annotate old/linux-2.6.37.6-ftdi_sio.c.patch @ 407:19e5a3e2f9c0

fcup-settime: moved time() retrieval a little closer to the output A fundamental problem with all simple time transfer tools is that there is always some delay between the time retrieval on the source system and that transmitted time being set on the destination, and the resulting time on the destination system is off by that delay amount. This delay cannot be fully eliminated when working in a simple environment like ours, but we should make our best effort to minimize it. In the present case, moving the atinterf_init() call before the time() retrieval should make a teensy-tiny improvement.
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 11 Aug 2018 21:52:17 +0000
parents 40f44aa49dd0
children
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1 --- ftdi_sio.c.orig 2011-03-27 11:01:41.000000000 -0800
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2 +++ ftdi_sio.c 2015-10-30 13:18:40.879000032 -0800
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3 @@ -949,7 +949,7 @@
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4 static const unsigned char divfrac[8] = { 0, 3, 2, 4, 1, 5, 6, 7 };
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5 __u32 divisor;
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6 /* divisor shifted 3 bits to the left */
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7 - int divisor3 = base / 2 / baud;
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8 + int divisor3 = (base / 2 + baud / 2) / baud;
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9 divisor = divisor3 >> 3;
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10 divisor |= (__u32)divfrac[divisor3 & 0x7] << 14;
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11 /* Deal with special cases for highest baud rates. */
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12 @@ -1087,6 +1087,17 @@
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13 baud = tty_get_baud_rate(tty);
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14 dbg("%s - tty_get_baud_rate reports speed %d", __func__, baud);
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16 + /*
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17 + * FreeCalypso hack: translate non-std high
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18 + * baud rates for GSM like CP2102 does.
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19 + */
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20 + if (baud == 230400)
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21 + baud = 203125;
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22 + else if (baud == 460800)
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23 + baud = 406250;
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24 + else if (baud == 921600)
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25 + baud = 812500;
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26 +
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27 /* 2. Observe async-compatible custom_divisor hack, update baudrate
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28 if needed */
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29