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gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL
Add support for requesting lines using the GPIO_V2_GET_LINE_IOCTL, and returning their current values using GPIO_V2_LINE_GET_VALUES_IOCTL. The struct linereq implementation is based on the v1 struct linehandle implementation. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
This commit is contained in:
Kent Gibson
Bartosz Golaszewski
parent
957ebb61a4
commit
3c0d9c635a
@ -1,7 +1,9 @@
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/anon_inodes.h>
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#include <linux/atomic.h>
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#include <linux/bitmap.h>
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#include <linux/build_bug.h>
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#include <linux/cdev.h>
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#include <linux/compat.h>
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#include <linux/device.h>
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@ -24,6 +26,25 @@
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#include "gpiolib.h"
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#include "gpiolib-cdev.h"
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/*
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* Array sizes must ensure 64-bit alignment and not create holes in the
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* struct packing.
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*/
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static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
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static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
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/*
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* Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
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*/
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static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
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static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
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static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
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static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
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static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
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static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
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static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
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static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
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/* Character device interface to GPIO.
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*
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* The GPIO character device, /dev/gpiochipN, provides userspace an
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@ -34,6 +55,7 @@
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* GPIO line handle management
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*/
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#ifdef CONFIG_GPIO_CDEV_V1
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/**
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* struct linehandle_state - contains the state of a userspace handle
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* @gdev: the GPIO device the handle pertains to
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@ -376,6 +398,402 @@ out_free_lh:
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linehandle_free(lh);
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return ret;
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}
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#endif /* CONFIG_GPIO_CDEV_V1 */
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/**
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* struct line - contains the state of a requested line
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* @desc: the GPIO descriptor for this line.
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*/
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struct line {
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struct gpio_desc *desc;
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};
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/**
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* struct linereq - contains the state of a userspace line request
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* @gdev: the GPIO device the line request pertains to
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* @label: consumer label used to tag GPIO descriptors
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* @num_lines: the number of lines in the lines array
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* @lines: the lines held by this line request, with @num_lines elements.
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*/
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struct linereq {
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struct gpio_device *gdev;
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const char *label;
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u32 num_lines;
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struct line lines[];
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};
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#define GPIO_V2_LINE_BIAS_FLAGS \
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(GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
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GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
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GPIO_V2_LINE_FLAG_BIAS_DISABLED)
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#define GPIO_V2_LINE_DIRECTION_FLAGS \
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(GPIO_V2_LINE_FLAG_INPUT | \
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GPIO_V2_LINE_FLAG_OUTPUT)
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#define GPIO_V2_LINE_DRIVE_FLAGS \
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(GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
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GPIO_V2_LINE_FLAG_OPEN_SOURCE)
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#define GPIO_V2_LINE_VALID_FLAGS \
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(GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
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GPIO_V2_LINE_DIRECTION_FLAGS | \
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GPIO_V2_LINE_DRIVE_FLAGS | \
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GPIO_V2_LINE_BIAS_FLAGS)
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static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
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unsigned int line_idx)
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{
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unsigned int i;
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u64 mask = BIT_ULL(line_idx);
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for (i = 0; i < lc->num_attrs; i++) {
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if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
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(lc->attrs[i].mask & mask))
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return lc->attrs[i].attr.flags;
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}
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return lc->flags;
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}
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static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
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unsigned int line_idx)
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{
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unsigned int i;
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u64 mask = BIT_ULL(line_idx);
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for (i = 0; i < lc->num_attrs; i++) {
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if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
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(lc->attrs[i].mask & mask))
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return !!(lc->attrs[i].attr.values & mask);
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}
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return 0;
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}
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static int gpio_v2_line_flags_validate(u64 flags)
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{
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/* Return an error if an unknown flag is set */
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if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
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return -EINVAL;
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/*
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* Do not allow both INPUT and OUTPUT flags to be set as they are
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* contradictory.
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*/
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if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
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(flags & GPIO_V2_LINE_FLAG_OUTPUT))
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return -EINVAL;
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/*
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* Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
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* request. If the hardware actually supports enabling both at the
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* same time the electrical result would be disastrous.
