c_read(priv, ICMCR) & FSDA))
return 0;
udelay(1);
}
return -EBUSY;
}
static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
u32 bus_speed,
struct device *dev)
{
u32 scgd, cdf;
u32 round, ick;
u32 scl;
u32 cdf_width;
unsigned long rate;
switch (priv->devtype) {
case I2C_RCAR_GEN1:
cdf_width = 2;
break;
case I2C_RCAR_GEN2:
cdf_width = 3;
break;
default:
dev_err(dev, "device type error\n");
return -EIO;
}
/*
* calculate SCL clock
* see
* ICCCR
*
* ick = clkp / (1 + CDF)
* SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
*
* ick : I2C internal clock < 20 MHz
* ticf : I2C SCL falling time = 35 ns here
* tr : I2C SCL rising time = 200 ns here
* intd : LSI internal delay = 50 ns here
* clkp : peripheral_clk
* F[] : integer up-valuation
*/
rate = clk_get_rate(priv->clk);
cdf = rate / 20000000;
if (cdf >= 1U << cdf_width) {
dev_err(dev, "Input clock %lu too high\n", rate);
return -EIO;
}
ick = rate / (cdf + 1);
/*
* it is impossible to calculate large scale
* number on u32. separate it
*
* F[(ticf + tr + intd) * ick]
* = F[(35 + 200 + 50)ns * ick]
* = F[285 * ick / 1000000000]
* = F[(ick / 1000000) * 285 / 1000]
*/
round = (ick + 500000) / 1000000 * 285;
round = (round + 500) / 1000;
/*
* SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
*
* Calculation result (= SCL) should be less than
* bus_speed for hardware safety
*
* We could use something along the lines of
* div = ick / (bus_speed + 1) + 1;
* scgd = (div - 20 - round + 7) / 8;
* scl = ick / (20 + (scgd * 8) + round);
* (not fully verified) but that would get pretty involved
*/
for (scgd = 0; scgd < 0x40; scgd++) {
scl = ick / (20 + (scgd * 8) + round);
if (scl <= bus_speed)
goto scgd_find;
}
dev_err(dev, "it is impossible to calculate best SCL\n");
return -EIO;
scgd_find:
dev_dbg(dev, "clk %d/%d(%lu), round %u, CDF:0x%x, SCGD: 0x%x\n",
scl, bus_speed, clk_get_rate(priv->clk), round, cdf, scgd);
/*
* keep icccr value
*/
priv->icccr = scgd << cdf_width | cdf;
return 0;
}
static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv)
{
int read = !!rcar_i2c_is_recv(priv);
rcar_i2c_write(priv, ICMAR, (priv->msg->addr << 1) | read);
rcar_i2c_write(priv, ICMSR, 0);
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND);
}
/*
* interrupt functions
*/
static int rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
{
struct i2c_msg *msg = priv->msg;
/*
* FIXME
* sometimes, unknown interrupt happened.
* Do nothing
*/
if (!(msr & MDE))
return 0;
/*
* If address transfer phase finished,
* goto data phase.
*/
if (msr & MAT)
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
if (priv->pos < msg->len) {
/*
* Prepare next data to ICRXTX register.
* This data will go to _SHIFT_ register.
*
* *
* [ICRXTX] -> [SHIFT] -> [I2C bus]
*/
rcar_i2c_write(priv, ICRXTX, msg->buf[priv->pos]);
priv->pos++;
} else {
/*
* The last data was pushed to ICRXTX on _PREV_ empty irq.
* It is on _SHIFT_ register, and will sent to I2C bus.
*
* *
* [ICRXTX] -> [SHIFT] -> [I2C bus]
*/
if (priv->flags & ID_LAST_MSG)
/*
* If current msg is the _LAST_ msg,
* prepare stop condition here.
* ID_DONE will be set on STOP irq.
*/
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
else
/*
* If current msg is _NOT_ last msg,
* it doesn't call stop phase.
* thus, there is no STOP irq.
