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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2009-12-27 20:05:43 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2009-12-27 20:05:43 +0000 |
commit | 4b252f09c5532b5b24f20b3924abb1363c400c3d (patch) | |
tree | 5f510c20a7c8d6de15407198368038c570e21703 /nuttx/arch/arm/src/lpc313x | |
parent | 2a3ab58a75a6fe51bf323a83f78a2e86ca2bc133 (diff) | |
download | px4-nuttx-4b252f09c5532b5b24f20b3924abb1363c400c3d.tar.gz px4-nuttx-4b252f09c5532b5b24f20b3924abb1363c400c3d.tar.bz2 px4-nuttx-4b252f09c5532b5b24f20b3924abb1363c400c3d.zip |
Add logic to obtain clock frequency
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2441 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/arch/arm/src/lpc313x')
-rwxr-xr-x | nuttx/arch/arm/src/lpc313x/Make.defs | 3 | ||||
-rwxr-xr-x | nuttx/arch/arm/src/lpc313x/lpc313x_cgu.h | 4 | ||||
-rwxr-xr-x | nuttx/arch/arm/src/lpc313x/lpc313x_cgudrvr.h | 12 | ||||
-rwxr-xr-x | nuttx/arch/arm/src/lpc313x/lpc313x_clkfreq.c | 177 |
4 files changed, 193 insertions, 3 deletions
diff --git a/nuttx/arch/arm/src/lpc313x/Make.defs b/nuttx/arch/arm/src/lpc313x/Make.defs index 9d9a7dd49..2eee54cc8 100755 --- a/nuttx/arch/arm/src/lpc313x/Make.defs +++ b/nuttx/arch/arm/src/lpc313x/Make.defs @@ -46,7 +46,8 @@ CMN_CSRCS = up_assert.c up_blocktask.c up_copystate.c up_createstack.c \ up_undefinedinsn.c up_usestack.c CGU_ASRCS = -CGU_CSRCS = lpc313x_clkdomain.c lpc313x_fdcndx.c lpc313x_esrndx.c +CGU_CSRCS = lpc313x_clkdomain.c lpc313x_clkfreq.c lpc313x_esrndx.c \ + lpc313x_fdcndx.c CHIP_ASRCS = $(CGU_ASRCS) CHIP_CSRCS = lpc313x_irq.c lpc313x_allocateheap.c $(CGU_CSRCS) diff --git a/nuttx/arch/arm/src/lpc313x/lpc313x_cgu.h b/nuttx/arch/arm/src/lpc313x/lpc313x_cgu.h index 4733a2605..3d31fe4b6 100755 --- a/nuttx/arch/arm/src/lpc313x/lpc313x_cgu.h +++ b/nuttx/arch/arm/src/lpc313x/lpc313x_cgu.h @@ -1197,7 +1197,7 @@ #define CGU_FDC_MSUB_SHIFT (11) /* Bits 11-18: Modulo subtraction value */ #define CGU_FDC_MSUB_MASK (255 << CGU_FDC_MSUB_SHIFT) -#define CGU_FDC_MADD_SHIFT (3) /* Bits 3-10: Modulo addition value */ +#define CGU_FDC_MADD_SHIFT (3) /* Bits 3-10: Modulo addition value */ #define CGU_FDC_MADD_MASK (255 << CGU_FDC_MADD_SHIFT) #define CGU_FDC_STRETCH (1 << 2) /* Bit 2: Enables the stretching option */ #define CGU_FDC_RESET (1 << 1) /* Bit 1: Reset fractional divider */ @@ -1205,7 +1205,7 @@ #define CGU_FDC17_MSUB_SHIFT (16) /* Bits 16-28: Modulo subtraction value */ #define CGU_FDC17_MSUB_MASK (0x1fff << CGU_FDC17_MSUB_SHIFT) -#define CGU_FDC17_MADD_SHIFT (3) /* Bits 3-15: Modulo addition value */ +#define CGU_FDC17_MADD_SHIFT (3) /* Bits 3-15: Modulo addition value */ #define CGU_FDC17_MADD_MASK (0x1fff << CGU_FDC17_MADD_SHIFT) #define CGU_FDC17_STRETCH (1 << 2) /* Bit 2: Enables the stretching option */ #define CGU_FDC17_RESET (1 << 1) /* Bit 1: Reset fractional divider */ diff --git a/nuttx/arch/arm/src/lpc313x/lpc313x_cgudrvr.h b/nuttx/arch/arm/src/lpc313x/lpc313x_cgudrvr.h index 0fb105c8d..5d3089191 100755 --- a/nuttx/arch/arm/src/lpc313x/lpc313x_cgudrvr.h +++ b/nuttx/arch/arm/src/lpc313x/lpc313x_cgudrvr.h @@ -457,6 +457,18 @@ EXTERN int lp313x_esrndx(enum lpc313x_clockid_e clkid); EXTERN int lpc313x_fdcndx(enum lpc313x_clockid_e clkid, enum lpc313x_domainid_e dmnid); +/************************************************************************ + * Name: lpc313x_fdcndx + * + * Description: + * Given a clock ID and its domain ID, return the frequency of the + * clock. + * + ************************************************************************/ + +EXTERN uint32_t lpc313x_clkfreq(enum lpc313x_clockid_e clkid, + enum lpc313x_domainid_e dmnid); + #undef EXTERN #ifdef __cplusplus } diff --git a/nuttx/arch/arm/src/lpc313x/lpc313x_clkfreq.c b/nuttx/arch/arm/src/lpc313x/lpc313x_clkfreq.c new file mode 100755 index 000000000..8d4f9fb35 --- /dev/null +++ b/nuttx/arch/arm/src/lpc313x/lpc313x_clkfreq.c @@ -0,0 +1,177 @@ +/************************************************************************ + * arch/arm/src/lpc313x/lpc313x_clkfreq.c + * + * Copyright (C) 2009 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * References: + * - UM10314 LPC3130/31 User manual Rev. 1.01 — 9 September 2009 + * - lpc313x.cdl.drivers.zip example driver code + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "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 + * COPYRIGHT OWNER OR CONTRIBUTORS 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. + * + ************************************************************************/ + +/************************************************************************ + * Included Files + ************************************************************************/ + +#include <nuttx/config.h> +#include <stdint.h> + +#include "up_arch.h" +#include "lpc313x_cgudrvr.h" + +/************************************************************************ + * Pre-processor Definitions + ************************************************************************/ + +/************************************************************************ + * Private Data + ************************************************************************/ + +/************************************************************************ + * Private Functions + ************************************************************************/ + +/************************************************************************ + * Public Functions + ************************************************************************/ + +/************************************************************************ + * Name: lpc313x_fdcndx + * + * Description: + * Given a clock ID and its domain ID, return the frequency of the + * clock. + * + ************************************************************************/ + +uint32_t lpc313x_clkfreq(enum lpc313x_clockid_e clkid, + enum lpc313x_domainid_e dmnid) +{ + uint32_t freq = 0; + uint32_t fdcndx; + uint32_t regval; + + /* Get then fractional divider register index for this clock */ + + fdcndx = lpc313x_fdcndx(clkid, dmnid); + + /* Get base frequency for the domain */ + + freq = lpc313x_basefreq(dmnid); + + /* If there is no fractional divider associated with the clodk, then the + * connection is directo and we just return the base frequency. + */ + + if (fdcndx == FDCNDX_INVALID) + { + return freq; + } + + /* Read fractional divider control (FDC) register value and double check that + * it is enabled (not necessary since lpc313x_fdcndx() also does this check + */ + + regval = getreg32(LPC313X_CGU_FDC_OFFSET(fdcndx)); + if ((regval & CGU_ESR_ESREN) != 0) + { + int32_t msub; + int32_t madd; + int32_t n; + int32_t m; + + /* Yes, extract modulo subtraction and addition values, msub and madd. + * Fractional divider 17 is a special case because its msub and madd + * fields have greater range. + */ + + if (fdcndx == 17) + { + /* Range is 0-0x1fff for both */ + + msub = (regval & CGU_FDC17_MSUB_MASK) >> CGU_FDC17_MSUB_SHIFT; + madd = (regval & CGU_FDC17_MADD_MASK) >> CGU_FDC17_MADD_SHIFT; + } + else + { + /* Range is 0-255 for both */ + + msub = (regval & CGU_FDC_MSUB_MASK) >> CGU_FDC_MSUB_SHIFT; + madd = (regval & CGU_FDC_MADD_MASK) >> CGU_FDC_MADD_SHIFT; + } + + /* Handle a corner case that would result in an infinite loop below */ + + if (msub == 0 && madd == 0) + { + return 0; + } + + /* Reduce to the greatest common power-of-2 denominator. To minimize + * power consumption, the lpc313x user manual recommends that madd and msub + * be shifted right to have as many trailing zero's as possible. The + * following undoes that shift. + */ + + while ((msub & 1) == 0 && (madd & 1) == 0) + { + madd = madd >> 1; + msub = msub >> 1; + } + + /* Then compute n and m values: + * + * fout = n/m * fin + * + * where + * + * madd = m - n + * msub = -n + */ + + n = -msub; + m = madd + n; + + /* Check that both m and n are non-zero values */ + + if ((n == 0) || (m == 0)) + { + return 0; + } + + /* Finally, calculate the frequency based on m and n values */ + + freq = (freq * n) / m ; + } + + return freq; +} + |