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*/
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if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
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(flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
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return -EINVAL;
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/* Drive requires explicit output direction. */
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if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
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!(flags & GPIO_V2_LINE_FLAG_OUTPUT))
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return -EINVAL;
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/* Bias requires explicit direction. */
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if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
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!(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
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return -EINVAL;
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/* Only one bias flag can be set. */
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if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
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(flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
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GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
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((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
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(flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
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return -EINVAL;
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return 0;
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}
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static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
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unsigned int num_lines)
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{
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unsigned int i;
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u64 flags;
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int ret;
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if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
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return -EINVAL;
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if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
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return -EINVAL;
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for (i = 0; i < num_lines; i++) {
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flags = gpio_v2_line_config_flags(lc, i);
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ret = gpio_v2_line_flags_validate(flags);
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if (ret)
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return ret;
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}
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return 0;
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}
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static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
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unsigned long *flagsp)
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{
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assign_bit(FLAG_ACTIVE_LOW, flagsp,
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flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
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if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
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set_bit(FLAG_IS_OUT, flagsp);
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else if (flags & GPIO_V2_LINE_FLAG_INPUT)
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clear_bit(FLAG_IS_OUT, flagsp);
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assign_bit(FLAG_OPEN_DRAIN, flagsp,
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flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
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assign_bit(FLAG_OPEN_SOURCE, flagsp,
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flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
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assign_bit(FLAG_PULL_UP, flagsp,
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flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
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assign_bit(FLAG_PULL_DOWN, flagsp,
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flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
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assign_bit(FLAG_BIAS_DISABLE, flagsp,
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flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
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}
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static long linereq_get_values(struct linereq *lr, void __user *ip)
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{
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struct gpio_v2_line_values lv;
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DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
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struct gpio_desc **descs;
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unsigned int i, didx, num_get;
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int ret;
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/* NOTE: It's ok to read values of output lines. */
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if (copy_from_user(&lv, ip, sizeof(lv)))
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return -EFAULT;
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for (num_get = 0, i = 0; i < lr->num_lines; i++) {
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if (lv.mask & BIT_ULL(i)) {
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num_get++;
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descs = &lr->lines[i].desc;
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}
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}
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if (num_get == 0)
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return -EINVAL;
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if (num_get != 1) {
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descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
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if (!descs)
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return -ENOMEM;
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for (didx = 0, i = 0; i < lr->num_lines; i++) {
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if (lv.mask & BIT_ULL(i)) {
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descs[didx] = lr->lines[i].desc;
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didx++;
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}
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}
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}
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ret = gpiod_get_array_value_complex(false, true, num_get,
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descs, NULL, vals);
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if (num_get != 1)
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kfree(descs);
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if (ret)
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return ret;
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lv.bits = 0;
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for (didx = 0, i = 0; i < lr->num_lines; i++) {
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if (lv.mask & BIT_ULL(i)) {
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if (test_bit(didx, vals))
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lv.bits |= BIT_ULL(i);
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didx++;
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}
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}
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if (copy_to_user(ip, &lv, sizeof(lv)))
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return -EFAULT;
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return 0;
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}
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static long linereq_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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struct linereq *lr = file->private_data;
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void __user *ip = (void __user *)arg;
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if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
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return linereq_get_values(lr, ip);
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return -EINVAL;
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}
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#ifdef CONFIG_COMPAT
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static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
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}
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#endif
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static void linereq_free(struct linereq *lr)
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{
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unsigned int i;
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for (i = 0; i < lr->num_lines; i++) {
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if (lr->lines[i].desc)
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gpiod_free(lr->lines[i].desc);
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}
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kfree(lr->label);
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put_device(&lr->gdev->dev);
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kfree(lr);
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}
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static int linereq_release(struct inode *inode, struct file *file)
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{
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struct linereq *lr = file->private_data;
