From bf9346f5d47b4506aafbc384dfb5796b0adc3f8d Mon Sep 17 00:00:00 2001 From: Janusz Krzysztofik Date: Wed, 5 Sep 2018 23:50:06 +0200 Subject: gpiolib: Identify arrays matching GPIO hardware Certain GPIO array lookup results may map directly to GPIO pins of a single GPIO chip in hardware order. If that condition is recognized and handled efficiently, significant performance gain of get/set array functions may be possible. While processing a request for an array of GPIO descriptors, identify those which represent corresponding pins of a single GPIO chip. Skip over pins which require open source or open drain special processing. Moreover, identify pins which require inversion. Pass a pointer to that information with the array to the caller so it can benefit from enhanced performance as soon as get/set array functions can accept and make efficient use of it. Cc: Jonathan Corbet Signed-off-by: Janusz Krzysztofik Signed-off-by: Linus Walleij --- Documentation/driver-api/gpio/consumer.rst | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'Documentation/driver-api') diff --git a/Documentation/driver-api/gpio/consumer.rst b/Documentation/driver-api/gpio/consumer.rst index ed68042ddccf..7e0298b9a7b9 100644 --- a/Documentation/driver-api/gpio/consumer.rst +++ b/Documentation/driver-api/gpio/consumer.rst @@ -109,9 +109,11 @@ For a function using multiple GPIOs all of those can be obtained with one call:: enum gpiod_flags flags) This function returns a struct gpio_descs which contains an array of -descriptors:: +descriptors. It also contains a pointer to a gpiolib private structure which, +if passed back to get/set array functions, may speed up I/O proocessing:: struct gpio_descs { + struct gpio_array *info; unsigned int ndescs; struct gpio_desc *desc[]; } -- cgit v1.2.3