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![Matti Vaittinen](/assets/img/avatar_default.png)
Do not allow exporting GPIOs which are set invalid
by the driver's valid mask.
Fixes: 726cb3ba49
("gpiolib: Support 'gpio-reserved-ranges' property")
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
849 lines
20 KiB
C
849 lines
20 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/idr.h>
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#include <linux/mutex.h>
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#include <linux/device.h>
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#include <linux/sysfs.h>
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#include <linux/gpio/consumer.h>
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#include <linux/gpio/driver.h>
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#include <linux/interrupt.h>
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#include <linux/kdev_t.h>
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#include <linux/slab.h>
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#include <linux/ctype.h>
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#include "gpiolib.h"
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#include "gpiolib-sysfs.h"
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#define GPIO_IRQF_TRIGGER_FALLING BIT(0)
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#define GPIO_IRQF_TRIGGER_RISING BIT(1)
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#define GPIO_IRQF_TRIGGER_BOTH (GPIO_IRQF_TRIGGER_FALLING | \
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GPIO_IRQF_TRIGGER_RISING)
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struct gpiod_data {
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struct gpio_desc *desc;
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struct mutex mutex;
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struct kernfs_node *value_kn;
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int irq;
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unsigned char irq_flags;
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bool direction_can_change;
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};
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/*
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* Lock to serialise gpiod export and unexport, and prevent re-export of
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* gpiod whose chip is being unregistered.
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*/
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static DEFINE_MUTEX(sysfs_lock);
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/*
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* /sys/class/gpio/gpioN... only for GPIOs that are exported
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* /direction
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* * MAY BE OMITTED if kernel won't allow direction changes
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* * is read/write as "in" or "out"
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* * may also be written as "high" or "low", initializing
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* output value as specified ("out" implies "low")
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* /value
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* * always readable, subject to hardware behavior
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* * may be writable, as zero/nonzero
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* /edge
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* * configures behavior of poll(2) on /value
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* * available only if pin can generate IRQs on input
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* * is read/write as "none", "falling", "rising", or "both"
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* /active_low
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* * configures polarity of /value
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* * is read/write as zero/nonzero
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* * also affects existing and subsequent "falling" and "rising"
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* /edge configuration
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*/
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static ssize_t direction_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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struct gpio_desc *desc = data->desc;
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ssize_t status;
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mutex_lock(&data->mutex);
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gpiod_get_direction(desc);
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status = sprintf(buf, "%s\n",
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test_bit(FLAG_IS_OUT, &desc->flags)
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? "out" : "in");
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mutex_unlock(&data->mutex);
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return status;
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}
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static ssize_t direction_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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struct gpio_desc *desc = data->desc;
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ssize_t status;
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mutex_lock(&data->mutex);
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if (sysfs_streq(buf, "high"))
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status = gpiod_direction_output_raw(desc, 1);
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else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
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status = gpiod_direction_output_raw(desc, 0);
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else if (sysfs_streq(buf, "in"))
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status = gpiod_direction_input(desc);
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else
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status = -EINVAL;
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mutex_unlock(&data->mutex);
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return status ? : size;
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}
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static DEVICE_ATTR_RW(direction);
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static ssize_t value_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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struct gpio_desc *desc = data->desc;
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ssize_t status;
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mutex_lock(&data->mutex);
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status = gpiod_get_value_cansleep(desc);
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if (status < 0)
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goto err;
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buf[0] = '0' + status;
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buf[1] = '\n';
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status = 2;
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err:
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mutex_unlock(&data->mutex);
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return status;
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}
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static ssize_t value_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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struct gpio_desc *desc = data->desc;
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ssize_t status = 0;
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mutex_lock(&data->mutex);
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if (!test_bit(FLAG_IS_OUT, &desc->flags)) {
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status = -EPERM;
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} else {
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long value;
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if (size <= 2 && isdigit(buf[0]) &&
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(size == 1 || buf[1] == '\n'))
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value = buf[0] - '0';
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else
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status = kstrtol(buf, 0, &value);
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if (status == 0) {
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gpiod_set_value_cansleep(desc, value);
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status = size;
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}
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}
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mutex_unlock(&data->mutex);
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return status;
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}
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static DEVICE_ATTR_PREALLOC(value, S_IWUSR | S_IRUGO, value_show, value_store);
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static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
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{
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struct gpiod_data *data = priv;
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sysfs_notify_dirent(data->value_kn);
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return IRQ_HANDLED;
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}
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/* Caller holds gpiod-data mutex. */
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static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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struct gpio_desc *desc = data->desc;
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unsigned long irq_flags;
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int ret;
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data->irq = gpiod_to_irq(desc);
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if (data->irq < 0)
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return -EIO;
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data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value");
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if (!data->value_kn)
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return -ENODEV;
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irq_flags = IRQF_SHARED;
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if (flags & GPIO_IRQF_TRIGGER_FALLING)
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irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
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IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
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if (flags & GPIO_IRQF_TRIGGER_RISING)
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irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
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IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
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/*
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* FIXME: This should be done in the irq_request_resources callback
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* when the irq is requested, but a few drivers currently fail
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* to do so.
