Re: [RFC RFT PATCH 0/4] gpiolib: speed up GPIO array processing

Ulf Hansson
2018-08-29T10:19:46Z

On 21 August 2018 at 01:43, Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:
>
> This series is a follow up of the former "mtd: rawnand: ams-delta: Use
> gpio-omap accessors for data I/O" which already contained some changes
> to gpiolib. Those previous attempts were commented by Borris Brezillon
> who suggested using GPIO API modified to accept bitmaps, and by Linus
> Walleij who suggested still more great ideas for further immprovement
> of the proposed API changes - thanks!
>
> The goal is to boost performans of get/set array functions while
> processing GPIO arrays which represent pins of a signle chip in
> hardware order. If resulting performance is close to PIO, GPIO API
> can be used for data I/O without much loss of speed.
>
> Created and tested on a low end Amstrad Delta board with NAND driver
> updated to use GPIO API for data I/O. Performance degrade compared to
> PIO is much better than before the optimization but still not quite
> satisfactory.
>
>
> Janusz Krzysztofik (4):
> gpiolib: Pass bitmaps, not integer arrays, to get/set array
> gpiolib: Identify arrays matching GPIO hardware
> gpiolib: Pass array info to get/set array functions
> gpiolib: Implement fast processing path in get/set array
>
>
> Documentation/driver-api/gpio/board.rst | 15 +
> Documentation/driver-api/gpio/consumer.rst | 48 +++-
> drivers/auxdisplay/hd44780.c | 64 +++---
> drivers/bus/ts-nbus.c | 25 --
> drivers/gpio/gpio-max3191x.c | 23 +-
> drivers/gpio/gpiolib.c | 279 ++++++++++++++++++++++------
> drivers/gpio/gpiolib.h | 15 +
> drivers/i2c/muxes/i2c-mux-gpio.c | 5
> drivers/mmc/core/pwrseq_simple.c | 15 -
> drivers/mux/gpio.c | 7
> drivers/net/phy/mdio-mux-gpio.c | 5
> drivers/pcmcia/soc_common.c | 14 -
> drivers/phy/motorola/phy-mapphone-mdm6600.c | 21 +-
> drivers/staging/iio/adc/ad7606.c | 12 -
> drivers/tty/serial/serial_mctrl_gpio.c | 9
> include/linux/gpio/consumer.h | 35 ++-
> 16 files changed, 410 insertions(+), 182 deletions(-)
>

For the mmc related changes:

Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

Kind regards
Uffe