[PATCH 0/4] More SD / GPS noise reduction
Andy Green
andy at openmoko.com
Wed Jul 30 13:52:13 CEST 2008
The following series takes two actions to further reduce SD
Card access noise on GPS on GTA02.
- use the minimum negotiated voltage for the SD Card,
it is 2.7V for the shipping Sandisk card. This reduces
the power we put out by estimated 1.7dBm
- when the GPS unit is powered, we dynamically reduce the
clock rate to the SD Card. By default we will reduce it
by a factor of 8 (this can be overridden from kernel
or ash commandlines), from 16MHz to 2MHz. This also
reduces the average energy on the SD Card lines by a
factor of 8
---
Andy Green (4):
use-gta02-glamo-mci-sd-dynamic-clock.patch
add-glamo-mci-slower-clocking-dynamic-switching.patch
fix-glamo-mci-dont-filter-voltage-change.patch
fix-allow-full-sd-voltage-range-selection.patch
arch/arm/mach-s3c2440/mach-gta02.c | 22 ++++++++++++-----
arch/arm/plat-s3c24xx/neo1973_pm_gps.c | 12 +++++++--
drivers/mfd/glamo/glamo-core.c | 15 +++++++++++-
drivers/mfd/glamo/glamo-core.h | 2 ++
drivers/mfd/glamo/glamo-mci.c | 41 ++++++++++++++++++++++++++------
include/linux/glamofb.h | 2 ++
6 files changed, 76 insertions(+), 18 deletions(-)
--
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