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*
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* Remove this redundant call (along with the corresponding
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* unlock) when those drivers have been fixed.
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*/
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ret = gpiochip_lock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc));
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if (ret < 0)
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goto err_put_kn;
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ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags,
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"gpiolib", data);
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if (ret < 0)
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goto err_unlock;
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data->irq_flags = flags;
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return 0;
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err_unlock:
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gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc));
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err_put_kn:
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sysfs_put(data->value_kn);
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return ret;
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}
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/*
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* Caller holds gpiod-data mutex (unless called after class-device
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* deregistration).
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*/
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static void gpio_sysfs_free_irq(struct device *dev)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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struct gpio_desc *desc = data->desc;
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data->irq_flags = 0;
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free_irq(data->irq, data);
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gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc));
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sysfs_put(data->value_kn);
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}
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static const struct {
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const char *name;
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unsigned char flags;
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} trigger_types[] = {
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{ "none", 0 },
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{ "falling", GPIO_IRQF_TRIGGER_FALLING },
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{ "rising", GPIO_IRQF_TRIGGER_RISING },
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{ "both", GPIO_IRQF_TRIGGER_BOTH },
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};
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static ssize_t edge_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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ssize_t status = 0;
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int i;
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mutex_lock(&data->mutex);
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for (i = 0; i < ARRAY_SIZE(trigger_types); i++) {
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if (data->irq_flags == trigger_types[i].flags) {
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status = sprintf(buf, "%s\n", trigger_types[i].name);
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break;
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}
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}
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mutex_unlock(&data->mutex);
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return status;
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}
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static ssize_t edge_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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unsigned char flags;
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ssize_t status = size;
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int i;
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for (i = 0; i < ARRAY_SIZE(trigger_types); i++) {
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if (sysfs_streq(trigger_types[i].name, buf))
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break;
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}
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if (i == ARRAY_SIZE(trigger_types))
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return -EINVAL;
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flags = trigger_types[i].flags;
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mutex_lock(&data->mutex);
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if (flags == data->irq_flags) {
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status = size;
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goto out_unlock;
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}
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if (data->irq_flags)
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gpio_sysfs_free_irq(dev);
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if (flags) {
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status = gpio_sysfs_request_irq(dev, flags);
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if (!status)
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status = size;
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}
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out_unlock:
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mutex_unlock(&data->mutex);
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return status;
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}
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static DEVICE_ATTR_RW(edge);
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/* Caller holds gpiod-data mutex. */
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static int gpio_sysfs_set_active_low(struct device *dev, int value)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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struct gpio_desc *desc = data->desc;
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int status = 0;
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unsigned int flags = data->irq_flags;
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if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
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return 0;
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if (value)
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set_bit(FLAG_ACTIVE_LOW, &desc->flags);
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else
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clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
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/* reconfigure poll(2) support if enabled on one edge only */
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if (flags == GPIO_IRQF_TRIGGER_FALLING ||
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flags == GPIO_IRQF_TRIGGER_RISING) {
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gpio_sysfs_free_irq(dev);
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status = gpio_sysfs_request_irq(dev, flags);
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}
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return status;
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}
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static ssize_t active_low_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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struct gpio_desc *desc = data->desc;
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ssize_t status;
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mutex_lock(&data->mutex);
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status = sprintf(buf, "%d\n",
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!!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
