diff options
| -rw-r--r-- | drivers/i2c/omap24xx_i2c.c | 74 | ||||
| -rw-r--r-- | include/asm-arm/arch-omap24xx/i2c.h | 44 | ||||
| -rw-r--r-- | include/asm-arm/arch-omap3/i2c.h | 70 |
3 files changed, 174 insertions, 14 deletions
diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c index 6784603..1a4c8c9 100644 --- a/drivers/i2c/omap24xx_i2c.c +++ b/drivers/i2c/omap24xx_i2c.c @@ -31,7 +31,69 @@ static void flush_fifo(void); void i2c_init (int speed, int slaveadd) { - u16 scl; + int psc, fsscll, fssclh; + int hsscll = 0, hssclh = 0; + u32 scll, sclh; + + /* Only handle standard, fast and high speeds */ + if ((speed != OMAP_I2C_STANDARD) && + (speed != OMAP_I2C_FAST_MODE) && + (speed != OMAP_I2C_HIGH_SPEED)) { + printf("Error : I2C unsupported speed %d\n", speed); + return; + } + + psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK; + psc -= 1; + if (psc < I2C_PSC_MIN) { + printf("Error : I2C unsupported prescalar %d\n", psc); + return; + } + + if (speed == OMAP_I2C_HIGH_SPEED) { + /* High speed */ + + /* For first phase of HS mode */ + fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK / + (2 * OMAP_I2C_FAST_MODE); + + fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM; + fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM; + if (((fsscll < 0) || (fssclh < 0)) || + ((fsscll > 255) || (fssclh > 255))) { + printf("Error : I2C initializing first phase clock\n"); + return; + } + + /* For second phase of HS mode */ + hsscll = hssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed); + + hsscll -= I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM; + hssclh -= I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM; + if (((fsscll < 0) || (fssclh < 0)) || + ((fsscll > 255) || (fssclh > 255))) { + printf("Error : I2C initializing second phase clock\n"); + return; + } + + scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll; + sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh; + + } else { + /* Standard and fast speed */ + fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed); + + fsscll -= I2C_FASTSPEED_SCLL_TRIM; + fssclh -= I2C_FASTSPEED_SCLH_TRIM; + if (((fsscll < 0) || (fssclh < 0)) || + ((fsscll > 255) || (fssclh > 255))) { + printf("Error : I2C initializing clock\n"); + return; + } + + scll = (unsigned int)fsscll; + sclh = (unsigned int)fssclh; + } writew(0x2, I2C_SYSC); /* for ES2 after soft reset */ udelay(1000); @@ -42,12 +104,10 @@ void i2c_init (int speed, int slaveadd) udelay (50000); } - /* 12MHz I2C module clock */ - writew (0, I2C_PSC); - speed = speed/1000; /* 100 or 400 */ - scl = ((12000/(speed*2)) - 7); /* use 7 when PSC = 0 */ - writew (scl, I2C_SCLL); - writew (scl, I2C_SCLH); + writew(psc, I2C_PSC); + writew(scll, I2C_SCLL); + writew(sclh, I2C_SCLH); + /* own address */ writew (slaveadd, I2C_OA); writew (I2C_CON_EN, I2C_CON); diff --git a/include/asm-arm/arch-omap24xx/i2c.h b/include/asm-arm/arch-omap24xx/i2c.h index 7248950..44db7a2 100644 --- a/include/asm-arm/arch-omap24xx/i2c.h +++ b/include/asm-arm/arch-omap24xx/i2c.h @@ -104,4 +104,48 @@ #define I2C_SYSTEST_SDA_I (1 << 1) /* SDA line sense input value */ #define I2C_SYSTEST_SDA_O (1 << 0) /* SDA line drive output value */ +/* These values were copied from omap3, include/asm-arm/arch-omap3/i2c.h. */ +#define OMAP_I2C_STANDARD 100000 +#define OMAP_I2C_FAST_MODE 400000 +#define OMAP_I2C_HIGH_SPEED 3400000 + +#define SYSTEM_CLOCK_12 12000000 +#define SYSTEM_CLOCK_13 13000000 +#define SYSTEM_CLOCK_192 19200000 +#define SYSTEM_CLOCK_96 96000000 + +#ifndef I2C_IP_CLK +#define I2C_IP_CLK SYSTEM_CLOCK_96 +#endif + +#ifndef I2C_INTERNAL_SAMPLING_CLK +#define I2C_INTERNAL_SAMPLING_CLK 