diff options
Diffstat (limited to 'target/linux/s3c24xx/patches-2.6.24/1087-introduce-fiq-hdq.patch.patch')
| -rw-r--r-- | target/linux/s3c24xx/patches-2.6.24/1087-introduce-fiq-hdq.patch.patch | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/target/linux/s3c24xx/patches-2.6.24/1087-introduce-fiq-hdq.patch.patch b/target/linux/s3c24xx/patches-2.6.24/1087-introduce-fiq-hdq.patch.patch new file mode 100644 index 0000000000..ada6b7cd2e --- /dev/null +++ b/target/linux/s3c24xx/patches-2.6.24/1087-introduce-fiq-hdq.patch.patch @@ -0,0 +1,87 @@ +From ab6e925546e3d3361ab59c2b090eccf0cb411c7b Mon Sep 17 00:00:00 2001 +From: Andy Green <andy@openmoko.com> +Date: Sun, 13 Apr 2008 07:25:48 +0100 +Subject: [PATCH] introduce-fiq-hdq.patch + +This adds a platform driver and device which performs HDQ +battery protocol using a single GPIO pin which is set +through platform data. + +HDQ has some hard latency requirements which can't +be met if interrupts are enabled, so normally using +a GPIO for this will require blocking out all other +interrupts and processes for several milliseconds +per register being read or written. + +This HDQ protocol engine is a FSM implemented inside the +the FIQ ISR and regulated by timer interrupts happening +at 20us intervals. The path through the FSM on any +"clock" is very short and should be over with in ~ +1us. Because FIQ has guaranteed latencies of <1us, +it means we can service the HDQ protocol without +blocking interrupts or any other process other than +the caller that is waiting for the result. It's pretty +cool performance from 1 GPIO ;-) + +Due to it being hard to do locking from the FIQ ISR +the code simply sleeps 10ms or whatever the scheduler +gives it and checks if the transfer took place yet. + +This platform driver doesn't have any knowledge about +the device it is talking to, it just knows it is a +HDQ device. It exports three functions for read, write +and confirming HDQ is initialized. It also exports two +/sys nodes that are usable by humans, one dumps the whole +127 register HDQ register space + +# cat /sys/devices/platform/gta02-hdq.0/hdq/dump +00 44 55 00 00 00 ba 04 a2 0d 50 00 00 00 00 00 +00 00 9a 1a 00 00 ff ff ff ff 29 00 00 00 80 2b +00 00 00 00 00 00 ff ff 00 00 00 00 00 32 af 06 +a0 d8 37 4e 00 00 00 00 00 00 00 34 2e 03 b4 e7 +00 00 06 00 41 00 4c 02 00 00 00 00 00 00 00 00 +83 02 00 00 94 09 59 b9 a5 0d 7f 21 00 00 7a ff +df ff 62 ff a7 04 2e 05 00 00 00 01 00 07 00 00 +2a 78 36 67 7b b5 1b a9 af 19 38 89 63 57 42 7c +# + +and the other allows to set one register + +# echo 2 170 > /sys/devices/platform/gta02-hdq.0/hdq/write + +writes 0xAA into register 2. + +Signed-off-by: Andy Green <andy@openmoko.com> +--- + defconfig-2.6.24 | 1 + + drivers/power/Kconfig | 8 ++++++++ + 2 files changed, 9 insertions(+), 0 deletions(-) + +diff --git a/defconfig-2.6.24 b/defconfig-2.6.24 +index 833e15e..6d750a5 100644 +--- a/defconfig-2.6.24 ++++ b/defconfig-2.6.24 +@@ -1825,3 +1825,4 @@ CONFIG_TEXTSEARCH_FSM=m + CONFIG_PLIST=y + CONFIG_HAS_IOMEM=y + CONFIG_HAS_DMA=y ++CONFIG_GTA02_HDQ=y +diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig +index feb8b0a..5ace872 100644 +--- a/drivers/power/Kconfig ++++ b/drivers/power/Kconfig +@@ -63,3 +63,11 @@ config GTA02_HDQ + at least BATTERY_BQ27000_HDQ as well + + endif # POWER_SUPPLY ++ ++config GTA02_HDQ ++ tristate "Neo Freerunner HDQ" ++ depends on MACH_NEO1973_GTA02 && FIQ && S3C2440_C_FIQ ++ help ++ Say Y to enable support for communicating with an HDQ battery ++ on the Neo Freerunner. You probably want to select ++ at least BATTERY_BQ27000_HDQ as well +-- +1.5.6.5 + |