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uboot-1.1.4-kirkwood/cpu/mpc8220/i2c.c
Olaf Rempel f69754bccc u-boot 1.1.4
2024-01-07 23:57:24 +01:00

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8.0 KiB
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/*
* (C) Copyright 2004, Freescale, Inc
* TsiChung Liew, Tsi-Chung.Liew@freescale.com.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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; either version 2 of
* the License, or (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#ifdef CONFIG_HARD_I2C
#include <mpc8220.h>
#include <i2c.h>
typedef struct mpc8220_i2c {
volatile u32 adr; /* I2Cn + 0x00 */
volatile u32 fdr; /* I2Cn + 0x04 */
volatile u32 cr; /* I2Cn + 0x08 */
volatile u32 sr; /* I2Cn + 0x0C */
volatile u32 dr; /* I2Cn + 0x10 */
} i2c_t;
/* I2Cn control register bits */
#define I2C_EN 0x80
#define I2C_IEN 0x40
#define I2C_STA 0x20
#define I2C_TX 0x10
#define I2C_TXAK 0x08
#define I2C_RSTA 0x04
#define I2C_INIT_MASK (I2C_EN | I2C_STA | I2C_TX | I2C_RSTA)
/* I2Cn status register bits */
#define I2C_CF 0x80
#define I2C_AAS 0x40
#define I2C_BB 0x20
#define I2C_AL 0x10
#define I2C_SRW 0x04
#define I2C_IF 0x02
#define I2C_RXAK 0x01
#define I2C_TIMEOUT 100
#define I2C_RETRIES 1
struct mpc8220_i2c_tap {
int scl2tap;
int tap2tap;
};
static int mpc_reg_in (volatile u32 * reg);
static void mpc_reg_out (volatile u32 * reg, int val, int mask);
static int wait_for_bb (void);
static int wait_for_pin (int *status);
static int do_address (uchar chip, char rdwr_flag);
static int send_bytes (uchar chip, char *buf, int len);
static int receive_bytes (uchar chip, char *buf, int len);
static int mpc_get_fdr (int);
static int mpc_reg_in (volatile u32 * reg)
{
int ret;
ret = *reg >> 24;
__asm__ __volatile__ ("eieio");
return ret;
}
static void mpc_reg_out (volatile u32 * reg, int val, int mask)
{
int tmp;
if (!mask) {
*reg = val << 24;
} else {
tmp = mpc_reg_in (reg);
*reg = ((tmp & ~mask) | (val & mask)) << 24;
}
__asm__ __volatile__ ("eieio");
return;
}
static int wait_for_bb (void)
{
i2c_t *regs = (i2c_t *) MMAP_I2C;
int timeout = I2C_TIMEOUT;
int status;
status = mpc_reg_in (&regs->sr);
while (timeout-- && (status & I2C_BB)) {
#if 1
volatile int temp;
mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
temp = mpc_reg_in (&regs->dr);
mpc_reg_out (&regs->cr, 0, I2C_STA);
mpc_reg_out (&regs->cr, 0, 0);
mpc_reg_out (&regs->cr, I2C_EN, 0);
#endif
udelay (1000);
status = mpc_reg_in (&regs->sr);
}
return (status & I2C_BB);
}
static int wait_for_pin (int *status)
{
i2c_t *regs = (i2c_t *) MMAP_I2C;
int timeout = I2C_TIMEOUT;
*status = mpc_reg_in (&regs->sr);
while (timeout-- && !(*status & I2C_IF)) {
udelay (1000);
*status = mpc_reg_in (&regs->sr);
}
if (!(*status & I2C_IF)) {
return -1;
}
mpc_reg_out (&regs->sr, 0, I2C_IF);
return 0;
}
static int do_address (uchar chip, char rdwr_flag)
{
i2c_t *regs = (i2c_t *) MMAP_I2C;
int status;
chip <<= 1;
if (rdwr_flag)
chip |= 1;
mpc_reg_out (&regs->cr, I2C_TX, I2C_TX);
mpc_reg_out (&regs->dr, chip, 0);
if (wait_for_pin (&status))
return -2;
if (status & I2C_RXAK)
return -3;
return 0;
}
static int send_bytes (uchar chip, char *buf, int len)
{
i2c_t *regs = (i2c_t *) MMAP_I2C;
int wrcount;
int status;
for (wrcount = 0; wrcount < len; ++wrcount) {
mpc_reg_out (&regs->dr, buf[wrcount], 0);
if (wait_for_pin (&status))
break;
if (status & I2C_RXAK)
break;
}
return !(wrcount == len);
return 0;
}
static int receive_bytes (uchar chip, char *buf, int len)
{
i2c_t *regs = (i2c_t *) MMAP_I2C;
int dummy = 1;
int rdcount = 0;
int status;
int i;
mpc_reg_out (&regs->cr, 0, I2C_TX);
for (i = 0; i < len; ++i) {
buf[rdcount] = mpc_reg_in (&regs->dr);
if (dummy)
dummy = 0;