* return ID_DONE here.
*/
return ID_DONE;
}
rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_SEND);
return 0;
}
static int rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
{
struct i2c_msg *msg = priv->msg;
/*
* FIXME
* sometimes, unknown interrupt happened.
* Do nothing
*/
if (!(msr & MDR))
return 0;
if (msr & MAT) {
/*
* Address transfer phase finished,
* but, there is no data at this point.
* Do nothing.
*/
} else if (priv->pos < msg->len) {
/*
* get received data
*/
msg->buf[priv->pos] = rcar_i2c_read(priv, ICRXTX);
priv->pos++;
}
/*
* If next received data is the _LAST_,
* go to STOP phase,
* otherwise, go to DATA phase.
*/
if (priv->pos + 1 >= msg->len)
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
else
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV);
return 0;
}
static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
{
u32 ssr_raw, ssr_filtered;
u8 value;
ssr_raw = rcar_i2c_read(priv, ICSSR) & 0xff;
ssr_filtered = ssr_raw & rcar_i2c_read(priv, ICSIER);
if (!ssr_filtered)
return false;
/* address detected */
if (ssr_filtered & SAR) {
/* read or write request */
if (ssr_raw & STM) {
i2c_slave_event(priv->slave, I2C_SLAVE_READ_REQUESTED, &value);
rcar_i2c_write(priv, ICRXTX, value);
rcar_i2c_write(priv, ICSIER, SDE | SSR | SAR);
} else {
i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
rcar_i2c_read(priv, ICRXTX); /* dummy read */
rcar_i2c_write(priv, ICSIER, SDR | SSR | SAR);
}
rcar_i2c_write(priv, ICSSR, ~SAR & 0xff);
}
/* master sent stop */
if (ssr_filtered & SSR) {
i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value);
rcar_i2c_write(priv, ICSIER, SAR | SSR);
rcar_i2c_write(priv, ICSSR, ~SSR & 0xff);
}
/* master wants to write to us */
if (ssr_filtered & SDR) {
int ret;
value = rcar_i2c_read(priv, ICRXTX);
ret = i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
/* Send NACK in case of error */
rcar_i2c_write(priv, ICSCR, SIE | SDBS | (ret < 0 ? FNA : 0));
rcar_i2c_write(priv, ICSSR, ~SDR & 0xff);
}
/* master wants to read from us */
if (ssr_filtered & SDE) {
i2c_slave_event(priv->slave, I2C_SLAVE_READ_PROCESSED, &value);
rcar_i2c_write(priv, ICRXTX, value);
rcar_i2c_write(priv, ICSSR, ~SDE & 0xff);
}
return true;
}
static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
{
struct rcar_i2c_priv *priv = ptr;
irqreturn_t result = IRQ_HANDLED;
u32 msr;
/*-------------- spin lock -----------------*/
spin_lock(&priv->lock);
if (rcar_i2c_slave_irq(priv))
goto exit;
msr = rcar_i2c_read(priv, ICMSR);
/* Only handle interrupts that are currently enabled */
msr &= rcar_i2c_read(priv, ICMIER);
if (!msr) {
result = IRQ_NONE;
goto exit;
}
/* Arbitration lost */
if (msr & MAL) {
rcar_i2c_flags_set(priv, (ID_DONE | ID_ARBLOST));
goto out;
}
/* Nack */
if (msr & MNR) {
/* go to stop phase */
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);
rcar_i2c_flags_set(priv, ID_NACK);
goto out;
}
/* Stop */
if (msr & MST) {
rcar_i2c_flags_set(priv, ID_DONE);
goto out;
}
if (rcar_i2c_is_recv(priv))
rcar_i2c_flags_set(priv, rcar_i2c_irq_recv(priv, msr));