19200000 +#endif + +/* These are the trim values for standard and fast speed */ +#ifndef I2C_FASTSPEED_SCLL_TRIM +#define I2C_FASTSPEED_SCLL_TRIM 6 +#endif +#ifndef I2C_FASTSPEED_SCLH_TRIM +#define I2C_FASTSPEED_SCLH_TRIM 6 +#endif + +/* These are the trim values for high speed */ +#ifndef I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM +#define I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM I2C_FASTSPEED_SCLL_TRIM +#endif +#ifndef I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM +#define I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM I2C_FASTSPEED_SCLH_TRIM +#endif +#ifndef I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM +#define I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM I2C_FASTSPEED_SCLL_TRIM +#endif +#ifndef I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM +#define I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM I2C_FASTSPEED_SCLH_TRIM +#endif + +#define I2C_PSC_MAX 0x0f +#define I2C_PSC_MIN 0x00 + + #endif diff --git a/include/asm-arm/arch-omap3/i2c.h b/include/asm-arm/arch-omap3/i2c.h index 3937f35..8b339cc 100644 --- a/include/asm-arm/arch-omap3/i2c.h +++ b/include/asm-arm/arch-omap3/i2c.h @@ -112,16 +112,72 @@ #define I2C_SCLH_HSSCLH 8 #define I2C_SCLH_HSSCLH_M 0xFF -#define OMAP_I2C_STANDARD 100 -#define OMAP_I2C_FAST_MODE 400 -#define OMAP_I2C_HIGH_SPEED 3400 +#define OMAP_I2C_STANDARD 100000 +#define OMAP_I2C_FAST_MODE 400000 +#define OMAP_I2C_HIGH_SPEED 3400000 -#define SYSTEM_CLOCK_12 12000 -#define SYSTEM_CLOCK_13 13000 -#define SYSTEM_CLOCK_192 19200 -#define SYSTEM_CLOCK_96 96000 +#define SYSTEM_CLOCK_12 12000000 +#define SYSTEM_CLOCK_13 13000000 +#define SYSTEM_CLOCK_192 19200000 +#define SYSTEM_CLOCK_96 96000000 +/* Use the reference value of 96MHz if not explicitly set by the board */ +#ifndef I2C_IP_CLK #define I2C_IP_CLK SYSTEM_CLOCK_96 +#endif + +/* + * The reference minimum clock for high speed is 19.2MHz. + * The linux 2.6.30 kernel uses this value. + * The reference minimum clock for fast mode is 9.6MHz + * The reference minimum clock for standard mode is 4MHz + * In TRM, the value of 12MHz is used. + */ +#ifndef I2C_INTERNAL_SAMPLING_CLK +#define I2C_INTERNAL_SAMPLING_CLK 19200000 +#endif + +/* + * The equation for the low and high time is + * tlow = scll + scll_trim = (sampling clock * tlow_duty) / speed + * thigh = sclh + sclh_trim = (sampling clock * (1 - tlow_duty)) / speed + * + * If the duty cycle is 50% + * + * tlow = scll + scll_trim = sampling clock / (2 * speed) + * thigh = sclh + sclh_trim = sampling clock / (2 * speed) + * + * In TRM + * scll_trim = 7 + * sclh_trim = 5 + * + * The linux 2.6.30 kernel uses + * scll_trim = 6 + * sclh_trim = 6 + * + * These are the trim values for standard and fast speed + */ +#ifndef I2C_FASTSPEED_SCLL_TRIM +#define I2C_FASTSPEED_SCLL_TRIM 6 +#endif +#ifndef I2C_FASTSPEED_SCLH_TRIM +#define I2C_FASTSPEED_SCLH_TRIM 6 +#endif + +/* These are the trim values for high speed */ +#ifndef I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM +#define I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM I2C_FASTSPEED_SCLL_TRIM +#endif +#ifndef I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM +#define I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM I2C_FASTSPEED_SCLH_TRIM +#endif +#ifndef I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM +#define I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM I2C_FASTSPEED_SCLL_TRIM +#endif +#ifndef I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM +#define I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM I2C_FASTSPEED_SCLH_TRIM +#endif + #define I2C_PSC_MAX 0x0f #define I2C_PSC_MIN 0x00 |