The DRA74/72 control module pins have a weak pull up and pull down.
This is configured by bit offset 17. if BIT(17) is 1, a pull up is
selected, else a pull down is selected.
However, this pull resisstor is applied based on BIT(16) -
PULLUDENABLE - if BIT(18) is *0*, then pull as defined in BIT(17) is
applied, else no weak pulls are applied. We defined this in reverse.
Reference: Table 18-5 (Description of the pad configuration register
bits) in Technical Reference Manual Revision (DRA74x revision Q:
SPRUHI2Q Revised June 2014 and DRA72x revision F: SPRUHP2F - Revised
June 2014)
Fixes: 6e58b8f1daaf1a ("ARM: dts: DRA7: Add the dts files for dra7 SoC and dra7-evm board")
Signed-off-by: Nishanth Menon <nm@xxxxxx>
---
Patch based on v3.16-rc5 tag
1: dra72x-evm: Boot ok: http://slexy.org/raw/s20I6QXQa (needs MMC filesystem that current dts does not have.
- Fails in plain Vanilla 3.16-rc5 kernel due to missing patch to handle USB IP instance delta (between dra72x and dra74x) appropriately.
- Tested with fixes needed: https://patchwork.kernel.org/patch/4565431/ and https://patchwork.kernel.org/patch/4565461/
2: dra7xx-evm: Boot PASS: http://slexy.org/raw/s21c6X2wOd
Equivalent testing on 3.14 based product kernel:
dra72x-evm: Boot PASS: http://slexy.org/raw/s21yIgttJw
dra7xx-evm: Boot PASS: http://slexy.org/raw/s20w7OZaJJ
It is obvious that current users of padconf have'nt had trouble with
the wrong definitions. I think I might have been the first to discover
this as emmc on beagleboard-X15 (an upcoming platform) exposed this problem.
include/dt-bindings/pinctrl/dra.h | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/include/dt-bindings/pinctrl/dra.h b/include/dt-bindings/pinctrl/dra.h
index 002a285..3d33794 100644
--- a/include/dt-bindings/pinctrl/dra.h
+++ b/include/dt-bindings/pinctrl/dra.h
@@ -30,7 +30,8 @@
#define MUX_MODE14 0xe
#define MUX_MODE15 0xf
-#define PULL_ENA (1 << 16)
+#define PULL_ENA (0 << 16)
+#define PULL_DIS (1 << 16)
#define PULL_UP (1 << 17)
#define INPUT_EN (1 << 18)
#define SLEWCONTROL (1 << 19)
@@ -38,10 +39,10 @@
#define WAKEUP_EVENT (1 << 25)
/* Active pin states */
-#define PIN_OUTPUT 0
+#define PIN_OUTPUT (0 | PULL_DIS)
#define PIN_OUTPUT_PULLUP (PIN_OUTPUT | PULL_ENA | PULL_UP)
#define PIN_OUTPUT_PULLDOWN (PIN_OUTPUT | PULL_ENA)
-#define PIN_INPUT INPUT_EN
+#define PIN_INPUT (INPUT_EN | PULL_DIS)
#define PIN_INPUT_SLEW (INPUT_EN | SLEWCONTROL)
#define PIN_INPUT_PULLUP (PULL_ENA | INPUT_EN | PULL_UP)
#define PIN_INPUT_PULLDOWN (PULL_ENA | INPUT_EN)
--
1.7.9.5
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