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// SPDX-License-Identifier: GPL-2.0+
/*
* Renesas RCar IIC driver
*
* Copyright (C) 2017 Marek Vasut <marek.vasut@gmail.com>
*
* Based on
* Copyright (C) 2011, 2013 Renesas Solutions Corp.
* Copyright (C) 2011, 2013 Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
*/
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <i2c.h>
#include <asm/io.h>
struct rcar_iic_priv {
void __iomem *base;
struct clk clk;
u8 iccl;
u8 icch;
};
#define RCAR_IIC_ICDR 0x00
#define RCAR_IIC_ICCR 0x04
#define RCAR_IIC_ICSR 0x08
#define RCAR_IIC_ICIC 0x0c
#define RCAR_IIC_ICCL 0x10
#define RCAR_IIC_ICCH 0x14
/* ICCR */
#define RCAR_IIC_ICCR_ICE BIT(7)
#define RCAR_IIC_ICCR_RACK BIT(6)
#define RCAR_IIC_ICCR_RTS BIT(4)
#define RCAR_IIC_ICCR_BUSY BIT(2)
#define RCAR_IIC_ICCR_SCP BIT(0)
/* ICSR / ICIC */
#define RCAR_IC_BUSY BIT(4)
#define RCAR_IC_TACK BIT(2)
#define RCAR_IC_DTE BIT(0)
#define IRQ_WAIT 1000
static void sh_irq_dte(struct udevice *dev)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
int i;
for (i = 0; i < IRQ_WAIT; i++) {
if (RCAR_IC_DTE & readb(priv->base + RCAR_IIC_ICSR))
break;
udelay(10);
}
}
static int sh_irq_dte_with_tack(struct udevice *dev)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
int i;
for (i = 0; i < IRQ_WAIT; i++) {
if (RCAR_IC_DTE & readb(priv->base + RCAR_IIC_ICSR))
break;
if (RCAR_IC_TACK & readb(priv->base + RCAR_IIC_ICSR))
return -ETIMEDOUT;
udelay(10);
}
return 0;
}
static void sh_irq_busy(struct udevice *dev)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
int i;
for (i = 0; i < IRQ_WAIT; i++) {
if (!(RCAR_IC_BUSY & readb(priv->base + RCAR_IIC_ICSR)))
break;
udelay(10);
}
}
static int rcar_iic_set_addr(struct udevice *dev, u8 chip, u8 read)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
clrbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE);
setbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE);
writeb(priv->iccl, priv->base + RCAR_IIC_ICCL);
writeb(priv->icch, priv->base + RCAR_IIC_ICCH);
writeb(RCAR_IC_TACK, priv->base + RCAR_IIC_ICIC);
writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RTS | RCAR_IIC_ICCR_BUSY,
priv->base + RCAR_IIC_ICCR);
sh_irq_dte(dev);
clrbits_8(priv->base + RCAR_IIC_ICSR, RCAR_IC_TACK);
writeb(chip << 1 | read, priv->base + RCAR_IIC_ICDR);
return sh_irq_dte_with_tack(dev);
}
static void rcar_iic_finish(struct udevice *dev)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
writeb(0, priv->base + RCAR_IIC_ICSR);
clrbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE);
}
static int rcar_iic_read_common(struct udevice *dev, struct i2c_msg *msg)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
int i, ret = -EREMOTEIO;
if (rcar_iic_set_addr(dev, msg->addr, 1) != 0)
goto err;
udelay(10);
writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_SCP,
priv->base + RCAR_IIC_ICCR);
for (i = 0; i < msg->len; i++) {
if (sh_irq_dte_with_tack(dev) != 0)
goto err;
msg->buf[i] = readb(priv->base + RCAR_IIC_ICDR) & 0xff;
if (msg->len - 1 == i) {
writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RACK,
priv->base + RCAR_IIC_ICCR);
}
}
sh_irq_busy(dev);
ret = 0;
err:
rcar_iic_finish(dev);
return ret;
}
static int rcar_iic_write_common(struct udevice *dev, struct i2c_msg *msg)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
int i, ret = -EREMOTEIO;
if (rcar_iic_set_addr(dev, msg->addr, 0) != 0)
goto err;
udelay(10);
for (i = 0; i < msg->len; i++) {
writeb(msg->buf[i], priv->base + RCAR_IIC_ICDR);
if (sh_irq_dte_with_tack(dev) != 0)
goto err;
}
if (msg->flags & I2C_M_STOP) {
writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RTS,
priv->base + RCAR_IIC_ICCR);
if (sh_irq_dte_with_tack(dev) != 0)
goto err;
}
sh_irq_busy(dev);
ret = 0;
err:
rcar_iic_finish(dev);
return ret;
}
static int rcar_iic_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
{
int ret;
for (; nmsgs > 0; nmsgs--, msg++) {
if (msg->flags & I2C_M_RD)
ret = rcar_iic_read_common(dev, msg);
else
ret = rcar_iic_write_common(dev, msg);
if (ret)
return -EREMOTEIO;
}
return ret;
}
static int rcar_iic_set_speed(struct udevice *dev, uint speed)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
const unsigned int ratio_high = 4;
const unsigned int ratio_low = 5;
int clkrate, denom;
clkrate = clk_get_rate(&priv->clk);
if (clkrate < 0)
return clkrate;
/*
* Calculate the value for ICCL and ICCH. From the data sheet:
* iccl = (p-clock / transfer-rate) * (L / (L + H))
* icch = (p clock / transfer rate) * (H / (L + H))
* where L and H are the SCL low and high ratio.
*/
denom = speed * (ratio_high + ratio_low);
priv->iccl = DIV_ROUND_CLOSEST(clkrate * ratio_low, denom);
priv->icch = DIV_ROUND_CLOSEST(clkrate * ratio_high, denom);
return 0;
}
static int rcar_iic_probe_chip(struct udevice *dev, uint addr, uint flags)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
int ret;
rcar_iic_set_addr(dev, addr, 1);
writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_SCP,
priv->base + RCAR_IIC_ICCR);
ret = sh_irq_dte_with_tack(dev);
rcar_iic_finish(dev);
return ret;
}
static int rcar_iic_probe(struct udevice *dev)
{
struct rcar_iic_priv *priv = dev_get_priv(dev);
int ret;
priv->base = dev_read_addr_ptr(dev);
ret = clk_get_by_index(dev, 0, &priv->clk);
if (ret)
return ret;
ret = clk_enable(&priv->clk);
if (ret)
return ret;
rcar_iic_finish(dev);
return rcar_iic_set_speed(dev, 100000);
}
static const struct dm_i2c_ops rcar_iic_ops = {
.xfer = rcar_iic_xfer,
.probe_chip = rcar_iic_probe_chip,
.set_bus_speed = rcar_iic_set_speed,
};
static const struct udevice_id rcar_iic_ids[] = {
{ .compatible = "renesas,rmobile-iic" },
{ }
};
U_BOOT_DRIVER(iic_rcar) = {
.name = "iic_rcar",
.id = UCLASS_I2C,
.of_match = rcar_iic_ids,
.probe = rcar_iic_probe,
.priv_auto_alloc_size = sizeof(struct rcar_iic_priv),
.ops = &rcar_iic_ops,
};
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