> On Tue, 16 Mar 2010 10:19:00 +0100
I bet you thought I'd forgotten.
Marc Zyngier <[email protected]> wrote:
> max732x datasheets indicate that open-drain pins must be
> configured as output-high to be used as input...
>
> Signed-off-by: Marc Zyngier <[email protected]>
> ---
> drivers/gpio/max732x.c | 12 +++++++++++-
> 1 files changed, 11 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/gpio/max732x.c b/drivers/gpio/max732x.c
> index f786824..3618feb 100644
> --- a/drivers/gpio/max732x.c
> +++ b/drivers/gpio/max732x.c
> @@ -179,15 +179,25 @@ static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
> {
> struct max732x_chip *chip;
> unsigned int mask = 1u << off;
> + unsigned int is_input;
>
> chip = container_of(gc, struct max732x_chip, gpio_chip);
>
> - if ((mask & chip->dir_input) == 0) {
> + is_input = mask & chip->dir_input;
> +
> + if (!is_input) {
> dev_dbg(&chip->client->dev, "%s port %d is output only\n",
> chip->client->name, off);
> return -EACCES;
> }
>
> + /*
> + * Open-drain pins must be set to high impedance (which is
> + * equivalent to output-high) to be turned into an input.
> + */
> + if ((is_input & chip->dir_output))
You really did mean `&' here, but one very much expects a variable
called is_foo to be a boolean, and booleans want `&&'.
Can you think of a more appropriate name for this guy? input_lines, maybe?
> + max732x_gpio_set_value(gc, off, 1);
> +
> return 0;
> }
On Tue, 20 Apr 2010 16:51:48 -0700, Andrew Morton
<[email protected]> wrote:
>> On Tue, 16 Mar 2010 10:19:00 +0100
>
> I bet you thought I'd forgotten.
Naaaah... I trust your memory more than mine... ;-)
> You really did mean `&' here, but one very much expects a variable
> called is_foo to be a boolean, and booleans want `&&'.
Actually, the attached patch is a much simpler solution to this particular
one. We already checked that the pin is input-capable. Use the same mask to
check that the pin is also output-capable, and thus open-drain. No need for
an additional variable.
Thanks,
M.
--
Who you jivin' with that Cosmik Debris?