Em Fri, 14 Apr 2017 11:22:37 +0900 <[email protected]> escreveu:
> From: Yasunari Takiguchi <[email protected]> > > Provide some math support functions (fixed-point log functions) > for the Sony CXD2880 DVB-T2/T tuner + demodulator driver. No need. The Kernel already provide log functions. You should use the existing ones, instead of reinventing the wheel. The log2 functions are at: include/linux/log2.h We also have both log2 and log10 functions at: drivers/media/dvb-core/dvb_math.h That should likely what you want. > > Signed-off-by: Yasunari Takiguchi <[email protected]> > Signed-off-by: Masayuki Yamamoto <[email protected]> > Signed-off-by: Hideki Nozawa <[email protected]> > Signed-off-by: Kota Yonezawa <[email protected]> > Signed-off-by: Toshihiko Matsumoto <[email protected]> > Signed-off-by: Satoshi Watanabe <[email protected]> > --- > drivers/media/dvb-frontends/cxd2880/cxd2880_math.c | 89 > ++++++++++++++++++++++ > drivers/media/dvb-frontends/cxd2880/cxd2880_math.h | 40 ++++++++++ > 2 files changed, 129 insertions(+) > create mode 100644 drivers/media/dvb-frontends/cxd2880/cxd2880_math.c > create mode 100644 drivers/media/dvb-frontends/cxd2880/cxd2880_math.h > > diff --git a/drivers/media/dvb-frontends/cxd2880/cxd2880_math.c > b/drivers/media/dvb-frontends/cxd2880/cxd2880_math.c > new file mode 100644 > index 000000000000..434c827898ff > --- /dev/null > +++ b/drivers/media/dvb-frontends/cxd2880/cxd2880_math.c > @@ -0,0 +1,89 @@ > +/* > + * cxd2880_math.c > + * Sony CXD2880 DVB-T2/T tuner + demodulator driver > + * mathmatics functions > + * > + * Copyright (C) 2016, 2017 Sony Semiconductor Solutions Corporation > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU General Public License as published by the > + * Free Software Foundation; version 2 of the License. > + * > + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED > + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF > + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN > + * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, > + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT > + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF > + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON > + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT > + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF > + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. > + * > + * You should have received a copy of the GNU General Public License along > + * with this program; if not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include "cxd2880_math.h" > + > +#define MAX_BIT_PRECISION 5 > +#define FRAC_BITMASK 0x1F > +#define LOG2_10_100X 332 > +#define LOG2_E_100X 144 > + > +static const u8 log2_look_up[] = { > + 0, 4, > + 9, 13, > + 17, 21, > + 25, 29, > + 32, 36, > + 39, 43, > + 46, 49, > + 52, 55, > + 58, 61, > + 64, 67, > + 70, 73, > + 75, 78, > + 81, 83, > + 86, 88, > + 91, 93, > + 95, 98 > +}; > + > +u32 cxd2880_math_log2(u32 x) > +{ > + u8 count = 0; > + u8 index = 0; > + u32 xval = x; > + > + for (x >>= 1; x > 0; x >>= 1) > + count++; > + > + x = count * 100; > + > + if (count > 0) { > + if (count <= MAX_BIT_PRECISION) { > + index = > + (u8)(xval << (MAX_BIT_PRECISION - count)) & > + FRAC_BITMASK; > + x += log2_look_up[index]; > + } else { > + index = > + (u8)(xval >> (count - MAX_BIT_PRECISION)) & > + FRAC_BITMASK; > + x += log2_look_up[index]; > + } > + } > + > + return x; > +} > + > +u32 cxd2880_math_log10(u32 x) > +{ > + return ((100 * cxd2880_math_log2(x) + LOG2_10_100X / 2) / LOG2_10_100X); > +} > + > +u32 cxd2880_math_log(u32 x) > +{ > + return ((100 * cxd2880_math_log2(x) + LOG2_E_100X / 2) / LOG2_E_100X); > +} > diff --git a/drivers/media/dvb-frontends/cxd2880/cxd2880_math.h > b/drivers/media/dvb-frontends/cxd2880/cxd2880_math.h > new file mode 100644 > index 000000000000..94211835a4ad > --- /dev/null > +++ b/drivers/media/dvb-frontends/cxd2880/cxd2880_math.h > @@ -0,0 +1,40 @@ > +/* > + * cxd2880_math.h > + * Sony CXD2880 DVB-T2/T tuner + demodulator driver > + * mathmatics definitions > + * > + * Copyright (C) 2016, 2017 Sony Semiconductor Solutions Corporation > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU General Public License as published by the > + * Free Software Foundation; version 2 of the License. > + * > + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED > + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF > + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN > + * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, > + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT > + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF > + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON > + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT > + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF > + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. > + * > + * You should have received a copy of the GNU General Public License along > + * with this program; if not, see <http://www.gnu.org/licenses/>. > + */ > + > +#ifndef CXD2880_MATH_H_ > +#define CXD2880_MATH_H_ > + > +#include "cxd2880_common.h" > + > +u32 cxd2880_math_log2(u32 x); > +u32 cxd2880_math_log10(u32 x); > +u32 cxd2880_math_log(u32 x); > + > +#ifndef min > +#define min(a, b) (((a) < (b)) ? (a) : (b)) > +#endif We also have min() macro at the Kernel. > + > +#endif Thanks, Mauro
