diff options
Diffstat (limited to 'drivers/omap1510_i2c.c')
| -rw-r--r-- | drivers/omap1510_i2c.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/omap1510_i2c.c b/drivers/omap1510_i2c.c new file mode 100644 index 000000000..04400fbcd --- /dev/null +++ b/drivers/omap1510_i2c.c @@ -0,0 +1,281 @@ +/* + * Basic I2C functions + * + * Copyright (c) 2003 Texas Instruments + * + * This package is free software; you can redistribute it and/or + * modify it under the terms of the license found in the file + * named COPYING that should have accompanied this file. + * + * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED + * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. + * + * Author: Jian Zhang jzhang@ti.com, Texas Instruments + * + * Copyright (c) 2003 Wolfgang Denk, wd@denx.de + * Rewritten to fit into the current U-Boot framework + * + */ + +#include <common.h> + +#ifdef CONFIG_DRIVER_OMAP1510_I2C + +static void wait_for_bb (void); +static u16 wait_for_pin (void); + +void i2c_init (int speed, int slaveadd) +{ + u16 scl; + + if (inw (I2C_CON) & I2C_CON_EN) { + outw (0, I2C_CON); + udelay (5000); + } + + /* 12Mhz I2C module clock */ + outw (0, I2C_PSC); + outw (I2C_CON_EN, I2C_CON); + outw (0, I2C_SYSTEST); + /* have to enable intrrupts or OMAP i2c module doesn't work */ + outw (I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE | + I2C_IE_NACK_IE | I2C_IE_AL_IE, I2C_IE); + scl = (12000000 / 2) / speed - 6; + outw (scl, I2C_SCLL); + outw (scl, I2C_SCLH); + /* own address */ + outw (slaveadd, I2C_OA); + outw (0, I2C_CNT); + udelay (1000); +} + +static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value) +{ + int i2c_error = 0; + u16 status; + + /* wait until bus not busy */ + wait_for_bb (); + + /* one byte only */ + outw (1, I2C_CNT); + /* set slave address */ + outw (devaddr, I2C_SA); + /* no stop bit needed here */ + outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, I2C_CON); + + status = wait_for_pin (); + + if (status & I2C_STAT_XRDY) { + /* Important: have to use byte access */ + *(volatile u8 *) (I2C_DATA) = regoffset; + udelay (20000); + if (inw (I2C_STAT) & I2C_STAT_NACK) { + i2c_error = 1; + } + } else { + i2c_error = 1; + } + + if (!i2c_error) { + /* free bus, otherwise we can't use a combined transction */ + outw (0, I2C_CON); + while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) { + udelay (10000); + /* Have to clear pending interrupt to clear I2C_STAT */ + inw (I2C_IV); + } + + wait_for_bb (); + /* set slave address */ + outw (devaddr, I2C_SA); + /* read one byte from slave */ + outw (1, I2C_CNT); + /* need stop bit here */ + outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, + I2C_CON); + + status = wait_for_pin (); + if (status & I2C_STAT_RRDY) { + *value = inw (I2C_DATA); + udelay (20000); + } else { + i2c_error = 1; + } + + if (!i2c_error) { + outw (I2C_CON_EN, I2C_CON); + while (inw (I2C_STAT) + || (inw (I2C_CON) & I2C_CON_MST)) { + udelay (10000); + inw (I2C_IV); + } + } + } + + return i2c_error; +} + +static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value) +{ + int i2c_error = 0; + u16 status; + + /* wait until bus not busy */ + wait_for_bb (); + + /* two bytes */ + outw (2, I2C_CNT); + /* set slave address */ + outw (devaddr, I2C_SA); + /* stop bit needed here */ + outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX | + I2C_CON_STP, I2C_CON); + + /* wait until state change */ + status = wait_for_pin (); + + if (status & I2C_STAT_XRDY) { + /* send out two bytes */ + outw ((value << 8) + regoffset, I2C_DATA); + /* must have enough delay to allow BB bit to go low */ + udelay (30000); + if (inw (I2C_STAT) & I2C_STAT_NACK) { + i2c_error = 1; + } + } else { + i2c_error = 1; + } + + if (!i2c_error) { + outw (I2C_CON_EN, I2C_CON); + while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) { + udelay (1000); + /* have to read to clear intrrupt */ + inw (I2C_IV); + } + } + + return i2c_error; +} + +int i2c_probe (uchar chip) +{ + int res = 1; + + if (chip == inw (I2C_OA)) { + return res; + } + + /* wait until bus not busy */ + wait_for_bb (); + + /* try to read one byte */ + outw (1, I2C_CNT); + /* set slave address */ + outw (chip, I2C_SA); + /* stop bit needed here */ + outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, I2C_CON); + /* enough delay for the NACK bit set */ + udelay (2000); + if (!(inw (I2C_STAT) & I2C_STAT_NACK)) { + res = 0; + } else { + outw (inw (I2C_CON) | I2C_CON_STP, I2C_CON); + udelay (20); + wait_for_bb (); + } + + return res; +} + +int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len) +{ + int i; + + if (alen > 1) { + printf ("I2C read: addr len %d not supported\n", alen); + return 1; + } + + if (addr + len > 256) { + printf ("I2C read: address out of range\n"); + return 1; + } + + for (i = 0; i < len; i++) { + if (i2c_read_byte (chip, addr + i, &buffer[i])) { + printf ("I2C read: I/O error\n"); + i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE); + return 1; + } + } + + return 0; +} + +int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len) +{ + int i; + + if (alen > 1) { + printf ("I2C read: addr len %d not supported\n", alen); + return 1; + } + + if (addr + len > 256) { + printf ("I2C read: address out of range\n"); + return 1; + } + + for (i = 0; i < len; i++) { + if (i2c_write_byte (chip, addr + i, buffer[i])) { + printf ("I2C read: I/O error\n"); + i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE); + return 1; + } + } + + return 0; +} + +static void wait_for_bb (void) +{ + int timeout = 10; + + while ((inw (I2C_STAT) & I2C_STAT_BB) && timeout--) { + inw (I2C_IV); + udelay (1000); + } + + if (timeout <= 0) { + printf ("timed out in wait_for_bb: I2C_STAT=%x\n", + inw (I2C_STAT)); + } +} + +static u16 wait_for_pin (void) +{ + u16 status, iv; + int timeout = 10; + + do { + udelay (1000); + status = inw (I2C_STAT); + iv = inw (I2C_IV); + } while (!iv && + !(status & + (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY | + I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK | + I2C_STAT_AL)) && timeout--); + + if (timeout <= 0) { + printf ("timed out in wait_for_pin: I2C_STAT=%x\n", + inw (I2C_STAT)); + } + + return status; +} + +#endif /* CONFIG_DRIVER_OMAP1510_I2C */ |