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linux-stable/include/linux/w1-gpio.h

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w1-gpio: add GPIO w1 bus master driver Add a GPIO 1-wire bus master driver. The driver used the GPIO API to control the wire and the GPIO pin can be specified using platform data similar to i2c-gpio. The driver was tested with AT91SAM9260 + DS2401. Signed-off-by: Ville Syrjala <syrjala@sci.fi> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06 09:39:01 +00:00
/*
* w1-gpio interface to platform code
*
* Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*/
#ifndef _LINUX_W1_GPIO_H
#define _LINUX_W1_GPIO_H
w1: w1-gpio: Convert to use GPIO descriptors 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>
2017-09-26 18:27:09 +00:00
struct gpio_desc;
w1-gpio: add GPIO w1 bus master driver Add a GPIO 1-wire bus master driver. The driver used the GPIO API to control the wire and the GPIO pin can be specified using platform data similar to i2c-gpio. The driver was tested with AT91SAM9260 + DS2401. Signed-off-by: Ville Syrjala <syrjala@sci.fi> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06 09:39:01 +00:00
/**
* struct w1_gpio_platform_data - Platform-dependent data for w1-gpio
*/
struct w1_gpio_platform_data {
w1: w1-gpio: Convert to use GPIO descriptors 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>
2017-09-26 18:27:09 +00:00
struct gpio_desc *gpiod;
struct gpio_desc *pullup_gpiod;
w1-gpio: add external pull-up enable callback On embedded devices, sleep mode conditions can be tricky to handle, Especially when processors tend to pull-down the w1 bus during sleep. Bus slaves (such as the ds2760) may interpret this as a reason for power-down conditions and entirely switch off the device. This patch adds a callback function pointer to let users switch on and off the external pull-up resistor. This lets the outside world know whether the processor is currently actively driving the bus or not. When this callback is not provided, the code behaviour won't change. Signed-off-by: Daniel Mack <daniel@caiaq.de> Acked-by: Ville Syrjala <syrjala@sci.fi> Acked-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-17 23:28:15 +00:00
void (*enable_external_pullup)(int enable);
drivers/w1/masters/w1-gpio.c: add strong pullup emulation Strong pullup is emulated by driving pin logic high after write command when using tri-state push-pull GPIO. Signed-off-by: Evgeny Boger <boger@contactless.ru> Cc: Greg KH <greg@kroah.com> Acked-by: David Fries <david@fries.net> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 23:56:18 +00:00
unsigned int pullup_duration;
w1-gpio: add GPIO w1 bus master driver Add a GPIO 1-wire bus master driver. The driver used the GPIO API to control the wire and the GPIO pin can be specified using platform data similar to i2c-gpio. The driver was tested with AT91SAM9260 + DS2401. Signed-off-by: Ville Syrjala <syrjala@sci.fi> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06 09:39:01 +00:00
};
#endif /* _LINUX_W1_GPIO_H */
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