else
rcar_i2c_flags_set(priv, rcar_i2c_irq_send(priv, msr));
out:
if (rcar_i2c_flags_has(priv, ID_DONE)) {
rcar_i2c_write(priv, ICMIER, 0);
rcar_i2c_write(priv, ICMSR, 0);
wake_up(&priv->wait);
}
exit:
spin_unlock(&priv->lock);
/*-------------- spin unlock -----------------*/
return result;
}
static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs,
int num)
{
struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
struct device *dev = rcar_i2c_priv_to_dev(priv);
unsigned long flags;
int i, ret, timeout;
pm_runtime_get_sync(dev);
/*-------------- spin lock -----------------*/
spin_lock_irqsave(&priv->lock, flags);
rcar_i2c_init(priv);
/* start clock */
rcar_i2c_write(priv, ICCCR, priv->icccr);
spin_unlock_irqrestore(&priv->lock, flags);
/*-------------- spin unlock -----------------*/
ret = rcar_i2c_bus_barrier(priv);
if (ret < 0)
goto out;
for (i = 0; i < num; i++) {
/* This HW can't send STOP after address phase */
if (msgs[i].len == 0) {
ret = -EOPNOTSUPP;
break;
}
/*-------------- spin lock -----------------*/
spin_lock_irqsave(&priv->lock, flags);
/* init each data */
priv->msg = &msgs[i];
priv->pos = 0;
priv->flags = 0;
if (i == num - 1)
rcar_i2c_flags_set(priv, ID_LAST_MSG);
rcar_i2c_prepare_msg(priv);
spin_unlock_irqrestore(&priv->lock, flags);
/*-------------- spin unlock -----------------*/
timeout = wait_event_timeout(priv->wait,
rcar_i2c_flags_has(priv, ID_DONE),
5 * HZ);
if (!timeout) {
ret = -ETIMEDOUT;
break;
}
if (rcar_i2c_flags_has(priv, ID_NACK)) {
ret = -ENXIO;
break;
}
if (rcar_i2c_flags_has(priv, ID_ARBLOST)) {
ret = -EAGAIN;
break;
}
if (rcar_i2c_flags_has(priv, ID_IOERROR)) {
ret = -EIO;
break;
}
ret = i + 1; /* The number of transfer */
}
out:
pm_runtime_put(dev);
if (ret < 0 && ret != -ENXIO)
dev_err(dev, "error %d : %x\n", ret, priv->flags);
return ret;
}
static int rcar_reg_slave(struct i2c_client *slave)
{
struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
if (priv->slave)
return -EBUSY;
if (slave->flags & I2C_CLIENT_TEN)
return -EAFNOSUPPORT;
pm_runtime_forbid(rcar_i2c_priv_to_dev(priv));
priv->slave = slave;
rcar_i2c_write(priv, ICSAR, slave->addr);
rcar_i2c_write(priv, ICSSR, 0);
rcar_i2c_write(priv, ICSIER, SAR | SSR);
rcar_i2c_write(priv, ICSCR, SIE | SDBS);
return 0;
}
static int rcar_unreg_slave(struct i2c_client *slave)
{
struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
WARN_ON(!priv->slave);
rcar_i2c_write(priv, ICSIER, 0);
rcar_i2c_write(priv, ICSCR, 0);
priv->slave = NULL;
pm_runtime_allow(rcar_i2c_priv_to_dev(priv));
return 0;
}
static u32 rcar_i2c_func(struct i2c_adapter *adap)
{
/* This HW can't do SMBUS_QUICK and NOSTART */
return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}
static const struct i2c_algorithm rcar_i2c_algo = {
.master_xfer = rcar_i2c_master_xfer,
.functionality = rcar_i2c_func,
.reg_slave = rcar_reg_slave,
.unreg_slave = rcar_unreg_slave,
};
static const struct of_device_id rcar_i2c_dt_ids[] = {
{ .compatible = "renesas,i2c-rcar", .data = (void *)I2C_RCAR_GEN1 },
