| Message ID | 20170917093906.16325-1-linus.walleij@linaro.org |
|---|---|
| Headers | show |
| Series | I2C GPIO to use gpiolibs open drain | expand |
Hi Linus, On Sun, Sep 17, 2017 at 11:38 AM, Linus Walleij <linus.walleij@linaro.org> wrote: > This augments the I2C GPIO driver to use open drain emulation > or hardware support for open drain from the GPIO driver. > > This version layers Geert Uytterhoeven's idea to use explicit > sda-gpios and scl-gpios for the GPIO lines, and strongly > encourage the (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN) flags to be > used in all device trees. > > We have collected ACKs from the ARM SoC maintainers and the > MFD maintainer and are looking for testers to try this out. > > Geert Uytterhoeven (1): > dt-bindings: i2c: i2c-gpio: Add support for named gpios > > Linus Walleij (6): > i2c: gpio: Convert to use descriptors > gpio: Make it possible for consumers to enforce open drain > i2c: gpio: Enforce open drain through gpiolib > i2c: gpio: Augment all boardfiles to use open drain > i2c: gpio: Local vars in probe > i2c: gpio: Add support for named gpios in DT Thanks for doing this, and picking up my patch. I gave this a try on r8a7740/armadillo800eva. Without DT changes, the GPIO i2c bus still works fine, but a warning is printed, as expected: gpio-208 (sda): enforced open drain please flag it properly in DT/ACPI DSDT/board file gpio-91 (scl): enforced open drain please flag it properly in DT/ACPI DSDT/board file After - sda-gpios = <&pfc 208 GPIO_ACTIVE_HIGH>; - scl-gpios = <&pfc 91 GPIO_ACTIVE_HIGH>; + sda-gpios = <&pfc 208 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; + scl-gpios = <&pfc 91 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; the warning is gone, and the GPIO i2c bus still works. Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Sun, Sep 17, 2017 at 11:39:05AM +0200, Linus Walleij wrote: > From: Geert Uytterhoeven <geert+renesas () glider ! be> > > The current i2c-gpio DT bindings use a single unnamed "gpios" property > to refer to the SDA and SCL signal lines by index. This is error-prone > for the casual DT writer and reviewer, as one has to look up the order > in the DT bindings. > > Fix this by amending the DT bindings to use two separate named gpios > properties, and deprecate the old unnamed variant. > > Take this opportunity to clearly deprecate the "i2c-gpio,sda-open-drain" > and "i2c-gpio,scl-open-drain" flags as well. The commit describes > in detail what these flags actually mean, and why they should not be > used in new device trees. > > Cc: devicetree@vger.kernel.org > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > [Augmented to what I and Rob would like] > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> > --- > ChangeLog v1->v2: > - Create a special section for the deprecated bindings > - Also deprecate the open drain bool properties > - Update the example to use the new style of bindings > --- > Documentation/devicetree/bindings/i2c/i2c-gpio.txt | 32 ++++++++++++++++------ > 1 file changed, 23 insertions(+), 9 deletions(-) Acked-by: Rob Herring <robh@kernel.org>