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mutex_unlock(&data->mutex);
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return status;
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}
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static ssize_t active_low_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct gpiod_data *data = dev_get_drvdata(dev);
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ssize_t status;
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long value;
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mutex_lock(&data->mutex);
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status = kstrtol(buf, 0, &value);
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if (status == 0)
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status = gpio_sysfs_set_active_low(dev, value);
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mutex_unlock(&data->mutex);
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return status ? : size;
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}
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static DEVICE_ATTR_RW(active_low);
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static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
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int n)
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{
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struct device *dev = kobj_to_dev(kobj);
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struct gpiod_data *data = dev_get_drvdata(dev);
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struct gpio_desc *desc = data->desc;
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umode_t mode = attr->mode;
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bool show_direction = data->direction_can_change;
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if (attr == &dev_attr_direction.attr) {
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if (!show_direction)
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mode = 0;
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} else if (attr == &dev_attr_edge.attr) {
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if (gpiod_to_irq(desc) < 0)
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mode = 0;
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if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags))
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mode = 0;
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}
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return mode;
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}
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static struct attribute *gpio_attrs[] = {
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&dev_attr_direction.attr,
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&dev_attr_edge.attr,
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&dev_attr_value.attr,
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&dev_attr_active_low.attr,
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NULL,
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};
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static const struct attribute_group gpio_group = {
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.attrs = gpio_attrs,
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.is_visible = gpio_is_visible,
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};
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static const struct attribute_group *gpio_groups[] = {
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&gpio_group,
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NULL
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};
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/*
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* /sys/class/gpio/gpiochipN/
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* /base ... matching gpio_chip.base (N)
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* /label ... matching gpio_chip.label
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* /ngpio ... matching gpio_chip.ngpio
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*/
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static ssize_t base_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_chip *chip = dev_get_drvdata(dev);
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return sprintf(buf, "%d\n", chip->base);
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}
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static DEVICE_ATTR_RO(base);
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static ssize_t label_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_chip *chip = dev_get_drvdata(dev);
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return sprintf(buf, "%s\n", chip->label ? : "");
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}
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static DEVICE_ATTR_RO(label);
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static ssize_t ngpio_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_chip *chip = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", chip->ngpio);
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}
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static DEVICE_ATTR_RO(ngpio);
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static struct attribute *gpiochip_attrs[] = {
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&dev_attr_base.attr,
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&dev_attr_label.attr,
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&dev_attr_ngpio.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(gpiochip);
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/*
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* /sys/class/gpio/export ... write-only
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* integer N ... number of GPIO to export (full access)
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* /sys/class/gpio/unexport ... write-only
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* integer N ... number of GPIO to unexport
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*/
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static ssize_t export_store(struct class *class,
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struct class_attribute *attr,
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const char *buf, size_t len)
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{
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long gpio;
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struct gpio_desc *desc;
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int status;
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struct gpio_chip *gc;
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int offset;
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status = kstrtol(buf, 0, &gpio);
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if (status < 0)
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goto done;
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desc = gpio_to_desc(gpio);
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/* reject invalid GPIOs */
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if (!desc) {
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pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
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return -EINVAL;
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}
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gc = desc->gdev->chip;
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offset = gpio_chip_hwgpio(desc);
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if (!gpiochip_line_is_valid(gc, offset)) {
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pr_warn("%s: GPIO %ld masked\n", __func__, gpio);
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return -EINVAL;
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}
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/* No extra locking here; FLAG_SYSFS just signifies that the
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* request and export were done by on behalf of userspace, so
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* they may be undone on its behalf too.
