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u-boot/drivers/i2c/rcar_i2c.c
Nobuhiro Iwamatsu cd818a381d i2c: rcar_i2c: Fix order of restart and clear status 
In case of repeated START condition, the restart has to be kicked
before clear status (MSR register). If it is kicked after clear status,
R-Car I2C may transfer data (TXD register) or receive data (RXD register)
instead of transferring slave address (MAR register).

Signed-off-by: Ryo Kataoka <ryo.kataoka.wt@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
2014-11-10 06:47:37 +01:00

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/*
* drivers/i2c/rcar_i2c.c
*
* Copyright (C) 2013 Renesas Electronics Corporation
* Copyright (C) 2013 Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
*
* SPDX-License-Identifier: GPL-2.0
*/
#include <common.h>
#include <i2c.h>
#include <asm/io.h>
DECLARE_GLOBAL_DATA_PTR;
struct rcar_i2c {
u32 icscr;
u32 icmcr;
u32 icssr;
u32 icmsr;
u32 icsier;
u32 icmier;
u32 icccr;
u32 icsar;
u32 icmar;
u32 icrxdtxd;
u32 icccr2;
u32 icmpr;
u32 ichpr;
u32 iclpr;
};
#define MCR_MDBS 0x80 /* non-fifo mode switch */
#define MCR_FSCL 0x40 /* override SCL pin */
#define MCR_FSDA 0x20 /* override SDA pin */
#define MCR_OBPC 0x10 /* override pins */
#define MCR_MIE 0x08 /* master if enable */
#define MCR_TSBE 0x04
#define MCR_FSB 0x02 /* force stop bit */
#define MCR_ESG 0x01 /* en startbit gen. */
#define MSR_MASK 0x7f
#define MSR_MNR 0x40 /* nack received */
#define MSR_MAL 0x20 /* arbitration lost */
#define MSR_MST 0x10 /* sent a stop */
#define MSR_MDE 0x08
#define MSR_MDT 0x04
#define MSR_MDR 0x02
#define MSR_MAT 0x01 /* slave addr xfer done */
static const struct rcar_i2c *i2c_dev[CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS] = {
(struct rcar_i2c *)CONFIG_SYS_RCAR_I2C0_BASE,
(struct rcar_i2c *)CONFIG_SYS_RCAR_I2C1_BASE,
(struct rcar_i2c *)CONFIG_SYS_RCAR_I2C2_BASE,
(struct rcar_i2c *)CONFIG_SYS_RCAR_I2C3_BASE,
};
static void rcar_i2c_raw_rw_common(struct rcar_i2c *dev, u8 chip, uint addr)
{
/* set slave address */
writel(chip << 1, &dev->icmar);
/* set register address */
writel(addr, &dev->icrxdtxd);
/* clear status */
writel(0, &dev->icmsr);
/* start master send */
writel(MCR_MDBS | MCR_MIE | MCR_ESG, &dev->icmcr);
while ((readl(&dev->icmsr) & (MSR_MAT | MSR_MDE))
!= (MSR_MAT | MSR_MDE))
udelay(10);
/* clear ESG */
writel(MCR_MDBS | MCR_MIE, &dev->icmcr);
/* start SCLclk */
writel(~(MSR_MAT | MSR_MDE), &dev->icmsr);
while (!(readl(&dev->icmsr) & MSR_MDE))
udelay(10);
}
static void rcar_i2c_raw_rw_finish(struct rcar_i2c *dev)
{
while (!(readl(&dev->icmsr) & MSR_MST))
udelay(10);
writel(0, &dev->icmcr);
}
static int
rcar_i2c_raw_write(struct rcar_i2c *dev, u8 chip, uint addr, u8 *val, int size)
{
rcar_i2c_raw_rw_common(dev, chip, addr);
/* set send date */
writel(*val, &dev->icrxdtxd);
/* start SCLclk */
writel(~MSR_MDE, &dev->icmsr);
while (!(readl(&dev->icmsr) & MSR_MDE))
udelay(10);
/* set stop condition */
writel(MCR_MDBS | MCR_MIE | MCR_FSB, &dev->icmcr);
/* start SCLclk */
writel(~MSR_MDE, &dev->icmsr);
rcar_i2c_raw_rw_finish(dev);
return 0;
}
static u8
rcar_i2c_raw_read(struct rcar_i2c *dev, u8 chip, uint addr)
{
u8 ret;
rcar_i2c_raw_rw_common(dev, chip, addr);
/* set slave address, receive */
writel((chip << 1) | 1, &dev->icmar);
/* start master receive */
writel(MCR_MDBS | MCR_MIE | MCR_ESG, &dev->icmcr);
/* clear status */
writel(0, &dev->icmsr);
while ((readl(&dev->icmsr) & (MSR_MAT | MSR_MDR))
!= (MSR_MAT | MSR_MDR))
udelay(10);
/* clear ESG */
writel(MCR_MDBS | MCR_MIE, &dev->icmcr);
/* prepare stop condition */
writel(MCR_MDBS | MCR_MIE | MCR_FSB, &dev->icmcr);
