linux-kernel - Re: [PATCH] plat-mxc: add missing initialisation of basic_mmio_gpio shadow variables

Open Source and information security mailing list archives

Date:	Thu, 7 Jul 2011 12:43:21 -0600
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Lothar Waßmann <LW@...O-electronics.de>
Cc:	linux-arm-kernel@...ts.infradead.org,
	Sascha Hauer <s.hauer@...gutronix.de>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] plat-mxc: add missing initialisation of basic_mmio_gpio
 shadow variables

On Thu, Jul 07, 2011 at 02:50:16PM +0200, Lothar Waßmann wrote:
> The bgpio_init() function does not initialise the shadow register for
> the GPIO direction register. Thus, when configuring the first GPIO with
> gpio_set_direction() all other GPIOs of the same bank will be
> configured as inputs. Since the bgpio layer cannot know whether the
> register is readable, the initialisation should be done by the caller
> of bgpio_init().
> 
> Also, the 'data' shadow variable that is used inside basic_mmio_gpio
> to cache the current value of the GPIO_DR register is initialised from
> the GPIO_PSR register within bgpio_init(). Thus when setting the
> output value of a certain GPIO, the other GPIO outputs of the same
> bank will be set or cleared depending on the pin state of the GPIO
> inputs during bgpio_init().
> 
> 
> Signed-off-by: Lothar Waßmann <LW@...O-electronics.de>

Applied, thanks.

g.

> ---
>  drivers/gpio/gpio-mxc.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
> index b351952..f7944ca 100644
> --- a/drivers/gpio/gpio-mxc.c
> +++ b/drivers/gpio/gpio-mxc.c
> @@ -337,6 +337,8 @@ static int __devinit mxc_gpio_probe(struct platform_device *pdev)
>  		goto out_iounmap;
>  
>  	port->bgc.gc.base = pdev->id * 32;
> +	port->bgc.dir = port->bgc.read_reg(port->bgc.reg_dir);
> +	port->bgc.data = port->bgc.read_reg(port->bgc.reg_set);
>  
>  	err = gpiochip_add(&port->bgc.gc);
>  	if (err)
> -- 
> 1.5.6.5
> 
> 
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> linux-arm-kernel@...ts.infradead.org
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