From mboxrd@z Thu Jan 1 00:00:00 1970 From: Axel Lin Subject: [PATCH v2] gpio: zevio: Get correct gpio output value Date: Tue, 08 Apr 2014 07:59:39 +0800 Message-ID: <1396915179.4729.1.camel@phoenix> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pd0-f169.google.com ([209.85.192.169]:48628 "EHLO mail-pd0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754695AbaDGX7o (ORCPT ); Mon, 7 Apr 2014 19:59:44 -0400 Received: by mail-pd0-f169.google.com with SMTP id fp1so179015pdb.0 for ; Mon, 07 Apr 2014 16:59:44 -0700 (PDT) Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Linus Walleij , Alexandre Courbot Cc: Gerhard Sittig , Fabian Vogt , linux-gpio@vger.kernel.org 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 --- 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