From bac7f4c1bf5e7c6ccd5bb71edc015b26c77f7460 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 20 Oct 2015 17:25:09 +0900 Subject: [PATCH] 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: 6e9088920258 ("pinctrl: UniPhier: add UniPhier pinctrl core support") Signed-off-by: Masahiro Yamada Reported-by: Dai Okamura Signed-off-by: Linus Walleij --- drivers/pinctrl/uniphier/pinctrl-uniphier-core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c b/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c index 918f3b643f1b..589872cc8adb 100644 --- a/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c +++ b/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c @@ -539,6 +539,12 @@ static int uniphier_pmx_set_one_mux(struct pinctrl_dev *pctldev, unsigned pin, unsigned reg, reg_end, shift, mask; int ret; + /* some pins need input-enabling */ + ret = uniphier_conf_pin_input_enable(pctldev, + &pctldev->desc->pins[pin], 1); + if (ret) + return ret; + reg = UNIPHIER_PINCTRL_PINMUX_BASE + pin * mux_bits / 32 * reg_stride; reg_end = reg + reg_stride; shift = pin * mux_bits % 32; @@ -563,9 +569,7 @@ static int uniphier_pmx_set_one_mux(struct pinctrl_dev *pctldev, unsigned pin, return ret; } - /* some pins need input-enabling */ - return uniphier_conf_pin_input_enable(pctldev, - &pctldev->desc->pins[pin], 1); + return 0; } static int uniphier_pmx_set_mux(struct pinctrl_dev *pctldev, -- 2.11.0