/* * rational fractions * * Copyright (C) 2009 emlix GmbH, Oskar Schirmer * * helper functions when coping with rational numbers */ #include #include #include /* * calculate best rational approximation for a given fraction * taking into account restricted register size, e.g. to find * appropriate values for a pll with 5 bit denominator and * 8 bit numerator register fields, trying to set up with a * frequency ratio of 3.1415, one would say: * * rational_best_approximation(31415, 10000, * (1 << 8) - 1, (1 << 5) - 1, &n, &d); * * you may look at given_numerator as a fixed point number, * with the fractional part size described in given_denominator. * * for theoretical background, see: * http://en.wikipedia.org/wiki/Continued_fraction */ void rational_best_approximation( unsigned long given_numerator, unsigned long given_denominator, unsigned long max_numerator, unsigned long max_denominator, unsigned long *best_numerator, unsigned long *best_denominator) { unsigned long n, d, n0, d0, n1, d1; n = given_numerator; d = given_denominator; n0 = d1 = 0; n1 = d0 = 1; for (;;) { unsigned long t, a; if ((n1 > max_numerator) || (d1 > max_denominator)) { n1 = n0; d1 = d0; break; } if (d == 0) break; t = d; a = n / d; d = n % d; n = t; t = n0 + a * n1; n0 = n1; n1 = t; t = d0 + a * d1; d0 = d1; d1 = t; } *best_numerator = n1; *best_denominator = d1; } EXPORT_SYMBOL(rational_best_approximation); xt.git/'>summaryrefslogtreecommitdiff
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authorLinus Walleij <linus.walleij@linaro.org>2016-12-09 14:18:00 +0100
committerDavid S. Miller <davem@davemloft.net>2016-12-09 23:05:16 -0500
commitab4e4c07aca7b33f8d00c5d6b083a564660ca8a5 (patch)
tree5715298586d832ca3c47577df26681bb293bc9bc /drivers
parent7b5967389f5a8dfb9d32843830f5e2717e20995d (diff)
net: smsc911x: back out silently on probe deferrals
When trying to get a regulator we may get deferred and we see this noise: smsc911x 1b800000.ethernet-ebi2 (unnamed net_device) (uninitialized): couldn't get regulators -517 Then the driver continues anyway. Which means that the regulator may not be properly retrieved and reference counted, and may be switched off in case noone else is using it. Fix this by returning silently on deferred probe and let the system work it out. Cc: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')