u-boot/drivers/i2c/rcar_iic.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

270 lines
5.8 KiB
C

// 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,
};