From: Yasunari Takiguchi <yasunari.takigu...@sony.com> Provide some math support functions (fixed-point log functions) for the Sony CXD2880 DVB-T2/T tuner + demodulator driver.
Signed-off-by: Yasunari Takiguchi <yasunari.takigu...@sony.com> Signed-off-by: Masayuki Yamamoto <masayuki.yamam...@sony.com> Signed-off-by: Hideki Nozawa <hideki.noz...@sony.com> Signed-off-by: Kota Yonezawa <kota.yonez...@sony.com> Signed-off-by: Toshihiko Matsumoto <toshihiko.matsum...@sony.com> Signed-off-by: Satoshi Watanabe <satoshi.c.watan...@sony.com> --- 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 + +#endif -- 2.11.0
