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