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e0fc62a655
The w1 master driver includes a complete open drain emulation reimplementation among other things. This converts the driver and all board files using it to use GPIO descriptors associated with the device to look up the GPIO wire, as well ass the optional pull-up GPIO line. When probed from the device tree, the driver will just pick descriptors and use them right off. For the two board files in the kernel, we add descriptor lookups so we do not need to keep any old platform data handling around for the GPIO lines. As the platform data is also a state container for this driver, we augment it to contain the GPIO descriptors. w1_gpio_write_bit_dir() and w1_gpio_write_bit_val() are gone since this pair was a reimplementation of open drain emulation which is now handled by gpiolib. The special "linux,open-drain" flag is a bit of mishap here: it has the same semantic as the same flags in I2C: it means that something in the platform is setting up the line as open drain behind our back. We handle this the same way as in I2C. To drive the pull-up, we need to bypass open drain emulation in gpiolib for the line, and this is done by driving it high using gpiod_set_raw_value() which has been augmented to have the semantic of overriding the open drain emulation. We also augment the documentation to reflect the way to pass GPIO descriptors from the machine. Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
26 lines
639 B
C
26 lines
639 B
C
/*
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* w1-gpio interface to platform code
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*
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* Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*/
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#ifndef _LINUX_W1_GPIO_H
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#define _LINUX_W1_GPIO_H
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struct gpio_desc;
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/**
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* struct w1_gpio_platform_data - Platform-dependent data for w1-gpio
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*/
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struct w1_gpio_platform_data {
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struct gpio_desc *gpiod;
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struct gpio_desc *pullup_gpiod;
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void (*enable_external_pullup)(int enable);
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unsigned int pullup_duration;
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};
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#endif /* _LINUX_W1_GPIO_H */
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