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author | 2015-08-28 09:58:54 +0800 | |
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committer | 2015-09-01 12:44:00 +0800 | |
commit | e44e3482bdb4d0ebde2d8b41830ac2cdb07948fb (patch) | |
tree | 66b09f592c55df2878107a468a91d21506104d3f /qemu/roms/u-boot/include/asm-generic/gpio.h | |
parent | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (diff) |
Add qemu 2.4.0
Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
Diffstat (limited to 'qemu/roms/u-boot/include/asm-generic/gpio.h')
-rw-r--r-- | qemu/roms/u-boot/include/asm-generic/gpio.h | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/qemu/roms/u-boot/include/asm-generic/gpio.h b/qemu/roms/u-boot/include/asm-generic/gpio.h new file mode 100644 index 000000000..e325df40d --- /dev/null +++ b/qemu/roms/u-boot/include/asm-generic/gpio.h @@ -0,0 +1,185 @@ +/* + * Copyright (c) 2011 The Chromium OS Authors. + * Copyright (c) 2011, NVIDIA Corp. All rights reserved. + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef _ASM_GENERIC_GPIO_H_ +#define _ASM_GENERIC_GPIO_H_ + +/* + * Generic GPIO API for U-Boot + * + * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined + * by the SOC/architecture. + * + * Each GPIO can be an input or output. If an input then its value can + * be read as 0 or 1. If an output then its value can be set to 0 or 1. + * If you try to write an input then the value is undefined. If you try + * to read an output, barring something very unusual, you will get + * back the value of the output that you previously set. + * + * In some cases the operation may fail, for example if the GPIO number + * is out of range, or the GPIO is not available because its pin is + * being used by another function. In that case, functions may return + * an error value of -1. + */ + +/** + * Request a gpio. This should be called before any of the other functions + * are used on this gpio. + * + * @param gp GPIO number + * @param label User label for this GPIO + * @return 0 if ok, -1 on error + */ +int gpio_request(unsigned gpio, const char *label); + +/** + * Stop using the GPIO. This function should not alter pin configuration. + * + * @param gpio GPIO number + * @return 0 if ok, -1 on error + */ +int gpio_free(unsigned gpio); + +/** + * Make a GPIO an input. + * + * @param gpio GPIO number + * @return 0 if ok, -1 on error + */ +int gpio_direction_input(unsigned gpio); + +/** + * Make a GPIO an output, and set its value. + * + * @param gpio GPIO number + * @param value GPIO value (0 for low or 1 for high) + * @return 0 if ok, -1 on error + */ +int gpio_direction_output(unsigned gpio, int value); + +/** + * Get a GPIO's value. This will work whether the GPIO is an input + * or an output. + * + * @param gpio GPIO number + * @return 0 if low, 1 if high, -1 on error + */ +int gpio_get_value(unsigned gpio); + +/** + * Set an output GPIO's value. The GPIO must already be an output or + * this function may have no effect. + * + * @param gpio GPIO number + * @param value GPIO value (0 for low or 1 for high) + * @return 0 if ok, -1 on error + */ +int gpio_set_value(unsigned gpio, int value); + +/* State of a GPIO, as reported by get_state() */ +enum { + GPIOF_INPUT = 0, + GPIOF_OUTPUT, + GPIOF_UNKNOWN, +}; + +struct device; + +/** + * struct struct dm_gpio_ops - Driver model GPIO operations + * + * Refer to functions above for description. These function largely copy + * the old API. + * + * This is trying to be close to Linux GPIO API. Once the U-Boot uses the + * new DM GPIO API, this should be really easy to flip over to the Linux + * GPIO API-alike interface. + * + * Akso it would be useful to standardise additional functions like + * pullup, slew rate and drive strength. + * + * gpio_request)( and gpio_free() are optional - if NULL then they will + * not be called. + * + * Note that @offset is the offset from the base GPIO of the device. So + * offset 0 is the device's first GPIO and offset o-1 is the last GPIO, + * where o is the number of GPIO lines controlled by the device. A device + * is typically used to control a single bank of GPIOs. Within complex + * SoCs there may be many banks and therefore many devices all referring + * to the different IO addresses within the SoC. + * + * The uclass combines all GPIO devices togther to provide a consistent + * numbering from 0 to n-1, where n is the number of GPIOs in total across + * all devices. Be careful not to confuse offset with gpio in the parameters. + */ +struct dm_gpio_ops { + int (*request)(struct device *dev, unsigned offset, const char *label); + int (*free)(struct device *dev, unsigned offset); + int (*direction_input)(struct device *dev, unsigned offset); + int (*direction_output)(struct device *dev, unsigned offset, + int value); + int (*get_value)(struct device *dev, unsigned offset); + int (*set_value)(struct device *dev, unsigned offset, int value); + int (*get_function)(struct device *dev, unsigned offset); + int (*get_state)(struct device *dev, unsigned offset, char *state, + int maxlen); +}; + +/** + * struct gpio_dev_priv - information about a device used by the uclass + * + * The uclass combines all active GPIO devices into a unified numbering + * scheme. To do this it maintains some private information aobut each + * device. + * + * To implement driver model support in your GPIO driver, add a probe + * handler, and set @gpio_count and @bank_name correctly in that handler. + * This tells the uclass the name of the GPIO bank and the number of GPIOs + * it contains. + * + * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called + * 'A0', 'A1', etc. + * @gpio_count: Number of GPIOs in this device + * @gpio_base: Base GPIO number for this device. For the first active device + * this will be 0; the numbering for others will follow sequentially so that + * @gpio_base for device 1 will equal the number of GPIOs in device 0. + */ +struct gpio_dev_priv { + const char *bank_name; + unsigned gpio_count; + unsigned gpio_base; +}; + +/* Access the GPIO operations for a device */ +#define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops) + +/** + * gpio_get_bank_info - Return information about a GPIO bank/device + * + * This looks up a device and returns both its GPIO base name and the number + * of GPIOs it controls. + * + * @dev: Device to look up + * @offset_count: Returns number of GPIOs within this bank + * @return bank name of this device + */ +const char *gpio_get_bank_info(struct device *dev, int *offset_count); + +/** + * gpio_lookup_name - Look up a GPIO name and return its details + * + * This is used to convert a named GPIO into a device, offset and GPIO + * number. + * + * @name: GPIO name to look up + * @devp: Returns pointer to device which contains this GPIO + * @offsetp: Returns the offset number within this device + * @gpiop: Returns the absolute GPIO number, numbered from 0 + */ +int gpio_lookup_name(const char *name, struct device **devp, + unsigned int *offsetp, unsigned int *gpiop); + +#endif /* _ASM_GENERIC_GPIO_H_ */ |