lkml.org 
[lkml]   [2010]   [Jan]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patches in this message
    /
    From
    Date
    SubjectRe: [PATCH] gpio: introduce gpio_request_one() and friends
    > > Global, exported-to-modules interfaces should be documented, IMO.
    > >
    >
    > OK, will do.
    >

    Andrew,

    Attached is the patch against Documentation/gpio.txt (also inlined),
    which you may either use as an incremental patch, or merge with
    the last one, or if you want, use the other one attached for a merged
    version.

    diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
    index 1866c27..c2c6e9b 100644
    --- a/Documentation/gpio.txt
    +++ b/Documentation/gpio.txt
    @@ -253,6 +253,70 @@ pin setup (e.g. controlling which pin the GPIO
    uses, pullup/pulldown).
    Also note that it's your responsibility to have stopped using a GPIO
    before you free it.

    +Considering in most cases GPIOs are actually configured right after they
    +are claimed, three additional calls are defined:
    +
    + /* request a single GPIO, with initial configuration specified by
    + * 'flags', identical to gpio_request() wrt other arguments and
    + * return value
    + */
    + int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
    +
    + /* request multiple GPIOs in a single call
    + */
    + int gpio_request_array(struct gpio *array, size_t num);
    +
    + /* release multiple GPIOs in a single call
    + */
    + void gpio_free_array(struct gpio *array, size_t num);
    +
    +where 'flags' is currently defined to specify the following properties:
    +
    + * GPIOF_DIR_IN - to configure direction as input
    + * GPIOF_DIR_OUT - to configure direction as output
    +
    + * GPIOF_INIT_LOW - as output, set initial level to LOW
    + * GPIOF_INIT_HIGH - as output, set initial level to HIGH
    +
    +since GPIOF_INIT_* are only valid when configured as output, so group valid
    +combinations as:
    +
    + * GPIOF_IN - configure as input
    + * GPIOF_OUT_INIT_LOW - configured as output, initial level LOW
    + * GPIOF_OUT_INIT_HIGH - configured as output, initial level HIGH
    +
    +In the future, these flags can be extended to support more properties such
    +as open-drain status.
    +
    +Further more, to ease the claim/release of multiple GPIOs, 'struct gpio' is
    +introduced to encapsulate all three fields as:
    +
    + struct gpio {
    + unsigned gpio;
    + unsigned long flags;
    + const char *label;
    + };
    +
    +A typical example of usage:
    +
    + static struct gpio leds_gpios[] = {
    + { 32, GPIOF_OUT_INIT_HIGH, "Power LED" }, /* default to ON */
    + { 33, GPIOF_OUT_INIT_LOW, "Green LED" }, /* default to OFF */
    + { 34, GPIOF_OUT_INIT_LOW, "Red LED" }, /* default to OFF */
    + { 35, GPIOF_OUT_INIT_LOW, "Blue LED" }, /* default to OFF */
    + { ... },
    + };
    +
    + err = gpio_request_one(31, GPIOF_IN, "Reset Button");
    + if (err)
    + ...
    +
    + err = gpio_request_array(leds_gpios, ARRAY_SIZE(leds_gpios));
    + if (err)
    + ...
    +
    + gpio_free_array(leds_gpios, ARRAY_SIZE(leds_gpios));
    +

    GPIOs mapped to IRQs
    --------------------diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
    index 1866c27..c2c6e9b 100644
    --- a/Documentation/gpio.txt
    +++ b/Documentation/gpio.txt
    @@ -253,6 +253,70 @@ pin setup (e.g. controlling which pin the GPIO uses, pullup/pulldown).
    Also note that it's your responsibility to have stopped using a GPIO
    before you free it.