else
rdcount++;
if (wait_for_pin (&status))
return -4;
}
mpc_reg_out (&regs->cr, I2C_TXAK, I2C_TXAK);
buf[rdcount++] = mpc_reg_in (&regs->dr);
if (wait_for_pin (&status))
return -5;
mpc_reg_out (&regs->cr, 0, I2C_TXAK);
return 0;
}
/**************** I2C API ****************/
void i2c_init (int speed, int saddr)
{
i2c_t *regs = (i2c_t *) MMAP_I2C;
mpc_reg_out (&regs->cr, 0, 0);
mpc_reg_out (&regs->adr, saddr << 1, 0);
/* Set clock
*/
mpc_reg_out (&regs->fdr, mpc_get_fdr (speed), 0);
/* Enable module
*/
mpc_reg_out (&regs->cr, I2C_EN, I2C_INIT_MASK);
mpc_reg_out (&regs->sr, 0, I2C_IF);
return;
}
static int mpc_get_fdr (int speed)
{
DECLARE_GLOBAL_DATA_PTR;
static int fdr = -1;
if (fdr == -1) {
ulong best_speed = 0;
ulong divider;
ulong ipb, scl;
ulong bestmatch = 0xffffffffUL;
int best_i = 0, best_j = 0, i, j;
int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8 };
struct mpc8220_i2c_tap scltap[] = {
{4, 1},
{4, 2},
{6, 4},
{6, 8},
{14, 16},
{30, 32},
{62, 64},
{126, 128}
};
ipb = gd->bus_clk;
for (i = 7; i >= 0; i--) {
for (j = 7; j >= 0; j--) {
scl = 2 * (scltap[j].scl2tap +
(SCL_Tap[i] -
1) * scltap[j].tap2tap + 2);
if (ipb <= speed * scl) {
if ((speed * scl - ipb) < bestmatch) {
bestmatch = speed * scl - ipb;
best_i = i;
best_j = j;
best_speed = ipb / scl;
}
}
}
}
divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2);
if (gd->flags & GD_FLG_RELOC) {
fdr = divider;
} else {
printf ("%ld kHz, ", best_speed / 1000);
return divider;
}
}
return fdr;
}
int i2c_probe (uchar chip)
{
i2c_t *regs = (i2c_t *) MMAP_I2C;
int i;
for (i = 0; i < I2C_RETRIES; i++) {
mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
if (!do_address (chip, 0)) {
mpc_reg_out (&regs->cr, 0, I2C_STA);
break;
}
mpc_reg_out (&regs->cr, 0, I2C_STA);
udelay (50);
}
return (i == I2C_RETRIES);
}
int i2c_read (uchar chip, uint addr, int alen, uchar * buf, int len)
{
uchar xaddr[4];
i2c_t *regs = (i2c_t *) MMAP_I2C;
int ret = -1;
xaddr[0] = (addr >> 24) & 0xFF;
xaddr[1] = (addr >> 16) & 0xFF;
xaddr[2] = (addr >> 8) & 0xFF;
xaddr[3] = addr & 0xFF;
if (wait_for_bb ()) {
printf ("i2c_read: bus is busy\n");
goto Done;
}
mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
if (do_address (chip, 0)) {
printf ("i2c_read: failed to address chip\n");
goto Done;
}
if (send_bytes (chip, (char *)&xaddr[4 - alen], alen)) {
printf ("i2c_read: send_bytes failed\n");
goto Done;
}
mpc_reg_out (&regs->cr, I2C_RSTA, I2C_RSTA);
if (do_address (chip, 1)) {
printf ("i2c_read: failed to address chip\n");
goto Done;
}
if (receive_bytes (chip, (char *)buf, len)) {
printf ("i2c_read: receive_bytes failed\n");
goto Done;
}
ret = 0;
Done:
mpc_reg_out (&regs->cr, 0, I2C_STA);
return ret;
}
int i2c_write (uchar chip, uint addr, int alen, uchar * buf, int len)
{
uchar xaddr[4];
i2c_t *regs = (i2c_t *) MMAP_I2C;
int ret = -1;
xaddr[0] = (addr >> 24) & 0xFF;
xaddr[1] = (addr >> 16) & 0xFF;
xaddr[2] = (addr >> 8) & 0xFF;
xaddr[3] = addr & 0xFF;
if (wait_for_bb ()) {
printf ("i2c_write: bus is busy\n");
goto Done;
}
mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
if (do_address (chip, 0)) {
printf ("i2c_write: failed to address chip\n");
goto Done;
}
if (send_bytes (chip, (char *)&xaddr[4 - alen], alen)) {
printf ("i2c_write: send_bytes failed\n");
goto Done;
}
if (send_bytes (chip, (char *)buf, len)) {
printf ("i2c_write: send_bytes failed\n");
goto Done;
}
ret = 0;
Done:
mpc_reg_out (&regs->cr, 0, I2C_STA);
return ret;
}
uchar i2c_reg_read (uchar chip, uchar reg)
{
uchar buf;
i2c_read (chip, reg, 1, &buf, 1);
return buf;
}
void i2c_reg_write (uchar chip, uchar reg, uchar val)
{
i2c_write (chip, reg, 1, &val, 1);
return;
}
#endif /* CONFIG_HARD_I2C */
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