From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Agner Subject: [PATCH] pinctrl: freescale: avoid overwriting pin config when freeing GPIO Date: Mon, 26 Sep 2016 17:26:50 -0700 Message-ID: <20160927002650.4316-1-stefan@agner.ch> Return-path: Received: from mail.kmu-office.ch ([178.209.48.109]:39838 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750741AbcI0A1O (ORCPT ); Mon, 26 Sep 2016 20:27:14 -0400 Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: linus.walleij@linaro.org Cc: shawnguo@kernel.org, vladimir_zapolskiy@mentor.com, aalonso@freescale.com, b38343@freescale.com, ldewangan@nvidia.com, van.freenix@gmail.com, p.zabel@pengutronix.de, linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Agner If a GPIO gets freed after selecting a new pinctrl configuration the driver should not change pinctrl anymore. Otherwise this will likely lead to a unusable pin configuration for the newly selected pinctrl. Signed-off-by: Stefan Agner --- This turned out to be problematic when using the I2C GPIO bus recovery functionality. After muxing back to I2C, the GPIO is being freed, which cased I2C to stop working completely. -- Stefan drivers/pinctrl/freescale/pinctrl-imx.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/pinctrl/freescale/pinctrl-imx.c b/drivers/pinctrl/freescale/pinctrl-imx.c index 4761320..61cfa95 100644 --- a/drivers/pinctrl/freescale/pinctrl-imx.c +++ b/drivers/pinctrl/freescale/pinctrl-imx.c @@ -361,8 +361,13 @@ static void imx_pmx_gpio_disable_free(struct pinctrl_dev *pctldev, if (pin_reg->mux_reg == -1) return; - /* Clear IBE/OBE/PUE to disable the pin (Hi-Z) */ reg = readl(ipctl->base + pin_reg->mux_reg); + + /* Only change pad configuration if pad is still a GPIO */ + if (reg & (0x7 << 20)) + return; + + /* Clear IBE/OBE/PUE to disable the pin (Hi-Z) */ reg &= ~0x7; writel(reg, ipctl->base + pin_reg->mux_reg); } -- 2.10.0