The latest AN2919 has changed the way FDR/DFSR should be calculated. Update the driver according to spec. However, Condition 2 is not accounted for as it is not clear how to do so.
Signed-off-by: Joakim Tjernlund Joakim.Tjernlund@transmode.se --- drivers/i2c/fsl_i2c.c | 90 ++++++++++++++++++++++++++++++------------------- 1 files changed, 55 insertions(+), 35 deletions(-)
diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c index 0c5f6be..78f21c7 100644 --- a/drivers/i2c/fsl_i2c.c +++ b/drivers/i2c/fsl_i2c.c @@ -100,29 +100,9 @@ static const struct fsl_i2c *i2c_dev[2] = { */ 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}, - {608, 22, 3}, {640, 1, 5}, {672, 32, 3}, {704, 11, 5}, {736, 43, 3}, - {768, 1, 6}, {800, 54, 3}, {832, 11, 6}, {896, 1, 42}, {960, 1, 7}, - {1024, 1, 43}, {1088, 22, 7}, {1152, 1, 8}, {1216, 43, 7}, {1280, 1, 9}, - {1408, 22, 9}, {1536, 1, 10}, {1664, 22, 10}, {1792, 1, 46}, - {1920, 1, 11}, {2048, 1, 47}, {2176, 43, 11}, {2304, 1, 12}, - {2560, 1, 13}, {2816, 43, 13}, {3072, 1, 14}, {3328, 43, 14}, - {3584, 1, 50}, {3840, 1, 15}, {4096, 1, 51}, {4608, 1, 16}, - {5120, 1, 17}, {6144, 1, 18}, {7168, 1, 54}, {7680, 1, 19}, - {8192, 1, 55}, {9216, 1, 20}, {10240, 1, 21}, {12288, 1, 22}, - {14336, 1, 58}, {15360, 1, 23}, {16384, 1, 59}, {18432, 1, 24}, - {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__) +#ifdef __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}, @@ -158,7 +138,6 @@ static unsigned int set_i2c_bus_speed(const struct fsl_i2c *dev, unsigned int i2c_clk, unsigned int speed) { unsigned short divider = min(i2c_clk / speed, (unsigned short) -1); - unsigned int i;
/* * We want to choose an FDR/DFSR that generates an I2C bus speed that @@ -166,31 +145,72 @@ static unsigned int set_i2c_bus_speed(const struct fsl_i2c *dev, * want the first divider that is equal to or greater than the * calculated divider. */ - - 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; + u8 dfsr, fdr = 0x31; /* Default if no FDR found */ + /* a, b and dfsr matches identifiers A,B and C respectively in AN2919 */ + unsigned short a, b, ga, gb; + unsigned long c_div, est_div; + #ifdef CONFIG_FSL_I2C_CUSTOM_DFSR - dfsr = CONFIG_FSL_I2C_CUSTOM_DFSR; + dfsr = CONFIG_FSL_I2C_CUSTOM_DFSR; #else - dfsr = fsl_i2c_speed_map[i].dfsr; -#endif - writeb(dfsr, &dev->dfsrr); /* set default filter */ + /* Condition 1: dfsr <= 50/T */ + dfsr = (5 * (i2c_clk / 1000)) / 100000; #endif #ifdef CONFIG_FSL_I2C_CUSTOM_FDR - fdr = CONFIG_FSL_I2C_CUSTOM_FDR; - speed = i2c_clk / divider; /* Fake something */ + fdr = CONFIG_FSL_I2C_CUSTOM_FDR; + speed = i2c_clk / divider; /* Fake something */ #else + debug("Requested speed:%d, i2c_clk:%d\n", speed, i2c_clk); + if (!dfsr) + dfsr = 1; + + est_div = ~0; + for (ga = 0x4, a = 10; a <= 30; ga++, a += 2) { + for (gb = 0; gb < 8; gb++) { + b = 16 << gb; + c_div = b * (a + ((3*dfsr)/b)*2); + if ((c_div > divider) && (c_div < est_div)) { + unsigned short bin_gb, bin_ga; + + est_div = c_div; + bin_gb = gb << 2; + bin_ga = (ga & 0x3) | ((ga & 0x4) << 3); + fdr = bin_gb | bin_ga; + speed = i2c_clk / est_div; + debug("FDR:0x%.2x, div:%ld, ga:0x%x, gb:0x%x, " + "a:%d, b:%d, speed:%d\n", + fdr, est_div, ga, gb, a, b, speed); + /* Condition 2 not accounted for */ + debug("Tr <= %d ns\n", + (b - 3 * dfsr) * 1000000 / + (i2c_clk / 1000)); + } + } + if (a == 20) + a += 2; + if (a == 24) + a += 4; + } + debug("divider:%d, est_div:%ld, DFSR:%d\n", divider, est_div, dfsr); + debug("FDR:0x%.2x, speed:%d\n", fdr, speed); +#endif + writeb(dfsr, &dev->dfsrr); /* set default filter */ + writeb(fdr, &dev->fdr); /* set bus speed */ +#else + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(fsl_i2c_speed_map); i++) + if (fsl_i2c_speed_map[i].divider >= divider) { + u8 fdr; + fdr = fsl_i2c_speed_map[i].fdr; speed = i2c_clk / fsl_i2c_speed_map[i].divider; -#endif writeb(fdr, &dev->fdr); /* set bus speed */
break; } - +#endif return speed; }