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849 lines
20 KiB
849 lines
20 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
#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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|
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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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|
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struct gpiod_data { |
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struct gpio_desc *desc; |
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|
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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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|
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bool direction_can_change; |
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}; |
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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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/* |
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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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|
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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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|
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mutex_lock(&data->mutex); |
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|
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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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|
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mutex_unlock(&data->mutex); |
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|
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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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|
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mutex_lock(&data->mutex); |
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|
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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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|
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mutex_unlock(&data->mutex); |
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|
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return status ? : size; |
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} |
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static DEVICE_ATTR_RW(direction); |
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|
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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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|
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mutex_lock(&data->mutex); |
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|
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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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|
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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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|
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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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|
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mutex_lock(&data->mutex); |
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|
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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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|
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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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|
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mutex_unlock(&data->mutex); |
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|
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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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|
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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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|
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sysfs_notify_dirent(data->value_kn); |
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|
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return IRQ_HANDLED; |
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} |
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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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|
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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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|
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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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|
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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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/* |
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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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|
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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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|
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data->irq_flags = flags; |
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|
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return 0; |
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|
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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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|
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return ret; |
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} |
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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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|
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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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|
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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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|
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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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|
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mutex_lock(&data->mutex); |
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|
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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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|
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mutex_unlock(&data->mutex); |
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|
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return status; |
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} |
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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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|
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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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|
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if (i == ARRAY_SIZE(trigger_types)) |
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return -EINVAL; |
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|
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flags = trigger_types[i].flags; |
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|
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mutex_lock(&data->mutex); |
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|
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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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|
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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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|
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return status; |
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} |
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static DEVICE_ATTR_RW(edge); |
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|
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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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|
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if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) |
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return 0; |
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|
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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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|
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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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|
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return status; |
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} |
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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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|
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mutex_lock(&data->mutex); |
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|
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status = sprintf(buf, "%d\n", |
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!!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); |
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|
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mutex_unlock(&data->mutex); |
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|
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return status; |
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} |
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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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|
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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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|
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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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|
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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); |
|
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; |
|
} else if (attr == &dev_attr_edge.attr) { |
|
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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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/ |
|
* /base ... matching gpio_chip.base (N) |
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* /label ... matching gpio_chip.label |
|
* /ngpio ... matching gpio_chip.ngpio |
|
*/ |
|
|
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static ssize_t base_show(struct device *dev, |
|
struct device_attribute *attr, char *buf) |
|
{ |
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const struct gpio_chip *chip = dev_get_drvdata(dev); |
|
|
|
return sprintf(buf, "%d\n", chip->base); |
|
} |
|
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) |
|
{ |
|
const struct gpio_chip *chip = dev_get_drvdata(dev); |
|
|
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return sprintf(buf, "%s\n", chip->label ? : ""); |
|
} |
|
static DEVICE_ATTR_RO(label); |
|
|
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static ssize_t ngpio_show(struct device *dev, |
|
struct device_attribute *attr, char *buf) |
|
{ |
|
const struct gpio_chip *chip = dev_get_drvdata(dev); |
|
|
|
return sprintf(buf, "%u\n", chip->ngpio); |
|
} |
|
static DEVICE_ATTR_RO(ngpio); |
|
|
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static struct attribute *gpiochip_attrs[] = { |
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&dev_attr_base.attr, |
|
&dev_attr_label.attr, |
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&dev_attr_ngpio.attr, |
|
NULL, |
|
}; |
|
ATTRIBUTE_GROUPS(gpiochip); |
|
|
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/* |
|
* /sys/class/gpio/export ... write-only |
|
* integer N ... number of GPIO to export (full access) |
|
* /sys/class/gpio/unexport ... write-only |
|
* integer N ... number of GPIO to unexport |
|
*/ |
|
static ssize_t export_store(struct class *class, |
|
struct class_attribute *attr, |
|
const char *buf, size_t len) |
|
{ |
|
long gpio; |
|
struct gpio_desc *desc; |
|
int status; |
|
struct gpio_chip *gc; |
|
int offset; |
|
|
|
status = kstrtol(buf, 0, &gpio); |
|
if (status < 0) |
|
goto done; |
|
|
|
desc = gpio_to_desc(gpio); |
|
/* reject invalid GPIOs */ |
|
if (!desc) { |
|
pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); |
|
return -EINVAL; |
|
} |
|
gc = desc->gdev->chip; |
|
offset = gpio_chip_hwgpio(desc); |
|
if (!gpiochip_line_is_valid(gc, offset)) { |
|
pr_warn("%s: GPIO %ld masked\n", __func__, gpio); |
|
return -EINVAL; |
|
} |
|
|
|
/* 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. |
|
*/ |
|
|
|
status = gpiod_request(desc, "sysfs"); |
|
if (status) { |
|
if (status == -EPROBE_DEFER) |
|
status = -ENODEV; |
|
goto done; |
|
} |
|
|
|
status = gpiod_set_transitory(desc, false); |
|
if (!status) { |
|
status = gpiod_export(desc, true); |
|
if (status < 0) |
|
gpiod_free(desc); |
|
else |
|
set_bit(FLAG_SYSFS, &desc->flags); |
|
} |
|
|
|
done: |
|
if (status) |
|
pr_debug("%s: status %d\n", __func__, status); |
|
return status ? : len; |
|
} |
|
static CLASS_ATTR_WO(export); |
|
|
|
static ssize_t unexport_store(struct class *class, |
|
struct class_attribute *attr, |
|
const char *buf, size_t len) |
|
{ |
|
long gpio; |
|
struct gpio_desc *desc; |
|
int status; |
|
|
|
status = kstrtol(buf, 0, &gpio); |
|
if (status < 0) |
|
goto done; |
|
|
|
desc = gpio_to_desc(gpio); |
|
/* reject bogus commands (gpio_unexport ignores them) */ |
|
if (!desc) { |
|
pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); |
|
return -EINVAL; |
|
} |
|
|
|
status = -EINVAL; |
|
|
|
/* 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);
|
|
|