plat-mxc: add missing initialisation of basic_mmio_gpio shadow variables

Submitted by Lothar Waßmann on July 7, 2011, 12:50 p.m.

Details

Message ID 1310043016-1121-1-git-send-email-LW@KARO-electronics.de
State New
Headers show

Commit Message

Lothar Waßmann July 7, 2011, 12:50 p.m.
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@KARO-electronics.de>
---
 drivers/gpio/gpio-mxc.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

Comments

Grant Likely July 7, 2011, 6:43 p.m.
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@KARO-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 mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Patch hide | download patch | download mbox

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)