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linereq_free(lr);
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return 0;
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}
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static const struct file_operations line_fileops = {
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.release = linereq_release,
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.owner = THIS_MODULE,
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.llseek = noop_llseek,
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.unlocked_ioctl = linereq_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = linereq_ioctl_compat,
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#endif
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};
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static int linereq_create(struct gpio_device *gdev, void __user *ip)
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{
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struct gpio_v2_line_request ulr;
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struct gpio_v2_line_config *lc;
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struct linereq *lr;
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struct file *file;
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u64 flags;
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unsigned int i;
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int fd, ret;
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if (copy_from_user(&ulr, ip, sizeof(ulr)))
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return -EFAULT;
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if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
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return -EINVAL;
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if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
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return -EINVAL;
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lc = &ulr.config;
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ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
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if (ret)
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return ret;
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lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
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if (!lr)
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return -ENOMEM;
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lr->gdev = gdev;
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get_device(&gdev->dev);
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/* Make sure this is terminated */
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ulr.consumer[sizeof(ulr.consumer)-1] = '\0';
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if (strlen(ulr.consumer)) {
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/* label is only initialized if consumer is set */
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lr->label = kstrdup(ulr.consumer, GFP_KERNEL);
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if (!lr->label) {
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ret = -ENOMEM;
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goto out_free_linereq;
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}
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}
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lr->num_lines = ulr.num_lines;
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/* Request each GPIO */
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for (i = 0; i < ulr.num_lines; i++) {
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u32 offset = ulr.offsets[i];
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struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
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if (IS_ERR(desc)) {
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ret = PTR_ERR(desc);
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goto out_free_linereq;
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}
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ret = gpiod_request(desc, lr->label);
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if (ret)
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goto out_free_linereq;
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lr->lines[i].desc = desc;
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flags = gpio_v2_line_config_flags(lc, i);
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gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
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ret = gpiod_set_transitory(desc, false);
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if (ret < 0)
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goto out_free_linereq;
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/*
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* Lines have to be requested explicitly for input
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* or output, else the line will be treated "as is".
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*/
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if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
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int val = gpio_v2_line_config_output_value(lc, i);
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ret = gpiod_direction_output(desc, val);
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if (ret)
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goto out_free_linereq;
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} else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
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ret = gpiod_direction_input(desc);
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if (ret)
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goto out_free_linereq;
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}
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blocking_notifier_call_chain(&desc->gdev->notifier,
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GPIOLINE_CHANGED_REQUESTED, desc);
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dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
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offset);
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}
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fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
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if (fd < 0) {
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ret = fd;
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goto out_free_linereq;
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}
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file = anon_inode_getfile("gpio-line", &line_fileops, lr,
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O_RDONLY | O_CLOEXEC);
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if (IS_ERR(file)) {
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ret = PTR_ERR(file);
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goto out_put_unused_fd;
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}
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ulr.fd = fd;
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if (copy_to_user(ip, &ulr, sizeof(ulr))) {
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/*
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* fput() will trigger the release() callback, so do not go onto
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* the regular error cleanup path here.
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*/
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fput(file);
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put_unused_fd(fd);
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return -EFAULT;
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}
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fd_install(fd, file);
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dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
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lr->num_lines);
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return 0;
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out_put_unused_fd:
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put_unused_fd(fd);
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out_free_linereq:
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linereq_free(lr);
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return ret;
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}
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#ifdef CONFIG_GPIO_CDEV_V1
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/*
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* GPIO line event management
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@ -745,6 +1163,8 @@ out_free_le:
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return ret;
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}
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#endif /* CONFIG_GPIO_CDEV_V1 */
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static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
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struct gpioline_info *info)
|
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{
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@ -843,6 +1263,7 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
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return -EFAULT;
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return 0;
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#ifdef CONFIG_GPIO_CDEV_V1
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} else if (cmd == GPIO_GET_LINEINFO_IOCTL) {
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struct gpioline_info lineinfo;
|
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|
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@ -885,6 +1306,9 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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}
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return 0;
|
||||
#endif /* CONFIG_GPIO_CDEV_V1 */
|
||||
} else if (cmd == GPIO_V2_GET_LINE_IOCTL) {
|
||||
return linereq_create(gdev, ip);
|
||||
} else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
|
||||
if (copy_from_user(&offset, ip, sizeof(offset)))
|
||||
return -EFAULT;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user