    +Considering in most cases GPIOs are actually configured right after they
    +are claimed, three additional calls are defined:
    +
    + /* request a single GPIO, with initial configuration specified by
    + * 'flags', identical to gpio_request() wrt other arguments and
    + * return value
    + */
    + int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
    +
    + /* request multiple GPIOs in a single call
    + */
    + int gpio_request_array(struct gpio *array, size_t num);
    +
    + /* release multiple GPIOs in a single call
    + */
    + void gpio_free_array(struct gpio *array, size_t num);
    +
    +where 'flags' is currently defined to specify the following properties:
    +
    + * GPIOF_DIR_IN - to configure direction as input
    + * GPIOF_DIR_OUT - to configure direction as output
    +
    + * GPIOF_INIT_LOW - as output, set initial level to LOW
    + * GPIOF_INIT_HIGH - as output, set initial level to HIGH
    +
    +since GPIOF_INIT_* are only valid when configured as output, so group valid
    +combinations as:
    +
    + * GPIOF_IN - configure as input
    + * GPIOF_OUT_INIT_LOW - configured as output, initial level LOW
    + * GPIOF_OUT_INIT_HIGH - configured as output, initial level HIGH
    +
    +In the future, these flags can be extended to support more properties such
    +as open-drain status.
    +
    +Further more, to ease the claim/release of multiple GPIOs, 'struct gpio' is
    +introduced to encapsulate all three fields as:
    +
    + struct gpio {
    + unsigned gpio;
    + unsigned long flags;
    + const char *label;
    + };
    +
    +A typical example of usage:
    +
    + static struct gpio leds_gpios[] = {
    + { 32, GPIOF_OUT_INIT_HIGH, "Power LED" }, /* default to ON */
    + { 33, GPIOF_OUT_INIT_LOW, "Green LED" }, /* default to OFF */
    + { 34, GPIOF_OUT_INIT_LOW, "Red LED" }, /* default to OFF */
    + { 35, GPIOF_OUT_INIT_LOW, "Blue LED" }, /* default to OFF */
    + { ... },
    + };
    +
    + err = gpio_request_one(31, GPIOF_IN, "Reset Button");
    + if (err)
    + ...
    +
    + err = gpio_request_array(leds_gpios, ARRAY_SIZE(leds_gpios));
    + if (err)
    + ...
    +
    + gpio_free_array(leds_gpios, ARRAY_SIZE(leds_gpios));
    +

    GPIOs mapped to IRQs
    --------------------From c46dc165b6f8e720a9f04559140b38c20e750516 Mon Sep 17 00:00:00 2001
    From: Eric Miao <eric.y.miao@gmail.com>
    Date: Fri, 8 Jan 2010 12:16:28 +0800
    Subject: [PATCH] gpio: introduce gpio_request_one() and friends

    gpio_request() without initial configuration of the GPIO is normally
    useless, introduce gpio_request_one() together with GPIOF_ flags for
    input/output direction and initial output level.

    gpio_{request,free}_array() for multiple GPIOs.

    Cc: David Brownell <dbrownell@users.sourceforge.net>
    Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
    ---
    Documentation/gpio.txt | 64 ++++++++++++++++++++++++++++++++++++++++++++
    drivers/gpio/gpiolib.c | 42 ++++++++++++++++++++++++++++
    include/asm-generic/gpio.h | 20 +++++++++++++
    3 files changed, 126 insertions(+), 0 deletions(-)

    diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
    index 1866c27..c2c6e9b 100644
    --- a/Documentation/gpio.txt
    +++ b/Documentation/gpio.txt
    @@ -253,6 +253,70 @@ pin setup (e.g. controlling which pin the GPIO uses, pullup/pulldown).
    Also note that it's your responsibility to have stopped using a GPIO
    before you free it.