{ .compatible = "renesas,i2c-r8a7778", .data = (void *)I2C_RCAR_GEN1 },
{ .compatible = "renesas,i2c-r8a7779", .data = (void *)I2C_RCAR_GEN1 },
{ .compatible = "renesas,i2c-r8a7790", .data = (void *)I2C_RCAR_GEN2 },
{ .compatible = "renesas,i2c-r8a7791", .data = (void *)I2C_RCAR_GEN2 },
{ .compatible = "renesas,i2c-r8a7792", .data = (void *)I2C_RCAR_GEN2 },
{ .compatible = "renesas,i2c-r8a7793", .data = (void *)I2C_RCAR_GEN2 },
{ .compatible = "renesas,i2c-r8a7794", .data = (void *)I2C_RCAR_GEN2 },
{},
};
MODULE_DEVICE_TABLE(of, rcar_i2c_dt_ids);
static int rcar_i2c_probe(struct platform_device *pdev)
{
struct i2c_rcar_platform_data *pdata = dev_get_platdata(&pdev->dev);
struct rcar_i2c_priv *priv;
struct i2c_adapter *adap;
struct resource *res;
struct device *dev = &pdev->dev;
u32 bus_speed;
int irq, ret;
priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->clk = devm_clk_get(dev, NULL);
if (IS_ERR(priv->clk)) {
dev_err(dev, "cannot get clock\n");
return PTR_ERR(priv->clk);
}
bus_speed = 100000; /* default 100 kHz */
ret = of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed);
if (ret < 0 && pdata && pdata->bus_speed)
bus_speed = pdata->bus_speed;
if (pdev->dev.of_node)
priv->devtype = (long)of_match_device(rcar_i2c_dt_ids,
dev)->data;
else
priv->devtype = platform_get_device_id(pdev)->driver_data;
ret = rcar_i2c_clock_calculate(priv, bus_speed, dev);
if (ret < 0)
return ret;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->io = devm_ioremap_resource(dev, res);
if (IS_ERR(priv->io))
return PTR_ERR(priv->io);
irq = platform_get_irq(pdev, 0);
init_waitqueue_head(&priv->wait);
spin_lock_init(&priv->lock);
adap = &priv->adap;
adap->nr = pdev->id;
adap->algo = &rcar_i2c_algo;
adap->class = I2C_CLASS_DEPRECATED;
adap->retries = 3;
adap->dev.parent = dev;
adap->dev.of_node = dev->of_node;
i2c_set_adapdata(adap, priv);
strlcpy(adap->name, pdev->name, sizeof(adap->name));
ret = devm_request_irq(dev, irq, rcar_i2c_irq, 0,
dev_name(dev), priv);
if (ret < 0) {
dev_err(dev, "cannot get irq %d\n", irq);
return ret;
}
ret = i2c_add_numbered_adapter(adap);
if (ret < 0) {
dev_err(dev, "reg adap failed: %d\n", ret);
return ret;
}
pm_runtime_enable(dev);
platform_set_drvdata(pdev, priv);
dev_info(dev, "probed\n");
return 0;
}
static int rcar_i2c_remove(struct platform_device *pdev)
{
struct rcar_i2c_priv *priv = platform_get_drvdata(pdev);
struct device *dev = &pdev->dev;
i2c_del_adapter(&priv->adap);
pm_runtime_disable(dev);
return 0;
}
static struct platform_device_id rcar_i2c_id_table[] = {
{ "i2c-rcar", I2C_RCAR_GEN1 },
{ "i2c-rcar_gen1", I2C_RCAR_GEN1 },
{ "i2c-rcar_gen2", I2C_RCAR_GEN2 },
{},
};
MODULE_DEVICE_TABLE(platform, rcar_i2c_id_table);
static struct platform_driver rcar_i2c_driver = {
.driver = {
.name = "i2c-rcar",
.of_match_table = rcar_i2c_dt_ids,
},
.probe = rcar_i2c_probe,
.remove = rcar_i2c_remove,
.id_table = rcar_i2c_id_table,
};
module_platform_driver(rcar_i2c_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Renesas R-Car I2C bus driver");
MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");