From: Stefan Agner <stefan@agner.ch>
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 <stefan@agner.ch>
Subject: [PATCH] pinctrl: freescale: avoid overwriting pin config when freeing GPIO
Date: Mon, 26 Sep 2016 17:26:50 -0700 [thread overview]
Message-ID: <20160927002650.4316-1-stefan@agner.ch> (raw)
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 <stefan@agner.ch>
---
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
next reply other threads:[~2016-09-27 0:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-27 0:26 Stefan Agner [this message]
2016-09-27 12:12 ` [PATCH] pinctrl: freescale: avoid overwriting pin config when freeing GPIO Vladimir Zapolskiy
2016-09-27 16:37 ` Stefan Agner
2016-09-27 18:17 ` Vladimir Zapolskiy
2016-09-27 19:34 ` Stefan Agner
2016-09-27 20:28 ` Vladimir Zapolskiy
2016-09-28 2:00 ` Viresh Kumar
2016-09-28 3:38 ` Stefan Agner
2016-09-28 4:14 ` Viresh Kumar
2016-09-29 16:33 ` Stefan Agner
2016-09-30 2:12 ` Viresh Kumar
2016-10-10 8:32 ` Linus Walleij
2016-09-28 12:07 ` Vladimir Zapolskiy
2016-09-29 6:46 ` Viresh Kumar
2016-09-29 12:16 ` Vladimir Zapolskiy
2016-09-30 2:22 ` Viresh Kumar
2016-10-10 8:33 ` Linus Walleij
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