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2014-01-24drivers/w1/masters/w1-gpio.c: add strong pullup emulationEvgeny Boger1-0/+1
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>
2012-08-16onewire: w1-gpio: add ext_pullup_enable pin in platform dataDaniel Mack1-0/+1
In the process of porting boards to devicetree implemenation, we should keep information about external circuitry where they belong - the individual drivers. This patch adds a way to specify a GPIO to drive the (optional) external pull-up logic, rather than using a function pointer for that. Signed-off-by: Daniel Mack <zonque@gmail.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Acked-by: Ville Syrjälä <syrjala@sci.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2009-06-19w1-gpio: add external pull-up enable callbackDaniel Mack1-0/+1
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>
2008-02-06w1-gpio: add GPIO w1 bus master driverVille Syrjala1-0/+23
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>