diff options
Diffstat (limited to 'drivers/i2c/mxc_i2c.c')
| -rw-r--r-- | drivers/i2c/mxc_i2c.c | 86 |
1 files changed, 68 insertions, 18 deletions
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c index fd6db1855..c5ec486a7 100644 --- a/drivers/i2c/mxc_i2c.c +++ b/drivers/i2c/mxc_i2c.c @@ -72,11 +72,8 @@ #error "define CONFIG_SYS_I2C_MX<Processor>_PORTx to use the mx I2C driver" #endif -#ifdef DEBUG -#define DPRINTF(args...) printf(args) -#else -#define DPRINTF(args...) -#endif +#define I2C_MAX_TIMEOUT 10000 +#define I2C_MAX_RETRIES 3 static u16 div[] = { 30, 32, 36, 42, 48, 52, 60, 72, 80, 88, 104, 128, 144, 160, 192, 240, 288, 320, 384, 480, 576, 640, 768, 960, @@ -116,31 +113,61 @@ void i2c_init(int speed, int unused) i2c_reset(); } +static int wait_idle(void) +{ + int timeout = I2C_MAX_TIMEOUT; + + while ((readw(I2C_BASE + I2SR) & I2SR_IBB) && --timeout) { + writew(0, I2C_BASE + I2SR); + udelay(1); + } + return timeout ? timeout : (!(readw(I2C_BASE + I2SR) & I2SR_IBB)); +} + static int wait_busy(void) { - int timeout = 10000; + int timeout = I2C_MAX_TIMEOUT; - while (!(readw(I2C_BASE + I2SR) & I2SR_IIF) && --timeout) + while (!(readw(I2C_BASE + I2SR) & I2SR_IBB) && --timeout) udelay(1); writew(0, I2C_BASE + I2SR); /* clear interrupt */ return timeout; } +static int wait_complete(void) +{ + int timeout = I2C_MAX_TIMEOUT; + + while ((!(readw(I2C_BASE + I2SR) & I2SR_ICF)) && (--timeout)) { + writew(0, I2C_BASE + I2SR); + udelay(1); + } + udelay(200); + + writew(0, I2C_BASE + I2SR); /* clear interrupt */ + + return timeout; +} + + static int tx_byte(u8 byte) { writew(byte, I2C_BASE + I2DR); - if (!wait_busy() || readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK) + if (!wait_complete() || readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK) return -1; return 0; } -static int rx_byte(void) +static int rx_byte(int last) { - if (!wait_busy()) + if (!wait_complete()) return -1; + if (last) + writew(I2CR_IEN, I2C_BASE + I2CR); + return readw(I2C_BASE + I2DR); } @@ -160,21 +187,45 @@ int i2c_probe(uchar chip) static int i2c_addr(uchar chip, uint addr, int alen) { - writew(0, I2C_BASE + I2SR); - writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX, I2C_BASE + I2CR); + int i, retry = 0; + for (retry = 0; retry < 3; retry++) { + if (wait_idle()) + break; + i2c_reset(); + for (i = 0; i < I2C_MAX_TIMEOUT; i++) + udelay(1); + } + if (retry >= I2C_MAX_RETRIES) { + debug("%s:bus is busy(%x)\n", + __func__, readw(I2C_BASE + I2SR)); + return -1; + } + writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX, I2C_BASE + I2CR); - if (tx_byte(chip << 1)) + if (!wait_busy()) { + debug("%s:trigger start fail(%x)\n", + __func__, readw(I2C_BASE + I2SR)); return -1; + } + if (tx_byte(chip << 1) || (readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)) { + debug("%s:chip address cycle fail(%x)\n", + __func__, readw(I2C_BASE + I2SR)); + return -1; + } while (alen--) - if (tx_byte((addr >> (alen * 8)) & 0xff)) + if (tx_byte((addr >> (alen * 8)) & 0xff) || + (readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)) { + debug("%s:device address cycle fail(%x)\n", + __func__, readw(I2C_BASE + I2SR)); return -1; + } return 0; } int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len) { - int timeout = 10000; + int timeout = I2C_MAX_TIMEOUT; int ret; debug("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n", @@ -197,7 +248,8 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len) ret = readw(I2C_BASE + I2DR); while (len--) { - if ((ret = rx_byte()) < 0) + ret = rx_byte(len == 0); + if (ret < 0) return -1; *buf++ = ret; if (len <= 1) @@ -206,8 +258,6 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len) I2C_BASE + I2CR); } - wait_busy(); - writew(I2CR_IEN, I2C_BASE + I2CR); while (readw(I2C_BASE + I2SR) & I2SR_IBB && --timeout) |