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*/
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status = gpiod_request(desc, "sysfs");
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if (status) {
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if (status == -EPROBE_DEFER)
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status = -ENODEV;
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goto done;
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}
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status = gpiod_set_transitory(desc, false);
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if (!status) {
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status = gpiod_export(desc, true);
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if (status < 0)
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gpiod_free(desc);
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else
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set_bit(FLAG_SYSFS, &desc->flags);
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}
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done:
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if (status)
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pr_debug("%s: status %d\n", __func__, status);
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return status ? : len;
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}
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static CLASS_ATTR_WO(export);
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static ssize_t unexport_store(struct class *class,
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struct class_attribute *attr,
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const char *buf, size_t len)
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{
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long gpio;
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struct gpio_desc *desc;
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int status;
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status = kstrtol(buf, 0, &gpio);
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if (status < 0)
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goto done;
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desc = gpio_to_desc(gpio);
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/* reject bogus commands (gpio_unexport ignores them) */
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if (!desc) {
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pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
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return -EINVAL;
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}
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status = -EINVAL;
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|
|
/* No extra locking here; FLAG_SYSFS just signifies that the
|
|
* request and export were done by on behalf of userspace, so
|
|
* they may be undone on its behalf too.
|
|
*/
|
|
if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
|
|
status = 0;
|
|
gpiod_free(desc);
|
|
}
|
|
done:
|
|
if (status)
|
|
pr_debug("%s: status %d\n", __func__, status);
|
|
return status ? : len;
|
|
}
|
|
static CLASS_ATTR_WO(unexport);
|
|
|
|
static struct attribute *gpio_class_attrs[] = {
|
|
&class_attr_export.attr,
|
|
&class_attr_unexport.attr,
|
|
NULL,
|
|
};
|
|
ATTRIBUTE_GROUPS(gpio_class);
|
|
|
|
static struct class gpio_class = {
|
|
.name = "gpio",
|
|
.owner = THIS_MODULE,
|
|
|
|
.class_groups = gpio_class_groups,
|
|
};
|
|
|
|
|
|
/**
|
|
* gpiod_export - export a GPIO through sysfs
|
|
* @desc: GPIO to make available, already requested
|
|
* @direction_may_change: true if userspace may change GPIO direction
|
|
* Context: arch_initcall or later
|
|
*
|
|
* When drivers want to make a GPIO accessible to userspace after they
|
|
* have requested it -- perhaps while debugging, or as part of their
|
|
* public interface -- they may use this routine. If the GPIO can
|
|
* change direction (some can't) and the caller allows it, userspace
|
|
* will see "direction" sysfs attribute which may be used to change
|
|
* the gpio's direction. A "value" attribute will always be provided.
|
|
*
|
|
* Returns zero on success, else an error.