/* start SCLclk */
writel(~(MSR_MAT | MSR_MDR), &dev->icmsr);
while (!(readl(&dev->icmsr) & MSR_MDR))
udelay(10);
/* get receive data */
ret = (u8)readl(&dev->icrxdtxd);
/* start SCLclk */
writel(~MSR_MDR, &dev->icmsr);
rcar_i2c_raw_rw_finish(dev);
return ret;
}
/*
* SCL = iicck / (20 + SCGD * 8 + F[(ticf + tr + intd) * iicck])
* iicck : I2C internal clock < 20 MHz
* ticf : I2C SCL falling time: 35 ns
* tr : I2C SCL rising time: 200 ns
* intd : LSI internal delay: I2C0: 50 ns I2C1-3: 5
* F[n] : n rounded up to an integer
*/
static u32 rcar_clock_gen(int i2c_no, u32 bus_speed)
{
u32 iicck, f, scl, scgd;
u32 intd = 5;
int bit = 0, cdf_width = 3;
for (bit = 0; bit < (1 << cdf_width); bit++) {
iicck = CONFIG_HP_CLK_FREQ / (1 + bit);
if (iicck < 20000000)
break;
}
if (bit > (1 << cdf_width)) {
puts("rcar-i2c: Can not get CDF\n");
return 0;
}
if (i2c_no == 0)
intd = 50;
f = (35 + 200 + intd) * (iicck / 1000000000);
for (scgd = 0; scgd < 0x40; scgd++) {
scl = iicck / (20 + (scgd * 8) + f);
if (scl <= bus_speed)
break;
}
if (scgd > 0x40) {
puts("rcar-i2c: Can not get SDGB\n");
return 0;
}
debug("%s: scl: %d\n", __func__, scl);
debug("%s: bit %x\n", __func__, bit);
debug("%s: scgd %x\n", __func__, scgd);
debug("%s: iccr %x\n", __func__, (scgd << (cdf_width) | bit));
return scgd << (cdf_width) | bit;
}
static void
rcar_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
{
struct rcar_i2c *dev = (struct rcar_i2c *)i2c_dev[adap->hwadapnr];
u32 icccr = 0;
/* No i2c support prior to relocation */
if (!(gd->flags & GD_FLG_RELOC))
return;
/*
* reset slave mode.
* slave mode is not used on this driver
*/
writel(0, &dev->icsier);
writel(0, &dev->icsar);
writel(0, &dev->icscr);
writel(0, &dev->icssr);
/* reset master mode */
writel(0, &dev->icmier);
writel(0, &dev->icmcr);
writel(0, &dev->icmsr);
writel(0, &dev->icmar);
icccr = rcar_clock_gen(adap->hwadapnr, adap->speed);
if (icccr == 0)
puts("I2C: Init failed\n");
else
writel(icccr, &dev->icccr);
}
static int rcar_i2c_read(struct i2c_adapter *adap, uint8_t chip,
uint addr, int alen, u8 *data, int len)
{
struct rcar_i2c *dev = (struct rcar_i2c *)i2c_dev[adap->hwadapnr];
int i;
for (i = 0; i < len; i++)
data[i] = rcar_i2c_raw_read(dev, chip, addr + i);
return 0;
}
static int rcar_i2c_write(struct i2c_adapter *adap, uint8_t chip, uint addr,
int alen, u8 *data, int len)
{
struct rcar_i2c *dev = (struct rcar_i2c *)i2c_dev[adap->hwadapnr];
return rcar_i2c_raw_write(dev, chip, addr, data, len);
}
static int
rcar_i2c_probe(struct i2c_adapter *adap, u8 dev)
{
return rcar_i2c_read(adap, dev, 0, 0, NULL, 0);
}
static unsigned int rcar_i2c_set_bus_speed(struct i2c_adapter *adap,
unsigned int speed)
{
struct rcar_i2c *dev = (struct rcar_i2c *)i2c_dev[adap->hwadapnr];
u32 icccr;
int ret = 0;
rcar_i2c_raw_rw_finish(dev);
icccr = rcar_clock_gen(adap->hwadapnr, speed);
if (icccr == 0) {
puts("I2C: Init failed\n");
ret = -1;
} else {
writel(icccr, &dev->icccr);
}
return ret;
}
/*
* Register RCAR i2c adapters
*/
U_BOOT_I2C_ADAP_COMPLETE(rcar_0, rcar_i2c_init, rcar_i2c_probe, rcar_i2c_read,
rcar_i2c_write, rcar_i2c_set_bus_speed,
CONFIG_SYS_RCAR_I2C0_SPEED, 0, 0)
U_BOOT_I2C_ADAP_COMPLETE(rcar_1, rcar_i2c_init, rcar_i2c_probe, rcar_i2c_read,
rcar_i2c_write, rcar_i2c_set_bus_speed,
CONFIG_SYS_RCAR_I2C1_SPEED, 0, 1)
U_BOOT_I2C_ADAP_COMPLETE(rcar_2, rcar_i2c_init, rcar_i2c_probe, rcar_i2c_read,
rcar_i2c_write, rcar_i2c_set_bus_speed,
CONFIG_SYS_RCAR_I2C2_SPEED, 0, 2)
U_BOOT_I2C_ADAP_COMPLETE(rcar_3, rcar_i2c_init, rcar_i2c_probe, rcar_i2c_read,
rcar_i2c_write, rcar_i2c_set_bus_speed,
CONFIG_SYS_RCAR_I2C3_SPEED, 0, 3)
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