    +Considering in most cases GPIOs are actually configured right after they
    +are claimed, three additional calls are defined:
    +
    + /* request a single GPIO, with initial configuration specified by
    + * 'flags', identical to gpio_request() wrt other arguments and
    + * return value
    + */
    + int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
    +
    + /* request multiple GPIOs in a single call
    + */
    + int gpio_request_array(struct gpio *array, size_t num);
    +
    + /* release multiple GPIOs in a single call
    + */
    + void gpio_free_array(struct gpio *array, size_t num);
    +
    +where 'flags' is currently defined to specify the following properties:
    +
    + * GPIOF_DIR_IN - to configure direction as input
    + * GPIOF_DIR_OUT - to configure direction as output
    +
    + * GPIOF_INIT_LOW - as output, set initial level to LOW
    + * GPIOF_INIT_HIGH - as output, set initial level to HIGH
    +
    +since GPIOF_INIT_* are only valid when configured as output, so group valid
    +combinations as:
    +
    + * GPIOF_IN - configure as input
    + * GPIOF_OUT_INIT_LOW - configured as output, initial level LOW
    + * GPIOF_OUT_INIT_HIGH - configured as output, initial level HIGH
    +
    +In the future, these flags can be extended to support more properties such
    +as open-drain status.
    +
    +Further more, to ease the claim/release of multiple GPIOs, 'struct gpio' is
    +introduced to encapsulate all three fields as:
    +
    + struct gpio {
    + unsigned gpio;
    + unsigned long flags;
    + const char *label;
    + };
    +
    +A typical example of usage:
    +
    + static struct gpio leds_gpios[] = {
    + { 32, GPIOF_OUT_INIT_HIGH, "Power LED" }, /* default to ON */
    + { 33, GPIOF_OUT_INIT_LOW, "Green LED" }, /* default to OFF */
    + { 34, GPIOF_OUT_INIT_LOW, "Red LED" }, /* default to OFF */
    + { 35, GPIOF_OUT_INIT_LOW, "Blue LED" }, /* default to OFF */
    + { ... },
    + };
    +
    + err = gpio_request_one(31, GPIOF_IN, "Reset Button");
    + if (err)
    + ...
    +
    + err = gpio_request_array(leds_gpios, ARRAY_SIZE(leds_gpios));
    + if (err)
    + ...
    +
    + gpio_free_array(leds_gpios, ARRAY_SIZE(leds_gpios));
    +

    GPIOs mapped to IRQs
    --------------------
    diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
    index a25ad28..e80a1f8 100644
    --- a/drivers/gpio/gpiolib.c
    +++ b/drivers/gpio/gpiolib.c
    @@ -1239,6 +1239,48 @@ void gpio_free(unsigned gpio)
    }
    EXPORT_SYMBOL_GPL(gpio_free);

    +int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
    +{
    + int err;
    +
    + err = gpio_request(gpio, label);
    + if (err)
    + return err;
    +
    + if (flags & GPIOF_DIR_IN)
    + err = gpio_direction_input(gpio);
    + else
    + err = gpio_direction_output(gpio,
    + (flags & GPIOF_INIT_HIGH) ? 1 : 0);
    +
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(gpio_request_one);
    +
    +int gpio_request_array(struct gpio *array, size_t num)
    +{
    + int i, err;
    +
    + for (i = 0; i < num; i++, array++) {
    + err = gpio_request_one(array->gpio, array->flags, array->label);
    + if (err)
    + goto err_free;
    + }
    + return 0;
    +
    +err_free:
    + while (i--)
    + gpio_free((--array)->gpio);
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(gpio_request_array);
    +
    +void gpio_free_array(struct gpio *array, size_t num)
    +{
    + while (num--)
    + gpio_free((array++)->gpio);
    +}
    +EXPORT_SYMBOL_GPL(gpio_free_array);

    /**
    * gpiochip_is_requested - return string iff signal was requested
    diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
    index 485eeb6..5aaa56e 100644
    --- a/include/asm-generic/gpio.h
    +++ b/include/asm-generic/gpio.h
    @@ -136,6 +136,26 @@ extern int __gpio_cansleep(unsigned gpio);

    extern int __gpio_to_irq(unsigned gpio);

    +#define GPIOF_DIR_OUT (0 << 0)
    +#define GPIOF_DIR_IN (1 << 0)
    +
    +#define GPIOF_INIT_LOW (0 << 1)
    +#define GPIOF_INIT_HIGH (1 << 1)
    +
    +#define GPIOF_IN (GPIOF_DIR_IN)
    +#define GPIOF_OUT_INIT_LOW (GPIOF_DIR_OUT | GPIOF_INIT_LOW)
    +#define GPIOF_OUT_INIT_HIGH (GPIOF_DIR_OUT | GPIOF_INIT_HIGH)
    +
    +struct gpio {
    + unsigned gpio;
    + unsigned long flags;
    + const char *label;
    +};
    +
    +extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
    +extern int gpio_request_array(struct gpio *array, size_t num);
    +extern void gpio_free_array(struct gpio *array, size_t num);
    +
    #ifdef CONFIG_GPIO_SYSFS

    /*
    --
    1.6.3.3
    \
     
     \ /
      Last update: 2010-01-13 09:27    [W:0.036 / U:32.820 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site