Hi, Michele
the gpio only works is specified in the DTS file,
ralink,uartmux = "uartf"; /* not "gpio" since r36431*/
and define the gpio with name here an examples
gpio7 {
gpio-export,name = "gpio7";
gpio-export,output = <0>;
gpios = <&gpio0 7 1>;
};
ayyari
2013/5/2 Michel Stempin <[email protected]>
>
>
> Le 02/05/2013 16:06, [email protected] a écrit :
> > On Thu, May 2, 2013 at 9:49 AM, Michel Stempin
> > <[email protected]> wrote:
> >> Hi,
> >>
> >> It looks like the GPIOs are broken since the introduction of DTS for
> the ramips architecture.
> >>
> >> In the DTS include file ("target/linux/ramips/dts/rt3050.dtsi" in my
> case, by this is also true for the other ones), only the number of GPIOs
> for each gpio-controller is defined, but not the GPIO base number for each
> chip. For example:
> >>
> >> gpio0: gpio@600 {
> >> compatible = "ralink,rt3052-gpio",
> "ralink,rt2880-gpio";
> >> reg = <0x600 0x34>;
> >>
> >> gpio-controller;
> >> #gpio-cells = <2>;
> >>
> >> ralink,num-gpios = <24>;
> >> ralink,register-map = [ 00 04 08 0c
> >> 20 24 28 2c
> >> 30 34 ];
> >>
> >> This part of DTS is handled by the ralink_gpio_probe() function added
> by the "0130-GPIO-MIPS-ralink-adds-ralink-gpio-support.patch" file for the
> ramips architecture, which sets the GPIO base number to -1 to get a
> dynamically-allocated base GPIO number.
> >>
> >> This feature was introduced in Linux kernel 2.6.26-rc1 (<
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/gpio/gpiolib.c?id=8d0aab2f16c4fa170f32e7a74a52cd0122bbafef>),
> but unfortunately, it is not applicable here, since to avoid using any
> numbers that may have been explicitly assigned but not yet registered, this
> dynamic allocation assigns GPIO numbers from the biggest number on down,
> instead of from the smallest on up.
> >>
> >> This assignment is performed by function gpiochip_find_base() in the
> kernel's "drivers/gpio/gpiolib.c" file, and as the same patch above defines
> ARCH_NR_GPIOS to 128, this result in a base GPIO number of 128 - 24 = 104
> instead of the expected 0.
> >>
> >> Since changing the dynamic GPIO number feature in the kernel is out of
> question as it would break the userspace ABIs (<
> https://patchwork.kernel.org/patch/2084411/>), what is the best option to
> get the GPIOs back working?
> >>
> >> My first guess would be to add a "ralink,base-gpio" property for each
> gpio-controller chip to the DTS files for ralink...
> >>
> >> Any suggestions?
> >
> > Your code should not care about the assigned GPIO number.
> >
> > gpio_ebi_i2stx_0: gpio@13003040 {
> > #gpio-cells = <2>;
> > compatible = "nxp,lpc31xx-gpio";
> > reg = <0x13003040 0x40>;
> > gpio-controller;
> > };
> > gpio_spi: gpio@13003240 {
> > #gpio-cells = <2>;
> > compatible = "nxp,lpc31xx-gpio";
> > reg = <0x13003240 0x40>;
> > gpio-controller;
> > };
> >
> >
> > Spi device that uses the GPIO...
> >
> > spi@15002000 {
> > gpios = <&gpio_spi 4 0 /* chip selects */
> > &gpio_ebi_i2stx_0 3 0>;
> > s25sl032a@0 {
> > compatible = "code,s25sl032a";
> > reg = <0>;
> > spi-max-frequency = <1000000>;
> > };
> > };
> >
> > then use something like:
> >
> > gpio = of_get_gpio_flags(pdev->dev.of_node, i, &flags);
> > or
> > cs_gpio = of_get_named_gpio(pdev->dev.of_node, "cs-gpios", i);
> >
> > To attach your gpio.
>
> What about the /sys/class/gpio user interface, then?
>
> I get a gpiochip124 with a gpiochip124/base = 124 in my case...
>
> -Michel
> >
> >
> >
> >>
> >> -Michel
> >> _______________________________________________
> >> openwrt-devel mailing list
> >> [email protected]
> >> https://lists.openwrt.org/mailman/listinfo/openwrt-devel
> >
> >
> >
> > --
> > Jon Smirl
> > [email protected]
> > _______________________________________________
> > openwrt-devel mailing list
> > [email protected]
> > https://lists.openwrt.org/mailman/listinfo/openwrt-devel
> >
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