diff options
author | David S. Miller <davem@davemloft.net> | 2010-01-22 22:45:46 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2010-01-22 22:45:46 -0800 |
commit | 6be325719b3e54624397e413efd4b33a997e55a3 (patch) | |
tree | 57f321a56794cab2222e179b16731e0d76a4a68a /drivers/gpio/gpiolib.c | |
parent | 26d92f9276a56d55511a427fb70bd70886af647a (diff) | |
parent | 92dcffb916d309aa01778bf8963a6932e4014d07 (diff) |
Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
Diffstat (limited to 'drivers/gpio/gpiolib.c')
-rw-r--r-- | drivers/gpio/gpiolib.c | 159 |
1 files changed, 147 insertions, 12 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 50de0f5750d..350842ad363 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -53,6 +53,7 @@ struct gpio_desc { #define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */ #define FLAG_TRIG_FALL 5 /* trigger on falling edge */ #define FLAG_TRIG_RISE 6 /* trigger on rising edge */ +#define FLAG_ACTIVE_LOW 7 /* sysfs value has active low */ #define PDESC_ID_SHIFT 16 /* add new flags before this one */ @@ -210,6 +211,11 @@ static DEFINE_MUTEX(sysfs_lock); * * configures behavior of poll(2) on /value * * available only if pin can generate IRQs on input * * is read/write as "none", "falling", "rising", or "both" + * /active_low + * * configures polarity of /value + * * is read/write as zero/nonzero + * * also affects existing and subsequent "falling" and "rising" + * /edge configuration */ static ssize_t gpio_direction_show(struct device *dev, @@ -255,7 +261,7 @@ static ssize_t gpio_direction_store(struct device *dev, return status ? : size; } -static const DEVICE_ATTR(direction, 0644, +static /* const */ DEVICE_ATTR(direction, 0644, gpio_direction_show, gpio_direction_store); static ssize_t gpio_value_show(struct device *dev, @@ -267,10 +273,17 @@ static ssize_t gpio_value_show(struct device *dev, mutex_lock(&sysfs_lock); - if (!test_bit(FLAG_EXPORT, &desc->flags)) + if (!test_bit(FLAG_EXPORT, &desc->flags)) { status = -EIO; - else - status = sprintf(buf, "%d\n", !!gpio_get_value_cansleep(gpio)); + } else { + int value; + + value = !!gpio_get_value_cansleep(gpio); + if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) + value = !value; + + status = sprintf(buf, "%d\n", value); + } mutex_unlock(&sysfs_lock); return status; @@ -294,6 +307,8 @@ static ssize_t gpio_value_store(struct device *dev, status = strict_strtol(buf, 0, &value); if (status == 0) { + if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) + value = !value; gpio_set_value_cansleep(gpio, value != 0); status = size; } @@ -303,7 +318,7 @@ static ssize_t gpio_value_store(struct device *dev, return status; } -static /*const*/ DEVICE_ATTR(value, 0644, +static const DEVICE_ATTR(value, 0644, gpio_value_show, gpio_value_store); static irqreturn_t gpio_sysfs_irq(int irq, void *priv) @@ -352,9 +367,11 @@ static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev, irq_flags = IRQF_SHARED; if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) - irq_flags |= IRQF_TRIGGER_FALLING; + irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? + IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) - irq_flags |= IRQF_TRIGGER_RISING; + irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? + IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; if (!pdesc) { pdesc = kmalloc(sizeof(*pdesc), GFP_KERNEL); @@ -475,9 +492,79 @@ found: static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store); +static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, + int value) +{ + int status = 0; + + if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) + return 0; + + if (value) + set_bit(FLAG_ACTIVE_LOW, &desc->flags); + else + clear_bit(FLAG_ACTIVE_LOW, &desc->flags); + + /* reconfigure poll(2) support if enabled on one edge only */ + if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ + !!test_bit(FLAG_TRIG_FALL, &desc->flags))) { + unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; + + gpio_setup_irq(desc, dev, 0); + status = gpio_setup_irq(desc, dev, trigger_flags); + } + + return status; +} + +static ssize_t gpio_active_low_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + const struct gpio_desc *desc = dev_get_drvdata(dev); + ssize_t status; + + mutex_lock(&sysfs_lock); + + if (!test_bit(FLAG_EXPORT, &desc->flags)) + status = -EIO; + else + status = sprintf(buf, "%d\n", + !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); + + mutex_unlock(&sysfs_lock); + + return status; +} + +static ssize_t gpio_active_low_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t size) +{ + struct gpio_desc *desc = dev_get_drvdata(dev); + ssize_t status; + + mutex_lock(&sysfs_lock); + + if (!test_bit(FLAG_EXPORT, &desc->flags)) { + status = -EIO; + } else { + long value; + + status = strict_strtol(buf, 0, &value); + if (status == 0) + status = sysfs_set_active_low(desc, dev, value != 0); + } + + mutex_unlock(&sysfs_lock); + + return status ? : size; +} + +static const DEVICE_ATTR(active_low, 0644, + gpio_active_low_show, gpio_active_low_store); + static const struct attribute *gpio_attrs[] = { - &dev_attr_direction.attr, &dev_attr_value.attr, + &dev_attr_active_low.attr, NULL, }; @@ -662,12 +749,12 @@ int gpio_export(unsigned gpio, bool direction_may_change) dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), desc, ioname ? ioname : "gpio%d", gpio); if (!IS_ERR(dev)) { - if (direction_may_change) - status = sysfs_create_group(&dev->kobj, + status = sysfs_create_group(&dev->kobj, &gpio_attr_group); - else + + if (!status && direction_may_change) status = device_create_file(dev, - &dev_attr_value); + &dev_attr_direction); if (!status && gpio_to_irq(gpio) >= 0 && (direction_may_change @@ -744,6 +831,53 @@ done: } EXPORT_SYMBOL_GPL(gpio_export_link); + +/** + * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value + * @gpio: gpio to change + * @value: non-zero to use active low, i.e. inverted values + * + * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute. + * The GPIO does not have to be exported yet. If poll(2) support has + * been enabled for either rising or falling edge, it will be + * reconfigured to follow the new polarity. + * + * Returns zero on success, else an error. + */ +int gpio_sysfs_set_active_low(unsigned gpio, int value) +{ + struct gpio_desc *desc; + struct device *dev = NULL; + int status = -EINVAL; + + if (!gpio_is_valid(gpio)) + goto done; + + mutex_lock(&sysfs_lock); + + desc = &gpio_desc[gpio]; + + if (test_bit(FLAG_EXPORT, &desc->flags)) { + dev = class_find_device(&gpio_class, NULL, desc, match_export); + if (dev == NULL) { + status = -ENODEV; + goto unlock; + } + } + + status = sysfs_set_active_low(desc, dev, value); + +unlock: + mutex_unlock(&sysfs_lock); + +done: + if (status) + pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); + + return status; +} +EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low); + /** * gpio_unexport - reverse effect of gpio_export() * @gpio: gpio to make unavailable @@ -1094,6 +1228,7 @@ void gpio_free(unsigned gpio) } desc_set_label(desc, NULL); module_put(desc->chip->owner); + clear_bit(FLAG_ACTIVE_LOW, &desc->flags); clear_bit(FLAG_REQUESTED, &desc->flags); } else WARN_ON(extra_checks); |