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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.
Fixes: 6e90889202
("pinctrl: UniPhier: add UniPhier pinctrl core support")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reported-by: Dai Okamura <okamura.dai@socionext.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
parent
e0548004d4
commit
bac7f4c1bf
1 changed files with 7 additions and 3 deletions
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@ -539,6 +539,12 @@ static int uniphier_pmx_set_one_mux(struct pinctrl_dev *pctldev, unsigned pin,
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unsigned reg, reg_end, shift, mask;
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int ret;
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/* some pins need input-enabling */
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ret = uniphier_conf_pin_input_enable(pctldev,
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&pctldev->desc->pins[pin], 1);
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if (ret)
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return ret;
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reg = UNIPHIER_PINCTRL_PINMUX_BASE + pin * mux_bits / 32 * reg_stride;
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reg_end = reg + reg_stride;
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shift = pin * mux_bits % 32;
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@ -563,9 +569,7 @@ static int uniphier_pmx_set_one_mux(struct pinctrl_dev *pctldev, unsigned pin,
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return ret;
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}
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/* some pins need input-enabling */
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return uniphier_conf_pin_input_enable(pctldev,
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&pctldev->desc->pins[pin], 1);
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return 0;
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}
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static int uniphier_pmx_set_mux(struct pinctrl_dev *pctldev,
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