diff options
| author | Steve Sakoman <steve@sakoman.com> | 2010-07-19 20:31:55 -0700 |
|---|---|---|
| committer | Sandeep Paulraj <s-paulraj@ti.com> | 2010-08-05 10:11:24 -0400 |
| commit | d708395d2f83295fba9d9b18823ce17046793590 (patch) | |
| tree | 55341b83e3c4ed864af43932aa03d6df3308000c /drivers | |
| parent | 674e0b217f794800048d80de09a71255b890a53e (diff) | |
ARMV7: Modify i2c driver for more reliable operation on OMAP4
This patch modifies the init routine to follow the TRM
recommendations. It also modifies the i2c_read_byte function
to reflect subtle differences between the i2c controller in
OMAP3 and OMAP4.
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Acked-by: Nishanth Menon <menon.nishanth@gmail.com>
Acked-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/i2c/omap24xx_i2c.c | 31 | ||||
| -rw-r--r-- | drivers/i2c/omap24xx_i2c.h | 4 |
2 files changed, 25 insertions, 10 deletions
diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c index 3256133dc2..7c98f150d7 100644 --- a/drivers/i2c/omap24xx_i2c.c +++ b/drivers/i2c/omap24xx_i2c.c @@ -27,6 +27,8 @@ #include "omap24xx_i2c.h" +#define I2C_TIMEOUT 10 + static void wait_for_bb (void); static u16 wait_for_pin (void); static void flush_fifo(void); @@ -41,6 +43,7 @@ void i2c_init (int speed, int slaveadd) int psc, fsscll, fssclh; int hsscll = 0, hssclh = 0; u32 scll, sclh; + int timeout = I2C_TIMEOUT; /* Only handle standard, fast and high speeds */ if ((speed != OMAP_I2C_STANDARD) && @@ -102,15 +105,24 @@ void i2c_init (int speed, int slaveadd) sclh = (unsigned int)fssclh; } - writew(0x2, &i2c_base->sysc); /* for ES2 after soft reset */ - udelay(1000); - writew(0x0, &i2c_base->sysc); /* will probably self clear but */ - if (readw (&i2c_base->con) & I2C_CON_EN) { writew (0, &i2c_base->con); udelay (50000); } + writew(0x2, &i2c_base->sysc); /* for ES2 after soft reset */ + udelay(1000); + + writew(I2C_CON_EN, &i2c_base->con); + while (!(readw(&i2c_base->syss) & I2C_SYSS_RDONE) && timeout--) { + if (timeout <= 0) { + printf("ERROR: Timeout in soft-reset\n"); + return; + } + udelay(1000); + } + + writew(0, &i2c_base->con); writew(psc, &i2c_base->psc); writew(scll, &i2c_base->scll); writew(sclh, &i2c_base->sclh); @@ -159,15 +171,14 @@ static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value) } if (!i2c_error) { - /* free bus, otherwise we can't use a combined transction */ - writew (0, &i2c_base->con); - while (readw (&i2c_base->stat) || (readw (&i2c_base->con) & I2C_CON_MST)) { + writew (I2C_CON_EN, &i2c_base->con); + while (readw(&i2c_base->stat) & + (I2C_STAT_XRDY | I2C_STAT_ARDY)) { udelay (10000); /* Have to clear pending interrupt to clear I2C_STAT */ writew (0xFFFF, &i2c_base->stat); } - wait_for_bb (); /* set slave address */ writew (devaddr, &i2c_base->sa); /* read one byte from slave */ @@ -191,8 +202,8 @@ static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value) if (!i2c_error) { writew (I2C_CON_EN, &i2c_base->con); - while (readw (&i2c_base->stat) - || (readw (&i2c_base->con) & I2C_CON_MST)) { + while (readw (&i2c_base->stat) & + (I2C_STAT_RRDY | I2C_STAT_ARDY)) { udelay (10000); writew (0xFFFF, &i2c_base->stat); } diff --git a/drivers/i2c/omap24xx_i2c.h b/drivers/i2c/omap24xx_i2c.h index 92a3416e0e..650e33a888 100644 --- a/drivers/i2c/omap24xx_i2c.h +++ b/drivers/i2c/omap24xx_i2c.h @@ -85,6 +85,10 @@ #define I2C_SYSTEST_SDA_I (1 << 1) /* SDA line sense input value */ #define I2C_SYSTEST_SDA_O (1 << 0) /* SDA line drive output value */ +/* I2C System Status Register (I2C_SYSS): */ + +#define I2C_SYSS_RDONE (1 << 0) /* Internel reset monitoring */ + #define I2C_SCLL_SCLL 0 #define I2C_SCLL_SCLL_M 0xFF #define I2C_SCLL_HSSCLL 8 |