diff options
| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2016-03-04 15:56:16 +0900 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2016-03-09 01:10:52 +0900 |
| commit | fdd15b6a86312c2878f3c7a83c70bcf66bbd56a6 (patch) | |
| tree | 433c743906abc1d8ec79a60bb162a80196154edd /drivers/pinctrl | |
| parent | 51244a60805fb91112f61ef268f58fc6d47a3d0a (diff) | |
pinctrl: uniphier: set input-enable before pin-muxing
While IECTRL is disabled, input signals are pulled-down internally.
If pin-muxing is set up first, glitch signals (Low to High transition)
might be input to hardware blocks.
Bad case scenario:
[1] The hardware block is already running before pinctrl is handled.
(the reset is de-asserted by default or by a firmware, for example)
[2] The pin-muxing is set up. The input signals to hardware block
are pulled-down by the chip-internal biasing.
[3] The pins are input-enabled. The signals from the board reach the
hardware block.
Actually, one invalid character is input to the UART blocks for such
SoCs as PH1-LD4, PH1-sLD8, where UART devices start to run at the
power on reset.
To avoid such problems, pins should be input-enabled before muxing.
[ ported from Linux commit bac7f4c1bf5e7c6ccd5bb71edc015b26c77f7460 ]
Fixes: 5dc626f83619 ("pinctrl: uniphier: add UniPhier pinctrl core support")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'drivers/pinctrl')
| -rw-r--r-- | drivers/pinctrl/uniphier/pinctrl-uniphier-core.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c b/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c index 37a920ca8b..ffdccab4ad 100644 --- a/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c +++ b/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c @@ -74,6 +74,9 @@ static void uniphier_pinmux_set_one(struct udevice *dev, unsigned pin, unsigned reg, reg_end, shift, mask; u32 tmp; + /* some pins need input-enabling */ + uniphier_pinconf_input_enable(dev, pin); + reg = UNIPHIER_PINCTRL_PINMUX_BASE + pin * mux_bits / 32 * reg_stride; reg_end = reg + reg_stride; shift = pin * mux_bits % 32; @@ -94,9 +97,6 @@ static void uniphier_pinmux_set_one(struct udevice *dev, unsigned pin, if (priv->socdata->load_pinctrl) writel(1, priv->base + UNIPHIER_PINCTRL_LOAD_PINMUX); - - /* some pins need input-enabling */ - uniphier_pinconf_input_enable(dev, pin); } static int uniphier_pinmux_group_set(struct udevice *dev, |