e10f72bf4b
General support for state persistence is added to gpiolib with the introduction of a new pinconf parameter to propagate the request to hardware. The existing persistence support for sleep is adapted to include hardware support if the GPIO driver provides it. Persistence continues to be enabled by default; in-kernel consumers can opt out, but userspace (currently) does not have a choice. The *_SLEEP_MAY_LOSE_VALUE and *_SLEEP_MAINTAIN_VALUE symbols are renamed, dropping the SLEEP prefix to reflect that the concept is no longer sleep-specific. I feel that renaming to just *_MAY_LOSE_VALUE could initially be misinterpreted, so I've further changed the symbols to *_TRANSITORY and *_PERSISTENT to address this. The sysfs interface is modified only to keep consistency with the chardev interface in enforcing persistence for userspace exports. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
75 lines
2.4 KiB
C
75 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_GPIO_MACHINE_H
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#define __LINUX_GPIO_MACHINE_H
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#include <linux/types.h>
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#include <linux/list.h>
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enum gpio_lookup_flags {
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GPIO_ACTIVE_HIGH = (0 << 0),
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GPIO_ACTIVE_LOW = (1 << 0),
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GPIO_OPEN_DRAIN = (1 << 1),
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GPIO_OPEN_SOURCE = (1 << 2),
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GPIO_PERSISTENT = (0 << 3),
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GPIO_TRANSITORY = (1 << 3),
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};
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/**
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* struct gpiod_lookup - lookup table
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* @chip_label: name of the chip the GPIO belongs to
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* @chip_hwnum: hardware number (i.e. relative to the chip) of the GPIO
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* @con_id: name of the GPIO from the device's point of view
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* @idx: index of the GPIO in case several GPIOs share the same name
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* @flags: mask of GPIO_* values
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*
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* gpiod_lookup is a lookup table for associating GPIOs to specific devices and
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* functions using platform data.
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*/
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struct gpiod_lookup {
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const char *chip_label;
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u16 chip_hwnum;
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const char *con_id;
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unsigned int idx;
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enum gpio_lookup_flags flags;
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};
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struct gpiod_lookup_table {
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struct list_head list;
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const char *dev_id;
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struct gpiod_lookup table[];
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};
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/*
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* Simple definition of a single GPIO under a con_id
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*/
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#define GPIO_LOOKUP(_chip_label, _chip_hwnum, _con_id, _flags) \
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GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _con_id, 0, _flags)
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/*
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* Use this macro if you need to have several GPIOs under the same con_id.
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* Each GPIO needs to use a different index and can be accessed using
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* gpiod_get_index()
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*/
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#define GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _con_id, _idx, _flags) \
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{ \
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.chip_label = _chip_label, \
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.chip_hwnum = _chip_hwnum, \
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.con_id = _con_id, \
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.idx = _idx, \
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.flags = _flags, \
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}
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#ifdef CONFIG_GPIOLIB
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void gpiod_add_lookup_table(struct gpiod_lookup_table *table);
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void gpiod_add_lookup_tables(struct gpiod_lookup_table **tables, size_t n);
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void gpiod_remove_lookup_table(struct gpiod_lookup_table *table);
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#else
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static inline
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void gpiod_add_lookup_table(struct gpiod_lookup_table *table) {}
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static inline
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void gpiod_add_lookup_tables(struct gpiod_lookup_table **tables, size_t n) {}
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static inline
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void gpiod_remove_lookup_table(struct gpiod_lookup_table *table) {}
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#endif
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#endif /* __LINUX_GPIO_MACHINE_H */
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