|
|
*/
|
|
int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
|
|
{
|
|
struct gpio_chip *chip;
|
|
struct gpio_device *gdev;
|
|
struct gpiod_data *data;
|
|
unsigned long flags;
|
|
int status;
|
|
const char *ioname = NULL;
|
|
struct device *dev;
|
|
int offset;
|
|
|
|
/* can't export until sysfs is available ... */
|
|
if (!gpio_class.p) {
|
|
pr_debug("%s: called too early!\n", __func__);
|
|
return -ENOENT;
|
|
}
|
|
|
|
if (!desc) {
|
|
pr_debug("%s: invalid gpio descriptor\n", __func__);
|
|
return -EINVAL;
|
|
}
|
|
|
|
gdev = desc->gdev;
|
|
chip = gdev->chip;
|
|
|
|
mutex_lock(&sysfs_lock);
|
|
|
|
/* check if chip is being removed */
|
|
if (!chip || !gdev->mockdev) {
|
|
status = -ENODEV;
|
|
goto err_unlock;
|
|
}
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
|
|
test_bit(FLAG_EXPORT, &desc->flags)) {
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n",
|
|
__func__,
|
|
test_bit(FLAG_REQUESTED, &desc->flags),
|
|
test_bit(FLAG_EXPORT, &desc->flags));
|
|
status = -EPERM;
|
|
goto err_unlock;
|
|
}
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
data = kzalloc(sizeof(*data), GFP_KERNEL);
|
|
if (!data) {
|
|
status = -ENOMEM;
|
|
goto err_unlock;
|
|
}
|
|
|
|
data->desc = desc;
|
|
mutex_init(&data->mutex);
|
|
if (chip->direction_input && chip->direction_output)
|
|
data->direction_can_change = direction_may_change;
|
|
else
|
|
data->direction_can_change = false;
|
|
|
|
offset = gpio_chip_hwgpio(desc);
|
|
if (chip->names && chip->names[offset])
|
|
ioname = chip->names[offset];
|
|
|
|
dev = device_create_with_groups(&gpio_class, &gdev->dev,
|
|
MKDEV(0, 0), data, gpio_groups,
|
|
ioname ? ioname : "gpio%u",
|
|
desc_to_gpio(desc));
|
|
if (IS_ERR(dev)) {
|
|
status = PTR_ERR(dev);
|
|
goto err_free_data;
|
|
}
|
|
|
|
set_bit(FLAG_EXPORT, &desc->flags);
|
|
mutex_unlock(&sysfs_lock);
|
|
return 0;
|
|
|
|
err_free_data:
|
|
kfree(data);
|
|
err_unlock:
|
|
mutex_unlock(&sysfs_lock);
|
|
gpiod_dbg(desc, "%s: status %d\n", __func__, status);
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpiod_export);
|
|
|
|
static int match_export(struct device *dev, const void *desc)
|
|
{
|
|
struct gpiod_data *data = dev_get_drvdata(dev);
|
|
|
|
return data->desc == desc;
|
|
}
|
|
|
|
/**
|
|
* gpiod_export_link - create a sysfs link to an exported GPIO node
|
|
* @dev: device under which to create symlink
|
|
* @name: name of the symlink
|
|
* @desc: GPIO to create symlink to, already exported
|
|
*
|
|
* Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
|
|
* node. Caller is responsible for unlinking.
|
|
*
|
|
* Returns zero on success, else an error.
|
|
*/
|
|
int gpiod_export_link(struct device *dev, const char *name,
|
|
struct gpio_desc *desc)
|
|
{
|
|
struct device *cdev;
|
|
int ret;
|
|
|
|
if (!desc) {
|
|
pr_warn("%s: invalid GPIO\n", __func__);
|
|
return -EINVAL;
|
|
}
|
|
|
|
cdev = class_find_device(&gpio_class, NULL, desc, match_export);
|
|
if (!cdev)
|
|
return -ENODEV;
|
|
|
|
ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name);
|
|
put_device(cdev);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpiod_export_link);
|
|
|
|
/**
|
|
* gpiod_unexport - reverse effect of gpiod_export()
|
|
* @desc: GPIO to make unavailable
|
|
*
|
|
* This is implicit on gpiod_free().
|
|
*/
|
|
void gpiod_unexport(struct gpio_desc *desc)
|
|
{
|
|
struct gpiod_data *data;
|
|
struct device *dev;
|
|
|
|
if (!desc) {
|
|
pr_warn("%s: invalid GPIO\n", __func__);
|
|
return;
|
|
}
|
|
|
|
mutex_lock(&sysfs_lock);
|
|
|
|
if (!test_bit(FLAG_EXPORT, &desc->flags))
|
|
goto err_unlock;
|
|
|
|
dev = class_find_device(&gpio_class, NULL, desc, match_export);
|
|
if (!dev)
|
|
goto err_unlock;
|
|
|
|
data = dev_get_drvdata(dev);
|
|
|
|
clear_bit(FLAG_EXPORT, &desc->flags);
|
|
|
|
device_unregister(dev);
|
|
|
|
/*
|
|
* Release irq after deregistration to prevent race with edge_store.
