2013-03-05 20:22:50

by Jean Delvare

Subject: [PATCH 1/2 v2] gpio-ich: Check for pin availability at request time

Stop checking for pin availability in direction and get functions.
These functions can be called repeatedly, so checking every time is
bad for performance. Now that requesting GPIO pins is no longer
optional, checking for availability at pin request time is enough.

Signed-off-by: Jean Delvare <[email protected]>
Cc: Peter Tyser <[email protected]>
Cc: Grant Likely <[email protected]>
Cc: Linus Walleij <[email protected]>
---
Changes since v1:
* Also drop the check from direction functions, as suggested by Peter.

drivers/gpio/gpio-ich.c | 15 +++------------
1 file changed, 3 insertions(+), 12 deletions(-)

--- linux-3.7.orig/drivers/gpio/gpio-ich.c 2013-03-05 08:36:40.940199905 +0100
+++ linux-3.7/drivers/gpio/gpio-ich.c 2013-03-05 20:41:10.407249750 +0100
@@ -135,9 +135,6 @@ static bool ichx_gpio_check_available(st

static int ichx_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
{
- if (!ichx_gpio_check_available(gpio, nr))
- return -ENXIO;
-
/*
* Try setting pin as an input and verify it worked since many pins
* are output-only.
@@ -151,9 +148,6 @@ static int ichx_gpio_direction_input(str
static int ichx_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
int val)
{
- if (!ichx_gpio_check_available(gpio, nr))
- return -ENXIO;
-
/* Set GPIO output value. */
ichx_write_bit(GPIO_LVL, nr, val, 0);

@@ -169,9 +163,6 @@ static int ichx_gpio_direction_output(st

static int ichx_gpio_get(struct gpio_chip *chip, unsigned nr)
{
- if (!ichx_gpio_check_available(chip, nr))
- return -ENXIO;
-
return ichx_read_bit(GPIO_LVL, nr);
}

@@ -180,9 +171,6 @@ static int ich6_gpio_get(struct gpio_chi
unsigned long flags;
u32 data;

- if (!ichx_gpio_check_available(chip, nr))
- return -ENXIO;
-
/*
* GPI 0 - 15 need to be read from the power management registers on
* a ICH6/3100 bridge.
@@ -207,6 +195,9 @@ static int ich6_gpio_get(struct gpio_chi

static int ichx_gpio_request(struct gpio_chip *chip, unsigned nr)
{
+ if (!ichx_gpio_check_available(chip, nr))
+ return -ENXIO;
+
/*
* Note we assume the BIOS properly set a bridge's USE value. Some
* chips (eg Intel 3100) have bogus USE values though, so first see if


--
Jean Delvare

2013-03-27 08:11:44

by Linus Walleij

Subject: Re: [PATCH 1/2 v2] gpio-ich: Check for pin availability at request time

On Tue, Mar 5, 2013 at 9:22 PM, Jean Delvare <[email protected]> wrote:

> Stop checking for pin availability in direction and get functions.
> These functions can be called repeatedly, so checking every time is
> bad for performance. Now that requesting GPIO pins is no longer
> optional, checking for availability at pin request time is enough.
>
> Signed-off-by: Jean Delvare <[email protected]>
> Cc: Peter Tyser <[email protected]>
> Cc: Grant Likely <[email protected]>
> Cc: Linus Walleij <[email protected]>
> ---
> Changes since v1:
> * Also drop the check from direction functions, as suggested by Peter.

Patch applied.

Thanks!
Linus Walleij