From: Axel Lin <axel.lin@ingics.com>
To: Linus Walleij <linus.walleij@linaro.org>,
Alexandre Courbot <gnurou@gmail.com>
Cc: Gerhard Sittig <gsi@denx.de>, Fabian Vogt <fabian@ritter-vogt.de>,
linux-gpio@vger.kernel.org
Subject: [PATCH v2] gpio: zevio: Get correct gpio output value
Date: Tue, 08 Apr 2014 07:59:39 +0800 [thread overview]
Message-ID: <1396915179.4729.1.camel@phoenix> (raw)
Read gpio output value from ZEVIO_GPIO_OUTPUT.
The spin_lock is required to ensure the direction is not changed before reading
input/ouput value.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
---
drivers/gpio/gpio-zevio.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpio/gpio-zevio.c b/drivers/gpio/gpio-zevio.c
index 9bf5034..29b0150 100644
--- a/drivers/gpio/gpio-zevio.c
+++ b/drivers/gpio/gpio-zevio.c
@@ -81,9 +81,15 @@ static inline void zevio_gpio_port_set(struct zevio_gpio *c, unsigned pin,
static int zevio_gpio_get(struct gpio_chip *chip, unsigned pin)
{
struct zevio_gpio *controller = to_zevio_gpio(chip);
+ u32 val, dir;
- /* Only reading allowed, so no spinlock needed */
- u32 val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_INPUT);
+ spin_lock(&controller->lock);
+ dir = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION);
+ if (dir & BIT(ZEVIO_GPIO_BIT(pin)))
+ val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_INPUT);
+ else
+ val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT);
+ spin_unlock(&controller->lock);
return (val >> ZEVIO_GPIO_BIT(pin)) & 0x1;
}
--
1.8.3.2
next reply other threads:[~2014-04-07 23:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-07 23:59 Axel Lin [this message]
2014-04-10 17:56 ` [PATCH v2] gpio: zevio: Get correct gpio output value Linus Walleij
2014-04-11 0:16 ` Axel Lin
2014-04-22 12:29 ` Linus Walleij
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