|
|
*/
|
|
if (data->irq_flags)
|
|
gpio_sysfs_free_irq(dev);
|
|
|
|
mutex_unlock(&sysfs_lock);
|
|
|
|
put_device(dev);
|
|
kfree(data);
|
|
|
|
return;
|
|
|
|
err_unlock:
|
|
mutex_unlock(&sysfs_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpiod_unexport);
|
|
|
|
int gpiochip_sysfs_register(struct gpio_device *gdev)
|
|
{
|
|
struct device *dev;
|
|
struct device *parent;
|
|
struct gpio_chip *chip = gdev->chip;
|
|
|
|
/*
|
|
* Many systems add gpio chips for SOC support very early,
|
|
* before driver model support is available. In those cases we
|
|
* register later, in gpiolib_sysfs_init() ... here we just
|
|
* verify that _some_ field of gpio_class got initialized.
|
|
*/
|
|
if (!gpio_class.p)
|
|
return 0;
|
|
|
|
/*
|
|
* For sysfs backward compatibility we need to preserve this
|
|
* preferred parenting to the gpio_chip parent field, if set.
|
|
*/
|
|
if (chip->parent)
|
|
parent = chip->parent;
|
|
else
|
|
parent = &gdev->dev;
|
|
|
|
/* use chip->base for the ID; it's already known to be unique */
|
|
dev = device_create_with_groups(&gpio_class, parent, MKDEV(0, 0), chip,
|
|
gpiochip_groups, GPIOCHIP_NAME "%d",
|
|
chip->base);
|
|
if (IS_ERR(dev))
|
|
return PTR_ERR(dev);
|
|
|
|
mutex_lock(&sysfs_lock);
|
|
gdev->mockdev = dev;
|
|
mutex_unlock(&sysfs_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void gpiochip_sysfs_unregister(struct gpio_device *gdev)
|
|
{
|
|
struct gpio_desc *desc;
|
|
struct gpio_chip *chip = gdev->chip;
|
|
unsigned int i;
|
|
|
|
if (!gdev->mockdev)
|
|
return;
|
|
|
|
device_unregister(gdev->mockdev);
|
|
|
|
/* prevent further gpiod exports */
|
|
mutex_lock(&sysfs_lock);
|
|
gdev->mockdev = NULL;
|
|
mutex_unlock(&sysfs_lock);
|
|
|
|
/* unregister gpiod class devices owned by sysfs */
|
|
for (i = 0; i < chip->ngpio; i++) {
|
|
desc = &gdev->descs[i];
|
|
if (test_and_clear_bit(FLAG_SYSFS, &desc->flags))
|
|
gpiod_free(desc);
|
|
}
|
|
}
|
|
|
|
static int __init gpiolib_sysfs_init(void)
|
|
{
|
|
int status;
|
|
unsigned long flags;
|
|
struct gpio_device *gdev;
|
|
|
|
status = class_register(&gpio_class);
|
|
if (status < 0)
|
|
return status;
|
|
|
|
/* Scan and register the gpio_chips which registered very
|
|
* early (e.g. before the class_register above was called).
|
|
*
|
|
* We run before arch_initcall() so chip->dev nodes can have
|
|
* registered, and so arch_initcall() can always gpio_export().
|
|
*/
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
list_for_each_entry(gdev, &gpio_devices, list) {
|
|
if (gdev->mockdev)
|
|
continue;
|
|
|
|
/*
|
|
* TODO we yield gpio_lock here because
|
|
* gpiochip_sysfs_register() acquires a mutex. This is unsafe
|
|
* and needs to be fixed.
|
|
*
|
|
* Also it would be nice to use gpiochip_find() here so we
|
|
* can keep gpio_chips local to gpiolib.c, but the yield of
|
|
* gpio_lock prevents us from doing this.
|
|
*/
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
status = gpiochip_sysfs_register(gdev);
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
}
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
return status;
|
|
}
|
|
postcore_initcall(gpiolib_sysfs_init);
|