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Merge branch 'gpio-irqchip-rework' of /home/linus/linux-gpio into devel
This commit is contained in:
Linus Walleij
commit
bee67c7c9d
88 changed files with 3159 additions and 516 deletions
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@ -10,14 +10,30 @@ Guidelines for GPIOs consumers
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==============================
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Drivers that can't work without standard GPIO calls should have Kconfig entries
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that depend on GPIOLIB. The functions that allow a driver to obtain and use
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GPIOs are available by including the following file:
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that depend on GPIOLIB or select GPIOLIB. The functions that allow a driver to
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obtain and use GPIOs are available by including the following file:
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#include <linux/gpio/consumer.h>
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There are static inline stubs for all functions in the header file in the case
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where GPIOLIB is disabled. When these stubs are called they will emit
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warnings. These stubs are used for two use cases:
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- Simple compile coverage with e.g. COMPILE_TEST - it does not matter that
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the current platform does not enable or select GPIOLIB because we are not
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going to execute the system anyway.
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- Truly optional GPIOLIB support - where the driver does not really make use
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of the GPIOs on certain compile-time configurations for certain systems, but
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will use it under other compile-time configurations. In this case the
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consumer must make sure not to call into these functions, or the user will
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be met with console warnings that may be perceived as intimidating.
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All the functions that work with the descriptor-based GPIO interface are
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prefixed with gpiod_. The gpio_ prefix is used for the legacy interface. No
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other function in the kernel should use these prefixes.
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other function in the kernel should use these prefixes. The use of the legacy
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functions is strongly discouraged, new code should use <linux/gpio/consumer.h>
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and descriptors exclusively.
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Obtaining and Disposing GPIOs
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@ -279,9 +295,22 @@ as possible, especially by drivers which should not care about the actual
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physical line level and worry about the logical value instead.
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Set multiple GPIO outputs with a single function call
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-----------------------------------------------------
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The following functions set the output values of an array of GPIOs:
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Access multiple GPIOs with a single function call
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-------------------------------------------------
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The following functions get or set the values of an array of GPIOs:
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int gpiod_get_array_value(unsigned int array_size,
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struct gpio_desc **desc_array,
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int *value_array);
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int gpiod_get_raw_array_value(unsigned int array_size,
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struct gpio_desc **desc_array,
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int *value_array);
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int gpiod_get_array_value_cansleep(unsigned int array_size,
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struct gpio_desc **desc_array,
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int *value_array);
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int gpiod_get_raw_array_value_cansleep(unsigned int array_size,
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struct gpio_desc **desc_array,
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int *value_array);
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void gpiod_set_array_value(unsigned int array_size,
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struct gpio_desc **desc_array,
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@ -296,34 +325,40 @@ The following functions set the output values of an array of GPIOs:
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struct gpio_desc **desc_array,
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int *value_array)
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The array can be an arbitrary set of GPIOs. The functions will try to set
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The array can be an arbitrary set of GPIOs. The functions will try to access
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GPIOs belonging to the same bank or chip simultaneously if supported by the
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corresponding chip driver. In that case a significantly improved performance
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can be expected. If simultaneous setting is not possible the GPIOs will be set
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sequentially.
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can be expected. If simultaneous access is not possible the GPIOs will be
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accessed sequentially.
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The gpiod_set_array() functions take three arguments:
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The functions take three arguments:
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* array_size - the number of array elements
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* desc_array - an array of GPIO descriptors
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* value_array - an array of values to assign to the GPIOs
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* value_array - an array to store the GPIOs' values (get) or
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an array of values to assign to the GPIOs (set)
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The descriptor array can be obtained using the gpiod_get_array() function
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or one of its variants. If the group of descriptors returned by that function
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matches the desired group of GPIOs, those GPIOs can be set by simply using
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matches the desired group of GPIOs, those GPIOs can be accessed by simply using
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the struct gpio_descs returned by gpiod_get_array():
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struct gpio_descs *my_gpio_descs = gpiod_get_array(...);
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gpiod_set_array_value(my_gpio_descs->ndescs, my_gpio_descs->desc,
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my_gpio_values);
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It is also possible to set a completely arbitrary array of descriptors. The
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It is also possible to access a completely arbitrary array of descriptors. The
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descriptors may be obtained using any combination of gpiod_get() and
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gpiod_get_array(). Afterwards the array of descriptors has to be setup
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manually before it can be used with gpiod_set_array().
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manually before it can be passed to one of the above functions.
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Note that for optimal performance GPIOs belonging to the same chip should be
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contiguous within the array of descriptors.
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The return value of gpiod_get_array_value() and its variants is 0 on success
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or negative on error. Note the difference to gpiod_get_value(), which returns
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0 or 1 on success to convey the GPIO value. With the array functions, the GPIO
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values are stored in value_array rather than passed back as return value.
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GPIOs mapped to IRQs
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--------------------
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@ -254,7 +254,7 @@ GPIO irqchips usually fall in one of two categories:
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static irqreturn_t omap_gpio_irq_handler(int irq, void *gpiobank)
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unsigned long wa_lock_flags;
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raw_spin_lock_irqsave(&bank->wa_lock, wa_lock_flags);
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generic_handle_irq(irq_find_mapping(bank->chip.irqdomain, bit));
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generic_handle_irq(irq_find_mapping(bank->chip.irq.domain, bit));
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raw_spin_unlock_irqrestore(&bank->wa_lock, wa_lock_flags);
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* GENERIC CHAINED GPIO irqchips: these are the same as "CHAINED GPIO irqchips",
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@ -313,8 +313,8 @@ symbol:
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mark all the child IRQs as having the other IRQ as parent.
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If there is a need to exclude certain GPIOs from the IRQ domain, you can
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set .irq_need_valid_mask of the gpiochip before gpiochip_add_data() is
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called. This allocates an .irq_valid_mask with as many bits set as there
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set .irq.need_valid_mask of the gpiochip before gpiochip_add_data() is
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called. This allocates an .irq.valid_mask with as many bits set as there
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are GPIOs in the chip. Drivers can exclude GPIOs by clearing bits from this
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mask. The mask must be filled in before gpiochip_irqchip_add() or
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gpiochip_irqchip_add_nested() is called.
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