From: TsiChung Liew <[email protected]> Implement formula to obtain I2C speed and internal bus divider. This will provide accurate divider than fix table divider value.
Signed-off-by: TsiChung Liew <[email protected]> --- drivers/i2c/fsl_i2c.c | 76 +++++++++++++++++++++++++++++++++---------------- 1 files changed, 51 insertions(+), 25 deletions(-) diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c index 6ab7d3d..7f6d864 100644 --- a/drivers/i2c/fsl_i2c.c +++ b/drivers/i2c/fsl_i2c.c @@ -84,14 +84,12 @@ static const struct fsl_i2c *i2c_dev[2] = { * A different table is defined and are based on MCF5xxx user manual. * */ +#ifdef __PPC__ static const struct { unsigned short divider; -#ifdef __PPC__ u8 dfsr; -#endif u8 fdr; } fsl_i2c_speed_map[] = { -#ifdef __PPC__ {160, 1, 32}, {192, 1, 33}, {224, 1, 34}, {256, 1, 35}, {288, 1, 0}, {320, 1, 1}, {352, 6, 1}, {384, 1, 2}, {416, 6, 2}, {448, 1, 38}, {480, 1, 3}, {512, 1, 39}, {544, 11, 3}, {576, 1, 4}, @@ -108,26 +106,22 @@ static const struct { {20480, 1, 25}, {24576, 1, 26}, {28672, 1, 62}, {30720, 1, 27}, {32768, 1, 63}, {36864, 1, 28}, {40960, 1, 29}, {49152, 1, 30}, {61440, 1, 31}, {-1, 1, 31} +}; #elif defined(__M68K__) - {20, 32}, {22, 33}, {24, 34}, {26, 35}, - {28, 0}, {28, 36}, {30, 1}, {32, 37}, - {34, 2}, {36, 38}, {40, 3}, {40, 39}, - {44, 4}, {48, 5}, {48, 40}, {56, 6}, - {56, 41}, {64, 42}, {68, 7}, {72, 43}, - {80, 8}, {80, 44}, {88, 9}, {96, 41}, - {104, 10}, {112, 42}, {128, 11}, {128, 43}, - {144, 12}, {160, 13}, {160, 48}, {192, 14}, - {192, 49}, {224, 50}, {240, 15}, {256, 51}, - {288, 16}, {320, 17}, {320, 52}, {384, 18}, - {384, 53}, {448, 54}, {480, 19}, {512, 55}, - {576, 20}, {640, 21}, {640, 56}, {768, 22}, - {768, 57}, {960, 23}, {896, 58}, {1024, 59}, - {1152, 24}, {1280, 25}, {1280, 60}, {1536, 26}, - {1536, 61}, {1792, 62}, {1920, 27}, {2048, 63}, - {2304, 28}, {2560, 29}, {3072, 30}, {3840, 31}, - {-1, 31} -#endif +struct coldfire_i2c_tap { + int scl2tap; + int tap2tap; +} scltap[] = { + {4, 1}, + {4, 2}, + {6, 4}, + {6, 8}, + {14, 16}, + {30, 32}, + {62, 64}, + {126, 128} }; +#endif /** * Set the I2C bus speed for a given I2C device @@ -143,6 +137,7 @@ static const struct { static unsigned int set_i2c_bus_speed(const struct fsl_i2c *dev, unsigned int i2c_clk, unsigned int speed) { +#ifdef __PPC__ unsigned short divider = min(i2c_clk / speed, (unsigned short) -1); unsigned int i; @@ -156,20 +151,51 @@ static unsigned int set_i2c_bus_speed(const struct fsl_i2c *dev, for (i = 0; i < ARRAY_SIZE(fsl_i2c_speed_map); i++) if (fsl_i2c_speed_map[i].divider >= divider) { u8 fdr; -#ifdef __PPC__ u8 dfsr; dfsr = fsl_i2c_speed_map[i].dfsr; -#endif fdr = fsl_i2c_speed_map[i].fdr; speed = i2c_clk / fsl_i2c_speed_map[i].divider; writeb(fdr, &dev->fdr); /* set bus speed */ -#ifdef __PPC__ writeb(dfsr, &dev->dfsrr); /* set default filter */ -#endif break; } return speed; +#elif defined(__M68K__) + int fdr = -1; + ulong best_speed = 0; + ulong divider; + 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 }; + + ipb = gd->bus_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; + } + } + } + } + + divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2); + if (gd->flags & GD_FLG_RELOC) + fdr = divider; + else + printf("%ld kHz, ", best_speed / 1000); + + speed = best_speed; + + return speed; +#endif } void -- 1.5.6.4 _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
