diff options
Diffstat (limited to 'cpu/mpc5xxx/i2c.c')
| -rw-r--r-- | cpu/mpc5xxx/i2c.c | 58 |
1 files changed, 55 insertions, 3 deletions
diff --git a/cpu/mpc5xxx/i2c.c b/cpu/mpc5xxx/i2c.c index 640d14022f..74a610f940 100644 --- a/cpu/mpc5xxx/i2c.c +++ b/cpu/mpc5xxx/i2c.c @@ -28,15 +28,22 @@ #include <mpc5xxx.h> #include <i2c.h> -#ifdef CFG_I2C_MODULE +#if (CFG_I2C_MODULE == 2) #define I2C_BASE MPC5XXX_I2C2 -#else +#elif (CFG_I2C_MODULE == 1) #define I2C_BASE MPC5XXX_I2C1 +#else +#error CFG_I2C_MODULE is not properly configured #endif #define I2C_TIMEOUT 100 #define I2C_RETRIES 3 +struct mpc5xxx_i2c_tap { + int scl2tap; + int tap2tap; +}; + static int mpc_reg_in (volatile u32 *reg); static void mpc_reg_out (volatile u32 *reg, int val, int mask); static int wait_for_bb (void); @@ -44,6 +51,7 @@ static int wait_for_pin (int *status); static int do_address (uchar chip, char rdwr_flag); static int send_bytes (uchar chip, char *buf, int len); static int receive_bytes (uchar chip, char *buf, int len); +static int mpc_get_fdr (int); static int mpc_reg_in(volatile u32 *reg) { @@ -207,7 +215,7 @@ void i2c_init(int speed, int saddr) /* Set clock */ - mpc_reg_out(®s->mfdr, speed, 0); + mpc_reg_out(®s->mfdr, mpc_get_fdr(speed), 0); /* Enable module */ @@ -217,6 +225,50 @@ void i2c_init(int speed, int saddr) return; } +static int mpc_get_fdr(int speed) +{ + DECLARE_GLOBAL_DATA_PTR; + static int fdr = -1; + static int best_speed = 0; + + if (fdr == -1) { + ulong ipb, scl; + ulong bestmatch = 0xffffffffUL; + int best_i = 0, best_j = 0, i, j; + int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8}; + struct mpc5xxx_i2c_tap scltap[] = { + {4, 1}, + {4, 2}, + {6, 4}, + {6, 8}, + {14, 16}, + {30, 32}, + {62, 64}, + {126, 128} + }; + + ipb = gd->ipb_clk; + for (i = 7; i >= 0; i--) { + for (j = 7; j >= 0; j--) { + scl = 2 * (scltap[j].scl2tap + + (SCL_Tap[i] - 1) * scltap[j].tap2tap + 2); + if (ipb <= speed*scl) { + if ((speed*scl - ipb) < bestmatch) { + bestmatch = speed*scl - ipb; + best_i = i; + best_j = j; + best_speed = ipb/scl; + } + } + } + } + fdr = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2); + printf("%d kHz, ", best_speed / 1000); + } + + return fdr; +} + int i2c_probe(uchar chip) { struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE; |