diff options
| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2012-10-24 17:25:27 +0300 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2012-10-26 09:18:55 +0200 |
| commit | 80b0a6029272247f19146bf8f88e5d4bba94cba5 (patch) | |
| tree | 40cb6244bd1efb5e8e351952cf15e36d06801491 /drivers | |
| parent | d6a2fa0424aefe97289aa561444ec3ae09bdbba0 (diff) | |
| download | linux-80b0a6029272247f19146bf8f88e5d4bba94cba5.tar.bz2 | |
gpiolib: add gpio get direction callback support
Add .get_direction callback to gpio_chip. This allows gpiolib
to check the current direction of a gpio.
Used to show the correct gpio direction in sysfs and debug entries.
If callback is not set then gpiolib will work as previously;
e.g. guessing everything is input until a direction is set.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpio/gpiolib.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index d5f9742d9ac1..e468eed261c5 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -191,6 +191,32 @@ err: return ret; } +/* caller ensures gpio is valid and requested, chip->get_direction may sleep */ +static int gpio_get_direction(unsigned gpio) +{ + struct gpio_chip *chip; + struct gpio_desc *desc = &gpio_desc[gpio]; + int status = -EINVAL; + + chip = gpio_to_chip(gpio); + gpio -= chip->base; + + if (!chip->get_direction) + return status; + + status = chip->get_direction(chip, gpio); + if (status > 0) { + /* GPIOF_DIR_IN, or other positive */ + status = 1; + clear_bit(FLAG_IS_OUT, &desc->flags); + } + if (status == 0) { + /* GPIOF_DIR_OUT */ + set_bit(FLAG_IS_OUT, &desc->flags); + } + return status; +} + #ifdef CONFIG_GPIO_SYSFS /* lock protects against unexport_gpio() being called while @@ -223,6 +249,7 @@ static ssize_t gpio_direction_show(struct device *dev, struct device_attribute *attr, char *buf) { const struct gpio_desc *desc = dev_get_drvdata(dev); + unsigned gpio = desc - gpio_desc; ssize_t status; mutex_lock(&sysfs_lock); @@ -230,6 +257,7 @@ static ssize_t gpio_direction_show(struct device *dev, if (!test_bit(FLAG_EXPORT, &desc->flags)) status = -EIO; else + gpio_get_direction(gpio); status = sprintf(buf, "%s\n", test_bit(FLAG_IS_OUT, &desc->flags) ? "out" : "in"); @@ -1080,6 +1108,7 @@ int gpiochip_add(struct gpio_chip *chip) * inputs (often with pullups enabled) so power * usage is minimized. Linux code should set the * gpio direction first thing; but until it does, + * and in case chip->get_direction is not set, * we may expose the wrong direction in sysfs. */ gpio_desc[id].flags = !chip->direction_input @@ -1231,9 +1260,15 @@ int gpio_request(unsigned gpio, const char *label) desc_set_label(desc, NULL); module_put(chip->owner); clear_bit(FLAG_REQUESTED, &desc->flags); + goto done; } } - + if (chip->get_direction) { + /* chip->get_direction may sleep */ + spin_unlock_irqrestore(&gpio_lock, flags); + gpio_get_direction(gpio); + spin_lock_irqsave(&gpio_lock, flags); + } done: if (status) pr_debug("gpio_request: gpio-%d (%s) status %d\n", @@ -1769,6 +1804,7 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) continue; + gpio_get_direction(gpio); is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); seq_printf(s, " gpio-%-3d (%-20.20s) %s %s", gpio, gdesc->label, |