From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Ujfalusi , Linus Walleij , Tony Lindgren , linux-gpio@vger.kernel.org Subject: [PATCH 3.12 041/212] gpio: twl4030: Fix regression for twl gpio output Date: Mon, 2 Dec 2013 11:13:52 -0800 Message-Id: <20131202191252.976838459@linuxfoundation.org> In-Reply-To: <20131202191248.517975703@linuxfoundation.org> References: <20131202191248.517975703@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tony Lindgren commit 0b2aa8bed3e13892fcac77e4f50ec6e80125469d upstream. Commit c111feabe2e2 (gpio: twl4030: Cache the direction and output states in private data) improved things in general, but caused a regression for setting the GPIO output direction. The change reorganized twl_direction_out() and twl_set() and swapped the function names around in the process. While doing that, a bug got introduced that's not obvious while reading the patch as it appears as no change to the code. The bug is we now call function twl4030_set_gpio_dataout() twice in both twl_direction_out() and twl_set(). Instead, we should first call twl_direction_out() in twl_direction_out() followed by twl4030_set_gpio_dataout() in twl_set(). This regression probably has gone unnoticed for a long time as the bootloader may have set the GPIO direction properly in many cases. This fixes at least the LCD panel not turning on omap3 LDP for example. Cc: linux-gpio@vger.kernel.org Reviewed-by: Peter Ujfalusi Acked-by: Linus Walleij Signed-off-by: Tony Lindgren Signed-off-by: Greg Kroah-Hartman --- drivers/gpio/gpio-twl4030.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/gpio/gpio-twl4030.c +++ b/drivers/gpio/gpio-twl4030.c @@ -354,17 +354,18 @@ static void twl_set(struct gpio_chip *ch static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value) { struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); + int ret = -EINVAL; mutex_lock(&priv->mutex); if (offset < TWL4030_GPIO_MAX) - twl4030_set_gpio_dataout(offset, value); + ret = twl4030_set_gpio_direction(offset, 0); priv->direction |= BIT(offset); mutex_unlock(&priv->mutex); twl_set(chip, offset, value); - return 0; + return ret; } static int twl_to_irq(struct gpio_chip *chip, unsigned offset)