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git.ipfire.org Git - people/ms/u-boot.git/blob - drivers/i2c/omap1510_i2c.c
4 * Copyright (c) 2003 Texas Instruments
6 * This package is free software; you can redistribute it and/or
7 * modify it under the terms of the license found in the file
8 * named COPYING that should have accompanied this file.
10 * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
11 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
12 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
14 * Author: Jian Zhang jzhang@ti.com, Texas Instruments
16 * Copyright (c) 2003 Wolfgang Denk, wd@denx.de
17 * Rewritten to fit into the current U-Boot framework
23 static void wait_for_bb (void);
24 static u16
wait_for_pin (void);
26 void i2c_init (int speed
, int slaveadd
)
30 if (inw (I2C_CON
) & I2C_CON_EN
) {
35 /* 12Mhz I2C module clock */
37 outw (I2C_CON_EN
, I2C_CON
);
38 outw (0, I2C_SYSTEST
);
39 /* have to enable intrrupts or OMAP i2c module doesn't work */
40 outw (I2C_IE_XRDY_IE
| I2C_IE_RRDY_IE
| I2C_IE_ARDY_IE
|
41 I2C_IE_NACK_IE
| I2C_IE_AL_IE
, I2C_IE
);
42 scl
= (12000000 / 2) / speed
- 6;
46 outw (slaveadd
, I2C_OA
);
51 static int i2c_read_byte (u8 devaddr
, u8 regoffset
, u8
* value
)
56 /* wait until bus not busy */
61 /* set slave address */
62 outw (devaddr
, I2C_SA
);
63 /* no stop bit needed here */
64 outw (I2C_CON_EN
| I2C_CON_MST
| I2C_CON_STT
| I2C_CON_TRX
, I2C_CON
);
66 status
= wait_for_pin ();
68 if (status
& I2C_STAT_XRDY
) {
69 /* Important: have to use byte access */
70 *(volatile u8
*) (I2C_DATA
) = regoffset
;
72 if (inw (I2C_STAT
) & I2C_STAT_NACK
) {
80 /* free bus, otherwise we can't use a combined transction */
82 while (inw (I2C_STAT
) || (inw (I2C_CON
) & I2C_CON_MST
)) {
84 /* Have to clear pending interrupt to clear I2C_STAT */
89 /* set slave address */
90 outw (devaddr
, I2C_SA
);
91 /* read one byte from slave */
93 /* need stop bit here */
94 outw (I2C_CON_EN
| I2C_CON_MST
| I2C_CON_STT
| I2C_CON_STP
,
97 status
= wait_for_pin ();
98 if (status
& I2C_STAT_RRDY
) {
99 *value
= inw (I2C_DATA
);
106 outw (I2C_CON_EN
, I2C_CON
);
107 while (inw (I2C_STAT
)
108 || (inw (I2C_CON
) & I2C_CON_MST
)) {
118 static int i2c_write_byte (u8 devaddr
, u8 regoffset
, u8 value
)
123 /* wait until bus not busy */
128 /* set slave address */
129 outw (devaddr
, I2C_SA
);
130 /* stop bit needed here */
131 outw (I2C_CON_EN
| I2C_CON_MST
| I2C_CON_STT
| I2C_CON_TRX
|
132 I2C_CON_STP
, I2C_CON
);
134 /* wait until state change */
135 status
= wait_for_pin ();
137 if (status
& I2C_STAT_XRDY
) {
138 /* send out two bytes */
139 outw ((value
<< 8) + regoffset
, I2C_DATA
);
140 /* must have enough delay to allow BB bit to go low */
142 if (inw (I2C_STAT
) & I2C_STAT_NACK
) {
150 outw (I2C_CON_EN
, I2C_CON
);
151 while (inw (I2C_STAT
) || (inw (I2C_CON
) & I2C_CON_MST
)) {
153 /* have to read to clear intrrupt */
161 int i2c_probe (uchar chip
)
165 if (chip
== inw (I2C_OA
)) {
169 /* wait until bus not busy */
172 /* try to read one byte */
174 /* set slave address */
176 /* stop bit needed here */
177 outw (I2C_CON_EN
| I2C_CON_MST
| I2C_CON_STT
| I2C_CON_STP
, I2C_CON
);
178 /* enough delay for the NACK bit set */
180 if (!(inw (I2C_STAT
) & I2C_STAT_NACK
)) {
183 outw (inw (I2C_CON
) | I2C_CON_STP
, I2C_CON
);
191 int i2c_read (uchar chip
, uint addr
, int alen
, uchar
* buffer
, int len
)
196 printf ("I2C read: addr len %d not supported\n", alen
);
200 if (addr
+ len
> 256) {
201 printf ("I2C read: address out of range\n");
205 for (i
= 0; i
< len
; i
++) {
206 if (i2c_read_byte (chip
, addr
+ i
, &buffer
[i
])) {
207 printf ("I2C read: I/O error\n");
208 i2c_init (CONFIG_SYS_I2C_SPEED
, CONFIG_SYS_I2C_SLAVE
);
216 int i2c_write (uchar chip
, uint addr
, int alen
, uchar
* buffer
, int len
)
221 printf ("I2C read: addr len %d not supported\n", alen
);
225 if (addr
+ len
> 256) {
226 printf ("I2C read: address out of range\n");
230 for (i
= 0; i
< len
; i
++) {
231 if (i2c_write_byte (chip
, addr
+ i
, buffer
[i
])) {
232 printf ("I2C read: I/O error\n");
233 i2c_init (CONFIG_SYS_I2C_SPEED
, CONFIG_SYS_I2C_SLAVE
);
241 static void wait_for_bb (void)
245 while ((inw (I2C_STAT
) & I2C_STAT_BB
) && timeout
--) {
251 printf ("timed out in wait_for_bb: I2C_STAT=%x\n",
256 static u16
wait_for_pin (void)
263 status
= inw (I2C_STAT
);
267 (I2C_STAT_ROVR
| I2C_STAT_XUDF
| I2C_STAT_XRDY
|
268 I2C_STAT_RRDY
| I2C_STAT_ARDY
| I2C_STAT_NACK
|
269 I2C_STAT_AL
)) && timeout
--);
272 printf ("timed out in wait_for_pin: I2C_STAT=%x\n",